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David McNew for Quanta Magazine

As we go about our daily lives, we tend to assume that our perceptions — sights, sounds, textures, tastes — are an accurate portrayal of the real world. Sure, when we stop and think about it — or when we find ourselves fooled by a perceptual illusion — we realize with a jolt that what we perceive is never the world directly, but rather our brain’s best guess at what that world is like, a kind of internal simulation of an external reality. Still, we bank on the fact that our simulation is a reasonably decent one. If it wasn’t, wouldn’t evolution have weeded us out by now? The true reality might be forever beyond our reach, but surely our senses give us at least an inkling of what it’s really like.

Not so, says Donald D. Hoffman, a professor of cognitive science at the University of California, Irvine. Hoffman has spent the past three decades studying perception, artificial intelligence, evolutionary game theory and the brain, and his conclusion is a dramatic one: The world presented to us by our perceptions is nothing like reality. What’s more, he says, we have evolution itself to thank for this magnificent illusion, as it maximizes evolutionary fitness by driving truth to extinction.

Getting at questions about the nature of reality, and disentangling the observer from the observed, is an endeavor that straddles the boundaries of neuroscience and fundamental physics. On one side you’ll find researchers scratching their chins raw trying to understand how a three-pound lump of gray matter obeying nothing more than the ordinary laws of physics can give rise to first-person conscious experience. This is the aptly named “hard problem.”

On the other side are quantum physicists, marveling at the strange fact that quantum systems don’t seem to be definite objects localized in space until we come along to observe them — whether we are conscious humans or inanimate measuring devices. Experiment after experiment has shown — defying common sense — that if we assume that the particles that make up ordinary objects have an objective, observer-independent existence, we get the wrong answers. The central lesson of quantum physics is clear: There are no public objects sitting out there in some preexisting space. As the physicist John Wheeler put it, “Useful as it is under ordinary circumstances to say that the world exists ‘out there’ independent of us, that view can no longer be upheld.”

So while neuroscientists struggle to understand how there can be such a thing as a first-person reality, quantum physicists have to grapple with the mystery of how there can be anything but a first-person reality. In short, all roads lead back to the observer. And that’s where you can find Hoffman — straddling the boundaries, attempting a mathematical model of the observer, trying to get at the reality behind the illusion. Quanta Magazine caught up with him to find out more. An edited and condensed version of the conversation follows.

QUANTA MAGAZINE: People often use Darwinian evolution as an argument that our perceptions accurately reflect reality. They say, “Obviously we must be latching onto reality in some way because otherwise we would have been wiped out a long time ago. If I think I’m seeing a palm tree but it’s really a tiger, I’m in trouble.”

“Evolution has shaped us with perceptions that allow us to survive. But part of that involves hiding from us the stuff we don’t need to know. And that’s pretty much all of reality, whatever reality might be.”

DONALD HOFFMAN: Right. The classic argument is that those of our ancestors who saw more accurately had a competitive advantage over those who saw less accurately and thus were more likely to pass on their genes that coded for those more accurate perceptions, so after thousands of generations we can be quite confident that we’re the offspring of those who saw accurately, and so we see accurately. That sounds very plausible. But I think it is utterly false. It misunderstands the fundamental fact about evolution, which is that it’s about fitness functions — mathematical functions that describe how well a given strategy achieves the goals of survival and reproduction. The mathematical physicist Chetan Prakash proved a theorem that I devised that says: According to evolution by natural selection, an organism that sees reality as it is will never be more fit than an organism of equal complexity that sees none of reality but is just tuned to fitness. Never.

You’ve done computer simulations to show this. Can you give an example?

Suppose in reality there’s a resource, like water, and you can quantify how much of it there is in an objective order — very little water, medium amount of water, a lot of water. Now suppose your fitness function is linear, so a little water gives you a little fitness, medium water gives you medium fitness, and lots of water gives you lots of fitness — in that case, the organism that sees the truth about the water in the world can win, but only because the fitness function happens to align with the true structure in reality. Generically, in the real world, that will never be the case. Something much more natural is a bell curve  — say, too little water you die of thirst, but too much water you drown, and only somewhere in between is good for survival. Now the fitness function doesn’t match the structure in the real world. And that’s enough to send truth to extinction. For example, an organism tuned to fitness might see small and large quantities of some resource as, say, red, to indicate low fitness, whereas they might see intermediate quantities as green, to indicate high fitness. Its perceptions will be tuned to fitness, but not to truth. It won’t see any distinction between small and large — it only sees red — even though such a distinction exists in reality.

But how can seeing a false reality be beneficial to an organism’s survival?

There’s a metaphor that’s only been available to us in the past 30 or 40 years, and that’s the desktop interface. Suppose there’s a blue rectangular icon on the lower right corner of your computer’s desktop — does that mean that the file itself is blue and rectangular and lives in the lower right corner of your computer? Of course not. But those are the only things that can be asserted about anything on the desktop — it has color, position and shape. Those are the only categories available to you, and yet none of them are true about the file itself or anything in the computer. They couldn’t possibly be true. That’s an interesting thing. You could not form a true description of the innards of the computer if your entire view of reality was confined to the desktop. And yet the desktop is useful. That blue rectangular icon guides my behavior, and it hides a complex reality that I don’t need to know. That’s the key idea. Evolution has shaped us with perceptions that allow us to survive. They guide adaptive behaviors. But part of that involves hiding from us the stuff we don’t need to know. And that’s pretty much all of reality, whatever reality might be. If you had to spend all that time figuring it out, the tiger would eat you.

So everything we see is one big illusion?

We’ve been shaped to have perceptions that keep us alive, so we have to take them seriously. If I see something that I think of as a snake, I don’t pick it up. If I see a train, I don’t step in front of it. I’ve evolved these symbols to keep me alive, so I have to take them seriously. But it’s a logical flaw to think that if we have to take it seriously, we also have to take it literally.

If snakes aren’t snakes and trains aren’t trains, what are they?

Snakes and trains, like the particles of physics, have no objective, observer-independent features. The snake I see is a description created by my sensory system to inform me of the fitness consequences of my actions. Evolution shapes acceptable solutions, not optimal ones. A snake is an acceptable solution to the problem of telling me how to act in a situation. My snakes and trains are my mental representations; your snakes and trains are your mental representations.

How did you first become interested in these ideas?

As a teenager, I was very interested in the question “Are we machines?” My reading of the science suggested that we are. But my dad was a minister, and at church they were saying we’re not. So I decided I needed to figure it out for myself. It’s sort of an important personal question — if I’m a machine, I would like to find that out! And if I’m not, I’d like to know, what is that special magic beyond the machine? So eventually in the 1980s I went to the artificial intelligence lab at MIT and worked on machine perception. The field of vision research was enjoying a newfound success in developing mathematical models for specific visual abilities. I noticed that they seemed to share a common mathematical structure, so I thought it might be possible to write down a formal structure for observation that encompassed all of them, perhaps all possible modes of observation. I was inspired in part by Alan Turing. When he invented the Turing machine, he was trying to come up with a notion of computation, and instead of putting bells and whistles on it, he said, Let’s get the simplest, most pared down mathematical description that could possibly work. And that simple formalism is the foundation for the science of computation. So I wondered, could I provide a similarly simple formal foundation for the science of observation?

A mathematical model of consciousness.

That’s right. My intuition was, there are conscious experiences. I have pains, tastes, smells, all my sensory experiences, moods, emotions and so forth. So I’m just going to say: One part of this consciousness structure is a set of all possible experiences. When I’m having an experience, based on that experience I may want to change what I’m doing. So I need to have a collection of possible actions I can take and a decision strategy that, given my experiences, allows me to change how I’m acting. That’s the basic idea of the whole thing. I have a space X of experiences, a space G of actions, and an algorithm D that lets me choose a new action given my experiences. Then I posited a W for a world, which is also a probability space. Somehow the world affects my perceptions, so there’s a perception map P from the world to my experiences, and when I act, I change the world, so there’s a map A from the space of actions to the world. That’s the entire structure. Six elements. The claim is: This is the structure of consciousness. I put that out there so people have something to shoot at.

But if there’s a W, are you saying there is an external world?

Here’s the striking thing about that. I can pull the W out of the model and stick a conscious agent in its place and get a circuit of conscious agents. In fact, you can have whole networks of arbitrary complexity. And that’s the world.

David McNew for Quanta Magazine

Video: Donald Hoffman explains how our perceptions have evolved to become like a computer interface.

The world is just other conscious agents?

I call it conscious realism: Objective reality is just conscious agents, just points of view. Interestingly, I can take two conscious agents and have them interact, and the mathematical structure of that interaction also satisfies the definition of a conscious agent. This mathematics is telling me something. I can take two minds, and they can generate a new, unified single mind. Here’s a concrete example. We have two hemispheres in our brain. But when you do a split-brain operation, a complete transection of the corpus callosum, you get clear evidence of two separate consciousnesses. Before that slicing happened, it seemed there was a single unified consciousness. So it’s not implausible that there is a single conscious agent. And yet it’s also the case that there are two conscious agents there, and you can see that when they’re split. I didn’t expect that, the mathematics forced me to recognize this. It suggests that I can take separate observers, put them together and create new observers, and keep doing this ad infinitum. It’s conscious agents all the way down.

If it’s conscious agents all the way down, all first-person points of view, what happens to science? Science has always been a third-person description of the world.

The idea that what we’re doing is measuring publicly accessible objects, the idea that objectivity results from the fact that you and I can measure the same object in the exact same situation and get the same results — it’s very clear from quantum mechanics that that idea has to go. Physics tells us that there are no public physical objects. So what’s going on? Here’s how I think about it. I can talk to you about my headache and believe that I am communicating effectively with you, because you’ve had your own headaches. The same thing is true as apples and the moon and the sun and the universe. Just like you have your own headache, you have your own moon. But I assume it’s relevantly similar to mine. That’s an assumption that could be false, but that’s the source of my communication, and that’s the best we can do in terms of public physical objects and objective science.

It doesn’t seem like many people in neuroscience or philosophy of mind are thinking about fundamental physics. Do you think that’s been a stumbling block for those trying to understand consciousness?

I think it has been. Not only are they ignoring the progress in fundamental physics, they are often explicit about it. They’ll say openly that quantum physics is not relevant to the aspects of brain function that are causally involved in consciousness. They are certain that it’s got to be classical properties of neural activity, which exist independent of any observers — spiking rates, connection strengths at synapses, perhaps dynamical properties as well. These are all very classical notions under Newtonian physics, where time is absolute and objects exist absolutely. And then [neuroscientists] are mystified as to why they don’t make progress. They don’t avail themselves of the incredible insights and breakthroughs that physics has made. Those insights are out there for us to use, and yet my field says, “We’ll stick with Newton, thank you. We’ll stay 300 years behind in our physics.”

I suspect they’re reacting to things like Roger Penrose and Stuart Hameroff’s model, where you still have a physical brain, it’s still sitting in space, but supposedly it’s performing some quantum feat. In contrast, you’re saying, “Look, quantum mechanics is telling us that we have to question the very notions of ‘physical things’ sitting in ‘space.’”

I think that’s absolutely true. The neuroscientists are saying, “We don’t need to invoke those kind of quantum processes, we don’t need quantum wave functions collapsing inside neurons, we can just use classical physics to describe processes in the brain.” I’m emphasizing the larger lesson of quantum mechanics: Neurons, brains, space … these are just symbols we use, they’re not real. It’s not that there’s a classical brain that does some quantum magic. It’s that there’s no brain! Quantum mechanics says that classical objects — including brains — don’t exist. So this is a far more radical claim about the nature of reality and does not involve the brain pulling off some tricky quantum computation. So even Penrose hasn’t taken it far enough. But most of us, you know, we’re born realists. We’re born physicalists. This is a really, really hard one to let go of.

To return to the question you started with as a teenager, are we machines?

The formal theory of conscious agents I’ve been developing is computationally universal — in that sense, it’s a machine theory. And it’s because the theory is computationally universal that I can get all of cognitive science and neural networks back out of it. Nevertheless, for now I don’t think we are machines — in part because I distinguish between the mathematical representation and the thing being represented. As a conscious realist, I am postulating conscious experiences as ontological primitives, the most basic ingredients of the world. I’m claiming that experiences are the real coin of the realm. The experiences of everyday life — my real feeling of a headache, my real taste of chocolate — that really is the ultimate nature of reality.

This article was reprinted on TheAtlantic.com.

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  • Donald Hoffman is my friend.I love his Conscious Agents Theory.I think his theory change paradigm of Cognitive Sciences.
    Dear professor I'm proud to be associated with you.

  • Did I misunderstand, or is this a modern form of Kant's original arguments proving the difference between phenomenological reality and what's "really out there"?

  • Without using the word, Hoffman seems to be talking about abstraction, the idea of hiding complexity behind a simple interface. This is a coomon strategy, for example, in computer science.

    The mind adapted the most evolutionarily useful abstractions of reality given the senses we had.

    It's not that they're illusions, which has a pejorative sense to it, that we're being duped. It's that the most adaptive abstractions of reality were selected for and serve their purpose well, just as do the desktop file icons for files on the computer.

  • Micha Berger: no, you didn't misunderstand, but unfortunately today's scientists tend to be utterly ignorant of philosophy.

  • Sadly, the comments here aren't catching some of the conversation occurring on Twitter about this article:
    <blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">I’m certainly not an expert, but this seems misguided to me. Relies on a specious definition of “illusion.&quot; <a href="https://t.co/6TSSzkIiGg">https://t.co/6TSSzkIiGg</a></p>&mdash; Sean Carroll (@seanmcarroll) <a href="https://twitter.com/seanmcarroll/status/723206348209426432">April 21, 2016</a></blockquote>
    <script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script>

    <blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">I would go much further (being an expert). It's not just misguided, it's nonsense. <a href="https://t.co/Xz8eqvhiyA">https://t.co/Xz8eqvhiyA</a></p>&mdash; Christoph Adami (@ChristophAdami) <a href="https://twitter.com/ChristophAdami/status/723234922312413184">April 21, 2016</a></blockquote>
    <script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script>

  • "… we realize with a jolt that what we perceive is never the world directly, but rather our brain’s best guess at what that world is like …".

    Not quite: we perceive the world directly, just not completely accurately (and we fill in missing details).

    The distinction is important.

  • The link to Hoffmann et. al's paper is broken for me, but if I'm not mistaken, the paper in question is the one found here:


  • Shame neither the author nor his argument are real, but at least I needed to spend no time reading them.

    Actual people who've gotten this far might want to google "self-refuting argument" and read Aristotle on the blind man who can use words about colors, even he has no idea what he is talking about.

  • @ Micha. I believe you're right. It's great when philosophical ideas can be applied in scientific research.

  • Of course we do not experience reality as it is. If we did we would see naked information, vast emptiness punctuated by informational points called quarks with shimmering interacting force fields.

  • I've surprised myself by concluding for the first time, having read this article, that I might agree with those who criticise string theory and its sisters for being a pointless exercise (being unsusceptible to replication, testing or falsification).

    Whether Prof Hoffman is right or wrong (or, as I suspect, falling into a quasi-solipsistic philosophical trap), it seems ever more likely to me that we're making no real progress in understanding the fundamental structures of the universe because they exist in more dimensions than our crude lumpy chunks of chemistry are capable of processing.

    I actually admire the clever and ingenious thinking that has gone into string theory, M-theory, quantum supergravity and the rest, but I seriously wonder whether, even when the equations add up and seem to agree with reality, we have attained true understanding—or merely described what happens. We may get a What; but that's not the same as a Why.

    I'm feeling bad about such a negative view, and hope it's just the result of stupidity on my part. But better brains by far than mine have banged on the quantum cosmological door for 50 years now, and in truth, when you get right down to it—got nowhere.

  • Brains are large and hot, I honestly don't think that quantum effects are important… I believe that a sufficiently large and complex classical neuron network will eventually qualify as 'conscious'.

    Hoffman's theory seems to me a very interesting 'effective' or 'emergent' theory of consciousness, but it is certainly not more fundamental than elementary particles, or strings or whatever physical object turns out to be most fundamental.

    When confronted with the Chinese room experiment, I've always answered with a solution in line with Hoffman's theory. The room as a whole is a conscious agent that understands Chinese.

  • "The world is just other conscious agents?

    I call it conscious realism: Objective reality is just conscious agents, just points of view."

    What about a time before conscious agents? Say right after the big bang when life would have been impossible? Without getting into the semantics of "reality" or "conscious," it seems to me you either have reject the big bang theory, allow for some "4th dimension" conscious agent(s) outside our known universe, reject the known laws of physics, posit that matter just springs into existence simultaneously with conscious agents, or some combination of the above (along with others I have no doubt missed). Of course, when 95% of the universe is composed of dark energy and dark matter and we have no confirmed ideas what they are, it would appear anything is possible.

    Still, until more evidence is in, I'll stick with Einstein on this one:
    "I like to think that the moon is there even if I am not looking at it."

  • What he says is irrelevant. Insects, birds and humans all see reality differently. But their representations are as good as anything out there. For all intents and purposes our perception of reality can be banked on so claiming it is an illusion is just so much hippy talk. It's not an illusion if an asteroid hits or if I take a bullet to the back of my head. Things happen all the time that I never observed. This branch of science is a load of crap.

  • I just love all the commenters who claim to know more about the topic than the subject of this interview.

  • As a scientist Hoffman drinks the scientific Kool Aid and does not realize that his addiction to quantum theory is one point of view among many which are possible. There is no single objective reality, but instead we all choose our view of reality and live with the consequences. Thus the views of reality among physicists, chemists, biologists, anthropologists, psychologists and philosophers are all likely to be influenced by the field of knowledge in which each is most comfortable. Some then make the mistake that their view of reality is the only viable one. Too bad Hoffman did not pay more attention to his father's worldview or study more philosophy along the way.

