Laetitia Vancon for Quanta Magazine

Physicists George Ellis (center) and Joe Silk (right) at Ludwig Maximilian University in Munich on Dec. 7.

Physicists typically think they “need philosophers and historians of science like birds need ornithologists,” the Nobel laureate David Gross told a roomful of philosophers, historians and physicists last week in Munich, Germany, paraphrasing Richard Feynman.

But desperate times call for desperate measures.

Fundamental physics faces a problem, Gross explained — one dire enough to call for outsiders’ perspectives. “I’m not sure that we don’t need each other at this point in time,” he said.

It was the opening session of a three-day workshop, held in a Romanesque-style lecture hall at Ludwig Maximilian University (LMU Munich) one year after George Ellis and Joe Silk, two white-haired physicists now sitting in the front row, called for such a conference in an incendiary opinion piece in Nature. One hundred attendees had descended on a land with a celebrated tradition in both physics and the philosophy of science to wage what Ellis and Silk declared a “battle for the heart and soul of physics.”

The crisis, as Ellis and Silk tell it, is the wildly speculative nature of modern physics theories, which they say reflects a dangerous departure from the scientific method. Many of today’s theorists — chief among them the proponents of string theory and the multiverse hypothesis — appear convinced of their ideas on the grounds that they are beautiful or logically compelling, despite the impossibility of testing them. Ellis and Silk accused these theorists of “moving the goalposts” of science and blurring the line between physics and pseudoscience. “The imprimatur of science should be awarded only to a theory that is testable,” Ellis and Silk wrote, thereby disqualifying most of the leading theories of the past 40 years. “Only then can we defend science from attack.”

They were reacting, in part, to the controversial ideas of Richard Dawid, an Austrian philosopher whose 2013 book String Theory and the Scientific Method identified three kinds of “non-empirical” evidence that Dawid says can help build trust in scientific theories absent empirical data. Dawid, a researcher at LMU Munich, answered Ellis and Silk’s battle cry and assembled far-flung scholars anchoring all sides of the argument for the high-profile event last week.

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David Gross, a theoretical physicist at the University of California, Santa Barbara.

Gross, a supporter of string theory who won the 2004 Nobel Prize in physics for his work on the force that glues atoms together, kicked off the workshop by asserting that the problem lies not with physicists but with a “fact of nature” — one that we have been approaching inevitably for four centuries.

The dogged pursuit of a fundamental theory governing all forces of nature requires physicists to inspect the universe more and more closely — to examine, for instance, the atoms within matter, the protons and neutrons within those atoms, and the quarks within those protons and neutrons. But this zooming in demands evermore energy, and the difficulty and cost of building new machines increases exponentially relative to the energy requirement, Gross said. “It hasn’t been a problem so much for the last 400 years, where we’ve gone from centimeters to millionths of a millionth of a millionth of a centimeter” — the current resolving power of the Large Hadron Collider (LHC) in Switzerland, he said. “We’ve gone very far, but this energy-squared is killing us.”

As we approach the practical limits of our ability to probe nature’s underlying principles, the minds of theorists have wandered far beyond the tiniest observable distances and highest possible energies. Strong clues indicate that the truly fundamental constituents of the universe lie at a distance scale 10 million billion times smaller than the resolving power of the LHC. This is the domain of nature that string theory, a candidate “theory of everything,” attempts to describe. But it’s a domain that no one has the faintest idea how to access.

The problem also hampers physicists’ quest to understand the universe on a cosmic scale: No telescope will ever manage to peer past our universe’s cosmic horizon and glimpse the other universes posited by the multiverse hypothesis. Yet modern theories of cosmology lead logically to the possibility that our universe is just one of many.

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Whether the fault lies with theorists for getting carried away, or with nature, for burying its best secrets, the conclusion is the same: Theory has detached itself from experiment. The objects of theoretical speculation are now too far away, too small, too energetic or too far in the past to reach or rule out with our earthly instruments. So, what is to be done? As Ellis and Silk wrote, “Physicists, philosophers and other scientists should hammer out a new narrative for the scientific method that can deal with the scope of modern physics.”

“The issue in confronting the next step,” said Gross, “is not one of ideology but strategy: What is the most useful way of doing science?”

Over three mild winter days, scholars grappled with the meaning of theory, confirmation and truth; how science works; and whether, in this day and age, philosophy should guide research in physics or the other way around. Over the course of these pressing yet timeless discussions, a degree of consensus took shape.

Rules of the Game

Throughout history, the rules of science have been written on the fly, only to be revised to fit evolving circumstances. The ancients believed they could reason their way toward scientific truth. Then, in the 17th century, Isaac Newton ignited modern science by breaking with this “rationalist” philosophy, adopting instead the “empiricist” view that scientific knowledge derives only from empirical observation. In other words, a theory must be proved experimentally to enter the book of knowledge.

But what requirements must an untested theory meet to be considered scientific? Theorists guide the scientific enterprise by dreaming up the ideas to be put to the test and then interpreting the experimental results; what keeps theorists within the bounds of science?

Today, most physicists judge the soundness of a theory by using the Austrian-British philosopher Karl Popper’s rule of thumb. In the 1930s, Popper drew a line between science and nonscience in comparing the work of Albert Einstein with that of Sigmund Freud. Einstein’s theory of general relativity, which cast the force of gravity as curves in space and time, made risky predictions — ones that, if they hadn’t succeeded so brilliantly, would have failed miserably, falsifying the theory. But Freudian psychoanalysis was slippery: Any fault of your mother’s could be worked into your diagnosis. The theory wasn’t falsifiable, and so, Popper decided, it wasn’t science.

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Paul Teller (by window), a philosopher and professor emeritus at the University of California, Davis.

Critics accuse string theory and the multiverse hypothesis, as well as cosmic inflation — the leading theory of how the universe began — of falling on the wrong side of Popper’s line of demarcation. To borrow the title of the Columbia University physicist Peter Woit’s 2006 book on string theory, these ideas are “not even wrong,” say critics. In their editorial, Ellis and Silk invoked the spirit of Popper: “A theory must be falsifiable to be scientific.”

But, as many in Munich were surprised to learn, falsificationism is no longer the reigning philosophy of science. Massimo Pigliucci, a philosopher at the Graduate Center of the City University of New York, pointed out that falsifiability is woefully inadequate as a separator of science and nonscience, as Popper himself recognized. Astrology, for instance, is falsifiable — indeed, it has been falsified ad nauseam — and yet it isn’t science. Physicists’ preoccupation with Popper “is really something that needs to stop,” Pigliucci said. “We need to talk about current philosophy of science. We don’t talk about something that was current 50 years ago.”

Nowadays, as several philosophers at the workshop said, Popperian falsificationism has been supplanted by Bayesian confirmation theory, or Bayesianism, a modern framework based on the 18th-century probability theory of the English statistician and minister Thomas Bayes. Bayesianism allows for the fact that modern scientific theories typically make claims far beyond what can be directly observed — no one has ever seen an atom — and so today’s theories often resist a falsified-unfalsified dichotomy. Instead, trust in a theory often falls somewhere along a continuum, sliding up or down between 0 and 100 percent as new information becomes available. “The Bayesian framework is much more flexible” than Popper’s theory, said Stephan Hartmann, a Bayesian philosopher at LMU. “It also connects nicely to the psychology of reasoning.”

Gross concurred, saying that, upon learning about Bayesian confirmation theory from Dawid’s book, he felt “somewhat like the Molière character who said, ‘Oh my God, I’ve been talking prose all my life!’”

Another advantage of Bayesianism, Hartmann said, is that it is enabling philosophers like Dawid to figure out “how this non-empirical evidence fits in, or can be fit in.”

Another Kind of Evidence

Dawid, who is 49, mild-mannered and smiley with floppy brown hair, started his career as a theoretical physicist. In the late 1990s, during a stint at the University of California, Berkeley, a hub of string-theory research, Dawid became fascinated by how confident many string theorists seemed to be that they were on the right track, despite string theory’s complete lack of empirical support. “Why do they trust the theory?” he recalls wondering. “Do they have different ways of thinking about it than the canonical understanding?”

String theory says that elementary particles have dimensionality when viewed close-up, appearing as wiggling loops (or “strings”) and membranes at nature’s highest zoom level. According to the theory, extra dimensions also materialize in the fabric of space itself. The different vibrational modes of the strings in this higher-dimensional space give rise to the spectrum of particles that make up the observable world. In particular, one of the vibrational modes fits the profile of the “graviton” — the hypothetical particle associated with the force of gravity. Thus, string theory unifies gravity, now described by Einstein’s theory of general relativity, with the rest of particle physics.

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Video: Richard Dawid, a physicist-turned-philosopher at Ludwig Maximilian University in Munich.

However string theory, which has its roots in ideas developed in the late 1960s, has made no testable predictions about the observable universe. To understand why so many researchers trust it anyway, Dawid signed up for some classes in philosophy of science, and upon discovering how little study had been devoted to the phenomenon, he switched fields.

In the early 2000s, he identified three non-empirical arguments that generate trust in string theory among its proponents. First, there appears to be only one version of string theory capable of achieving unification in a consistent way (though it has many different mathematical representations); furthermore, no other “theory of everything” capable of unifying all the fundamental forces has been found, despite immense effort. (A rival approach called loop quantum gravity describes gravity at the quantum scale, but makes no attempt to unify it with the other forces.) This “no-alternatives” argument, colloquially known as “string theory is the only game in town,” boosts theorists’ confidence that few or no other possible unifications of the four fundamental forces exist, making it more likely that string theory is the right approach.