  • Micha: I believe to some extent, which is a bit abhorrent, but for an intriguing related work that doesn't quite indulge as much in that end of philosophy, I would recommend "The Ego Tunnel" by Thomas Metzinger. I do appreciate what Hoffman has to say about the "need to know", that's a whole other turn I'd like to think about.

  • Thanks Amanda & Quanta.
    @Brett_McS – I don't think we see the world directly at all. If we did everyone would know it's turtles all the way down.

  • "The idea that what we’re doing is measuring publicly accessible objects, the idea that objectivity results from the fact that you and I can measure the same object in the exact same situation and get the same results — it’s very clear from quantum mechanics that that idea has to go."

    What? No it doesn't. If scientist A measures the quantum state of object x, and then scientist B measures the quantum state of the same object in the same way before anything else has interacted with it, they will get the same answer.

    Just because you don't know in advance what answer scientist A will get, only the statistical distribution of the answers he can get, doesn't mean what another person measures will be different. It doesn't matter who or what performs a measurement, or for what reason, what matters is the measurement that's being performed.

    I don't mean to claim Hoffman doesn't know what he's talking about when it comes to his mathematical models – I'm sure he understands them quite a lot better than me – but the conclusions he's drawing from his experiments seem to based on a false premise.

    Just because people *can* fool each other into seeing the world a certain way, doesn't mean the world *is* that way, or that their view of the world is equally valuable as the view of people applying scientific rigor to figuring out what the world is like. Valuing personal experiences over using the scientific method to understand the world is the trap of postmodernism.

  • Has he actually ever studied quantum mechanics? Nowhere in physics does it say that objects are not real unless observed. All it says is that observing very small particles has an effect on their properties. For example, the precision with which you measure a particle's momentum has an inverse relationship to the precision with which you can know its position. There is absolutely nothing about requiring an observer. The supposedly scientific components of this article as related to physics end up sounding like new-age pseudo-scientific mumbo jumbo.

  • The assertion that evolution selects for survival and not for truth is empirically well-established. The further conclusion that an independent reality is an illusion is just blithering nonsense. Why isn't Mr. Hoffman affected by the same illusion? What gives him the privileged position to see the truth and pontificate that the rest of us are deluded ?

    Go back to Philosophy 101, sir, under the heading "self-refutation".

  • Again we have a person who has read a little bit of quantum mechanics, seen the double slit experiment and its followup the quantum eraser, and wrongfully deduce that reality is created by the observer, the fact they forget is the observer need not be a human, an electron is an observer if it happens to interact with something. At most these experiments show that a new understanding of space/distance and time may be needed, they do not conclude that the moon ceases to exist if every living creature on earth stopped looking at it.

  • Conscious realism – isn't this just animism?

    Or is it Buddhism?

    “…there is nothing more real than dream. This statement only makes sense once it is understood that normal waking life is as unreal as dream, and in exactly the same way.” – Tenzin Wangyal Rinpoche in The Tibetan Yogas of Dream and Sleep

  • Quantum physics does not disprove objective reality – that hypothesis is the creation of a weak mind. Quantum physics does however prove that reality is affected by measurement and measurement method.

  • Once upon a time, Chuang Chou dreamed that he was a butterfly, a butterfly flitting about happily enjoying himself. He didn’t know that he was Chou. Suddenly he awoke and was palpably Chou. He didn’t know whether he were Chou who had dreamed of being a butterfly, or a butterfly who was dreaming that he was Chou.

  • Physicists who hold an anti-realist position tend to get mystical, so it's hard to be sure what they think. But trying to find their common beliefs, it appears that they believe that reality is unknowable. This is not a problem for them since they dedicate themselves to finding formulas to relate the conditions of experiments with their results, which is what science is about, not the world. Everyday reality seems to be knowable, but the quantum superpositions or entanglements that make its incomprehensibility manifest are not observable because they interact with the environment and disappear from view. (The favored term now is "decoherence.") There is no experiment that includes the entire universe. The universe began as a Big Band, a quantum event of some kind, so it is unclear where this "environment' comes from, but, again, science in this view doesn't even attempt to describe reality (much less "explain" it.) Asking that sort of question is sort of rude and stupid, or at best, denial that reality is an illusion. Only experiment determines what is observable, i.e., measurable. And no doubt quantum gravity will somehow solve the problem of where the environment comes from.

    This view has indeed been the majority view among physicists since about 1930. It is also arguable that there has not really been any major agreed advances confirmed by experimental predictions. There have been empirical discoveries of new phenomena, such as as the apparent existence of dark matter and dark energy. But it's hard to think of very much that has been anticipated by quantum mechanics (or its natural development, quantum electrodynamics,) in decades. Perhaps there is something fundamentally debilitating for science in the anti-realist perspective?

    Be that as it may, or may not, be, it is unclear what this has to do with Hoffman's theories. One of the key principles in this view is that what is observable is determined by the experimental setup. In Hoffman's view, a mind that is creating its observables, that is to say, its reality, by its experimental setup with the outside world, should be observing different results when it changes its methods. It is not at all obvious By and large this is not the case for humanity, and exceptions like hallucinations tend to be deemed pathological.

    Further it is just as unclear where Hoffman's world W comes from, just as it hard to say where in QM/QED spacetime (aka the environment or the universe,) comes from. I mean, it's sort of there in the math (manifest variables instead of hidden ones, perhaps, for both physics and Hoffman? At any rate, it is no surprise that Hoffman thinks he can simply replace his W with "conscious agents." His W, swiped from conventional fundamental physics, isn't real. However his belief that two conscious agents interacting become another conscious agent is I think the equivalent of claiming two experimental setups constitute a third experimental setup. I should think this is nonsense physics. I'm afraid I suspect Hoffman is using quantum woo, not quantum physics.

    As lengthy as all that was, it's not at all clear that Hoffman's notions of elements of mind are genuinely coherent. They were space X of experiences; space G of actions; algorithm D for choosing actions; probability space W for the arena of actions, and two mysterious perception maps, P mapping from W to X, experiences and A, mapping from G, actions, to W. He says these are six elements, but it seems to me to number seven? Perhaps the mapping is a mathematical function, and it's the same in both cases? (But that would seem to be an assumption awfully close to making it a kind of reality function?)Regardless, it is unclear how there can be many experiences without actions. Seeing without opening your eyes seems to be a good trick. Even an experience like hunger is uncertain, because it is uncertain where the mind ends and the world begins. It is not clear how perception maps are genuinely different from experiences. And of course it is not at all clear that algorithm D isn't experience, learning.

    Lastly, perhaps the crux of his argument begins with his claim "the mathematical physicist Chetan Prakash proved a theorem that I devised that says: According to evolution by natural selection, an organism that sees reality as it is will never be more fit than an organism of equal complexity that sees none of reality but is just tuned to fitness. Never."

    Hoffman continues the argument, in an example using an ascending scale of goodness from water, "…suppose your fitness function is linear… in that case, the organism that sees the truth… can win, but only because the fitness function happens to align with the true structure in reality. Generically, in the real world, that will never be the case. Something much more natural is a bell curve — say, too little water you die of thirst, but too much water you drown, and only somewhere in between is good for survival. Now the fitness function doesn’t match the structure in the real world. And that’s enough to send truth to extinction."

    Well, the conclusion does follow from the premises as given. But first, it is not clear how one can write a fitness function, conscious agent or not. Thus for me it is not clear that a mathematical demonstration that such a fitness function is, more or less, tautologically equal to or superior to, I suppose you could call it a reality function, is moot. Is it relevant?

    It is not clear what, for Hoffman, the fitness function refers to. Further, I believe it is instead customary in evolutionary theory to emphasize that fitness functions are for individual traits, not an abstract fitness; individual traits do not have linear fitness functions; the multiplicity of traits means fitness for an organism is global, over all fitness, definitely not a linear function; fitness functions evolve over time and space.

    Hoffman concludes the interview by saying, "The experiences of everyday life — my real feeling of a headache, my real taste of chocolate — that really is the ultimate nature of reality." I'm not much for philosophy but this seems to be saying atoms of sensation, so to speak (called qualia I believe) are all there are.

    The thing is, I've never understood the remarkable uniformity in reports from individuals. When people disagree, as a personal suffering Daltonism will disagree on the difference between red and green, or a deaf person denies there is music, although there is not a consensus, there seems, remarkably, to be some sort of odd coincidence where the dissidents have some sort of marker, cones in eyes or damage to auditory nerves. If personal experience is constitutive of reality, shouldn't dissidence happen more or less randomly without such purportedly illusory causes of defects in perception of the non-existent real world?

    And perhaps this is just me, but I've never been able to reconcile my qualia as the elements of reality with the fact that my qualia seem to change. Notably, they're different when I'm asleep and dreaming. But I've noticed that, curiously, they change according to what appears to be environmental circumstances! But I suppose that could just mean I'm an illusion?

  • "Evolution … [is] hiding from us the stuff we don’t need to know. And that’s pretty much all of reality, whatever reality might be."
    Where is the scientific background which describes this "hiding" process etc?
    This article is for me as physicist science on the basis coffee ground.

  • However.

    When I describe the moon to you, I use words that evoke other descriptions. You agree with me about 90 percent of what all those basic descriptions also *mean*. Not in terms of the Moon only, but in terms of other things like colors and shapes and distances and brightness…. So it is a shared perception, or rather a network of shared meanings that we share, and not just us, but millions of other people. So that's a flaw in his presentation as described here.

  • As Laplace might have said
    Reality? I have no need of that hypothesis.

    All he really did was describe perceptual regulatities.

  • Let's take the "amount of water" analogy. The idea that a being might not see how much water there really is – but only "the right amount" versus "the wrong amount". That could certainly be the case – perceptually such a creature wouldn't be able to tell the difference between "too much" and "not enough".

    But as humans, we've learned to use scientific instruments to measure the amount of water and to MAP that information into other domains. So suppose we build a machine that measures the actual amount of water using a sensor that's not built by evolution…and displays that using a DIFFERENT sense. Suppose our animal uses vision to estimate the amount of water and gets "Red: too-much/too-little" and "Green: just right"…but our instrument generates "High-pitched-sound: Too much, medium-pitched sound: Just right, low-pitched sound: Not enough". Now, the animal is able to detect how much water there is using a sense that was evolved for an entirely different purpose. Now it can look at water and use both hearing AND vision to measure how much there is. If the color red comes up for two wildly different pitches of sound – then it knows that it's vision isn't giving it the true picture…but if sound and vision correlate nicely – then it knows that it's seeing reality.

    We do this all the time. Our eyes don't show us ultra-violet light – but we can make cameras that detect UV just fine – and map it into the range of colors we can see. When we do that, we can see that a flower has spots and stripes as shown by our UV camera – and DOESN'T have them in our normal vision. So in that case, we know that our eyes have limitations and don't truly show the world as it really is.

    Science is all about mapping things we can't sense (or mis-sense) into objective data and thereby into the range that our senses CAN perceive.

    Another great example is temperature. Our skin doesn't measure temperature – it measures rate-of-flow-of-heat-energy. So when you touch a piece of wood, it feels warmer than a piece of metal that's at the exact same temperature because wood is a good insulator and metal isn't. So we talk about "warm woodyness" and "cold metallics"…our senses fail us completley. But, a thermometer maps true temperature measurements into something our eyes can see – and now we know that we can't trust our skin as a temperature probe.

    Science is revealing what evolution has broken. It tells us that we can't measure temperature with our skin – BUT that we do actually hear sounds over the range 50Hz to 10,000Hz quite accurately.

    This demolishes the argument that we have no idea what reality really is…and that's why I think your article is nonsense.

  • Humans see only part of reality, therefore we see a false reality?

    How's that again?

    I won't more than mention that this is an example of the Epimenides paradox.

  • Jan Vones, this article reminded me of Aristotle as well, specifically, how aristotle describes our sences as imperfect and how he refers to balances in life (which correlates to the mention of a bell curve in the article). I agree with much of the article, those who are critics, do you simply not believe in the assertions that quantum physics make?

  • Ironically, I just watched a mediocre movie called Lucy. It's just this theorem – I we used 100% of our mental capacity, and consumed all the data reality has to give, it's simply too much. We have "dumbed down" reality so we can navigate it – we made it simple.

  • There are some fundamental fallacies in Donald Hoffman’s argument.

    1. While evolution does try to maximize fitness functions, the way it does this with perception and the modeling of reality is not as simplistic as he describes. Perception is required by an organism in order to respond to open-ended challenges. You can never foretell when you may need to accurately perceive an unknown object or organism that may be a threat or benefit to you. The only way to achieve this is to represent certain aspects of the world, such as object recognition, movement, depth perception etc. as accurately as possible. If you failed to see a yawning chasm a foot away from you, you’d be dead in no time. So these kinds of perceptual functions are honed by evolution to be as accurate as possible. Here the fitness function and the perception of reality are almost perfectly aligned.

    Yes, there are some minor ways in which perception can be aligned to the specific organism’s fitness to the slight detriment of accuracy. These happen generally in extreme or artificially constrained environmental conditions that the organism would not encounter normally, or in cases where further accuracy would not benefit the specific organismal niche. We see the first, for example, in visual illusions, some of which are usually generated in unnatural lighting conditions etc. We see the second in the limits of our perceptual abilities: for example, a hawk benefits from enhanced distance vision far more than we do, and so it can perceive more accurately at far distances. But in general, our perceptions, within their usual sphere of use, are remarkably accurate.

    All this is perfectly compatible with the theorem proved by Chetan Prakash.

    2. As others such as Tito Swineflu have pointed out, “Nowhere in physics does it say that objects are not real unless observed. All it says is that observing very small particles has an effect on their properties.” Also, it is all but certain that conscious observers are not required to cause quantum effects. Wojciech Zurek’s concept of decoherence is now widely accepted, and shows that large objects interacting with each other can essentially act as “observers” and cause irreversible changes in the quantum wave functions, in a way similar to the irreversibility of entropy in classical physics.

    3. As Jaime says, “Brains are large and hot, I honestly don't think that quantum effects are important… I believe that a sufficiently large and complex classical neuron network will eventually qualify as 'conscious'.” I agree completely. The moniker “ the hard problem,” has served the purpose of highlighting how different consciousness is from other fields of study, but at bottom, it is just a failure of imagination. It is not a coincidence that it is only the most complex structures in the world – brains – that generate consciousness. In order for consciousness to exist it requires a lot of complex functions that have to be very well accomplished, such as world modeling, object recognition, perceptual interpretation, memory persistence, attention and a host of other unconscious tasks. The idea, spawned by the hard problem talk, that consciousness is somehow a fundamental property of the world, and can exist in simple things like rocks and particles is magical thinking – it throws away everything we know about the complexity required for consciousness.

    In this regard, I will be giving a talk at the “2016 Science of Consciousness Conference” in Tucson next week. Its subtitle is “Exposing the Hard Problem as a Brilliant but Seductive Misconception.”

    Reality exists.

  • Anyone who has dealt with episodic severe depression and applied his analytic powers to both states understands that the reality perceived in one state is just as real as the other despite the manifest difference and that evolution has blessed mankind with the rose colored glasses that comprise the non-depressed or "normal" state of magnificent illusion in order to make existence not only bearable but even interesting.

  • Great article. The only thing missing is the name of Kant, also a reference to his transcendental aesthetics. Mathematicians (by Gauss and Lobacevsky) understood what it was about there after half a century; physicists (by leaders of quantum mechanics) after a century. The rest of sciences still indulging in the epistemological paradigm of Newton.

  • Pradeep Mutalik,

    You write:

    "Perception is required by an organism in order to respond to open-ended challenges. You can never foretell when you may need to accurately perceive an unknown object or organism that may be a threat or benefit to you. The only way to achieve this is to represent certain aspects of the world, such as object recognition, movement, depth perception etc. as accurately as possible. If you failed to see a yawning chasm a foot away from you, you’d be dead in no time. So these kinds of perceptual functions are honed by evolution to be as accurate as possible. Here the fitness function and the perception of reality are almost perfectly aligned."

    I don't see how Hoffman's argument contradicts that. In fact, I think his argument encompasses that.

    The point is that our perceptions are skewed to those things that are important to survival which means they omit parts of the reality that are not important to survival.

  • Yes, this is Kant's transcendental unity of apperception.

    Also, an inherent problem: if the author's thesis from the video (that we don't see reality, but it is purposefully hidden for our survival) is true, wouldn't that equally apply to his own theory? if so, the explanation is self-defeating.

  • Our reality is not a result of by our 'perceptions' as much as it is a result of our need to control and change reality. As living beings, we live by controlling and making use of our environment. All of our perceptions are designed to tell us about our environment – both internal and external, because living things advance – grow, reproduce, and evolve, by taking advantage of levers in the environment.

    We create "cause and effect" through our living. We then use the advanced theories of cause and effect to explain, even those things we cannot control. We create our reality, using terms developed from our need to observe, learn from and control cause and effect. That is the way of life. Our perceptions are a tool of life, a tool of our need to manage and control cause and effect in order to live.

    We create 'things' so that we can influence, control, or use them to our benefit. This begins even before cells began perceiving their environments in order to advance their lives, and continued through the development of tissue entities like algae and the more complex lichen, to the development of organs – 'internal things' to control internal and external environments, organ systems – to manage cooperation between organs, body, the physical thing that we are, mind that which we use to perceive what we are, spirit, that by which we perceive 'how' we are, and communities – through which we communicate and discuss 'things' that we perceive.
    founder: Healthicine.org

  • Pradeep Mutalik,

    I don't see how your first argument at all is at odds with Hoffman. It seems like his argument basically encompasses. He is saying our perception of reality is skewed by its survival advantage, that the two are aligned. However, that means we omit parts of reality that are not aligned with survival.

    Take the bat in Nagel's What is it like to be a bat?

    The bat's reality is built to a huge extend from echolocation because echolocation is critical for capturing food and flying in darkness.

    Human perceptual reality is built for daytime with fine visual acuity for pattern recognition.

    Which reality is more real?

  • @James Cross,

    Yes, we can't experience the bat's reality but we can be sure that such things as the positions of objects in its model of the world are concordant with our own perceptions, else the bat would fly into things.

    The point is there are real objects out there, and there are some aspects of reality that all observers share and can agree about. It's not all an illusion as Hoffman seems to be saying, especially when he talks about consciousness being the most basic ingredient of the world, and discounts an external reality of objects as the title of the article advertises. It's possible that his actual views are not that extreme.

    The reality of matter and objects exists, and has certain discoverable properties. Evolution has shaped our brains to discover these, more or less accurately. This external reality existed far before consciousness did, and it one day evolved brains complex enough to have consciousness.

  • I find it interesting — if not bringing any more understanding to the subject — how closely these arguments seem to echo the nearly 2000-year old central tenets of Buddhism (and I mean specifically the non-religious branches of Buddhism, like Zen, that do not posit a creator): form is emptiness, emptiness form, and that's all there is. The ontological arguments are certainly a tangled skein, but a tangled skein of WHAT, tangled by WHOM, and what do "TANGLED" and "SKEIN" represent anyway? That humans were exploring these questions that long ago — and certainly from traditions FAR older than what we call Buddhism: the Buddha was not a Buddhist, and the term is a Western one, only a couple centuries old — is either heartening, that whatever consciousness is, we've been whacking away at it along roughly similar lines for tens of thousands of years, or disheartening, that we've been whacking away at it along roughly similar lines for tens of thousands of years and seem not to have learned anything that informs us what "being" and "consciousness" are, or if they exist at all.

    It IS a great way to give yourself a headache, though.

  • Pradeep Mutalik,

    But I think we only share largely to the extent that similar things are important to us for survival whether we are cats, dogs, horses, or maybe even bats.

    We have developed similar equipment for perceiving the world and similar equipment for processing it because we have come from a similar evolutionary tree and because all living beings share similar requirements. That is the source of the consensus, the things we share and agree about.

    For all those saying this is just Kant, this is what he writes

    "Conscious realism is not the transcendental idealism of Kant (1781/
    104 Hoffman2003). Exegesis of Kant is notoriously difficult and controversial. The
    standard interpretation has him claiming, as Strawson (1966, p. 38) puts
    it, that “reality is supersensible and that we can have no knowledge of it”.
    We cannot know or describe objects as they are in themselves, the noumenal
    objects, we can only know objects as they appear to us, the phenomenal
    objects (see also Prichard 1909). This interpretation of Kant precludes
    any science of the noumenal, for if we cannot describe the noumenal then
    we cannot build scientific theories of it. Conscious realism, by contrast,
    offers a scientific theory of the noumenal, viz., a mathematical formulation
    of conscious agents and their dynamical interactions. This difference
    between Kant and conscious realism is, for the scientist, fundamental. It
    is the difference between doing science and not doing science. "


  • Yes! Only 1st Person experiential reality exists. As Gefter concludes in Trespassing on Einstein's Lawn (2014), "Everything is what nothing looks like from the inside." The Buddha worked this out 2500 years ago. He called it The Middle Way.

  • Donald Hoffman sounds like a very smart guy and makes a good case for his views for much of this article. That is until he wanders into Crazytown:

    "I’m emphasizing the larger lesson of quantum mechanics: Neurons, brains, space … these are just symbols we use, they’re not real. It’s not that there’s a classical brain that does some quantum magic. It’s that there’s no brain! Quantum mechanics says that classical objects — including brains — don’t exist. So this is a far more radical claim about the nature of reality and does not involve the brain pulling off some tricky quantum computation."

    "Objective reality is just conscious agents, just points of view."

    Call me old fashioned but I think extraordinary claims require extraordinary proof, or at least a theory which is not contradicted by the physical evidence and can be coherently explained, and with luck – or probably great luck in this case – proven at a later time. Otherwise you might as well be a midieval theologian discussing how many angels can dance on the head of a pin.

    Many ideas that were once deemed "crazy" were later proven true so my point is not that these things should not be discussed, just that in this case a much more rigorous presentation for the lack of a physical reality is needed if it is to be taken seriously.

  • Really amazing article. I will think of it for a long time. However my first question that risen from this article is: what is an algorithm in the realm of phisical reality? It comes from the misterious side of the ideas, as well as mathematics. I know that it can be seen as a series of events happening in a certain order and logic but somehow there's this feeling that there's something unseen.

  • It's tempting to suppose that this is the sort of thing that happens when a cognitive psychologist is exposed to too much popular quantum theory.

    The explanations of "fitness" vs. "something else that's not fitness but more a more complete perception of reality" as explained in Hoffman's discussion of the perception of water is, to be kind, naive. The argument proposes complete perception is an evolutionary disadvantage, and give an analogy that doesn't support itself.

    "According to evolution by natural selection, an organism that sees reality as it is will never be more fit than an organism of equal complexity that sees none of reality but is just tuned to fitness. Never."

    This assertion is based on the rather absurd and completely unsupported assertion an organism can be both "fit" and "unable to perceive reality as it is". Where is this supported? How is it demonstrated? It doesn't even make sense within the bounds of the assertion; it's internally inconsistent. At the very best, it claims a "perceptive" organism won't be more successful than a "fit" one, without ever showing there's a distinction between "perceptive" and "fit" or that a "fit" organism is somehow more successful than a "perceptive" one.

    Stand back from the physics books Hoffman and put your hands over your head. No more computer models for you.

  • This is the Third Culture: the science on TV. It is unfortunately, that it can make an appearance from the "Edge" to the "Quanta".

  • As some posters have said, this is the basis of Kant's argument. There is a rebuttal of it here, but that strikes me as hairsplitting. Kant basically said that we can ON NO ACCOUNT venture beyond the realm of our sense impressions into the thing in itself, the noumenon.

    Missing also is Nietzsche, who wrote a lot about "truth." Check out Beyond Good and Evil.

    So you can't regard the ideas above as particularly new other than perhaps a modernist perspective thrown on these ancient philosophical debates.

    "Snakes and trains, like the particles of physics, have no objective, observer-independent features. Snakes and trains, like the particles of physics, have no objective, observer-independent features." This is a very weird statement. Of course there are observer independent features. A table, eg: features: flatness, oneness, extension into space. If you are really going to classify external reality, ie., noumenon, as illusory you venture into the realm of Berkeley. You guys are just talking philosophy and superimposing some modern physics on top to make it look more respectable.

  • Honestly, I think most of you don't understand what the professor is claiming. He's years beyond your thinking. I can't wait to get home and sketch some of his thoughts out, so I can actually visualize them!

    We're always fighting the last war, so I guess it makes sense that no one wants to make the paradigm leap here, either, until the current one is totally untenable. Well, it is.

    Here's your path forward, if you can manage not to burn the witch at the stake long enough to shush, read, contemplate, and then talk back.

  • Everything, even consciousness is math, numbers, and can be measured. We just lack the tools currently to do it. https://www.newscientist.com/article/mg21528840-800-reality-is-everything-made-of-numbers/

  • A lot of what was said in this article has a flavor of Owen Barfield's work in "Saving the Appearances". He speaks of private representations (representations are our perceptions of reality) and public representations. One clue that we're observing something real is whether or not other consciousnesses observe the same thing: public representation. At some conglomeration the unrepresented, unseen particles come together to form something we recognize. If we see a collection of particles that we believe to be a tree, what we are seeing has as much to do with our inner experience of the conception of "tree" as it does with the actual extended object. I've built mathematical models to represent what is physically possible according to classical mechanics, and I recognize that my model is a symbol for something that is (or isn't if we believe quantum physics). I think making a mapping of our cognitive relation to the external world will be a similar endeavor; symbols representing what is (or isn't if our consciousness does not exist except as an intersection in this space). But, it's an interesting task. I suspect that if we plug our consciousness into those variables, the model will be accurate.

  • It's very hard for this ole country boy to believe that the distant galaxies didn't exist until we humans were able to observe them with enough clarity to distinguish that they were different than the other dots of light in the sky we came to know as stars – there is a blend between observer and observed and 'reality' that no one as yet has been able to express. Am I right.

  • Obviously, this is an interesting theory, but it seems to hinge on the belief in quantum physics that something is an uncertain state until the point of observation. Or, in the words of the article, there "don’t seem to be definite objects localized in space until we come along to observe them." But I would dispute that.

    What's to say that an object is "certain" after the point of observation. Can't an object be in a constant state of flux, with its physical properties governed by the probability of where the underlying quantum atomic structure lies at any given point? If I stare at the house outside of my window right now, I can see it. Yet when I'm not observing it, it doesn't mean that it goes away – It just means that every time I look at it, the underlying atomic structure (governed by quantum mechanics) is there. Now, if I stared at it for trillions of trillions of trillions of years, in theory it could disappear for a micro-second as its quantum properties acted "silly." But that doesn't change that it's there.

    In short, Hoffman's entire theory is based on things becoming certain only when they're observed. But it's silly to assume that mere observation changes the quantum properties of probability. Think of Schrodinger's cat. It's both alive and dead even when you observe it. You just have to stare at it a very, very, very long time to see it momentarily die before it is resurrected 🙂

  • I am gladdened by the majority opinion of the commentariat. If you want to employ quantum mech in your metaphysics, please try to understand it at more than a Sunday Times level, lest those of us who do understand it more deeply raise a proper ruckus.

  • @ Pradeep Mutalik,

    You wrote:

    "The idea, spawned by the hard problem talk, that consciousness is somehow a fundamental property of the world, and can exist in simple things like rocks and particles is magical thinking – it throws away everything we know about the complexity required for consciousness."

    Then, how did consciousness evolve? Or did it instantaneously spring into existence at a certain level of complexity?

  • Hi everyone,

    I would like to point out that the problem of consciousness and the fact that we, people, use the same language to describe personal experiences like "I see the moon" were very nicely discussed by E. Schrödinger in Mind and Matter.

    One thing that bothers me a lot, and was very well explained by Schödinger, is that to grasp the problem of unique/multiple consciousness(es) and sensitive experiences, people use Science but Science does not come first since the first proxy is sensitive experiences. It would be like a mathematical theorem proving the axioms.

    Any thoughts on this part?

  • Yes, if one is going to bandy about terms like "reality" and "perception," a little knowledge of philosophy would help. Never mind a little "post-philosophy"–like Nietzsche's "On Truth and Lie in the Extra-moral Sense." There's very little that "science" can tell us about these matters that hasn't been thought (through) already by Nietzsche.

  • Pradeep Mutalik nails it.

    For the most part, natural selection favors accurate mental modeling of the external world. It is the way we react to perceived reality that is shaped by natural selection. Natural selection acts in three main ways: first, by shaping instinctive responses to particular stimuli, second, by determining the reinforcements that give rise to learning, and third, by controlling the sensitivity of the organism to specific biologically significant stimuli.

    To say that the mind forms an accurate mental model of the external world is not to say that grass is really green, but that in the non-hallucinating individual, perception has a consistent relation to features of the external world: the greenness of grass, for example, or of unripe bananas, to the wave length of light reflected.

  • Forgive us our trespasses before truly digesting this stuff but,
    Snakes and trains, like the particles of physics, have no objective, observer-independent features. The snake I see is a description created by my sensory system to inform me of the fitness consequences of my actions. Evolution shapes acceptable solutions, not optimal ones. A snake is an acceptable solution to the problem of telling me how to act in a situation. My snakes and trains are my mental representations; your snakes and trains are your mental representations.

    This thingy in the quotes : is it summat to do with Shankara's Maya or the Idealism in Philosophy or some such? S. Radhakrishnan apparently wrote something about it.

    I'll leave it to more sage minds to plumb these depths of apparent reality.

  • I generally enjoy the articles in Quanta, but this one has made me doubt the wisdom of maintaining my subscription. Surely there are more interesting things happening in science than this?

    I agree with the many other comments that have pointed out logical flaws in just everything that was said. However my main objection is the simple point that this is not science, at least not by any definition I am aware of. Where are the definitions of terminology, especially when the terms used in this supposedly scientific argument are also used in everyday parlance with many different meanings and connotations? Where are the predictions and the possible grounds for refutation?

    No wonder science has slowed to a crawl, if this is the level of discussion in our universities.

  • Pradeep,

    If you think consciousness is a result of complexity I think you are in error.

    See An Empirical Case Against Materialism (google as don't believe links can be posted here but it's a freely available PDF), Andrew Clifton goes through the various attempts at explaining consciousness through appeals to "cryptic complexity" and shows that they are wanting.

    That said, as it is a materialism-is-inconceivable argument – though more advanced than what I've gotten from Chalmers – I'd say the stronger argument can be found in A Place for Consciousness in Nature: Probing the Deep Structure of the Natural World by Gregg Rosenberg.

    Sadly the latter isn't free though.

    I'd also recommend Philip Goff's update of the Knowledge Argument which can be found on his site Phillip Goff Philosophy.

  • Only philosophers would dream up silly ideas that everything we see, feel, and experience might be an illusion. Might be. Just as their own thoughts/view of the world/experiments might be an illusion.

    It's funny. They study humans as if they can exempt themselves from humanity and look at us objectively, but they forget that they too are humans and whatever is true of others is true of their own thought processes, opinions, etc.

    Oh, and of course, this is all based on his assumptions about evolution. So, this whole article has assumptions as it's foundation! Wonderful!

    And on top of that, those assumptions/interpretations of the data would also be subject to the same problem.

    This view of reality makes it impossible to ever know anything and undermines science itself.

  • So much nonsensical assertions in one article. Einstein wrote about how so many scientists seemed to him "like they have studied thousands of trees and never seen a forest." This professor has read just enough of philosophy and Quantum Theory to make him dangerous. What I am sure he doesn't realize is how much of his interpretations of his assumption programed model is from his basic worldview and has nothing to do with science. I personally believe quantum particles act the way they do because at the quantum level there is a border to extra dimensions. Whatever is going on is still real or Peter Higgs wouldn't have been able to sit down many years ago and do the maths that said there has to be a Higgs Boson and they just discovered it because it is really there just as the World is really there. I'm glad he figured out he isn't merely a machine.

    Neuroscientist Wilder Penfield figured that out and ceased being a materialist and became a dualist because in all of the experiments he performed on people with stimulating parts of the brain he could make them feel, hear, hallucinate and have seizures and just about everything you can think of except one thing. No matter how much he tried he couldn't make people think abstract thoughts. The so called machine-like brain physics didn't obey the machine laws. He should have been able to make his subjects think, but he never could by any mechanical means. He concluded that there is more to Mind than physics. See his book Penfield, The Mystery of the Mind, pp. 77-8. and this link

    I think the author Hoffman may benefit from reading Penfield's pioneering work as a neurosurgeon trying to treat epilepsy. It appears there is a ghost in the machine and that is why eternity is conceived there and as with so many other things that don't help us to survive methinks it may be from the top down and not the other way round which has been a dead end for origin of life researchers. The physics aren't the cause.

  • not this again: total full reality would be of no use to us. we'd never find the toilet. we saw -deduct- what is necessary for our survival. pattern recognition is de rigeur. [sic]
    so this endless, mainly ango-philosophy 101 argument what constitutes reality is a dead end. worse than wittgenstein.

  • I have no problem believing that our senses are not sufficient to perceive all of reality, even with the senses we can imagine and technologically develop, witness the THEORY of dark energy and matter. However to go from that to saying that there is no reality beyond my own perceptions is just nonsense. The sniper's bullet that I do not perceive or even think exists can still kill me and end all my perceptions of this world.

  • This guy is both philosophically naive and scientifically ignorant. If you want to read what real cognitive science says about our perception of reality, you can find the latest, most authoritative synthesis in Andy Clark's Surfing Uncertainty (Oxford UP, 2015).

  • He claims to be talking on the basis of scientific knowledge, but he's actually doing amateur metaphysics, mostly rehashing old and tired arguments in a philosophically naive way. For example, the argument about evolution and reality was originally made by Nietzsche, in pretty much the same form that he gives it here. This guy is both philosophically naive and scientifically ignorant. If you want to read what real cognitive science says about our perception of reality, you can find the latest, most authoritative synthesis in Andy Clark's Surfing Uncertainty (Oxford UP, 2015).

  • This is hilarious. Kant made the point that when we perceive "objective reality", we are really experiencing the perceptions in our heads. Now you are trying to zero in on this "perception of reality" in order to give it a "precise objective reality". Fun, but hardly seems worth all the verbiage in order to prove what you (and Kant) are saying really can't be proved, because we have no direct perceptual access to whether "reality" is "objectively real" or a "perceptual construct" in our heads. Sounds like the postmodern version of "how many angels can dance on the head of a pin". Have fun, though.

  • We cannot grasp infinity so we do everything in our power to reduce it to a measureable, quantifiable thing. In doing so we ignore reality. In an infinite universe the possibilities of what we are also infinite, and to allow our minds to expand outward to the infinite is to lose our sense of individuality, which gets too close to the feeling of death and is too scary to go there.