Second, string theory grew out of the Standard Model — the accepted, empirically validated theory incorporating all known fundamental particles and forces (apart from gravity) in a single mathematical structure — and the Standard Model also had no alternatives during its formative years. This “meta-inductive” argument, as Dawid calls it, buttresses the no-alternatives argument by showing that it has worked before in similar contexts, countering the possibility that physicists simply aren’t clever enough to find the alternatives that exist.

Emily Fuhrman for Quanta Magazine, with text by Natalie Wolchover and art direction by Olena Shmahalo.

Click on the interactive to start. Learn more about this map.

The third non-empirical argument is that string theory has unexpectedly delivered explanations for several other theoretical problems aside from the unification problem it was intended to address. The staunch string theorist Joe Polchinski of the University of California, Santa Barbara, presented several examples of these “unexpected explanatory interconnections,” as Dawid has termed them, in a paper read in Munich in his absence. String theory explains the entropy of black holes, for example, and, in a surprising discovery that has caused a surge of research in the past 15 years, is mathematically translatable into a theory of particles, such as the theory describing the nuclei of atoms.

Polchinski concludes that, considering how far away we are from the exceptionally fine grain of nature’s fundamental distance scale, we should count ourselves lucky: “String theory exists, and we have found it.” (Polchinski also used Dawid’s non-empirical arguments to calculate the Bayesian odds that the multiverse exists as 94 percent — a value that has been ridiculed by the Internet’s vocal multiverse critics.)

One concern with including non-empirical arguments in Bayesian confirmation theory, Dawid acknowledged in his talk, is “that it opens the floodgates to abandoning all scientific principles.” One can come up with all kinds of non-empirical virtues when arguing in favor of a pet idea. “Clearly the risk is there, and clearly one has to be careful about this kind of reasoning,” Dawid said. “But acknowledging that non-empirical confirmation is part of science, and has been part of science for quite some time, provides a better basis for having that discussion than pretending that it wasn’t there, and only implicitly using it, and then saying I haven’t done it. Once it’s out in the open, one can discuss the pros and cons of those arguments within a specific context.”

The Munich Debate

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The trash heap of history is littered with beautiful theories. The Danish historian of cosmology Helge Kragh, who detailed a number of these failures in his 2011 book, Higher Speculations, spoke in Munich about the 19th-century vortex theory of atoms. This “Victorian theory of everything,” developed by the Scots Peter Tait and Lord Kelvin, postulated that atoms are microscopic vortexes in the ether, the fluid medium that was believed at the time to fill space. Hydrogen, oxygen and all other atoms were, deep down, just different types of vortical knots. At first, the theory “seemed to be highly promising,” Kragh said. “People were fascinated by the richness of the mathematics, which could keep mathematicians busy for centuries, as was said at the time.” Alas, atoms are not vortexes, the ether does not exist, and theoretical beauty is not always truth.

Except sometimes it is. Rationalism guided Einstein toward his theory of relativity, which he believed in wholeheartedly on rational grounds before it was ever tested. “I hold it true that pure thought can grasp reality, as the ancients dreamed,” Einstein said in 1933, years after his theory had been confirmed by observations of starlight bending around the sun.

The question for the philosophers is: Without experiments, is there any way to distinguish between the non-empirical virtues of vortex theory and those of Einstein’s theory? Can we ever really trust a theory on non-empirical grounds?

In discussions on the third afternoon of the workshop, the LMU philosopher Radin Dardashti asserted that Dawid’s philosophy specifically aims to pinpoint which non-empirical arguments should carry weight, allowing scientists to “make an assessment that is not based on simplicity, which is not based on beauty.” Dawidian assessment is meant to be more objective than these measures, Dardashti explained — and more revealing of a theory’s true promise.

Gross said Dawid has “described beautifully” the strategies physicists use “to gain confidence in a speculation, a new idea, a new theory.”

“You mean confidence that it’s true?” asked Peter Achinstein, an 80-year-old philosopher and historian of science at Johns Hopkins University. “Confidence that it’s useful? confidence that …”

“Let’s give an operational definition of confidence: I will continue to work on it,” Gross said.

“That’s pretty low,” Achinstein said.

“Not for science,” Gross said. “That’s the question that matters.”

Kragh pointed out that even Popper saw value in the kind of thinking that motivates string theorists today. Popper called speculation that did not yield testable predictions “metaphysics,” but he considered such activity worthwhile, since it might become testable in the future. This was true of atomic theory, which many 19th-century physicists feared would never be empirically confirmed. “Popper was not a naive Popperian,” Kragh said. “If a theory is not falsifiable,” Kragh said, channeling Popper, “it should not be given up. We have to wait.”

But several workshop participants raised qualms about Bayesian confirmation theory, and about Dawid’s non-empirical arguments in particular.

Carlo Rovelli, a proponent of loop quantum gravity (string theory’s rival) who is based at Aix-Marseille University in France, objected that Bayesian confirmation theory does not allow for an important distinction that exists in science between theories that scientists are certain about and those that are still being tested. The Bayesian “confirmation” that atoms exist is essentially 100 percent, as a result of countless experiments. But Rovelli says that the degree of confirmation of atomic theory shouldn’t even be measured in the same units as that of string theory. String theory is not, say, 10 percent as confirmed as atomic theory; the two have different statuses entirely. “The problem with Dawid’s ‘non-empirical confirmation’ is that it muddles the point,” Rovelli said. “And of course some string theorists are happy of muddling it this way, because they can then say that string theory is ‘confirmed,’ equivocating.”

The German physicist Sabine Hossenfelder, in her talk, argued that progress in fundamental physics very often comes from abandoning cherished prejudices (such as, perhaps, the assumption that the forces of nature must be unified). Echoing this point, Rovelli said “Dawid’s idea of non-empirical confirmation [forms] an obstacle to this possibility of progress, because it bases our credence on our own previous credences.” It “takes away one of the tools — maybe the soul itself — of scientific thinking,” he continued, “which is ‘do not trust your own thinking.’”

The Munich proceedings will be compiled and published, probably as a book, in 2017. As for what was accomplished, one important outcome, according to Ellis, was an acknowledgment by participating string theorists that the theory is not “confirmed” in the sense of being verified. “David Gross made his position clear: Dawid’s criteria are good for justifying working on the theory, not for saying the theory is validated in a non-empirical way,” Ellis wrote in an email. “That seems to me a good position — and explicitly stating that is progress.”

In considering how theorists should proceed, many attendees expressed the view that work on string theory and other as-yet-untestable ideas should continue. “Keep speculating,” Achinstein wrote in an email after the workshop, but “give your motivation for speculating, give your explanations, but admit that they are only possible explanations.”

“Maybe someday things will change,” Achinstein added, “and the speculations will become testable; and maybe not, maybe never.” We may never know for sure the way the universe works at all distances and all times, “but perhaps you can narrow the live possibilities to just a few,” he said. “I think that would be some progress.”

This article was reprinted on TheAtlantic.com.

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  • String theory is an amazing project that has yielded many mathematical tools – but until and unless it yields testable predictions, I just don't see how anyone can claim it for true. If you have two theories, one of them hopelessly complex, the other beautifully simple, both predicting the exact same things, it's clear that adopting the simpler theory is the way forward. But this isn't even *remotely* true of String theory. It may be beautifully simple at its core, but it gets hopelessly complex in practice, and we don't even know what it predicts!

    I think instead of asking these philosophical questions, which ultimately boil down to what people *want* to be true, string theorists should consider applying their considerable intellects to fields that aren't as far along (like, yes, quantum gravity). These are brilliant minds, and it's an absolute shame to trap them in this frustrating, increasingly (seemingly) hopeless quest – but it doesn't mean we should just abandon reason to make them feel better.

  • Wasn't the word hypothesis mentioned at the conference at any time? Such as String Hypothesis, Multiverse Hypothesis, which would make it all a lot clearer to everyone.

  • If a hypothesis is not falsifiable it's Not scientifically valid and if a hypothesis is falsified it also is not scientifically valid… If a hypothesis is falsifiable and makes a prediction which is experimentally verified then and only then is it Scientifically Valid and can be called a Theory..

  • Massimo Pigliucci, a philosopher at the Graduate Center of the City University of New York, pointed out that falsifiability is woefully inadequate as a separator of science and nonscience, as Popper himself recognized. Astrology, for instance, is falsifiable — indeed, it has been falsified ad nauseam — and yet it isn’t science. Physicists’ preoccupation with Popper “is really something that needs to stop,” Pigliucci said. “We need to talk about current philosophy of science. We don’t talk about something that was current 50 years ago.”

    ​how could Pigliucci not know the difference between a condition being necessary and being sufficient​.?

  • Many people say, including Ed. Witten, that the intrinsic beauty of string theory is the best reason it is a correct theory!!!!?????? However, I have not noticed anything particularly beautiful in the string business, rather it is actually very ugly! So much input, and so many free parameters can only make a wrong theory. Lastly, the "STRING" business is not even a theory! if you don't believe me please have a look at the definition of a theory, and then judge by yourself if STRING is a theory.

  • "an operational definition of confidence: I will continue to work on it" – David Gross

    People will continue to work on anything they like that they can get funding for. Since string theorists dominate modern theoretical physics, it is (relatively) easy to get funding for string theory. Therefore, we can be confident … that string theory will continue to get funded.

    If one accepts the above argument-form, then it seems to me one is also forced to conclude that Russian scientists had every right to be confident in Lysenkoism. That, roughly, is the current level of validation of string theory.