    What we perceive is a projection of the one mind behind all minds. We are simply aspects of this one mind and this is why we are able to perceive the sameness in all things. But what we perceive is not real, it is simply a thought similar to pictures we see in our minds as we imagine something. This is also why there is nothing permanent in the observable universe. Everything we see is a thought that eventually fades just as out thoughts fade as we let go of them.

  • So science is post-Kantian now? Finally:)
    Reading this article is like the introduction to Arthur Schopenhauer's The World as Will and Representation, but with contemporary techno babble.
    Greek philosophers deduced atoms 2000 years before they were discovered.
    British and German philosophers deduced the subjective nature of reality 300 years before science started more or less accepting it.
    …And they say metaphysics are a waste of time…

  • Quote from the opening of Arthur Schopenhouer's The World as Will and Representation:

    "THE world is my idea":— this is a truth which holds good for everything that lives and knows, though man alone can bring it into reflective and abstract consciousness. If he really does this, he has attained to philosophical wisdom. It then becomes clear and certain to him that what he knows is not a sun and an earth, but only an eye that sees a sun, a hand that feels an earth; that the world which surrounds him is there only as idea, i.e., only in relation to something else, the consciousness, which is himself.

    If any truth can be asserted a priori, it is this: for it is the expression of the most general form of all possible and thinkable experience: a form which is more general than time, or space, or causality, for they all presuppose it; and each of these, which we have seen to be just so many modes of the principle of sufficient reason, is valid only for a particular class of ideas; whereas the antithesis of object and subject is the common form of all these classes, is that form under which alone any idea of whatever kind it may be, abstract or intuitive, pure or empirical, is possible and thinkable. No truth therefore is more certain, more independent of all others, and less in need of proof than this, that all that exists for knowledge, and therefore this whole world, is only object in relation to subject/perception of a perceiver, in a word, idea.

    This is obviously true of the past and the future, as well as of the present, of what is farthest off, as of what is near; for it is true of time and space themselves, in which alone these distinctions arise. All that in any way belongs or can belong to the world is inevitably thus conditioned through the subject, and exists only for the subject. The world is idea.

    This truth is by no means new. It was implicitly involved in the sceptical reflections from which Descartes started. Berkeley, however, was the first who distinctly enunciated it, and by this he has rendered a permanent service to philosophy, even though the rest of his teaching should not endure. Kant's primary mistake was the neglect of this principle, as is shown in the appendix.

    How early again this truth was recognised by the wise men of India, appearing indeed as the fundamental tenet of the Vedanta philosophy ascribed to Vyasa, is pointed out by Sir William Jones in the last of his essays: "On the philosophy of the Asiatics" (Asiatic Researches, vol. iv., p. 164), where he says, "The fundamental tenet of the Vedanta school consisted not in denying the existence of matter, that is, of solidity, impenetrability, and extended figure (to deny which would be lunacy), but in correcting the popular notion of it, and in contending that it has no essence independent of mental perception; that existence and perceptibility are convertible terms." These words adequately express the compatibility of empirical reality and transcendental ideality.

  • I'm sorry to break it to you, because it does sound like an exciting theory but it has a major flow that makes it completely irrelevant to our daily experience (but still keeps it relevant to computer modeling)
    the one thing this entire theory is missing is the term computation.
    Hoffman gave a great example of a computer desktop that shows to it's users all they need to know in order to achieve what they want most effectively without knowing "what goes on behind the curtains" but like so he leaved a huge gap – the method by which the movement of countless electrons is transformed into a coherent and concise experience – the computation done by the CPU.
    this computation is not done by magic, or by the natural laws of the universe, but instead has to engineered almost to perfection by man and machine. in order to achieve that result ENERGY must be expended.
    if by some magic means the screen would have mirrored exactly what goes on inside the CPU then we would not have needed to expend that energy and our system would be more "fit" than the former to our daily uses.

    this is exactly why Hoffman got his result that indicated that a being that "just knows" when to take each action has a huge advantage over a being who has to think about it, the former has no need to expend all the energy that the latter has to use to compute his chances of survival.

    this is exactly where we differ from computer simulations – we had no such luck as to have a being that preforms whose computation on our behalf, we have to do the leg work ourselves to figure it out.

    what Hoffman might argue, and rightly so, is that even if out unconscious brain has to preform those computation, our conscious brain has to get a filtered view in order to make sense of what we perceive – which is true. however once you already expanded the energy required for the computation it makes no sense to throw all the data you deem irrelevant because it leaves a very small margin for error which evolution acts against. the correct way to proceed would be to dump some of the data, amplify the parts of it that may help you the most, and reduce the weight you give to the parts that may not help you at all.
    we experience those things daily with out instincts and emotion (fear, anger, joy and so on), the ability to isolate someone's speech from a noisy crowd, the filtering of repeated noises and so on.

    also the reason we don't apply quantum mechanics in our common sense thinking is because it has little to none direct influence on the the scale we are living in, in which classical physics applies. it's not that we evolved to filter quantum mechanical effects – it's that it had almost zero influence on us so we had not gotten the chance to evolve to feel it.

  • "The cognitive scientist Donald Hoffman uses evolutionary game theory to show that our perceptions of an independent reality must be illusions." Oh so that's what he did. It sounded to me like the article was in fact an interview with a man who has spent his whole life searching for the sorts of answers my friends and I, with no scientific training, spout out when we're drunk.

  • Einstein said something like 'reality is an illusion but a very convincing one'. And that's really the point. We may not be perceiving what is 'real' but so what? It's real enough for our purposes. That we can't perceive what is really going on is ,ultimately, irrelevant. As with evolution where an organism finds it's niche in the physical world-as we perceive it- what is 'real' is sufficient for the task at hand.

  • Following Hoffman's logic to it's conclusion, then Hoffman isn't 'real' and neither is his hypothesis and only something I think I read. I wonder how he feels about that.

  • I am the prisoner of my brain, which has evolved to interact with a 'real world' in a very limited way, so as to increase my fitness.
    That makes sense to me.
    As this is the only brain I have, how can I interact with the 'real world', if indeed it exists.
    It is inaccessible to me.

  • Great article! Finally a scientist that owns up to the problems facing modern science instead of denying/pretending they dont exist to make a buck. It just does not make sense to me that different areas of science are incoherent. Personally Physics has been one of the greatest things to both liberate and stretch the possibilities of the human mind but personally I believe they should give up on reality and start putting more of their efforts into more tangible endeavours. It is a great failing of scientists today in that they are extremely stubborn and close minded it would have Einstein turning in his grave. The human race has known for thousands of years that observed reality depends entirely on the observer and addition to this the cosmos is interdependent and instantaneously changing so how the hell can you think for one second how you will figure out the universe into separate events let alone put the entire cosmos into one equation is beyond me. It is beyond stupidity.

  • Yes, as Korzybski said, "The map is not the territory". Yes, quantum theory shows the observer is involved at the lowest level. Hand waving while reciting these things does nothing to advance our knowledge of cognition. Move along, folks; nothing to see here.

  • The article intrigues at the beginning, then starts confusing by the unwarranted assumptions and eventually falls apart by contradicting itself.

    Many other people pointed out this and specific fallacies. My favorite comment is done by Steven Johnson on Apr 22 at 11:41


  • Concerning the question of why people experience similar realities instead of random ones–because species.
    Spiders experience a reality similar to other spiders, fish–to other fish, and so on. Each of those realities enables the species to survive and reproduce, but is not more or less real then the realities of other types of organisms.
    We are a species are synchronized to each other in our experience of reality, but it doesn't make it all that real. Which doesn't mean we shouldn't investigate everything we can–we totally should–we just should try to remember while we are investigating the aspects of our reality the one enormous caveat…

  • This reminds me of the hidden world of colors and ultraviolet light that bees and other insects can see. It blew my mind as a child to imagine there were colors that the human eye can't perceive. There are even little landing strips on flowers that Bee's can perceive. Similarly, Human's perception of gravity has been compared to a deep seas fishes sense of water: So ever-present that it's difficult to imagine it not existing.

  • What I get from this is that everything is its own experience – gravity, molecules, rocks, people. The train of thought points to consciousness as presence, rather than consciousness as a self-awareness.

  • Subject too complex to be even nearly understood.
    I went through it little impatiently and wants to give it more time if that ever happens.
    When I used to read relativity in my post graduation and lot more than really required, these questions used to touch me and go…not really able to grasp them….they were usually beyond me or I never sat down patiently to read and contemplate.

    Regarding reality, there is an element of truth in the paper by Hoffman.
    We learn from perceptions. I consider Ram very close to my heart amongst all Hindu Gods.
    Today morning I was wondering why it is so?
    Then I thought that is so because we have been told about him and I value what he represents. Its our ancestors who taught us history and mythology and we perceive that as truth because we cannot experience everything in the universe that has happened already and will not happen again for sure. Given the chance, we want to observe everything through our own senses and learn about things outside us.
    Often perceptions mislead. A rope appears snake in a dark night and one might get heart attack with fear.
    A mother coming with a record playing of train sounds, might make you jump out of the way for fear of death.
    Perception is that a bullet kills if fired from gun. But it might not if it is made of say feathers.
    So our mind has been trained through various perceptions and at times can arrive at wrong conclusions.

    Now reality.
    Yes without any kind of complex interactions we cannot observe anything. And when we interact we irrevocably alter the object. But the alterations are so minuscule that they are imperceptible to capabilities of human brain and most of machines. So they are almost real as everyone is observing same and all experiments become repeatable. But in the realm of quantum mechanics probably the act of observing an object will change it with each observation and hence it will never be observed real. Not only that, if uncertainty principle is universal then no one in the first place can observe reality.

    So even during my student days i thought that lets live in comfort of classical mechanics where things are real and observations repeatable.

    Only when we have to enter in the realm of velocities near light, the fourth dimension, its effect and variability of each observation might start mattering. Here the observations stop telling us the reality about the objects.

    Hindu mythology always says that we are living in Maya.

    One of the comments on paper seems to say that Buddhism says same…
    James Cross says:
    April 22, 2016 at 11:19 am
    Conscious realism – isn't this just animism?

    Or is it Buddhism?

    “…there is nothing more real than dream. This statement only makes sense once it is understood that normal waking life is as unreal as dream, and in exactly the same way.” – Tenzin Wangyal Rinpoche in The Tibetan Yogas of Dream and Sleep

  • It seems to me that the only significant idea in here is that Hoffman tries to explain perception in terms of evolutionary fitness, i.e. What we see is what gives us greatest evolutionary fitness. The rest could just as well be claimed by a drunkard.

  • I, like my cat Ziva, am sniffing out a true dialectic here. Maybe it is time for philosophers, physicists, and academic theologians (who are really philosophers) to come up with a synthesis, say something like, is the true reality the hardware of existence or the software running perception ? I side with the latter.

  • It seems many commentators here claim a deterministic and dualistic stance is accurate. It remains to be proven that accuracy is actually achievable in a deterministic fashion.

    @Pradeep Mutalik
    Talking about scaling in the example of the hawk does not imply that scaling is actually a fundamental property. Your argument would equate a mathematical 'matrix' with reality, that scaling is not a conscious process first of all, but scales and measurements are empirically existent beyond human or animal application.
    This seems to be an assumption, similar to Tegmark's equating of a mathematical model of the universe with the universe itself. It is an (evolutionary) helpful ability to being able to use mathematics, yes.
    (I will also present at the SoC, and happy to talk more in person this week.)

    Many arguments here would be pointless once a dualistic understanding of a fixed sense of self would dissolve. It would be surprising if any neuroscientist or psychologist would talk about a 'solid' self entity. If the understanding of the sense of self as a fixed entity disappears, then conscious agents seem a more appropriate description.

    @ steven johnson
    For the lack of a better terminology in our description of selfhood, 'illusion' and embodiment, it seems somewhat appropriate to question if the 'I' is an illusion, yes. If we can make the argument our models are beyond our sensory abilities and capacities (and their limitations), then yes. It seems not plausible to make the case our modeling and reasoning is going beyond sensory limitations.

    Maybe it is worth asking how we can enhance our sensory perceptions, and to implement them as (re)discoveries with most likely newly emerging insights into the scientific inquiry. Mathematics and technology seem useful to support and advance faster. A recent PNAS study (Kox et al. 2014) examined a conscious activation of the 'autonomic' nervous system for instance by training of conscious connections to the body and thermogenesis. If it is 'impossible' to validate a model based on (limited) sensory perceptions equates reality, theorizing has its limits.
    Instead of claiming a deterministic stance is accurate when neuroscience and quantum physics do not provide such conclusions, maybe it is worth pursuing to investigate conscious agents and consciousness.

  • @Alfred Burdett

    Thank you for your support of my point about evolution favoring the accurate portrayal of reality, and your very nice explanation of it. To further support this argument, I would also like to commend Steve Baker’s excellent comment that there we can check and sharpen our model of reality by comparing and integrating data we receive from different modalities such as sight and hearing, and through our scientific instruments. All these confirm that our perception of an independent objective external reality is generally accurate and not just a fiction invented just for increasing our evolutionary fitness. As another commenter here, Jan, said “It’s not an illusion if an asteroid hits, or if I take a bullet to the back of my head.” Reality exists and has consequences – it can end our consciousness in short order.

    Or does Hoffman really think that consciousness believes in its own illusions and chooses to end itself?

    @James Cross,
    You say that Hoffman’s argument basically encompasses my first point. It most assuredly does not. Hoffman says, “an organism that sees reality as it is will never be more fit than an organism of equal complexity that sees none of reality but is just tuned to fitness.” This implies that being “tuned to fitness” and “seeing reality” are at cross-purposes. On the contrary, what I, and the commenters I cited are saying is that any complex organism “tuned to fitness” has to make its model of the world as accurate as possible for its sphere of activity and within the limitations of its senses. Being tuned to fitness requires seeing reality. There is no way to be just “tuned to fitness” without recognizing and accurately modeling external reality: no organism can see “none of the reality.”

    I also want to dilate on my second point. Quantum mechanics does not require conscious agents to produce objects localized in space, which is one of the premises of this interview. This false idea came about thanks to an erroneous result of Von Neumann’s and subsequently has achieved a life of its own. There is a great article (free on the internet) published by Michael Nauenberg in the Journal of Cosmology in 2011 that addresses precisely this point. Nauenberg was a collaborator of John S. Bell, discoverer of the “Bell’s theorem” a fundamental contribution which showed that non-locality is real in quantum mechanics. Bell was one of the clearest thinkers about the foundations of quantum mechanics in the last 50 years. The article has quotes by Bell and several prominent quantum scientists including Feynman, Gellmann and John A. Wheeler, all debunking the necessity of conscious agents.

    John Wheeler’s quote goes “Caution: "Consciousness" has nothing whatsover to do with the quantum process. We are dealing with an event that makes itself known by an irreversible act of amplification, by an indelible record, an act of registration.” (Law without law. In: Quantum Theory and Measurement, edited by Wheeler, J.A. and Zurek, W.H., Princeton Univ. Press, Princeton, p. 196.) This is in complete and explicit repudiation of the Wheeler quote in this article above – perhaps Wheeler was indulging in poetic license when he said that, or saying something subtler about object properties.

    A lot of this confusion arises because of the unfortunate anthropocentric terms “observer” and “act of measurement” frequently used in popular accounts of quantum mechanics. Far more useful terms to use and think of in this context are, per Wheeler’s quote “Registering entity” and “irreversible amplification”. These processes naturally happen within all large macroscopic objects. The “observer” in experiments that show quantum “observer effects” is usually just a macroscopic piece of lab apparatus.

  • @Pradeep Mutalik

    "Being tuned to fitness requires seeing reality."

    So the reality of the bat and the reality of the human must be the same unless you are saying there is more than one "reality" and bats and humans are tuned to different ones.

    Keep in mind that one main issue here is the nature of subjective experience.

    Hoffman actually gives a compelling reason why what we would be seeing is not anything like reality in his desktop analogy. When we delete a file by dragging an icon to recycle bin, we are initiating a series of actions in the CPU, memory, and disk of the computer. The icon and action of dragging simplifies the underlying reality of what happens in the computer and operating system so the complexities are hidden from us. In the same way our subjective experience hides from us the underlying complexities of the world so it can interact efficiently with it. How it represents reality no more needs to represent how reality actually is than the pixels of the icon needs to be the bytes of the underlying file on the computer desktop.

  • This is an exercise in philosophy, not science, by a person with too much time on his hands. If what we see is not reality, but we can never access the truth of reality, of what value is this entire proposition? In the (pardon the expression) real world, it has none. Further, if we postulate that objects we perceive have no actual reality because two people see them differently, from their own illusory perspective, it dismisses the argument that though two people may see the moon differently, there is a common agreement on the properties of the moon, thus giving it a useful form which can be acted on in the "real" world to produce expected results. How much more real does an object need to be?

  • @Pradeep Mutalik

    How can you reason discrete units within/and macro- and microscale exists beyond conscious attribution of the sensory perceived environment?

  • Chetan Prakash's theorem reminds me of one of Murphy's laws: “The chance of the bread falling with the buttered side down is directly proportional to the cost of the carpet”.
    That is, the conclusion is valid, but the premises are false.
    That our sense organs are some displays that, on the one hand, shows us the reality, and, on the other hand, conceal us the reality is an ancient and well-known philosophical conjecture. But its justification through evolutionist theory seems forced.
    Yes, we could say that a man hypersensitive, with a very acute perception of reality, highly intelligent and worship, even with a great creative imagination (a poet, say) is more socially disadvantaged than a ”pragmatic gorilla”, without education, but who knows well his interests, and manages very effective the little information he has about the environment in which he lives.
    Would be this the meaning of the evolution of species? In this case, phylogenesis of our human species should start with homo sapiens and to end with chimps.