    Bayesian reasoning is wonderful of course, but it requires (1) a prior estimate of likelihoods, and (2) experimental evidence (with calculable theoretical probabilities) that can be used to update the prior beliefs. String theory appears to be a non-starter on both counts. On the one hand, saying it is "the only game in town" is the same as saying that its prior likelihood is 100% and all competing theories are 0%, and no amount of evidence can move that prior (zero times anything is still zero). On the other hand, string theory is not testable, so no evidence for or against it can be generated. Either of these alone would make string theory completely immune to Bayesian analysis.

  • What if string theory and multiverses are symptomatic of much deeper issues and they are only the stage of reductio ad absurdum?
    For instance, what if time is not so much a measure from past to future events, but the process by which future becomes past. Essentially then it would be frequency and have more in common with temperature, than space. The conservation of energy means there is no physical past and time is asymmetric due to inertia.
    How can it be said that space expands, based on relativity, if the speed of light doesn't remain constant to the distance, i.e., more lightyears between galaxies, not expanded lightyears? It would seem the vacuum is the stable dimension.
    How can a theory even be falsified, if every time predictions don't match observations, another enormous force of nature is proposed, from inflation to dark energy?
    We are told matter is both particle and wave, but waves are dismissed as statistical. What if waves are elemental and particles are points of contact? Then "spooky action at a distance" might not be so spooky. It would also mean reality is more a hologram, than material, but our minds prefer objects, because they are the stable forms our minds are designed to grasp and those points of contact are what we can measure. According to theory, reality is 99+percent empty space, between those particles. Waves seem a logical option to me.
    If we can't keep going in the direction we have been going, then the only option will be to turn around and fully examine everything built into our theories. Future generations will have a field day with all the clutter in our collective mental attic.

  • Physics or metaphysics? Which is the right way to proceed to find out about the fundamental levels of the universe? I think there's a 3rd way, which combines metaphysics and physics and is similar to what Popper was quoted as saying "Popper called speculation that did not yield testable predictions “metaphysics,” but he considered such activity worthwhile, since it might become testable in the future. "

    The 3rd way I suggest goes like this. Because metaphysics is the study of being and existence, because the universe "be"s and exists, because physics is the study of how the universe works, then the laws of physics and of the universe should be theoretically derivable from the principles of metaphysics. To me, this seems logically correct. Therefore, one should theoretically be able to take metaphysical/philosophical ideas about the properties of fundamental existent entities and use them to build a model of the fundamental levels of the universe. This model, which can even be a computer simulation, should be able to make testable predictions. I think that using this metaphysics-to-physics approach may allow both physicists and philosophers to bypass the current roadblocks to progress and get some falsifiable, and therefore scientific, insights into the most fundamental levels of reality.

    As a lowly amateur, this is the approach I'm taking with my "crazy" ideas and is why I'm trying to learn 3D modeling software to model my ideas and maybe someday make testable predictions. I suggest it's a useful approach.

  • If we simply replaced the entire content of the Munich conference with the words, thoughts, and philosophies of the likes of Max Born, Richard Feynman, Einstein and other Nobel Laureates and Luminaries such as Sir Isaac Newton and Galileo, would not physics and its future be better off?
    R.P. Feynman: I don’t like that they’re not calculating anything. I don’t like that they don’t check their ideas. I don’t like that for anything that disagrees with an experiment, they cook up an explanation-a fix-up to say, “Well, it might be true.” For example, the theory requires ten dimensions. Well, maybe there’s a way of wrapping up six of the dimensions. Yes, that’s all possible mathematically, but why not seven? . . . So the fact that it might disagree with experience is very tenuous, it doesn’t produce anything; it has to be excused most of the time. It doesn’t look right.
    Max Born: All great discoveries in experimental physics have been made due to the intuition of men who made free use of models which for them were not products of the imagination but representations of real things.
    Einstein: Time and again the passion for understanding has led to the illusion that man is able to comprehend the objective world rationally by pure thought without any empirical foundations—in short, by metaphysics.
    Gerard ‘t’Hooft: Actually, I would not even be prepared to call string theory a “theory” rather a “model” or not even that: just a hunch. After all, a theory should come together with instructions on how to deal with it to identify the things one wishes to describe, in our case the elementary particles, and one should, at least in principle, be able to formulate the rules for calculating the properties of these particles, and how to make new predictions for them. Imagine that I give you a chair, while explaining that the legs are still missing, and that the seat, back and armrest will perhaps be delivered soon; whatever I did give you, can I still call it a chair?
    Einstein: Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius—and a lot of courage—to move in the opposite direction (dx4/dt=ic).
    Sheldon Glashow: It is tragic, but now, we have the string theorists, thousands of them, that also dream of explaining all the features of nature. They just celebrated the 20th anniversary of superstring theory. So when one person spends 30 years, it’s a waste, but when thousands waste 20 years in modern day, they celebrate with champagne. I find that curious.
    Einstein: The theory must not contradict empirical facts. . . The second point of view is not concerned with the relation to the material of observation but with the premises of the theory itself, with what may briefly but vaguely be characterized as the “naturalness” or “logical simplicity” of the premises of the basic concepts and of the relations between these which are taken as a basis.
    Sheldon Glashow: But superstring physicists have not yet shown that theory really works. They cannot demonstrate that the standard theory is a logical outcome of string theory. They cannot even be sure that their formalism includes a description of such things as protons and electrons. And they have not yet made even one teeny-tiny experimental prediction. Worst of all, superstring theory does not follow as a logical consequence of some appealing set of hypotheses about nature.
    Philip W. Anderson Physicist and Nobel laureate, Princeton: “Is string theory a futile exercise as physics, as I believe it to be? It is an interesting mathematical specialty and has produced and will produce mathematics useful in other contexts, but it seems no more vital as mathematics than other areas of very abstract or specialized math, and doesn’t on that basis justify the incredible amount of effort expended on it.
    My belief is based on the fact that string theory is the first science in hundreds of years to be pursued in pre-Baconian fashion, without any adequate experimental guidance. It proposes that Nature is the way we would like it to be rather than the way we see it to be; and it is improbable that Nature thinks the same way we do. The sad thing is that, as several young would-be theorists have explained to me, it is so highly developed that it is a full-time job just to keep up with it. That means that other avenues are not being explored by the bright, imaginative young people, and that alternative career paths are blocked.”
    Would not young physicists be better off hearing these words of wisdom, as opposed to the words of Bee, Kane, Dawid, et al.?
    How many undergraduates, graduate students, or professors could recite Newton’s or Einstein’s rules for physics?
    Einstein’s Three Rules of Work: 1. Out of clutter find simplicity (dx4/dt=ic). 2. From discord find harmony. 3. In the middle of difficulty lies opportunity.
    Newton’s Four Rules of Science and Natural Philosophy Rule 1: We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances.
    Rule 2: Therefore to the same natural effects we must, as far as possible, assign the same causes (dx4/dt=ic).
    Rule 3: The qualities of bodies, which admit neither intensification nor remission of degrees, and which are found to belong to all bodies within the reach of our experiments, are to be esteemed the universal qualities of all bodies whatsoever.
    Rule 4: In experimental philosophy we are to look upon propositions inferred by general induction from phenomena as accurately or very nearly true, not withstanding any contrary hypothesis that may be imagined, till such time as other phenomena occur, by which they may either be made more accurate, or liable to exceptions.
    I contend that if the brilliant light of this wisdom were allowed to shine forth, the murky string theory and multiverse fog would dissipate like an early morning sea mist kissed by the rising sun.
    What we need, more than ever, is to turn towards the wisdom of those who actually advanced physics. We should look to apply their diverse array of mathematical, philosophical, and physical methods in our own context!
    Einstein: The theory must not contradict empirical facts. . . (there are no empirical facts supporting 11 nor 42 dimensions; nor tiny, vibrating strings) The second point of view is not concerned with the relation to the material of observation but with the premises of the theory itself, with what may briefly but vaguely be characterized as the “naturalness” or “logical simplicity” of the premises of the basic concepts and of the relations between these which are taken as a basis.
    Schrodinger: The world is given but once. . . (No multiverse!) The world extended in space and time is but our representation. Experience does not give us the slightest clue of its being anything besides that.
    Nobel Laureate Robert Laughlin: [String Theory] has no practical utility, however, other than to sustain the myth of the ultimate theory. There is no experimental evidence for the existence of strings in nature, nor does the special mathematics of string theory enable known experimental behavior to be calculated or predicted more easily. . . String theory is, in fact, a textbook case of Deceitful Turkey, a beautiful set of ideas that will always remain just barely out of reach. Far from a wonderful technological hope for a greater tomorrow, it is instead the tragic consequence of an obsolete belief system-in which emergence plays no role and dark law does not exist.—A Different Universe, Laughlin
    Planck: That we do not construct the external world to suit our own ends in the pursuit of science, but that vice versa the external world forces itself upon our recognition with its own elemental power, is a point which ought to be categorically asserted again and again . . . From the fact that in studying the happenings of nature . . . it is clear that we always look for the basic thing behind the dependent thing, for what is absolute behind what is relative, for the reality behind the appearance and for what abides behind what is transitory. . this is characteristic not only of physical science but of all science.
    Einstein: Mathematics are well and good but nature keeps dragging us around by the nose.
    Poincare: Geometry is not true, it is advantageous.
    Sir Francis Bacon: And all depends on keeping the eye steadily fixed upon the facts of nature and so receiving their images simply as they are. For God forbid that we should give out a dream of our own imagination for a pattern of the world; rather may he graciously grant to us to write an apocalypse or true vision of the footsteps of the Creator imprinted on his creatures.
    In Einstein’s Mistakes, Dr. Hans Ohanian reports on how physics advances via the emphasis not on math, but on physical reality, “(Max) Born described the weak point in Einstein’s work in those final years: “. . . now he tried to do without any empirical facts, by pure thinking. He believed in the power of reason to guess the laws according to which God built the world.”
    In Disturbing the Universe, Freeman Dyson writes, “Dick [Feynman] fought back against my skepticism, arguing that Einstein had failed because he stopped thinking in concrete physical images (as MDT does!) and became a manipulator of equations. I had to admit that was true. The great discoveries of Einstein’s earlier years were all based on direct physical intuition. Einstein’s later unified theories failed because they were only sets of equations without physical meaning. Dick’s sum-over-histories theory was in the spirit of the young Einstein, not of the old Einstein. It was solidly rooted in physical reality.”[xxxiii] In The Trouble With Physics, Lee Smolin writes that Bohr was not a Feynman “shut up and calculate” physicist, and from the above Dyson quote, it appears that Feynman wasn’t either. Lee writes, “Mara Beller, a historian who has studied his [Bohr’s] work in detail, points out that there was not a single calculation in his research notebooks, which were all verbal arguments and pictures.”[xxxiv] Please see MDT’s Fig. 1, presenting a physical model, at the end of this document. (Many more to come!)
    In Dark Matters, Dr. Percy Seymour writes, “Albert Einstein was a great admirer of Newton, Faraday, and Maxwell. In his office he had framed copies of portraits of these scientists. He had this to say about Faraday and Maxwell: “The greatest change in the axiomatic basis of physics—in other words, of our conception of the structure—since Newton laid the foundation of theoretical physics was brought about by Faraday’s and Maxwell’s work on electromagnetic phenomena.”
    Yes! And in his book “Einstein,” Banesh Hoffman and the great Michael Faraday exalt physical reality over mere math:
    “Meanwhile, however, the English experimenter Michael Farady was making outstanding experimental discoveries in electricity and magnetism. Being largely self-taught and lacking mathematical facility, he could not interpret his results in the manner of Ampere. And this was fortunate, since it led to a revolution in science. . . most physicists adept at mathematics thought his concepts mathematically naïve.”
    “We don’t know what we are talking about.” –Nobel Laureate David Gross on string theory
    “It is anomalous to replace the four-dimensional continuum by a five-dimensional one and then subsequently to tie up artificially one of those five dimensions in order to account for the fact that it does not manifest itself.” -Einstein to Ehrenfest (Imagine doing this for 10-30+ dimensions!)
    “String theorists don’t make predictions, they make excuses.” – Feynman, Nobel Laureate
    “String theory is like a 50 year old woman wearing too much lipstick.” -Robert Laughlin, Nobel Laureate
    “Books on physics are full of complicated mathematical formulae. But thought and ideas (the fourth dimension is expanding relative to the three spatial dimensions at c), not formulae (dx4/dt=ic), are the beginning of every physical theory.” —Einstein/Infeld, The Evolution of Physics
    Einstein: “As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.”

  • I am a layperson, having studied physics at Cornell before becoming an Engineer. I am sure that the leading physicists of earlier eras, such as Feynman and Bohr, would have utterly eviscerated string theorists. Empiricism is at the core of science. Empiricism is what took us out of the dark ages and into the light. With the abandonment of empiricism in physics, I am sure we are in a bit of a dark age. Nobody living in a dark age would want to admit it. We like to think that the progression of time automatically brings the progression of science, but nowhere is such a law written.

    It is true that Einstein's relativity was the result of pure thought. But that was the work of one man, with empiricism following quickly behind. Now imagine instead if five hundred more scientists each in turn added to the edifice, each making it more elaborate, without ever testing if even the first stone is correctly placed. This resembles medieval speculation about the number of angels on the head of a pin when it hasn't even been proved that a single angel exists.

    And the claims that string theory (or multiverses) is elegant! Nobody examining either idea with fresh eyes would ever make such a claim. Those two ideas seem to be the antithesis of Occam's Razor. If you make a theory elaborate enough, it can accommodate any new data coming in, just as the Ptolemaic system could for 1500 years accommodate any observation with just geocentric spheres and lots of epicycles. Computing new epicycles was important work that surely occupied many across the long dark ages. Maybe pioneering new epicycles kept the royal grant money flowing.

  • Quantum Physics is Non-Local. However Ever Higher Energy physics is about ever more locality (as energies go up, wavelength become shorter, so do distances). One could call such endeavor hyper-local.

    A real theory of everything would also be a theory of Non-Locality, as the latter is an omnipresent feature of Quantum Physics. However, both the Standard Model and Strings (super or not) ignore the problem of Non-Locality, as if it did not belong to physics.

    That’s a major flaw. It means that the Standard Model and Strings have tunnel vision in what it considers relevant (the input).

    The mystery of Dark Matter may lay in these Non-Local effects (there is a simple little reasoning). The simple fact that one can invent a completely new type of physical theory by thinking Non-Local shows how unimaginative the ruling, hyper-local imagination is.

    But there is worse: suppose a unified theory such as strings would be “proven”. What would it predict? Nothing, really: the energies in question are not found in this world. It would “predict” the Big Bang. Thus, the output of Standard Model/Strings does not address this world.

    In particular they offer no explanations of Dark Energy and Dark Matter. (Both of these seem to have to do with Non-Local space, because they happen in special locations around, or between galaxies).

  • Natalie writes, "To borrow the title of the Columbia University physicist Peter Woit’s 2006 book on string theory, these ideas are “not even wrong,” say critics. "

    It must be pointed out that the Nobel Laureate physicist Wolfgang Pauli coined the phrase "not even wrong" and made it famous. This omission ties into the fact that the soul of Pauli, Einstein, et al. was omitted from the conference, just as it is oft omitted from Woit's blog.

    "Not even wrong" is a famous phrase and has an entire wikipedia page of its own which informs us, "The phrase is generally attributed to theoretical physicist Wolfgang Pauli, who was known for his colorful objections to incorrect or sloppy thinking."

  • It's not only a question of which theories are falsifiable, but, a question of which theories are mathematically rigorous. Recent results have shown that cosmic inflation, eternal inflation, and theories like a "Universe from Nothing" all have serious issues, as they are not even mathematically viable leading to all sorts of singularity behaviour. See, for example: http://arxiv.org/abs/1505.07770 and http://arxiv.org/abs/1408.2249.

    It is amusing to me that the convictions of scientists in these areas are believing in these theories even though they are not falsifiable, and even though they fail on levels of mathematical rigour!

  • Assuming the "Multiverse" is, philosophically speaking, as if one assumed something existed beyond all there is (the latter being the definition of the "Universe"). Assuming something existed beyond existence was tried before, by Middle Ages theologians. Whereas physics, the study of nature, is about what can be observed, not about what cannot be observed, as a matter of principle.
    (I know there are different versions of the "Multiverse", including some which may be, in some sense, observable. But then it's not of a "Multiverse" that one is talking anymore, but, really, of a much bigger universe.)

  • Natalie writes, "Then, in the 17th century, Isaac Newton ignited modern science by breaking with this “rationalist” philosophy, adopting instead the “empiricist” view that scientific knowledge derives only from empirical observation. In other words, a theory must be proved experimentally to enter the book of knowledge."

    This is not true. Galileo exalted the "empiricist” view well before Newton. Do not take my word for it, but heed the words of Einstein:

    Albert Einstein: "But before mankind could be ripe for a science which takes in the whole of reality, a second fundamental truth was needed, which only became common property among philosophers with the advent of Kepler and Galileo. Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts form experience and ends in it. Propositions arrived at by purely logical means are completely empty as regards reality. Because Galileo saw this, and particularly because he drummed it into the scientific world, he is the father of modern physics — indeed, of modern science altogether."

    It are exactly these words and sentiments which the dominant Stringy Inflationary Multiverse maniacs (and their regime's bought-and-paid for philosophers) must deny and disappear.

  • If not String Theory then what? Seems to me to be our current best hope at a Theory of Everything. Become famous, come up with a frame work better then String Theory. Good luck!

  • The conception of Popperian falsification espoused by Pigliucci and some others is incorrect and not at all Popper's view. The idea of logical falsification being sufficient for science is a conception attached to "dogmatic" falsificationism, which is even more oversimplified than so-called "naive" falsificationism–to employ Lakatosian terms. http://errorstatistics.com/2015/09/16/popper-on-pseudoscience-a-comment-on-pigliucci-i/
    As for the idea that philosophers of science have replaced falsificationism with Bayesian confirmation, well, I'm afraid that too has been falsified.

  • What I find incredible is that the article – and the scientists grappling with what constitutes good science – cite Karl Popper's concept of falsifiability as the basis for what constitutes good science – that is – a theory must be testable to the point that if it contains flaws, they will be revealed through tests. Their whole debate is whether they can abandon this seemingly robust basis for current science. Shockingly, what they seem utterly oblivious to, it that Karl Popper's falsifiability has been shown for several decades to be a NOT sufficient basis for what constitutes good science. Why? Because outcomes from test on theories can neither validate nor invalidate theories, when done in isolation. Indeed, Science Philosophy has already replaced falsifiability with a more recent concept called Auxiliary Hypothesis – as in – science actually works when loosely related bunches of theories either support each other over time, or not. A good example being cratering impact rates on the Moon supporting the age of the Earth. So these scientists are utterly out of date in even their premise! Anything after that is pointless. So their conference, and conclusions, have already been nullified – in as much as – science has moved on. Hence – it is insufficient even if far reaching tests validate far reaching theories – in isolation – because, it has been proved through logic that individual tests on individual theories can neither validate nor invalidate them! So they are in a worse position than they imagine. Of course, this is all beside the point in any case. What we're seeing here is a bunch of career-minded, impatient theoretical physicists who just want to by-pass real science so that they can get recognition – or funding – for their ideas. They say "the end of evidence" as if that is the situation for all time. Well, what if it takes another 200 years to devise experiments to test their theories? Why is that a problem? Whose agenda are they working too, and how long should it take humanity to understand the fundamental nature of existence? It's nothing short or arrogance that they think their ideas should be considered valid – just because they think they are good – let alone considering the arrogance to think they are right. The whole point of testing and anonymous peer review was to remove that arrogance that kept science at a snails pace for centuries; where demi-God 'experts' ruled until they died. But to underline the entire debacle, why would anyone ever desire their description to be accepted as in any way valid when the purpose of their work is nothing more than an attempt to describe the workings of nature – and they are calling for a situation where the checks to see if their description of nature bears any relation to reality be abandoned. What's the point of that? It beggars belief that minds of such mathematical and theoretical capability exhibit such devastating poor judgment and 'scientific intelligence'. Perhaps that's why they became theoretical physicists in the first place!