  • I think that idealist philosophers have clearly shown that there is no reason whatsoever to default to the idea that consciousness is a function of the brain or that we even live in a material universe outside of mind. We're just waiting for the physicalists to catch up with us.

  • This title is suspiciously close to Alvin Plantinga's Evolutionary Argument Against Naturalism (see Wikipedia, or for an accessible introduction check this page: https://leesomniac.wordpress.com/2015/05/08/an-introduction-to-plantingas-evolutionary-argument-against-naturalism/), and after reading the first few paragraphs I hoped that this would provide a scientific underpinning for that argument by filling out some of Plantinga's hand-waving around why optimising for fitness in cognitive faculties would probably be at odds with optimising for truth.

    But, alas, that wasn't to be. And worse, Hoffman's position here (as in his March 2015 TED Talk, though less so there) suffers from the kind of chronic incoherence that's characteristic of this sort of anti-realism.

  • Some last comments before I call it quits.

    Hoffman doesn't believe everything is subjective. A few more quotes.

    "If you think that this train thundering down the tracks is just an icon of your user interface, and does not exist when you do not perceive it, then why don’t you step in front of it? You will soon find out that it is more than an icon. And I will see, after you are gone, that it still exists. This argument confuses taking something literally and taking it seriously. If your MUI functions properly, you should take its icons seriously, but not literally. The point of the icons is to inform your behavior in your niche. Creatures that do not take their well-adapted icons seriously have a pathetic habit of going extinct. The train icon usefully informs your behaviors, including such laudable behaviors as staying off of train-track icons. The MUI theorist is careful about stepping before trains for the same reason that computer users are careful about dragging file icons to the recycle bin."

    "Something does exist whether or not you look at the moon, and that something triggers your visual system to construct a moon icon. But that something that exists independent of you is not the moon. The moon is an icon of your MUI, and therefore depends on your perception for its existence. The something that exists independent of your perceptions is always, according to conscious realism, systems of conscious agents. "

    All in all I can buy readily into the MUI part of his theory but am still not sure about the leap to perceptions are systems of conscious agents. However, keep in mind that multiple conscious agent are what compose the neural system (except the neural system is another icon!).

    To me the core part I take away is related to the unconscious nature of mental function. We have certain things presented to our consciousness but underlying that is a robust series of processes that do not reach consciousness (maybe as much as 90-95% of mental functioning). It makes a lot of sense that what is presented to consciousness need have little relation to the objects in the world or the complex mental processes that generated it as long as what is presented allows good enough evolutionary decision making that the organism survives. The less, but the only the essential, information presented in many cases would fit the requirement nicely and with greatest efficiency.

  • @Paul Eisenkramer

    Consciousness almost certainly didn't just "pop" into existence, but that's because consciousness isn't something black and white. Chimpanzees, ravens and dolphins all recognize themselves in the mirror. Most complex animals show some degree of conscious thought, even if they don't recognize their own reflection. Consciousness is something that developed over millions of years as an increasingly self-aware conglomeration of subconscious systems. We don't know exactly *how*, but that doesn't mean you need some sort of fundamental "consciousness" particle to generate it.

  • To be honest, I'm dissappointed to see quantamagazine post such an article. In my eyes it reads like total pseudo-scientific new age drivel.

    What's next? An interview with Rupert Sheldrake or Deepak Chopra?

    As others have pointed out, Hoffman has completely missunderstood quantum mechanics.

    An observer does not have to be conscious. Elementary particles "observe" each other all the time. For instance, otherwise nuclear decay couldn't happen if there wasn't anyone around. It would be great though if a conscious observer was needed for quantum events to happen, because then we'd just have to remove all conscious beings from Chernobyl and fukushima – and the problem would be fixed.

    The whole missunderstanding comes from Niels Borh's first lectures on the Copenhagen interpretation. He never meant a conscious observer, but was misunderstood that way emmidiately (Schroedingers cat, for instance, is based on that misunderstanding too. There was never a paradox for Niels Borh) – and that misundersanding seems to have persisted, and to even be perpetuated among certain people if it fits their worldview.

    Also, it's not true, as I have seen people posit in this thread, that quantum mechanics hasn't made advances since the 1930. I don't have time to find links to all the advances that have been made, but the first that comes to mind, is the work that David J. Wineland and Serge Haroche were given the Nobel prize for in 2012. Any one interested can use google.


  • Hoffman is correct that evolution has selected for perception that maximizes fitness. His premise is accurate, but then he proceeds to draw the wrong conclusions from it. Maximizing fitness comes from selecting for conformal mapping from reality to perception. Otherwise – as Pradeep Mutalik has already noted above – unexpected sensory inputs could result in faulty perceptions. Faulty perceptions get selected out, as our ancestors found out. And for everyone alive today, it's ancestors all the way down.

    So sure, our perceptions are just a symbolic desktop. But that desktop is a conformal map of real reality. And while quantum mechanics describes counter-intuitive stuff happening at the quantum level, that's not where we live. It's not even where neurons and synapses live. A synapse is big by QM standards. No Penrosey quantum mumbo-jumbo required.

    The idea that QM shows everything is an illusion is a bridge too far. Or a bridge to nowhere. The real world has been demonstrating its reality to every generation of living things, right from the start and continuing into the foreseeable future. It's reality all the way down.

  • He's written a paper on his "water level" claims. I've read it (so you don't have to) and it doesn't hold water.

    In his model, the most efficient organism would be the one that simply "perceives" its own eventual decision. If it has to chose between three fields to move to, it would do best to just "perceive" that field and be done with it.

    His paper is simply lacking a principled way to account for the (time and energy) cost of the whole perception-decision chain. He imputes a cost based on the representational size (bits) of a "perception." However, what stage of a hypothetical processing chain he calls the "perception" is entirely arbitrary. There is no cost model for forming a "perception", so it easily follows that it would be cheapest to just "perceive" the final decision.

  • Ho hum. I wonder how much neuroscience and physics will have to learn about reality before they are prepared to concede the plausibility of Buddhist doctrine. At this time they still seem to think that reality is what they always thought it was and are thus very confused, when all that's happening is that they are waking up to their long-standing mistake, a mistake that has been pointed out to them countless times.

    Materialism indeed. Time for the academic community to catch up with the program.

  • Sounds interesting- but is this not a re-shaping of a old debate in philosophy- between mind and matter, structure and non-structure, language and perception? It seems quite dated when one considers post-structuralism, linguistics and phenomenology- is it maybe the case that scientist have finally been able to accept with their "empiricism" debates which were previously dismissed as wishy-washy humanities?

  • This helps explain why polarization is inevitable any time groups are given a choice between two positions.

  • Very disappointed to see an article like this posted on Quanta. Trust me, I'm all for being open to new and interesting ideas, but the idea posited here seems not only self-defeating but a giant step back in terms of our scientific understanding of the world.

  • This is an interesting but confusing interview of a neuroscientist on the admittedly difficult problem of “reality”. It is clear that we humans are classical physics objects and we live in a world which looks classical to a good approximation. Thus survival or fitness may very well require knowledge of classical reality. But the fundamental reality is quantum beyond any doubt. Even though, he says that neuroscientists should pay attention to quantum physics, his solution uses ideas of classical physics and look contradictory sometimes. On the one hand he says that “Physics tells us that there are no public physical objects.” But then he says “I can talk to you about my headache …you have your own moon. But I assume it’s relevantly similar to mine. That’s an assumption that could be false” And in the middle he says “but part of that involves hiding from us the stuff we don’t need to know and that’s pretty much all of reality, whatever reality might be.” In the last paragraph his statement is: “As a conscious realist, I am postulating conscious experiences as ontological primitives, the most basic ingredients of the world.” So my guess is that lot of work remains to be done!
    I should point out that eastern religions (especially Hinduism and Buddhism) go one step further in philosophy. Quantum mechanics says that we cannot talk about objective reality independent of the observer and every time we measure a system, we are increasing our knowledge of the system (at least in Bohr’s interpretation). Particles have some kind of suspended status and no properties (no reality) before measurement! Hindu philosophy agrees with this and moreover ascribes this lack of perception of ultimate reality to Maya (loosely translated as illusion) which covers the ultimate reality “Brahman”. The author does call the lack of knowledge of reality as “grand illusion”, but does not follow that line of thought and falls back on classical physics ideas. We must accept that we evolved on a measly little planet attached to an average star (sun), while the universe is full of billions of galaxies, each with billions of stars and planets and there could be even infinite number of universes. It is not very likely that our ideas of ultimate (classical) reality can be correct. If I am permitted a shameless (!!) personal promotion, I have discussed these ideas in detail in a guest blog http://motls.blogspot.com/2014/04/hinduism-for-physicists.html.

  • How can you determine (measure, conclude) that maximizing work-ability "wins" over really knowing the truth about things out there if no one really knows the truth about things out there? Or even that a better attempt to maximize work ability "wins" over a lesser attempt at maximizing it? The proof would be tautological: those whose work-ability quotient works did well and we know they did because they are here. Tautology.

    We cannot answer "Why" questions. This is because "cause" – while seeming to be a noun – is indeed an adjective, an opinion, a guess, a qualifier. We cannot see a "cause"; we can only measure … well, we can measure what we can measure and stack it up against other measurements.

    God did not put little "tags" or "bar-codes" on things or actions that read "cause" or "good" or "bad." Nor did God sign his or her paintings. Each event, each action arises from mystery. This is not to say we cannot build bridges or launch rocket ships or cure cancer. Those are actions – and with any luck, they might work.

  • Those people who claim to be scientist, but see everything as black and white should be disqualified immediately. A scientist must be one willing to live a life of shades of gray, and willing to give up cherished ideas. Those lives filled with black and white dogma are nothing other than activists and the religious. These activists/religious wolves will wear scientist clothing and blowing up social media leading the ignorant astray with their coveted dogma. The masses can't tell the false scientists from the real ones and so they mostly just go about their business.

    Anyway loved the article and Donald Hoffman's work. As I like to say, "A hundred years from now the truth will be evident."

  • Does artificial intelligence perceive the world differently from humans? If so, is this perception also an illusion, more or less than our own and in what way would it be different?

  • I'm an advanced Buddhist, so these concepts are now commonplace for me. Read Nagarjuna. I was born severely autistic which progressed to Asperger's syndrome. I use these ideas to create my own reality. I am ultra-high functioning, but not conventional or standard.

  • And you think your experience of consciousness isn't just as much an illusion as your other perceptions? Pshaw. Consciousness and qualia are also illusions – you just think you are experiencing them.

  • Really pretty worrisome that Quanta would publish such obvious drivel. Don't any of their editors know some physics??

  • This is absurd. People are killed by things they never observe all the time, and yet we can tell postmortem what killed them. This would not be possible if Hoffman's theory were correct. Hoffman confuses the rules of QM for the rules of EVERYTHING, which they patently are not.

  • Simply put, if in Donald Hoffman's words, " The world presented to us by our perceptions is nothing like reality.", then his explanation of the "world he presents" is nothing like reality. That being the case, the logic used to make his case does not hold water. I prefer the Catenada described Yaqui Indian view of the world where one sees Energy directly vs. the physical world we have become conditioned to see, even if it turns out he made it all up.

  • Split brain patients still have one awareness, one consciousness.
    But yes, consciousness creates reality. To those who want proof, see the Delayed Choice Quantum Eraser experiment for another absolute confirmation.

  • A Paean to Materialism

    @Najas and other idealists,

    Thank you for the pointers to Andrew Clifton and Gregg Rosenberg’s works purporting to show that materialism can never account for consciousness. I did go through what I could find on the web, and I am thoroughly unconvinced: I still maintain that all such arguments show is a lack of imagination, and a disregard of empirical knowledge to boot. The lack of imagination lies in failing to consider that these kinds of armchair “materialism is inconceivable” arguments are based on rigid philosophical categories like materialism and idealism that nature is far too flexible to be imprisoned in, and can easily circumvent. In addition, the disregard of empirical knowledge in these arguments is like theorizing about the structure of the Orion nebula without a telescope, or like insisting that the world is flat in spite of being shown pictures of the round earth – it is obscurantism of the worst kind.

    I think that anyone who doubts the potential of materialism to give rise to consciousness should spend a year in a neurology ward. There you will see that mere milligrams of a material substance can drastically alter consciousness, and a tiny pea-sized lesion or growth in the appropriate region of the brain can transform the very ‘soul’ of a person — turning a morally upright citizen into a compulsive child abuser. And then you realize that the more principled intellectual approach to consciousness is to figure out *how* the material brain gives rise to consciousness, as it demonstrably does, rather than construct philosophical arguments to “show” how impossible it is.

    Here is my possible way that this philosophical cage can be escaped — of course, it’s speculative (is there anything written about consciousness that isn’t?) but it respects all the hard won knowledge of science that we have gleaned.

    Consider the representation of the number “5” in a calculator. It is fully material — it is just the configuration of electrons in the chip. Yet, at the same time, it is fully abstract: it is constrained to faithfully follow to express the properties of the number 5 in the rules of arithmetic. It fully belongs to both the materialist and abstract realms. It rigidly follows the laws of physics and chemistry, yet equally rigidly follows the rules of mathematics’ Platonic realm. I call this “embodied abstraction.” Now, your brain has millions of such representations of concrete objects and abstract entities in it in the form of neural patterns, all rigidly constrained to follow in their interactions, the rules and logic of how these things actually behave in the world. In every conscious moment, whenever any of these representations is activated, thousands of “atoms of meaning” comprising its associations, and its rules of interactions with everything else are also activated in milliseconds, like a swarm of gnats encircling your head on a hot and humid day. These buzzing swarms of “meaning atoms” that are also neural firings —simultaneously material and abstract with their meanings recognized by other neural networks in a hierarchical, bootstrapping cascade—represent hundreds of potential actions you could do, and their calculated consequences, averaged, mashed and smeared together in a single moment. These may be nothing other than our experienced qualia. Yes, we “experience” them as unitary, but that is just a result of “cognitive impenetrability”—the limit of our introspective probing mechanisms.

    For me, consciousness is the sum-total of internal meaning that is abstracted by the brain in a single moment or “meaning gathering cycle” lasting a few hundred milliseconds. This internal meaning is based on at least two things: 1) perceptual and inferred information about the world (represented as embodied abstraction as mentioned above), which is acquired from the ground up by our built-in object recognition skills and learning abilities conferred on us at birth by evolution; and 2) an absolute intrinsic value scale: “Is this good or bad for me?”— also conferred from the ground up by evolution. Such a value scale that creates internal meaning operating in every algorithm at every level of the brain, can only exist in autonomous, living entities created by evolution. Our robotic creations, in contrast, can gather data from the world, but have meaning imposed on them only at the highest level in top-down fashion. They are as different from living creatures as a Hollywood set is from a real building. I am skeptical that any amount of complexity can make them conscious in the way we are — in particular, I doubt they will ever have qualia.

    The idea that the qualia of consciousness have meaningful parts consisting of information and value, is not new: it was well known to introspective Eastern mystics and thinkers as well as to Western philosophers. In Spinoza’s “Ethics” for example, you can find declarations such as “Love is happiness accompanied by the idea of an external cause.” We all know that even the enigmatic color qualia do share meaningful sub-qualia with emotions: red evokes excitement, boldness, danger, fear. Perhaps in more primitive brains, where the meaning cycle takes less time, these qualities can be parsed better and made more explicit (there is some evidence for this in the disquieting effect that the color red has on monkeys, as the psychologist Nicholas Humphrey has demonstrated). Even we can still appreciate these undertones, dulled as they might have been by our exposure to the safe homogenized multicolored building blocks and crayons of our childhood. (In my view, Mary the color deprived subject darling of philosophers, would, under the assumed non-physiological premises, be able to instantly recognize what red is, based on these kinds of undertones. Of course, this experiment is deeply non-realistic physiologically: the color processing neurons in Mary’s visual cortex, deprived of visual input, would probably be recruited for other tasks in the brain, and she might have to learn to see color or not see color at all.)

    I have composed a little ditty to express the above idea about qualia, in a parody of a nursery rhyme called “The Siphonaptera*” (google it!)

    Big qualia have little qualia,
    That make up their internality;
    Little qualia have lesser still,
    …Bootstrapped from intentionality.

    (*My favorite Siphonaptera is this one by Lewis Richardson about fluid dynamics):
    Big whorls have little whorls
    That feed on their velocity;
    And little whorls have lesser whorls
    And so on to viscosity.

    That is my paean to materialism: a picture of the most complex material structure in the world working hard to produce this miraculous internal show that we call consciousness. Every time we experience something, every time we communicate, millions of neurons have to fire in precise ways exchanging what are electrical potentials, but also meaningful messages. That’s what we should expect. Any other explanation that conjures consciousness out of thin air, diminishes it immeasurably.

    I hope I have convinced at least some people that the real, exciting challenge is figuring out how the brain produces consciousness. Our initial ideas will probably be wrong, but they will teach us something, and we will make progress. To follow the introspection or cleverness of philosophers, who speculated about the nature of consciousness centuries ago, no matter how brilliant, and to conjure consciousness out of thin air as some kind of primitive, is irresponsible. After all, these geniuses had only a fraction of the knowledge of the workings of the brain that we have today, they did not know anything about the myriad ways in which the brain fools us, and they had no idea about what Dennett has called “the greatest idea that any human being ever had” —that of evolution. This idea, and the overwhelming evidence we have for it, changes everything, and it is only about 150 years old.