  • This meeting of physicists and philosophers is long overdue. Too long, many in the physical sciences have mocked attempts by philosophers to provide analysis of the pre-suppositions used – even to the extent of popularizing the mockery (I'm looking at you Lawrence Krauss with your book presentation an review you did in Sweden). As we delve into the depths of the microcosm, the attributes that we are ascribing are increasingly abstract, and so criticism of the pre-suppositions is absolutely necessary. I see recent work by physicist Lee Smolin with philosopher Roberto Mangabeira Unger as a great example of co-operation, with fresh ideas put forward with predictions that can be falsified. I believe that we are at a point where not only do we need people to work IN physics, but we need more sharp minds working ON physics itself – in the way it is practiced, in the way it is taught, and the way it is communicated to the public.

  • The problem the author and participants of this conference are wrestling with is fundamentally the main ontological problem of man as identified by Descartes. How can we know anything is true if we only have our senses to guide us? It turns out that continual doubt, i.e. "science" is the answer.
    However what gets lost is the reason this question was asked in the first place. Human beings have definite physical needs that require our work and understanding. These needs are met through technology. Thus the test for purpose is usefulness. "Truth" in the sense of producing a syllogism that explains what the universe actually is, may be beyond our epistemological abilities, and is in fact art, if it cannot produce technology. Producing technology that solves the reason we intentionally conceptualized metaphysical truth to begin with is the only purpose of science. And in an existential sense, with real world concrete consequences, solves the practical question of truth.

  • We have always suspended disbelief for a time to see where things lead. Irrationalities in mathematics comes to mind as an example. The square root of -1 makes no sense, surely, but if you follow along, the results come back as being testable.

    I see no problem in continuing along the veins that are being delved, except that we must be mindful of the language we use. We say "String Theory" but there is no connection between that hypothesis and reality, so we should be referring to it as the 'String Hypothesis" or the "String Complex." As long as we are careful with our language, sniffing up even dead ends is certainly defensible.

    And for those who say we just can't "go there," the obligation is upon them to come up with alternate hypotheses that are testable. The scientific establishment should be open to both.

  • If it cannot be tested and shown by experiment to be true it is not science.
    It may be an intesting hypthesis or a philosophy, or episode of Start Trek, and smart people may have worked on it but…so what?

  • There are a lot of questions that science cannot answer. To think that it can seems religious to me.

    onno

  • The overlap of Science and Philosophy is the development of tests or observations that can verify or falsify the Theory

  • Smacks of the Physics of Despair – "I've spent a whole career chasing this phantasm, and it's not been conclusively disproved, but it's not going anywhere either; so let's redefine 'correct' so that my life hasn't been wholly wasted." Sorry – pragmatism rules that out. If it isn't in principle (and, more to the point, practice) capable of disproof, it's not Science.

    Basically, some parts of Physics are moving into the realm that much of Mathematics has occupied for centuries, and needs to understand the mindset. If a description of the universe is rigorous and self-consistent, there's nothing wrong with that. But until it makes predictions, it is just a pretty mathematical construct. Which is not to say that it isn't worthy of further examination – plenty of supposedly-"pure" maths has proven to have surprising real-world applications in the past, as we all know, and there's no reason to suppose that such a construct may not be in principle capable of simplification or expansion to the point where it suggests novel, testable consequences – but the idea that we simply say "It's pretty, it can't be disproved, so it's RIGHT" is, frankly, rank idiocy of the first water.

  • Natural Philosophers (Newton), Geologists (Lyell), Earth Scientists (any modern Department of) – call them what you will, have rumbled along for three centuries with the greater part of its content (earth history) unfalsifiable in what would turn out to be (at least a couple of centuries after it started) the Popperian sense. To put it very bluntly you cannot experiment on a dinosaur, you cannot impact a large asteroid in the Yucatan to see what will happen, you cannot regenerate an early Pleistocene Ice Age and watch it suck water out of the oceans, or depress the earth's crust, and alter natural environments. Virtually everything we know about ancient events has been learnt indirectly, with great ingenuity, and the same can surely be said about deep space astronomy?
    Is there a lesson to be learnt here?

  • Too much conflict starts from a premise that you can draw a pie chart of the various opinions on a subject such as religion or politics as examples, and decide by popularity, the numerical divisions are drawn, opinions ranked or evaluated against some scale or other. It is a contest, the winners are those with the greatest score while the losers are the ones who score the lower. There can be only one winner in a race… and this is a race to the bottom. An example is the eternal struggle for religious supremacy on the earth. The Christians and their many sects are “winning” by dint of numbers and other groups are currently “losing”. Attempts to change these ratios have included coercion, intimidation and brute force. The winners get to set the rules for all losers. These are the tools of the Institutions which forge the political/religious structure of this world. In the end maybe the Buddhists were right all along. In numbers… they just do not rate that highly in numbers at any point in time, but their approach is from “outside the box”, and by their own unique definition of success are “winners” by draining the “Pooliverse of Opinion” of it's best and brightest. A “Oneness” rather than a “One”. .. completeness rather than the biggest remaining part… the “distillate” rather than the “dregs”.

    In the matter of Science there has been a similar debate. Out of the Enlightenment came the Light on the Hill, testable science. It created great advances in thinking. It marginalized all religions based on beliefs and raised up rationalism based on experiment. The book they based this revolution on was not the Bible but the Encyclopedia. Today the Empiricists vs the String Theory Proponents searching for the ultimate answer to Life the Universe and Everything. Currently the “winners” are the Empiricists with the “runner ups” beating at the door as a possible successor. Nobody cares that there may be other ways of approaching this problem. Both of these groups are making a race to the bottom… towards total deconstructionism… the race is without a finishing post and almost everybody has suggested there is no experimentally derivable answer to this “contest” anyway because as the nominated instruments (LHC) probe higher and higher energy scales without any natural limit, all the String Theorists have to do to “win” is to keep modifying their process and at the same time suggesting “vaguely” their approach has produced some useful results of a sort. I think the claim for their “clear indication that we are on the correct path” lies with the “discovery” that at the heart of everything there is a reciprocal symmetry that has been called T-Duality and perhaps also S-Duality. On the largest scale there is a symmetry that connects it with the smallest scales… a reciprocal relationship.

    It is one of those dirty little secrets that this String Theory “discovery” is not that obvious when you consider that this is a connection with Juan Maldacena's AdS/CFT Proposition. And that theory is compatible with the same symmetry as the one found in Fourier Theory probably first enunciated in 1815 by Joseph Fourier… the “reciprocal space” of Fourier Theory connects with our real space through a simple reciprocal relationship. The Theory can be easily extended to as many dimensions as needed and to include time. A very useful and practical experimental concept. You don't have to “believe” in a String Theory at all, it just works. Space replaced with “reciprocal space” (reciprocal lattice of crystallography are points arranged in a lattice) and time replaced with reciprocal time or “Frequency”. Is it no wonder that the LHC “discovers” a lattice symmetry which converts spacetime to point scattering function? From this original concept of Fourier sprung a natural version of Heisenberg's Uncertainty Principle. It is a duality theory that transforms “waves” into “point particles” and visa versa. It is “assumed” that these two interpretations are equivalent. But to “assume” is to make an “ass” out of “U” and me”.

    There is more to this as well. At the sub-atomic scale there is a “new connection”… a new symmetry that connects all point particles and their associated entanglement with waves… virtually universally. It is called quantum entanglement… it is much more than the deconstructionism we have seen before where the theory of deconstructionism meets it's match in a Holographic Theory of Everything where everything in the Universe is “ultimately” connected to everything else. It is also a theory that shows that Information in the past is never lost but may be revived.. the Beckenstein Bound of Black Hole Theory. It opposes the Theories of the String Theorists and the HEP Experimentalists who are both deconstructionists, or even the Cosmologists who don't know which side of this discussion they are on yet (but can wait it out)… the direction to approach this problem might very well be from universal connectedness of an implicative order as indicated in David Bohm's Book “Wholeness And The Implicate Order”, 1980. Bohm could be called Einstein's "understudy".

    Maybe in the struggle on the way to get to the bottom through a process of absolute deconstructionism, we should have looked around and “sniffed the daises”. You can't know “everything” about the Universe by simply inspecting smaller and smaller fragments at higher and higher energies without limits. It is “tunnel vision”. We need to stop and take a page out of the study of Condensed Matter Theorists. Every modern theory of physics is capable of being simulated using a quantum simulator. If the physical theory you are searching for cannot be simulated in a “naturally” suggested way, using a quantum simulator, it is highly probable that the theory does not exist in the real world. That means you need to simulate the strings or the branes of the String Theorists to show that at least they are cognizant with an ultimate theory of everything first and that that theory is deconstructionally “simple”. I believe an analysis of that problem, even theoretically, will show that the assumptions of “strings” is not deconstructionally “simple” as a functional quantum program, since something smaller than a single string will be required to simulate that system in it's entirety, in a “real world”. It will fail. Those who suggest otherwise should prove their conjecture through a real experiment.

    The recent attempt to show that the Universe was a hologram – Hogan's Holometer – failed probably because it was based on a String Theory Interpretation of the Holographic Universe Theory. As all string theories at present are, it was just one of many untested classes of string theories that was tested, certainly was not like the experiments on the LHC where the bulk of the scientists working on it were convinced they were on to something “big”. It was a “cleaver” experiment, but it did not settle other interpretations of how a Holographic Universe “works” in the first place. That view proffered by a string theorists, was probably not wrong, it was not even wrong. This simply because to know it was “wrong”, you first need to know what is “right” and then compare the two. What we might suggest is Hogan's Theory of Strings was not the Real Theory of our Universe. You cannot reverse the argument and say the Holographic Theory of the Universe is proven “wrong” as a result. It was a reasonable argument to infer this approach to prematurely stifle a really good theory that can still be tested. We need to know how entanglement works at a deeply functional level.

    There was nothing “uniquely” correct about how Hogan's String Theory was to find a resolution to the ultimate question. The theory is not falsified by the experiments failure. Perhaps rather than deconstructionism we need to look far more carefully at the Holographic Theory and at Quantum Entanglement in general (which appears closely related). If the entanglement we see at the largest scales (bar the last few scales), it appears to me this phenomena might have “frozen out” of the Universe subsequent to the Big Bang. A remnant still appears. Yet at the coldest temperatures and even at room temperature, these phenomena persist not only in gases but in biological systems and if in biological systems links into our theory of mind and the way we appear to entangle mind with quantum theory itself. Currently we do not know this mechanism that appears to link every “point particle” through a wavelike connection to everything else in the Universe, that is if you extrapolate this process way back to the Big Bang and possibly beyond. That limit leads us to where these limits are currently placed, on the inside wall of a black hole in which the total Information of our Universe may be distilled in it's super-fluid surface as raw information in that apparent two dimensional surface. A surface that is not to be subjected to ultimate deconstruction.

    It may be that every Universe is just such a quantum state (the wavefunction) and all particles are Black Holes of some sort and every Universe is a de-facto quantum computer because that is the way the Universe ultimately works whether they are "synthetic" Universes or not. The ultimate nature of the Universe is just a global wavefunction, and "reality" is just the way our "senses" interpret it using our "mind". It could be that a single indivisible "matter wave" Hologram is what connects the large to the small processes at all scales provides the answer that the deconstructionists are searching for. That might be testable at any scale.

    So instead of String Theorists or the Empiricist LHC Deconstructionists, both groups have it wrong and maybe the Universe is finally a Hologram on the surface of a black hole (… our black hole), a theory that cannot be believed by the majority (who are deconstructionists at heart).

    This “Crusade” for Ultimate Truth cannot be “won” or “lost” to the numbers. It is not just here and now that we decide the rational basis of Science or decide that there is no rational basis but a philosophical one that gives "rest". Science is not to be decided on by a show of hands. Scientists are also not “high priests” who dispense “Truth”. Truth is always a minority concern in this world of “loudest voice” conquers all, a still small voice may still be saying “You can't get there from here”.

  • A basic comment from a non-scientist: could it be that a single unified theory of everything will never be found?
    Recently I watched a BBC4 documentary about Einstein's achievements,and found myself wondering about this.
    Is there an essential aspect of nature which defies a tidy unification?

  • There are quite afew unsolved problems in physics ad cosmology. All this methodological wriggle makes me giggle. String Theory not a sure thing? Yes!, but what abou tBig Bang Theory (for instance)?

  • I highly recommend the article "A mathematical framework for falsifiability" in Physics Today by Ilya Nemenman:
    http://scitation.aip.org/content/aip/magazine/physicstoday/article/68/10/10.1063/PT.3.2929

  • We need an understanding of man kind’s place in the cosmos. For calibration purposes let us go through some numbers: our Universe originated 13.8 billion years ago in the Big Bang; our planetary system was formed 4.7 billion years ago; the first primordial bacteria originated 3.7 billion years ago; the first animal organism originated 590 million years ago; homosapiens emerged from the animal kingdom 2-3 million years ago; our direct ancestors, Cro-Magnons lived 50 thousand years ago; the first civilization was in existence ten thousand years ago; and science as an organized activity began 500 years ago. Based on such calibration, one cannot escape the conclusion that we humans are an emerging embryonic-stage intelligence. We should be proud of what we have been able to accomplish in such a short period of history. Our science is very young. For us to show impatience and declare that we are approaching the ultimate scientific truth, such as the Theory of Everything, is presumptuous and naïve.

    The string theory drives development of theoretical physics toward an impasse, providing no visualization, no explanation, no predictions, no experimental confirmations, no applications. It is nothing but exotic mathematics possibly understandable only to a small group of string scientists.

    String theory is pseudoscience – what a waste of talent and effort. Vibrating energy strings is a misconception. The principal mode of existence of elementary particles is spin. That includes spin-0 particles with two opposite one-half spins. Humans can easily visualize such spinning in 3D space.

  • As long as physicists insist on expressing quantum mechanics through classical mechanics this problem will exist. Non locality may or may not be the actual nature of the subatomic world, but the observed phenomenon is limited not just by the observer, but by the classical mechanics they use to describe their observations. It is hard to imagine that radio, television and the internet could even be possible without the language of calculus. It is possible, perhaps even probable, that if hunches such as multiverses exist, a new language that is distinctly different from, but at the same time harmonious with classical mechanics might facilitate affordable technology allowing actual measurement of this phenomenon…if multiverses do exist.

    It seems inevitable, after discovering the quantum world but declining to write a new language to express it, that this new paradigm would lead to a divorce with the scientific method. After the divorce, it seems inevitable that more and more science would divorce itself from the scientific method. A scientists job is to protect the paradigm, but this is not the job of the the scientific method. The protecting of the paradigm, it seems, tends to stultify scientific progress.

  • I'm surprised to see no mention of Lee Smolin and especially his work with philosopher Roberto Unger in their recently published "The Singular Universe", Cambridge University Press.

  • Birds of endangered species are blissfully unaware that their continued existence depends on ornithologists persuading the rest of us that they are worth saving. But of course scientists are much smarter…

  • “A basic comment from a non-scientist: could it be that a single unified theory of everything will never be found?”
    There cannot be a final unified theory of everything, for one simple reason: the Universe is open-ended and evolving. A Grand Unified Theory (GUT) would mean it is invariable, static and dead.

  • Doesn't look like the identification of Bayesian statistics with the "philosophy of science" is universally accepted, at least not by the Bayesian statistician Andrew Gelman:

    http://arxiv.org/abs/1006.3868

    Too bad that this article which is out since 2010 isn't more discussed. Instead the priors are just restated.

  • Alternative means of arriving at 'proof' are perfectly OK to discuss, but they have a pretty high level of danger to them. We have utilized such means in the past. And their result has been genocide, supported by 'science'. It has been birth defects, death, disease, racism, and more, backed by 'science'. Those who are comfortable assuming responsibility for the wholesale destruction of human life, and of the creation of sources of boundless suffering are dangerous people, indeed.

    It is not inappropriate to point out that certain methods of determining truth can and have supported disgusting conclusions in the past. While some may find the topic offensive, it must be broached. The tragedies of the past (at least those which were supported by prevailing scientific opinion of the time) universally lie at the feet of cutting the most inconsequential-seeming corners at the time. They seemed so consistent, so CLOSE to being true that their lack of complete proof seemed irresponsible and excessively hard-lined to permit to stand in the way of their adoption.

    If your proposed 'new method of discovering knowledge' can not avoid supporting eugenics, opposition to the germ theory of disease, supporting the use of drugs which are safe for children and adults on pregnant women, supporting the widespread use of leaded gasoline, supporting the ideas of racism and sexism, when given only the scientific knowledge which was known at the time those ideas were errantly supported by the scientific community in spite of them all falling short of the rigid traditional criteria of proof, then I will personally fight fervently to oppose it. Call me old-fashioned, or a stick in the mud, or paranoid, or hyperbolic, or whatever you wish, but I will not personally be responsible for any portion of the acceptance of an idea which those of the future will look back upon and be able to say "they had the tools and they should have known better."

  • I have a naive question. Why isn't astrology considered a scientific theory (albeit a very wrong one)? Indian astrology seems to have a semi-logical structure. It can be roughly tested. It was tested many times and proved to be wrong. Why isn't it then similar to the knot theory of atoms proposed by Kelvin? Same question holds for indian traditional medicine (ayurveda).

  • Very glad to have stumbled onto this useful report on a meeting I would dearly have loved to attend. I appreciate the references to 3 books I missed, and I will watch for other articles by author Natalie Wolchover.

    Is there more detail to be had on the curious "map" of fundamental theories explaining or justifying the associations?

  • When the subject of physics is not testable (as is the universe as a whole), the physics becomes a metaphysics. The question then is: Is the metaphysics possible as a science?
    This is precisely the question of Kant’s Critique of Pure Reason.
    About this dilemma of modern science someone did a doctoral thesis and published a book in 2004, but I can not give more details here.

  • Since I am not a scientist and have no depth in understanding the intricacies of the various conflicts in the discussion I cannot even take my own comment very seriously. Nevertheless it does strike me that elements of the disturbance are tied in with language as to the nature of truth and why that label is of concern. Human minds differ a great deal and my involvement with mine has taught me something of the limitations and acrobatics of that one which may or may not be generalizable. My most useful tool in puzzling out the nature of what seems to be is analogy, which is taking what seems to be and figuring out how that fits into what I find acceptable.