    What would Spinoza or Kant or the Buddha have said had they known about modern cognitive psychology and neurology, about DNA, about the way the brain can be materially manipulated to change consciousness? Buddhism tacitly accepted the idealistic view of the world that pervaded Indian thought 25 centuries ago, but the Buddha, “the silent sage,” who had an analytical mind as sharp as a world-class scientist today, refused to speculate about the metaphysics of consciousness, apart from his deep, practical, empirical introspective findings. Perhaps he judged that there just wasn’t enough information in his day and age to reach the truth about its nature. I am quite convinced that, were the Buddha alive today, he — the “enlightened one” who had the wisdom and the gumption to be an atheist in those times when religion had an even greater hold on people’s mind than it does now—he, and most Western philosophers of yesteryear, would have whole-heartedly espoused materialism today.

    May the flame wars begin ☺

    @Paul Eisenkramer,

    Ver Greeneyes has already given an excellent answer to your question about the evolution of consciousness, especially with respect to self-consciousness. As Ver said, it probably evolved very very slowly, little by little, probably over many many millions of years. The first creatures who experienced it probably had internal experiences only very, very sporadically.

    I like to say that almost all the really interesting things about consciousness—like qualia—occurred millions of years ago. Our higher order thoughts encompassing reason, language, analysis, memory recall etc. don’t really have much of a “feel” to them as contrasted with primitive occupants of consciousness such as emotion and colors and sense impressions. On my model above, that’s because higher order thoughts are almost pure information, purely propositional, with an almost neutral value component. They can be precisely parsed by the brain within a meaning gathering cycle unlike the buzzing gnats of diverse values, meanings and associations that the more primitive qualia have, and which have to be mashed together into a single experience (incidentally, this is also the reason I don’t think robots will have qualia). I would expect that the most primitive quale experienced by a conscious creature might have been the one that expresses the most fundamental value — that of pain. Pain would be the meaning expressed by a thousand neural networks effectively screaming in broken mentalese “Stop this, this is bad, bad, bad.”

    Anyone who has ever seen an animal in pain will know what I mean.

  • Bryan Magee makes the same claim in his book on Schopenhauer. It's simply not credible. I challenge this view in an essay targeting my Buddhist colleagues who are in love with Schopenhauer. 'Buddhism and the Limits of Transcendental Idealism.' http://jayarava.blogspot.co.uk/2016/04/buddhism-limits-of-transcendental.html

    "The world presented to us by our perceptions is nothing like reality."

    Unfortunately this cannot be true. If it were then we could not effectively navigate the world, much less efficiently. There must be a correlation between perception and the world. That our conscious perception is partial and prone to error is not in dispute. The simulation in our heads is not reality, but it must, at the very least be *like* reality. The idea that it is *nothing* like reality is not plausible.

    I'm really not impressed by computer simulations or Game Theory. Both are artificial constructs that tell us nothing about ourselves or reality.

  • A short paper criticizing Roger Penrose's similarly Platonic view of consciousness:


    For more on the history of the "hard problem," see ch. 12 in my biography of Emil du Bois-Reymond:


  • Hannes Bend says, "If it is 'impossible' to validate a model based on (limited) sensory perceptions equates reality, theorizing has its limits." But I think scientific validation is an inherently collective process, with systematic confirmation of experiences, ideally with testing by manipulation. It does not rely upon direct perception by an individual, much less intuition. It does not provide a logical a priori proof of the necessity of any scientific proposition. But in science that does not constitute knowledge. In science, knowledge is what has been shown to be how the world is. It is true that unlike a philosophical system that deduces the world from intuitions, the collective process of scientific validation means that what is known is corrigible, unlike mathematical demonstrations. Perhaps it is objected that true knowledge must be infallible but this seems to me to be more of a religious aim, removed from genuine scientific curiosity about the way things are. What seems important to me is that the correction is not a matter of fashion but of systematic investigation of, yes, reality as confirmed by the scientific community (which of course overlaps with the rest of humanity.)

  • I tend to believe that Penrose & Hameroff are correct, and I'm inclined toward skepticism about Hoffmann. They are engaged in wholly different projects.

    Penrose & Hameroff and their associates are examining how neurons work, which at root is a matter of testable hypotheses and measurements. Hoffmann is questioning the entire philosophical framework in which we assume that measurement is meaningful.

    It's reasonable and wholly conventional to assert that perception is imperfect, selective, and subject to error. But it appears that Hoffmann makes an error of binary thinking by equating "imperfect" to "fatally flawed and therefore irrelevant."

    If we were to design a whole series of Darwinian fitness tests, we would discover that most of them entail a requirement for accuracy of perception of the world and movement in the world. The fact that humans can't see ultraviolet does not prevent us recognizing lions and tigers and bears (oh my!). Our limited and imperfect perception is "good enough," and our means of measurement are very substantial improvements that enable us to observe reliably from the subatomic scale to the cosmic scale.

    Perhaps it's my limited grasp of things, but I can't disregard the successes of empirical methods, and it's a leap too far to claim that they are meaningless coincidences.

    I'll have to re-read this and give it more thought.

  • Hoffman and others like him seem willing to ignore all experimentally established biologically-based facts. I wonder what compels them to put their theories first. The reality of experimental evidence linked from top-down causation to cell type differentiation in all living genera via the physiology of energy-dependent reproduction must come first in the real world.

    See also: A quantum theory for the irreplaceable role of docosahexaenoic acid in neural cell signalling throughout evolution http://www.ncbi.nlm.nih.gov/pubmed/23206328

  • That was so interesting to read. Passed on by a friend; I feel like my mind has had a refreshing shower. Thankyou for that!

  • "On the other side are quantum physicists, marveling at the strange fact that quantum systems don’t seem to be definite objects localized in space until we come along to observe them — whether we are conscious humans or inanimate measuring devices. Experiment after experiment has shown — defying common sense — that if we assume that the particles that make up ordinary objects have an objective, observer-independent existence, we get the wrong answers. The central lesson of quantum physics is clear: There are no public objects sitting out there in some preexisting space."

    It is completely false to claim this as a known fact. This is wrong. There are a number of interpretations (all equally evidentially valid) of qm that state otherwise. See here:


  • "I am postulating conscious experiences as ontological primitives, the most basic ingredients of the world"

    This sounds very similar to Liebniz's theory of reality, in which the fundamental unit of reality was a quantum of consciousness. See https://en.wikipedia.org/wiki/Monadology for an introduction.

  • Did a more extended post on my blog.


  • @ Flavien Lambert:
    Since you are familiar with Schrodinger's writings, I would remind you that Schrodinger quotes Vedas in explaining why our consciousness looks similar in spite of the fact that all of us look different. There the explanation is that the source of consciousness is external and we are merely reflecting it like multiple mirrors would reflect a single object. Presumably bats and spiders have different kind of mirrors! Anyway, it seems that science, at present, does not have good explanation for this puzzle.

  • So are you suggesting that inanimate objects are like lesser conscious experiences where they don't have the connective structure to share information and control a body for instance, but two rocks sitting on a beach still somehow experience the sunlight hitting their surfaces, and not just that, but really each fundamental particle is 'experiencing' the other particles around it, and that is the fundamental thing making up the universe? And would this just be entanglement? or something else being postulated? If you can compose consciousnesses together, you have to be able to describe how two of the smallest pieces interact, and then three and more…

  • For Pradeep:I think you would find the experience and writing of B.Alan Wallace very helpful

  • @David: I am a retired physics professor and understand delayed choice quantum erasure expt. But concluding from it that consciousness creates reality may be problematic. In particular, quantum mechanical reactions went on in the universe long before any conscious life appeared. How would you answer that? One way out may be the religious conclusion that there was universal consciousness all the time. This is ok with me. I am theist. But pursuing that line of argument gets into logical difficulty.

  • Hoffman has come a full circle, ending up where the Copernican Revolution started. Noumenal reality / phenomenal reality.
    For Kant the noumenal realm remains unknowable except insofar as we determine who we are. That grounds us in a moral world far removed from the physical, objective and ahistorical scientific understanding of ourselves. For those who cringe at morality, feel love, caring, altruism, compassion and the like. Don;t limit the world to cognition and knowledge. Kant spoke of divine like bliss in the First Critique.

    We are children of the Enlightenment. It gave us the world we have today. It is also destroying our future. This is what happens when the picture remains incomplete. I hope it does not take another 200 years for us to complete the picture.


  • For physics, Kants Metaphysics Of Natural Science explains lots about science and its limitations. Its circular reasoning and inductive reasoning. Its circular because we have to assume atoms exist before we start. Its inductive because its only observation.

    The Two Capacitor paradox is a proof that the world does not exist as we see it. Many have claimed to dissect it, or disprove it, none have.

    This is all Kantian thinking, but he gives no credit to Kant. Kant is the most significant philosopher that ever lived and the Western world is a Kantian one, that is, it was, until silly and stupid progressivism took over.

    Kant says that we can only process the world through a set of ontological predicates: Quality, Quantity, Relation & Modality. Not only do our senses limit us but our thought does as as well (Critique Of Pure Reason) – when did time begin? How big is the universe? We frame ideas and thoughts within the concept of purpose (Critique Of Teleological Judgement). The only freedom is the excercise of virtue – Categorical imperative, The end doesn't justify the means – these are all core ideas from the Critique Of Practical Reason. He even gives us an adult version of Christianity in Religion Within The Boundaries Of Mere Reason.

  • So, reality is a crutch, allowing us two-legged to persist when our bodily nature's broken. Plus we all get to be deceivers, a distinct advantage, in the race to the finish line.
    Oh the tally man, when the bill comes due, for the old advantage in a Klein bottle.
    Feedback appears to be the point to painting such a wide brush stroke.

    We weren't here any more to pass it forward than to pass it back in time.
    We were built to spread the wealth, to smear the colors, then be slain.
    We are built of time and space materials, energies, change, life and death.
    We are endings of beginnings, never the same, never lost or stolen.

    We only loose ourselves, in our own estimations, love of life.
    The others are all alive in perpetuity, perpetual motion, stillness.
    We lie down, go to sleep, dream, soak back into God. Get up again.
    Endless invention seems a rule, no thing stays a same.

  • I appreciate everyone’s comments, and I’m hoping to clear up a few misunderstandings. First, I respect the skepticism people have shown here. Nine times out of ten, when you see “consciousness” and “quantum” in the same article, you are reading crackpot, pseudoscience nonsense, so it’s important to be cautious. I am too. But having spoken with Hoffman at great length (this Q&A, of course, being a piece of a much larger conversation), I can assure you that he is a serious, thoughtful, rigorous scientist. He could always be wrong, of course, but he’s making subtle, important points that unfortunately have been lost in the discussion.

    Hoffman is not claiming anything like “quantum wavefunctions are collapsed by consciousness” or “consciousness can be explained by some kind of quantum voodoo.” The two were not being invoked to explain one another, or to conflate quantum weirdness with cognitive mysteries. Indeed, Hoffman emphasizes that his model of consciousness is computationally universal – which is to say, there’s no magic to it. It could be implemented by man or machine; there’s nothing about the brain that fundamentally sets it apart from any other physical system. Hoffman also distinguishes his view from something like the Penrose-Hameroff model, where you have quantum coherence within neurons. As one commenter said, the brain is warm and wet. It seems impossible to keep decoherence at bay. Even if it weren’t, it’s unclear (to me, anyway) how quantum superpositions could possibly help to explain consciousness. It doesn’t matter – none of this is what Hoffman is saying. As he put it, the brain is not “doing some quantum magic.” At the scale of neurons in an environment like the brain, quantum effects are virtually irrelevant. I think we can all agree.

    On the quantum side, Hoffman is not endorsing a Copenhagen-esque view. He does not think that consciousness magically reaches out of the skull and into the world to collapse quantum wavefunctions. (As it happens, he’s partial to the QBist interpretation.) That is to say: quantum mechanics does not require conscious observers. (Ok, maybe if you consider the wavefunction to be epistemic from the start, it does by definition. But that’s a subtle point, and it doesn’t suffer the inexplicable dualism of Copenhagen.) As for me, when I spoke of “observer-dependence” I did not mean that an observer is something with consciousness. It could be a reference frame, a Geiger counter, dust, whatever. “Observer” is shorthand for a perspective or point of view. (In relativity, an “observer” might be a spacetime coordinate system. In quantum mechanics, it’s something like an algebra of quantum operators or a Boolean lattice. What matters is that it’s some limited, bounded perspective. Whether that perspective is “conscious”…well I doubt that’s even a well-posed question. Either way, it’s irrelevant.)

    Ok, so why are consciousness and quantum mechanics appearing in a single conversation? To emphasize that they are two sides of a coin when it comes to the fundamental nature of reality. (If you believe science shouldn’t deal with the nature of reality, you might want to stop reading here. For me, this is exactly where we need science the most, lest we get lost in bad metaphysics.) Look at the “hard problem”. It’s usually phrased something like this: “How, in a world made of ordinary matter, can anything like consciousness or first-person experience ever arise?” Matter is posed as the known element, consciousness as the mystery. The “ordinary matter” assumed is a kind of folk ontology derived from classical physics, and not the actual ontology given (or allowed) by fundamental physics. “How, in an objective universe, can something like subjectivity exist?” The question de facto assumes that there is an objective universe. But that’s not a claim that can be made by neuroscience or philosophy of mind. That’s physics.

    So what does physics actually say about it? Well, it says something super subtle that one would be an idiot to try to unpack in the comments section…so here I go. People talk about quantum mechanics being mysterious. But really, it only becomes mysterious when you try to apply it to more than one observer simultaneously. (Observer = reference frame; see above.) This is something every interpretation of quantum mechanics has to contend with. In fact, it’s why there are different interpretations to begin with. If you try to assume that particles have definite values or locations in spacetime and then run an experiment (like EPR) you will get the wrong answers. Those values and locations only exist relative to a given measurement. What’s the electron doing when it’s not interacting with anything? It’s a meaningless question because there can be no interaction-independent answer. The common sense notion that there are objects with features everyone would agree on that are sitting in some objective space shared by multiple observers is simply not upheld by quantum mechanics. (Yes, yes, of course decoherence can save appearances, it can hide this fact, it does it really well, hence our common sense notions! But the whole point is that we’re not interested in mere appearances, we’re trying to get to the nature of things.) So what is the world, according to quantum mechanics? It’s a bunch of “first-person” points of view, full stop.

    One might protest: I can make a measurement and then you can make a measurement and we can compare notes, find that we agree and in doing so glimpse an observer-independent reality. But quantum mechanics doesn’t allow you to do that. There’s no non-quantum, God’s eye point of view from which one can compare. You can only compare points of view from within a point of view. In other words, the comparison itself is a quantum measurement. It’s quantum all the way up. (Does this veer toward solipsism? Kinda. But with science, you get what you get. And it’s not a make-up-your-own-reality situation, there are physical laws that impose strict consistency conditions within a point of view. And there may be ways to link them into something less solipsistic – but no one’s quite done it yet. Things like the black hole firewall paradox frustrate the efforts. That’s for another day, another comment.)

    Back to Hoffman. He’s saying, look, cognitive scientists are scrambling to figure out how our first-person perspectives relate to the actual objects that are sitting out there in the external space that we all share and meanwhile, physicists are saying that the premise is flawed from the start. (The physicist Tom Banks put it this way: “Space arises from the quantum mechanical relations between different observers.” That is, space (a the third-person objective point of view) is derived from the relations among first-person perspectives—not the other way around. Or take Carlo Rovelli: “A universal observer-independent description of the state of affairs of the world does not exist.”) So when Hoffman’s evolutionary game theory simulations turned up a model of perception that ran counter to our common sense metaphysics, he realized, hey, quantum mechanics already ruled that out that metaphysics anyway. Does any of this matter at the scale of your everyday life? Does it discount everything we’ve learned about neurons and brains and objects and perception? No. Don’t pick up snakes, don’t step in front of trains. But should we discount a model of cognition that runs counter to folk physics, reject some deep truth because it defies experience at the scales of our everyday life? No. Carlo Rovelli wrote, “My effort is not to modify quantum mechanics to make it consistent with my view of the world, but to modify my view of the world to make it consistent with quantum mechanics.” That is what Hoffman is trying to do here.

  • Of course we place our specific, flawed-by-specific-function template on reality to further only what is most fit for our human niche, and that template includes wild and useful stories about gods and quarks and independent reality. You can't beat the system, in the same way Susan Sontag said: "A self-hater still loves themselves as a self-hater."

  • @dukewalker,

    Thank you for mentioning the great Buddhist teacher B. Alan Wallace. I don't know in what sense you meant it would be "helpful" but let me clarify my views lest there is any misunderstanding. First of all, let me say that I love B. Alan Wallace (his meditative teachings, not his philosophical position). I also personally think that the Buddha was one of the greatest human beings who ever lived, if even a fraction of the legends about him are true: individuals such as this who combined astonishing introspective genius, Franciscan compassion, a world-class analytical mind, seemingly limitless wisdom and regal bearing and grace, are rare in history. I try to follow Buddhist tenets in my life to the best of my ability (as I try to follow the best teachings of all religions though I am an atheist).

    When I was talking about materialism I was, of course, not talking about the materialist attitude to life in the sense of gathering material wealth (I am a bit of an ascetic in this regard, actually), but in the sense of materialism or physicalism as a philosophical position concerning the nature of reality and the brain. Also, the variety of materialism that I was espousing, as my model clearly shows, is not "reductive materialism" — the straw man of many non-scientists — but "emergence" — where materialism is the base, and abstract qualities and consciousness emerge from the structure of the brain. My model reflects what we all know from experience: that the brain can be modified both by material and abstract means. That's the amazing beauty of the brain: it can be changed by love and compassion and beliefs and attitudes as much it can by physical and chemical treatments. That follows from my explanation of "Embodied Abstraction": the concrete and the abstract are two sides of the same coin in a brain representation — change the one, and you change the other.

    That being said, my point is that the physical structure of the brain is the necessary base for consciousness. Remove that, and you remove consciousness. There is no place where consciousness goes when the brain dies: it ends too. So a person can be a saint or a Bodhisattva, can have achieved Nirvana and have had the subjective experience of Eternity, but this too, only persists as long as the brain is intact. In a final Buddhist irony, what we have discovered after 2500 years, is that Nirvana is impermanent too.

    None of this takes away from the fact that the greatest moral value and ideal in life is to strive to be good, to be a saint or Bodhisattva. May we all strive to be that way, not only for our own sakes, but for the sake of the world.

  • > “How, in a world made of ordinary matter, can anything like consciousness or first-person experience ever arise?”

    I think this question is meaningless without defining what we mean by 'consciousness' and by extension 'first-person experience'. And if we had a clear definition of these emergent phenomena, perhaps the 'how' would already be answered, since we would be able to understand how they emerge. The whole question seems like putting the cart in front of the horse to me.

    > What’s the electron doing when it’s not interacting with anything? It’s a meaningless question because there can be no interaction-independent answer.

    But if the electron's last interaction was used by us to determine its state, can't we still predict what it's likely to be doing in the future? I agree that the question of what an electron that has never interacted with anything is doing is meaningless, but surely that doesn't apply to our high temperature, high density day to day lives.

    > If you try to assume that particles have definite values or locations in spacetime and then run an experiment (like EPR) you will get the wrong answers. Those values and locations only exist relative to a given measurement.

    I would say (perhaps wrongly) that the underlying state is there as part of the wave function, but interactions force it to take on one of a number of possible eigenstates depending on the perspective of the observer, with the probability of each eigenstate being determined by the wave function prior to interaction (which may be unknown).

    > One might protest: I can make a measurement and then you can make a measurement and we can compare notes, find that we agree and in doing so glimpse an observer-independent reality. But quantum mechanics doesn’t allow you to do that. There’s no non-quantum, God’s eye point of view from which one can compare. You can only compare points of view from within a point of view. In other words, the comparison itself is a quantum measurement. It’s quantum all the way up.

    This seems like a perspective from Greek philosophy to me, where the use of tools like lenses was considered useless since anything seen through a lens is indirect, and changed from the reality observed with our senses.

    The reason science didn't really take off until the renaissance is that ancient philosophers were too obsessed with deductive reasoning as the only tool capable of obtaining truth. Which lead to such leaps of logic as Aristotle assuming the world was a sphere simply because spheres are 'the perfect shape' (he was more or less correct, of course, but for all the wrong reasons).

    I'm sorry, but I still don't really understand how saying our perspectives of reality can never be objective, or objective reality doesn't exist, helps us to understand anything. Maybe if you shared some more information on how Hoffman's models can help us understand the world, I would find them more interesting, but right now they just seem like unmotivated distractions to me.

  • Class assignment: Hoffman's theory tends to prove (or disprove) Plato's notion of the ideal forms. Write an essay arguing one or the other.

  • I'm very much a layperson on this subject, but with the account of "observer" as refined by the author in her comment – isn't this simply saying that quantum behaviour is undetermined without a context, and how is this distinct from any other deterministic system? That aside, I always had a basic understanding/assumption that the physics as described in the standard theory were essentially the deterministic, "traditionally physical" artefacts of underlying (non-deterministic/probabilistic/whatever-the-case-may-be) quantum behaviour. Like I said, I don't really know what I'm talking about, but if anybody can suggest any reading/links that would sufficiently address any base misconceptions I have here I'd appreciate it.

  • Evolution would just be more icons on the desktop and just your perception. Why would evolution be "real"?

  • A gem of an article, though the philosophical side needs working on.
    For example: "The idea that what we’re doing is measuring publicly accessible objects, the idea that objectivity results from the fact that you and I can measure the same object in the exact same situation and get the same results — it’s very clear from quantum mechanics that that idea has to go"
    Inaccurate here, because (as Husserl points out) the body of 'objective' scientific knowledge is the result of intersubjective consensus based on collaboration and competition by scientists. Scientific enquiry is not disrupted, only the claim that it is based on a reading of a world that ever exists independently of the enquiring awareness or the experiencing scientists. The phenomenal world is very bit as real as before; however we must accept that the perception of it is always embedded and immanent in it, and no 'transcendent objectivity' is possible. If Hoffmann claims that reality itself is in question, then I agree that this may be true for the quantum world, but not for the Newtonian world of phenomena, of time, space and causality.
    Schopenhauer was right to make a distinction between the unknowable and uncommensurable Noumenon and the knowable Phenomenon (cf 'The World as Will & Representation, Bk 2, chap 18: 'The Possibility of Knowing the Thing in Itself'.).

  • I had a gullible teenager for a neighbor many years ago. She repeated these remarks in a dreamy way. Reality is an illusion. I invited her to experience her illusion by jumping off the second floor porch.
    She declined. Concluded, rather reluctantly, that her illusion would then have to call the EMT's and her mom didn't have insurance for that.

  • So we observed things, and did some math to explain our observations (and some vice versa), to develop theories of evolution and quantum physics. Now those theories tell us that our trust in observation and math to describe reality is misplaced? In which case, why trust the theories that our powers of observation and math led us to believe in? Seems a bit like sawing off the branch you're sitting on to me, but then I would dispute the untested/untestable hypothesis that evolution only selects for survival. If that's all there is to it, why all this increasing complexity?

  • How's this different from Holt's (now century-old) 'new' realism, other than the terminology used? The point of Holt's thesis was not to distinguish between material and mental on the basis of 'matter', which was difficult to specify even in the 19th century, but the simple recognition of any object (whether 'representation' or not) as 'being' regardless of whether it was public observable. Percepts that were useful remained, others not so much.
    At its most basic and useful level, the scientist/philosopher acknowledges a percept's being (recognition) in the concepts it denotes and accepts that they cannot be explained further down. Ascribing 'consciousness' to everything invokes it as an explanatory cause for nothing, making the author's claims moot.

    If I see a snake and you see a snake and the person standing there screams "Snake!", we will run away accordingly. Similarly, if levels of water were depicted by shades of color (the red-green argument specified above) and were observed by the members of our tribe as such (this is key), that would be the norm for them (instead of the way we perceive it now). Of course, logical coherence doesn't necessitate ontological validity (or else talking about unicorns would make them real!) but so what? Any scientist worth his/her mettle can see that.

  • the buddhists already know all of this and explain it in a way that cuts through the tit for tat , the arguments, the viewpoints, the exemplary comments of one's understanding of it all . The interviewee is right. None of this exists.

  • I read the article on the day that it was published and before any comments had been submitted.

    While reading the article I couldn't decide whether it was a very clever parody of 20th and 21st Century scientific findings that had been carefully contrived as some sort of psychological experiment, or if the authors were so hopelessly lost in their understanding of 21st Century science that they more than adequately qualify as being "not even wrong", which is, of course, a bright red warning flag for the promotion of pseudoscience, quackery, and/or outright antiscience.

    "Non-materialist neuroscience is one of the latest fronts in the war on science."

    I sincerely thank all of the very knowledgeable commentators who have taken the time to point out the multitude of errors in the article and its source.

    The only two things that I'd like to add…
    1. If nobody understood/grasped objective reality then the following things wouldn't exist: computers; the Internet; the recent images of Pluto and Charon; aircraft; antibiotics; fMRI scanners; light bulbs, LEDs, and LCDs; microwave ovens; mobile phones; photography; radar; television; thermometers; thermostats; vaccines; X-Ray scanners; domestic services such as electricity, gas, water, and sewerage. And the crucially important International System of Units that quantify objective reality for everyone who's interested in objective reality — even those who just rely on a pencil and a ruler or a tape measure.

    2. If one starts from the core premise that the term "reality" means "that which is experienced by each individual" then the term "objective reality" is thereby rendered nonsensical. All arguments based on this fundamental category error [aka: category mistake; fundamental domain error] are simply wishful thinking that is fuelled by the plethora of well established logical fallacies and cognitive biases. Gaining evidence in order to support a hypothesis/belief is the very definition of the pseudoscientific method, which is the antithesis of the scientific method.

  • @Pete Attkins:
    With reference to your comment, I would say the following.
    In our daily life there is of course some objective reality. If you see a tiger chasing you , it will be foolish not to run! But last 100 years of quantum physics has cast doubt on the existence of absolute objective reality. In fact most of the inventions you mention as proving objective reality use quantum physics devices (transistors, chips etc.) and principles underlying them. Also as experimental technology becomes more advanced, people are finding quantum effects in larger and larger systems. Lasers and superconductors are some common life examples. So the situation is not as clear cut as you are suggesting!

  • "Snakes and trains, like the particles of physics, have no objective, observer-independent features." — umm….

    I guess he has a definition of an observer that he can use to explain it away, but a snake you've not aware of can still bite you, and a train you don't see coming can still kill you.

  • @ Pete Attkins:
    Back in 2008 I wrote a piece for New Scientist slamming the "non-materialist neuroscientists" for their pseudoscience. You can find the piece here: https://www.newscientist.com/article/mg20026793-000-creationists-declare-war-over-the-brain/ (There's a paywall, sorry.)
    I also wrote this piece (https://www.newscientist.com/article/mg20126975-800-how-to-spot-a-hidden-religious-agenda/), warning readers of red flags that scream "crackpot!" and particularly mentioned the misuse of quantum physics, which I also wrote about here (https://www.newscientist.com/article/mg20227041-600-quantum-gods-dont-deserve-your-faith/).
    I point these out to emphasize that I appreciate your skepticism. However, having spent many years calling out pseudoscientific nonsense, particularly with regard to "quantum abuse" and "non-materialist neuroscience," I can also assure you that Hoffman's work does not fall into that camp.

  • This appears, to me at least, to be a scientifically reasoned and worded rehash of Friedrich Nietzsche's Perspectivism.

  • This confusion about what's real and what's observed is easily resolved.
    Scientists should know that quanta have properties like #standingwaves.

  • I disagree, deeply, not with the idea but it's conclusion: saying we are evolutionary subjective machines is saying every living species sees object, threat or resources differently (which is only true to some extent). However if any animal sees a snake, it will know that it's "red", if it sees water it will have more or less the same response as a human, if a monkey sees shapes forming numbers on a screen it can asses the shape in even order by which it should register them, heck even horses can count. Does it means we are more sophisticated animal in that we assert or develop more precisely our subjective apprehension of reality? Dangerous regressive idea.

    There are two unexplored concepts (that's in fact literally the word here) that seem to be left aside by scientists, in a general dangerous unreasoned ideology I call scientiscism: the denying of the human nature and that of the universe, even when quantum physics shows us that reality itself is relative. First, the blue rectangle on your desktop is not nothing: it is a real visual projection of a more complex mathematical description. Well the universe is a real, not only visual, but also physical, texture, dense etc…projection of a more mathematical description. And second, I use the word description with emphasis, mathematical description is not definition neither function. What Hoffman describes and aim to achieve, a mathematical model of the mind, is far from addressing the underlaying target that is at stake here: concept. Water is water not to just one human brain, nor just animal, and it is not nearly a mathematical entity in fact that's where the mathematical "language" has been limited into asserting what quantum information really is. It's the other "conceptual" language that is contained somewhere in the universe , underlaying even quantum physics, that we fail to approach and assert.

    This is also very false that quantum science ever stated that physical or objective reality doesn't exist or that there are not physical objects. The notion of physical is just not an end result in itself, but a projection of attribute, like visual, viscous, size are other projections.

  • To Conner Bryson

    I was glad to see that someone else noticed the similarities with Nietzsche's perspectivism.

  • I agree with Kent. The "perception" of a non-objective, observer-independent snake can kill you. When you read this, the notion of a quantum space, in which we all live and is perceived differently depending on the life forms participating in it, seems to be a hell of lot more consistent then this theory. Bees see ultraviolet, we don't, yet bees and humans perceive the same quantum space through differing perceptive devices (compound eye vs. non-compound eye). The same applies to the Mantis Shrimp's amazing eye set versis us vis a vis color perception. The entire presentation of reality will NEVER be perceived in its entirety by any life form in it yet the connected reality in which we all live, at the macro level, is consistent because otherwise, we would not be here, right?

  • Amanda, maybe this does not fall into the realm of pseudoscience, but I tend to agree with Sean Carrol's simple twitter response to this article:

    "I’m certainly not an expert, but this seems misguided to me. Relies on a specious definition of “illusion.""

  • @ Amanda Gefter:
    Thank you for your reply and the links to your excellent articles (I didn't read behind the paywall of the first one, but the intro with its links was great). Le Fanu's reply to "How to spot a hidden religious agenda" made me laugh: he seemed to be blissfully unaware that referring to "science’s radical reductionist programme" is a blatant demonstration of science denialism, and a failure to understand the core principles of the scientific method (which are epistemically sound for all forms of reasoning, whether they are scientific or non-scientific).

    Returning to your article here on Quanta Magazine, I hope that you will take the following as feedback rather than as personal criticism…

    The paper to which you linked, by Hoffman et al. "Natural selection and veridical perceptions", seems entirely reasonable to me, however, Hoffman in his replies to your questions claimed far beyond the cautious tentative conclusions in the Discussion section of that 2010 paper. Until his replies to you can be supported by evidence then it is prudent to invoke Hitchens's epistemological razor: "What can be asserted without evidence can be dismissed without evidence."

    You wrote: "… This is the aptly named 'hard problem'". The "hard problem of consciousness", proposed by the philosopher David Chalmers, has been properly addressed by Daniel C. Dennett and several other astute scientists within the fields of cognitive science and cognitive neuroscience. This problem seems to currently exist only in the minds of those who don't adequately understand modern science, and in the minds of those who don't want to accept the findings of recent science. The mind is what the brain does: it really is this simple; and it is in total accordance with the findings that humans rarely directly perceive objective reality, and that our conscious sense of "self" is a truly remarkable, awesome, illusion that is the direct result of evolution — our inaccurate heuristics have proven to be more beneficial to the survival of our species than having more accurate interpretations of objective reality. Human brains are orders of magnitude short of the processing power required to make vital, quick, decisions using logic combined with the accurate assimilation of objective reality.

    Mentioning quantum anything in an article on consciousness qualifies as an argumentum ad ignorantiam: an appeal to ignorance followed by special pleading to quantum mysticism / quantum woo / quantum flapdoodle. Computer hardware does indeed work at the quantum level, *but*, their hardware devices and their software would be totally useless if these machines exhibited, at their macro-scale, their fundamental micro-scale quantum uncertainties/probabilities. Invoking quantum mechanics in the context of macro-scale phenomena is also committing the logical fallacy of composition and/or the fallacy of division.

    You quoted the physicist John Wheeler as stating: "Useful as it is under ordinary circumstances to say that the world exists 'out there' independent of us, that view can no longer be upheld." I have no idea whom this physicist is, nor in which context he made the statement, but I do know that such statements are regarded as abhorrent pop-science / New Age nonsense by the mainstream physicists.

    You wrote: "In short, all roads lead back to the observer." No. That assertion is extremely easy to disprove as being fundamentally wrong using many branches of evidence-based science, but the easiest branch to understand this error is perhaps thermodynamics. Your steaming mug of coffee cools whether or not any observer is present; it doesn't suddenly reduce its temperature when you either drink it or put a thermometer in it. The cosmic microwave background is a wonderful example of how the universe has been working perfectly according to the laws of physics, for billions of years, in the absence of any 'observers'. Each and every one of us consists of atoms that were created in a multitude of stars that exploded eons ago — we are literally made of stardust. The simple fact that this stardust eventually resulted in humans on planet Earth, who have finally acquired the joint intellectual capacity and cooperation required to discover this simple fact, is very difficult for the vast majority of people to accept, let alone properly understand.

    You replied to me: "I can also assure you that Hoffman's work does not fall into that camp." I wasn't present during your interview with Hoffman therefore I cannot possibly know his motives for blatantly bastardising both 20th and 21st Century science and the conclusions of the excellent 2010 paper of which he was a co-author. I sincerely hope that you, Hoffman, and most of all Quanta Magazine, will soon decide to ascend from their descent into these (initially lucrative) rabbit holes of pop-science and pop-neuroscience.

  • @Pete Attkins
    Re: your first point – don't laugh too loud. He's litigious.

    Re the rest: I think we can respectfully agree to disagree. There are many scientists and philosophers who fully understand the state of modern science and are not satisfied that the hard problem has been solved. That certainly does not imply that science itself cannot solve it, but merely stating that the mind is what the brain does (or denying the existence of subjective experience a la Dennett etc etc) does not (for me) meet the criteria of a genuine scientific explanation. However, there are plenty of far more qualified neuroscientists and philosophers of mind hashing this out, so we certainly don't need to do so here. The point that I was attempting to raise was this: one half of the hard problem – objectivity – is a claim not about the brain but about the physical world, and as such requires a deep understanding of fundamental physics so as to avoid imposing flawed premises on the whole issue from the start. I believe this is an important point, and it is the reason that quantum mechanics was discussed in this piece. To proclaim by fiat that consciousness and quantum mechanics cannot be uttered in the same vicinity as one another regardless of context is surely a greater affront to the spirit of science than the silly misuse of quantum language by new age quacks.

    One last thing – I'm amazed you've never heard of John Wheeler. (Worked out nuclear fission with Bohr, mentor to Richard Feynman, coined terms like black hole and wormhole, father of quantum information theory…?) I highly recommend reading his work, but I'll caution you that, like Hoffman, one has to be willing to appreciate the nuance of it. Wheeler's ideas are often embraced by quacks, despite the fact that he spoke out passionately against such misuse.