    I think of myself as a curious rather hairless primate picking up various locked boxes and sticking small found objects like toothpicks or hairpins ir rusty nails into the keyholes to discover what my be inside the boxes. Many boxes never even get open but enough do that either can be rewarding, like a tasty wedge of cheese, or a small telescope , or a plastic whistle that a curious monkey can find amusing and I can toss it into my small plastic bag with the word TRUTH printed on one side and drag it along in my explorations.

    I have recently found a strange object in one open box that was shiny and glittered brightly from a box labeled "entanglement". It somehow appeared to be a key to other boxes but, so far, it hasn't fitted any other locks. It's in my bag and I keep trying but so far I haven't found the right box. Still, it seems valuable, and it's in my bag.

  • Hello Purushottam,
    The sense you have of connection (astrology & science) is astute & well founded. What can be said is that astrology as seen to be and practiced now is not science. The reason though, is much more to with the world-sense and goals of its practitioners. Simply put, we have science in our day, and so that's the great attractor for those with a objective-truth seeking world-sense, by and large; and not astrology. Which is one reason why astrology now gets ever more puerile and the connections with science ever harder to see.
    But go back to the 15th century and the astrology then, was really not anything like it is now. It was taken very seriously by the best minds in that day. Truth seeking minds. And that makes it something other than what our minds assemble with the word 'astrology'. Back then it was not only the closest parallel with modern science, but along with alchemy it was actually what Science emerged out of.
    Do you know what Isaac Newton's university chair actually was? It became about mathematics but primarily that was in hindsight. It was actually the chair for astrology. People dismiss that as if it was just rubbish and cobwebs that Newton cleared away. But there was no such thing as mathematics in the perception then. Maths was a tool that got certain done. The idea of it being, itself, a core subject or even a subject at all, would have been totally counter-intuitive. There wasn't a single chair in Europe for anything other than astrology and never had been.

    Maths came into existence as the thing we know today because of among some others more peripheral, two powerful drivers at the time. Cartography – people realized they need to improve mapping due to the explosion of travel and communication. And astrology – people believed it must be true, but they had long realized that it wasn't working. The reason they thought most likely was that the charting needed better precision. If they could improve the rigour and standards of the readings, the paradigm would begin to work.
    It was really the actions taken in trying to make astrology deliver, and the things along the way that distracted and elongated the paths pursued in pursuit of that, and how they eclipsed the original raison d'etre in terms of promise and fascination that brings us here.

  • Hello Roy Teddoff, you said "I'm surprised to see no mention of Lee Smolin and especially his work with philosopher Roberto Unger in their recently published "The Singular Universe", Cambridge University Press."

    I would have to agree strongly with you – but only if we could find a way to express that in a way that inferred criticism of the article least, or last, or not at all. Natalie Wolchover's piece is high quality, useful, timely and clearly well thought through.

    There is always something that by-rights, fairs-square, deserved to be in, and should have been. But had that thing been kept, the balance would then, by-rights fairs-square shed light on some further thing.

    I think the judgement call of the writer where to draw the circle and close things off where to close things off is well into the territory on the right side of reasonable.

    With all of that said, I do think you are right. I think you mention a stand-out case.

  • Schwab says: I highly recommend the article "A mathematical framework for falsifiability" in Physics Today by Ilya Nemenman:
    http://scitation.aip.org/content/aip/magazine/physicstoday/article/68/10/10.1063/PT.3.2929

    I had a look and her abstract permits me to say two things despite not reading further, and not currently planning to.
    1) Just in general, isn't it just one of those absurdities of our day, that at the very moment science approaches its darkest hour with the scientific method no longer working properly and/or no longer being put to work properly AND no good ideas why or what to do about it……at the very same moment as that, suddenly everyone has the scientific method nailed. Good tidings for sure. The crisis isn't real. Sort of, this season's multiverse.

    Everyone has an "all we gotta do" but no one makes a theory out of their idea and publishes that with its predictions along with their "No sh** Sherlock" all-we-gotta-do. And in the end, you have to question that.

    2) She mentions statistical approaches as the answer. When statistics, itself, is in crisis and very much part of the crisis.

  • I think the Kantian project of creating and connecting to foundational knowledge is over: we no longer seek stable, eternal, total descriptions of the world that are consistent and coherent. All that is bound up in old assumptions about what the world is and how we can know it.

    Nowadays the goal of most human activity, even science, is intersubjective agreement about what to do next, as Rorty put it. Science is one form of social action that, practiced well, can take us beyond the accidents of our personal prejudices and predilections, and broaden our intellectual vistas as Dewey probably said.

  • Seriously, this is a question that Aristotle solved nearly 2,500 years ago. He put the stuff he could test in the chapter Physics, and then put everything he couldn't test into the chapter that came next: or in Greek, Metaphysics (meta meaning after).

    Science is physics; String Theory is metaphysics. It isn't Science. Now this doesn't mean theorizing about String Theory is intellectually devoid of meaning, little detailed thought ever is, because one needs to probe the metaphysical realm in order to bring new fields into the realm of Science. Even failures can teach us something. However, those who confuse the two, who demand that metaphysics be treated the same as physics, that pure thought has as much value as empirical evidence. Well, that is where you enter into the more disreputable realms of theology.

  • Hello John Walsh, I have saved your comment to file. I found it very useful….you appear to know what you are talking about. It's hard to be so symmetric and rather beautiful in prose unless you're in a vein of truth.
    I want to better understand. To that end may I ask you to bestow a fulsome answer to a sticking point that I have?
    Why in string theory when we discover a duality involving, on the other side, a theory pre-existing strings, or otherwise not from String Theory, how come we always discover precisely that theory without adding to it, or taking away from, at all?
    I feel sure you see the problem here? the proposal is that this other theory is re-discovered in objective-space, without any psychological conscious or unconscious directing in play. Therefore the implication is that these pre-existing are absolutely perfect; god's own breath.

    That's very problematic. Or is it?

    Also, because the process of deriving these dualites involve over-complete functions that are adjusted consciously so as to fit the other side and make a duality, how is it possible for that duality to be fundamental….unless the adjustments are also fundamental? And if they are why are they left out?

  • Hello Purushottam, I forgot my answer for what you actually asked. Not forgot my answer as in forgetting what my answer was, but you know, forgot to say it.

    The fact India has embraced Science means the same brain drain away from things like astrology has happened in India the same as it would anywhere else. Of objective-truth seeking
    people.

    But the fact India embraced science relatively recently plausibly puts that brain drain at an earlier stage. And what that could mean is that some of the best authentic objective-truth seeking minds, are still in things like astrology. Particularly among those at or near retirement age, it's more than plausible there's vastly more talent in those fields in India, than in the West where that brain drain has been in play longer.
    I don't know if that adds anything for you, to your thoughts. But it's a way for which your perceptions could be true. That things like astrology over in India are not nuthin' the way they are, now, in the West.

  • To me the whole discussion is silly. It's one thing to use Bayesian to help decide whether you, personally, should pursue a given area of inquiry, but to suggest it as a valid way to confirm a theory which has no empirical tests is ridiculous.

    Note that I strongly disagree with the notion that just because String Theory currently has no empirical test, it has no usefulness and should not be pursued. I'm all about knowledge for its own sake and there is no doubt that history is littered with examples of results with no evident practical purpose turning up as key elements of great discoveries far into the future. Further, mathematical beauty is not something that should be easily dismissed even if the result is strictly esthetic.

    Unfortunately, this "Fight for the Soul of Science" is more properly termed the fight for funding and justifying one's existence in my opinion. Instead of misapplying Bayesian, why not just admit that your area of research has no practical value right now but it is worthwhile pursuing for its beauty alone? There are lots of people who would have no problem with that. To me it's much better than trying to hide the issue of what little String Theory can tell us about reality, which is nothing at the moment, behind a cloak of "credences."

    There is no crisis. It may take a long time before we can see a way beyond the current empirical impasse but we have no good reason to stop trying. Lastly, I agree with the person who commented that sometimes it's just necessary to take a step back and re-evaluate our most fundamental assumptions. Consider non-Euclidean geometry. If we allow a cadre to dictate what is worthwhile to pursue and what is not, we may blind ourselves to important alternatives.

    In a nutshell, get real.

  • It is selling Newton woefully short to claim that "Then, in the 17th century, Isaac Newton ignited modern science by breaking with this “rationalist” philosophy, adopting instead the “empiricist” view that scientific knowledge derives only from empirical observation." Instead, his approach featured tight interaction between theory (reasoning) and empirical experiment, i.e. a combination of rationalism and empiricism in which the products of the intellect are subordinated to the verdict of evidence ("nature"). Nowhere is this interaction more concisely demonstrated than in the "experimentum crucis" described in his Opticks, perhaps the single most elegant experiment in all of science.

  • To Purushottaman:
    You are quite right. Astrology is just a theory proved wrong. I had the same reaction to that passage in the article.

  • Are string theory and the multiverse somehow related to Milgrom's MOdified Newtonian Dynamics (MOND)?
    "I did encounter much opposition and sheer disregard, and this was against my expectation." — Mordehai Milgrom
    Google "witten milgrom" and "mcgaugh dark matter youtube".

  • >> As for what was accomplished, one important outcome, according to Ellis, was an acknowledgment by participating string theorists that the theory is not “confirmed” in the sense of being verified. “David Gross made his position clear: Dawid’s criteria are good for justifying working on the theory, not for saying the theory is validated in a non-empirical way,” Ellis wrote in an email. “That seems to me a good position — and explicitly stating that is progress.”