    Cutting edge ideas often sound crazy. Dismissing them outright is easy. Recognizing their importance is hard, even more so in our culture of social media. It takes intellectual perseverance and humility to resist superficial indictments and recognize a deeper value in something that doesn't immediately conform to one's common sense views of the world. That's ok. Eventually the nonsense gets weeded out and good ideas break through and science carries on.

  • Reply to Micha Berger … that is exactly what this is, a re-framing of Kant's critic of reason with a bit of Zen mixed in. There is a saying among chess players that …
    "When it comes to chess there is nothing new under the sun". Pop group The Bare Naked Ladies had a song by a similar name. Basically we're all living in a Platonic Cave here on earth where we humans are fragmented by many Babylonian tongues vying for attention. The author's analogy of the 'experience of the headache' metaphor is taken from Fred Hoyle's sci fi book 'The Dark Cloud'. Not to say that it isn't a good metaphor just to point out that you are exactly correct that this is very much neo-Kantism. Wouldn't we all love to see the author demonstrate his theory by stepping in from of a 'real' charging locomotive and show us he could break all of the chains of mental memes which enslave us to this world? (that is baring any stage magic; just a true demonstration of quantum physics in action). I've been listening to such rhetoric for over 50 years and would love to see it break out of the realm of egoism and grandstanding into the realm of the 'real'. Can we expect that it'll ever happen on this planet or is this just a proving ground for our souls?

  • I understand this article thusly:
    All that is real is Qualia. No such thing as the Ding an Sich.
    I don't agree with this, because if I don't act on the assumption that cars are heavy steel things when I am driving, I might die.
    However, nobody has yet explained Qualia. And Qualia are real, because they are the subjective experiences experienced by the 42,000 people from 30 milllion who experience consciousness under anaesthesia.

  • @ Amanda Gefter:
    I'm very surprised that John Archibald Wheeler made that statement, I'd wrongly assumed that you must've been quoting a different physicist named John Wheeler. I'm guessing that the context in which he made that statement was in his speculation that reality is created by conscious observers — the strong anthropic principle (he termed his version of it the Participatory Anthropic Principle). As I indicated previously, if we use this definition for the word "reality" then it renders the term "objective reality" nonsensical, and every discussion concerning the topic utterly futile.

    Is there some reason why (in order to avoid the decades of endless confusion) scientists can't, or won't, simply use the self-evident terms "subjective reality" and "objective reality"? My dictionary makes it clear that the word "reality" means the latter, not the former, definition.

  • Mathematical models cannot tell us the whys of anything, such as in why we purposefully leave some things out of our predictive thinking systems. We don't have to know whether a tree is alive or dead to cut it down and use the wood. We do need to know a lot about it's life to grow a new one.
    We don't have to know why the predator wants to eat us to know that we don't want to be eaten by it. But to successfully escape predators in the long term, more interest in the whats and whys of the matter would or should be a requisite.

  • @Amanda Gefter,
    Thank you for engaging with us, and for making some concessions to the arguments made here. You say it is your impression that Hoffman is a serious, thoughtful, rigorous scientist. I can go so far as to admit that Hoffman’s desktop computer analogy is a good way to explain subjective features of perception such as color, though it does not work for objective features such as object position. The forced false opposition that he has created between fitness and reality without thoughtfully making this distinction, throw serious doubts on his rigor.

    On the whole, for a myriad number of reasons already pointed out by many commenters here, and by his own statements in your interview with him, there is scant evidence Hofmann has the qualities you have ascribed. Hoffman may be a (serious, thoughtful, rigorous?) idealist *philosopher*, or at best an entirely new breed, an “idealist scientist” selectively using the some of the methods and results of mainstream science outside their scope, while blithely jettisoning whole swathes of rigorous, hard-won science and the scientific stance of epistemological parsimony. Hoffman purveys an “idealist science” that does not exist and would need to fully duplicate hundreds of years of scientific work under its own assumptions to qualify as a science. Such a science would need to independently address in a principled way what the nature of consensual reality is, why it can affect or end individual conscious beings, and answer a million other problems caused by the assumption that only conscious entities exist. Good luck with that.

    I was quite convinced about all this just by reading this article. My impression was amply confirmed when I heard a talk this week given by Deepak Chopra, one of the world’s greatest purveyors of pseudo-scientific woo to justify ancient idealistic doctrines. Chopra spoke warmly of his friend, Don Hoffman, while glowingly praising Hoffman’s work in a talk where he asserted that the entire universe is a “qualia machine.” By your friends are you known.

    Pete Atkins, Ver Greeneyes and others have already provided very good critiques of Hoffman here. Omar Claflin’s linked article also makes excellent points.

    I just want to highlight some of your quotes and Hoffman’s here to show that Hoffman’s scientific credibility is not salvageable.

    In your first comment you admitted two things: First, that “quantum mechanics doesn’t require conscious observers”; and second, that at the scale of neurons, quantum effects are irrelevant. So far, so good. Then you made the argument about what happens between observations in an isolated electron. This argument does not apply to any everyday object that we can perceive with our unaided senses, since such objects are continuously being “observed” by the environment and their own huge number of entangled particles that keep each other “honest”. All such objects therefore do exist all the time. Finally, after admitting all this, you slip back to talking about space being caused by relations between “first person perspectives.” This is unjustified — there are no “persons” or “perspectives” here. It is merely interactions between inanimate objects. Perhaps this was unintentional on your part, but if want to show that only consciousness exists, you cannot sneak idealism into your premises through the back door. You have to squarely face up to gigantically promiscuous assumption that you pulled out of thin air without evidence, and justify it in a principled way.

    If Hoffman made the statements below out of ignorance or error then he is not serious, thoughtful and rigorous. If he has made them knowingly, then he is dishonestly trying to sneak in his idealist beliefs into science as premises in his argument. Either way, there is no defense.

    Look at Hoffman’s statements. The following are completely counter to your admissions in your comment, and are flat-out, “flat earth” wrong:

    “Physics tells us there are no public physical objects.”

    “It’s not that there’s a classical brain that does some quantum magic. It’s that there’s no brain.”

    “Quantum mechanics says that classical objects — including brains — don’t exist”

    Hoffman’s chiding of neuroscientists for taking Newtonian physics, spike rates and synaptic connection strengths seriously, is completely wrong on two different counts. The first is that the reality that we as conscious beings live in is a classical reality—we cannot detect quantum phenomena unaided, hence the native theories of reality that evolution endows us with are about the classical world, not the quantum. Second, more than most theories, it has been clear from the beginning that QM is a theory that allows us to calculate results of observations and says nothing about the underlying reality between observations. That’s why it has so many interpretations that are compatible with its calculations, including, let me remind you, that of Bohm, in which even individual unobserved particles exist with all their properties between observations. So you cannot take a theory whose cardinal feature is that it says nothing about reality and use it to defend your stance that there is no objective reality.

    The hard problem, which seems to be the motivation for most of such attempts, is aptly named. But the intuition that it is based on is that we can “imagine” all the processes in the brain happening without resulting in consciousness. This is circular reasoning. It suggests that we are looking at this problem wrongly. As I suggested, you need to look at the brain at the level higher than the level of neurons —at the level of meaning, which is what we respond to in the natural world. After all, you respond to what a sound signifies to you, not to physical vibrations. When you do look at the meaning level, it is in fact easy to get your intuition going the other way – it’s hard not to imagine how you would not feel something when you perceive or do something. People who target straw man reductionist materialism — as opposed to the far more plausible “materialism with emergence” — make the mistake at going to a lower level of physicality instead of to the higher level of meaning. If you were to investigate a high level function in a computer, like how the screen changes when you click the mouse in a particular place, you would need to look at the level of the highest level software, not in the way voltages change in the CPU.

    Even though consciousness appears smooth to the experiencer, it is a masterfully staged “virtual reality” that requires tons of computation — like the banks of computers required for a simulator ride. Already we know many areas when the brain’s simulation breaks down. If you want to seriously study how the brain generates consciousness, you can join the grand search —or you can pull consciousness out of thin air, which solves nothing. It is clear what choice a serious scientist will make.

    It’s not the one Hoffman does.

    You say “it takes intellectual perseverance and humility to resist superficial indictments and recognize a deeper value in something that doesn't immediately conform to one's common sense views of the world”. True. But remember that there are a hundred quack theories for one paradigm-changing one. And you can recognize the bad ones by the fact that they make basic mistakes, and take things out of context, as Hoffman most definitely does.

  • Observations on the comments: This is an excerpt from an interview, not a refereed paper. It is (to me) obvously intended to give the flavor of Hoffman's thought so that the reader could follow up by reading more complete formulations if s/he were so inclined. Complaints concerning incompleteness of exposition would therefore seem misplaced. Absense of reference to the philosophical history of some of the ideas sketched therein is no indication that either of the participants is ignorant thereof. The utterances by the interviewer and the interviewee are distinguished typographically – there seems little justification for criticizing Hoffman for the content of Gefter's questions.

  • If he doesn't believe in taking the observed world literally (because of his experimental results), then why does he take his own experimental results literally?

  • @Pradeep Mutalik

    Thanks, as well, for your engagement, and I’m glad the clarifications have been helpful, though this will be my last comment on the thread, as I cannot imagine it’s useful to readers to keep going around and around in circles. But here are a few final replies:

    > I was quite convinced about all this just by reading this article. My impression was amply confirmed when I heard a talk this week given by Deepak Chopra, one of the world’s greatest purveyors of pseudo-scientific woo to justify ancient idealistic doctrines. Chopra spoke warmly of his friend, Don Hoffman, while glowingly praising Hoffman’s work in a talk where he asserted that the entire universe is a “qualia machine.” By your friends are you known.

    Yikes. Don’t get me wrong, I appreciate the skepticism behind this comment. But I genuinely hope that readers don’t get the impression that real scientific judgments can be made on the basis of one article, let alone by this kind of absurd reasoning. Deepak Chopra likes Hoffman’s work because believes that aspects of it happen to resonate with his spiritual views. (As a matter of a fact, he likes my work, too: https://twitter.com/DeepakChopra/status/705384327748689920. Like Hoffman, I can’t control how people react to my work – obviously, or I wouldn’t be having this conversation! Chopra recently asked me to come speak at one of his conferences, and I gladly agreed, as I believe it’s important – perhaps especially important – to help such audiences understand what science does and does not say.) Of course this is completely irrelevant to Hoffman’s science, and this kind of ad-hominem-by-association attack is so puerile as to be unworthy of our national politics, let alone of science.

    Now, getting back to the actual science, you say:
    > This argument does not apply to any everyday object that we can perceive with our unaided senses, since such objects are continuously being “observed” by the environment

    There are some real nuances to quantum mechanics that are being overlooked here, and I hope readers will take it upon themselves to read discussions of foundational issues in quantum mechanics by professional physicists and philosophers. But here’s a brief response in case it's helpful:
    If by this you mean that the quantum state of a system (say, an electron) gets scrambled and spread out through interactions with the environment so that any effects of quantum coherence (like an interference pattern) for *the electron alone* are smeared out, then of course that’s true – but that doesn’t buy you anything for these purposes, because the quantum effects haven’t disappeared. If you take electron-plus-environment as the system, you’re right back to the same deeper issues that Hoffman is talking about. And since the universe is by definition a closed-system, you can’t simply sweep these issues under the rug of decoherence. Decoherence explains why macroscopic objects *appear* classical. It doesn’t mean they *are* classical! What Hoffman's concerned about is precisely not everyday appearances, but the deeper ontology beneath them. In that context, "observation by the environment" is a trivial and irrelevant point. But perhaps you are trying to say something deeper?
    Perhaps, for instance, you are trying to say that the electron can be objectively described by some quantum wavefunction and that pieces of the environment “observe” the electron and “collapse” its wavefunction, leaving the electron in some definite state that all observers would agree on. Well in that case your point would be relevant to the discussion, but this Copenhagen view of the nature of observation would also suffer some likely fatal logical flaws. Look, for instance, at the “Wigner’s friend” paradox, which shows why one observer’s (here, environment's) measurement can’t actually determine the state of a system for other observers. Actually, the only way Wigner himself saw to get out of this mess was to postulate that consciousness has some magical quality that other physical systems don’t have – a kind of dualism that I find silly, and I suspect you do, too, though I’m not certain, as your “materialism with emergence” stance does seem to contain this kind of dualism.
    Perhaps, then, what you meant was simply that the electron has no objective, invariant, definite state but rather can only be defined contextually, as having a state relative to a given “observer”—in this case, the environment? Well then we fully agree!

  • @Amanda,
    Thank you for your classy reply. Although I still completely disagree with you, and don’t believe you have addressed some of my more specific criticisms, I think we can profitably spend time having a cordial discussion should we ever meet.

    I apologize for the Deepak Chopra guilt-by-association dig, but I do think it needs to be known because there is always the chance that this is more than just a case of Chopra liking Hofmann’s work. It could also be the case that these spiritual/philosophical allegiances motivate the science, instead of emerging as conclusions of the science that clearly preclude other explanations.

    I’d like to leave you with two points, both of which I’ve made before.

    The first is that the most devastating argument against Hoffman is the fact that there are over a dozen different models of reality that are all compatible with QM calculations and predictions — each assigning different realities to particles and wave functions, and different roles to observers and consciousness. This means that reasoning about the nature of reality using QM tells you nothing. All your ontological conclusions are based on the assumptions that you put into your interpretation of QM — it is just an echo chamber of your premises.

    Unfortunately, there is no easy way out of this impasse. Progress could happen if new observed phenomena, or unification requirements supported by experiment, require QM to be extended in a way that accommodates just one interpretation. This seems unlikely to happen anytime soon, if ever. Until it does, all ontological arguments based on QM will remain arguments about how many angels can dance on the head of a pin.

    Second, I’d urge you to read this 1-page paper of Michael Nauenberg in the Journal “Cosmology” in 2011. The paper is titled “Does Quantum Mechanics Require A Conscious Observer?” Nauenberg was a collaborator of John S. Bell. His paper clearly dispatches Wigner’s arguments and shows how they were based on a mistake.

    Here’s a web link:


    All in all, I do not think that Hoffman’s work has risen to the level of credibility necessary to be featured in a cutting edge mainstream science magazine like Quanta. Having got this opportunity, your article could have been more balanced if you had made this clear and included some of the concessions you have made in your comments.


  • This isn't Kant, or Nietzsche, or Spinoza. It's George Berkeley, just reheated with a little evolutionary biology, neuroscience, and quantum mechanics.

  • I loved reading this article. Thanks Donald Hoffman and Thanks Quanta.

    Hoffman says, "Objective reality is just conscious agents, just points of view." I love the idea that reality is "just points of view" but I would even take that further and say that there is no "objective reality" at all. It's ALL "points of view."

    Throughout the article, if I'm not mistaken, there is an implication that there is in fact "a" reality, "a" truth underneath everything.

    I have developed a theory called Relative Understanding and it holds that there is no singular underlying reality and that there is no universal truth. It also holds some interesting assertions about the nature of time.

    You can read about my theory here: http://relativeunderstanding.com/craigs-theory-of-relative-understanding

    I would be very grateful to hear opinions about my theory.

    Dr. Hoffman, is my Theory of Relative Understanding at odds with your notion of conscious realism? I actually think they are very compatible.

    Would love to hear your opinion. And from others.

    Thank you!

  • Sam, I'd totally agree with your astute and succinct observation had you substituted "a little" for "a bastardisation of" 🙂

  • Out on a limb here…when I pinch myself is that real pain? When I donate blood is that my real blood? When I read a book are the words real? Is the couch beneath me real? Are the words I'm typing right now in this moment real?

  • Oh my! How startling! Another claim that adherence to indirect realism is somehow revolutionary instead of nothing more than revamped Cartesian dualism. Here's a "heads-up" for you: our perception of the world is not a "portrayal" at all. See? That assumes representationalism. The question "Does our perception match the real world?" is automatically incoherent unless you are already assuming indirect realism. It's like asking "Is that rat's lever-press an accurate picture of the stimulus lamp?" Our responses "to the world" are simply not "portrayals" of it! Perception is behavior.


  • So he has spent years in laboratories doing experiments whic prove that there are no laboratories and experiments. Do words like "self-defeating" and "self-contradictory" mean anything to this fool?

  • Reminds me of:

    “We have to remember that what we observe is not nature in itself but nature exposed to our method of questioning” (Heisenberg).

    This means that we can never have the falcon, only the word “falcon.” To say that we have the falcon, and not the “falcon,” is to presume again that we know precisely what it is we have, that we can see it in its entirety, and that we can speak as nature itself."

    Carse, James (2011-10-11). Finite and Infinite Games (pp. 101-103). Free Press.

  • When Kant comes up, I always feel somewhat disappointed that he wasn't taken in the context of a time when metaphysics (and the whole kit and caboodle of theological Scholasticism) was only just on the wane (with Hume's assault and then Kant's). The noumenon is a metaphysical object, and if we could know it, we would know it via pure intellection. Geometry and related fields are known to us because they map the framework that we use to perceive and understand things. Concepts are mere forms of thought unless they are grounded in empirical observations. Kant thought that there is no purely intellectual access to objects of knowledge and it is assuming too much that there is (or is not) an ontological correlate that maps onto any phenomenon. It seems premature to me for Hoffman and colleagues to assume so many things about reality based on the fact that we have limited access to it (i.e., merely empirical, not the grand scholarly insight of the mediaeval theologians — Kant in his own words was an empirical realist. He was a true fan of Newton as well).

  • The question I can't grapple with is this: if an oncoming train is only in the mind of the person who perceives it, and that perception includes getting hit and dying, then when I see a video of the event on tv the next day, what am I really seeing?

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