    I am not sure much has been accomplished. Certainly not an acknowledgement, at best a clarification of positions.

    I have not never heard a single string theorists say that the theory is confirmed. I heard many say that "it must be true" or close to the truth or the only alternative we should work on, and that's why we keep on working on it to understand the mathematical structure better and to get to falsifiable statements that can be experimentally tested.

    An interesting economic/social question is for me: How much time and brain power should be used to work on it?

  • Hypothesis , theory and experimental verification- all these are part of science.
    String theory supposed a particle as a point and with velocity is a string. It has gone up to some distance. It can not be accepted as a complete theory it it gives some predictions that are possible for experimental verification(direct or indirect). If some other school of thought arises with more logical network it may provide some more deep insight and may give conclusions that can withstand for present experimental outlook.
    In the same way, Multi verse theory is right if we think Special theory of Relativity is wrong. If we think Special theory of Relativity (which limits velocity of light) is right there will not exist multi verse. Only one universe exists consisting an expanding space.
    These things require deep thought(philosophy ). Nothing is pseudo science. These are all part of science.

  • Unless string theorists can hold out the prospect of creating a "String Bomb" with which to unravel our enemies I have to consider their activity to be mathematical art, not science. Why can't scientists accept that they have reached practical limits and focus on searching for the vast array of harmonies waiting to be discovered within those limits?

  • I'm not sure how you'd falsify the theory of evolution, but there is excellent evidence that one of its components (descent with modification) is true. You can transplant the genes for some human proteins into yeast and have them function just as well as the original yeast protein.

  • My primary concern with the excellent issues raised by this article is: What % of great modern physics minds might make more practical (yet exciting) discoveries if they take a more "looking for keys under the lamplight" approach that tethered theory more closely to what is measurable?

    Because the antipode of this question is the danger that too many great minds are flitting self-indulgently after aesthetic self-creations and losing all sight of the original animating premises of science. There is a feeling of license, of self-indulgence to it, and I think science really is being reputationally damaged.

  • Allow me to point out the elephant in the room. The issues addressed in this (excellent) article are the result of a government program called "science" which, like every other such program, lacks the self-correction inherent in a free-market system. Science as a free-market activity is about producing useful products for consumers, which means that theory necessarily never strays far from practice.

  • If a physics theory is not Popper falsifiable in principle, then it should be classed as bad if not bogus pseudo-physics. That said, it is too early to believe that ideas of the multiverse and string theory are not Popper falsifiable.

  • As one who, alas, is more a student of mysticism than physics, let me try to bring that perspective to bear. All mystical systems tend to agree that as an individual intelligence ascends to higher planes of comprehension, its perceived sense of individuality begins to dissolve. So the ultimate mystical insight is fundamentally monistic — the separate mind merges into unitary consciousness. The separate mind is thus taken to be a false, provisional construct. Only universal consciousness is ultimately real. The dualism of self and other is limited and inadequate. For mystics the limitation of the scientific method as generally practiced is that the procedures of testing and observation are intrinsically dualistic and therefore cannot approach ultimate truth. The Newtonian universe is obviously dualistic.

    My wholly naive and unscientific intuition is that Einsteinian physics, quantum mechanics and string theory in all their present collective messiness are pushing cosmological inquiry inexorably toward monistic models. But the attempts at exploring and explaining these models falter because they remain locked into intrinscially dualistic descriptions. So the answer, if there is one, requires expanding our sense of what is true beyond experiments based purely in nature to encompass the greater totality of monistic non-descriptive experience. Don't ask me how exactly you get there (or how you get there in ways that accommodate some level of public verifiability), but I think that is the essential problem.

  • From my view, this is not the path where physics should go. Without experimental verification, there is no difference between science and religion, or politics for that matter. There is already significant among of collusion in many fields of science at the highest levels, where factions of people rubber stamp each other's papers, push research in their directions while benefiting themselves. Without possibility of verification, then the theory with the most political support will win. Beauty is of course in the eye of the beholder, nature doesn't have to have our sense of aesthetics.

    There are still plenty of important problems that require theory and experiments working in close tandem. Biology is clearly such an example. We haven't even begun to understand principles and mechanisms of the biological world. It is also a field where good experiments need to be done. Physicists should stop with the fetish of 'theory of everything' and admit that there are other possibilities. Dark matter is one of these fetish examples which would never happen in any other field: To explain the discrepancy between theory and experiment, we invent a missing mass that doesn't do anything else, just so that the theory fits. In any other field, the theorists would go back to the drawing board. This privileged position of theory is purely cultural and needs to change for physics to progress.

  • The article misrepresents the concept of falsifiability, particularly when it uses Astrology as an example of a theory that is falsifiable and thus concludes that falsifiability is either invalid or irrelevant to the validation of any theory. What the author – and others who discredit falsifiability – are saying is that falsifiability is a SUFFICIENT condition for the validity of a theory: they misrepresent falsifiability as being sold as the ONLY requirement for a theory to be valid. Obviously, this is not true. All scientists know that falsifiability ALONE is not sufficient to validate a theory (whether that theory is String Theory or Astrology, or any other). Validation of a theory requires many more inherent conditions and active processes to occur than falsifiability alone, which is what this whole String/Mulitverse controversy is all about. When they make this misrepresentation of falsifiability as being a sufficient quality to validate a theory, they can then point to Astrology and other invalid yet falsifiable theories and say "See, falsifiability is a red herring – it won't distinguish unscientific speculation from scientific theory." What they are not stating, even though they know this to be true, is that as a criteria of scientific theories, falsifiability is a NECESSARY, though not sufficient, condition: First, a theory must be falsifiable, then it must be verified by some empirical information, then it can be validated according a Bayesian or other measurable standard. If a theory is not falsifiable, that simply means that no amount of empirical information can EVER be gathered by ANY empirical means whatsoever, so its validity can NEVER be determined. It's still a theory, and there's nothing wrong with anyone working on it to whatever extent they so choose, especially if they can get funding and/or academic jobs and/or academic publications out of working on it. Perhaps, if enough people continue working on a non-falsifiable theory (including Astrology) for enough time, some day newly discovered empirical methods will be developed that will allow it to be empirically tested (the infinite monkeys with infinite typewriters and infinite time model). For example, the early Greek and Indian atomic theories were not falsifiable when they were developed, and hence were not scientific theories in that era – they were philosophical theories. That doesn't mean that atomic theory was pointless and somehow harmful before it became falsifiable, it was merely not scientific – yet. Continued theoretical work centuries later, and the even later addition of new empirical testing methods, eventually came together to provide the opportunity for a true science of the atom and truly scientific atomic theories. So, for now, String/Multiverse theories are strictly philosophical in nature, not scientific (I presume I don't have to explain why mathematics alone cannot replace empirical evidence in verifying and validating a scientific theory), and they represent no danger – and some possible future opportunity – to science and scientists AS LONG AS all claims that they are The Now Correct Scientific Theories of Physics – or that they are any kind of actual scientific theories of physics – are consistently rejected by the scientific community until they are made falsifiable.

  • I post the following comment here only because I first tried to post it (without apparent or immediate success) in the Disqus Forum at The Atlantic, which picked up and published this article separately. My rationale for posting my comment here is found in the parenthetical adjunct below.

    In other words: in the medieval period philosophy was pleased to be regarded as "the handmaiden of theology", whereas in the modern period philosophy has consented to become the whore of science.
    A distinct pity that with all those Austrians and philosophers of science roaming and roving through Munich for this conference, not a single admirer of the late Paul Feyerabend could be found. Surely, THAT phenomenon would have brought liveliness to the proceedings.

    (This comment is being re-posted explicitly because some Atlantic word-parsing machine or editor appears to be adjudicating propriety with neo-Victorian regard. Do the editors of Quanta exhibit identical scruples? or do the editors of Quanta endorse The Atlantic's preferences for scruples-enforcement?)

  • This reality is that the soul of physics is on a path to irrelevance. The dream of physics has been to find some ultimate truth. The fact of science is that there is no ultimate truth. There is no way to be certain what more random information of some practical value that physics might stumble on. But, most likely physics has already found everything of practical significance it has any potential of finding. The focus of science has turned towards the understanding of the specifics of the chemical system that determines our being and the rest of life. Perhaps some day the results of that effort will help us understand why some people are prepared to waste their time dreaming about mathematical models that have so little potential connection to the real world of their immediate experience that there is no possibility of testing them.

  • From a mathematician's point of view, I've never understood the idea that string theory needs experiments to be interesting. String theory is pretty obviously a (beautiful, deep) piece of mathematics. Maybe there are pieces that aren't completely rigorous yet (that's ok, often that takes quite a while)– it's far enough from my area that I don't keep up with all the details. But the fact that it's neat math is certainly enough reason to work on it (and to fund it, for what that's worth).

    Whether it describes the physical phenomena that it was originally designed to seems to be beside the point. A lot of work on ordinary differential equations was quite explicitly motivated by concerns arising from Newtonian physics (experts– I'm thinking about Poincare, dynamics, and the three body problem here). Nobody thinks that theory became meaningless or uninteresting when we realized that Newtonian physics was only an approximation.

    So string theory, like ordinary differential equations, seems to have a wide variety of potential uses. Perhaps one of them is a theory of very small length scales. Perhaps not. If you are personally a string theorist, this question is deeply important. But if you aren't, there's no reason to worry about it. Virtually every mathematical theory with sufficient depth seems to turn out to be useful for something eventually (often something very different from what its' creators originally intended) and you can bet that this one will, too.

  • Let us imagine that 500 years ago, some thinker had developed exactly the theory that Einstein developed, complete with the exact mathematics. At that time, no technology existed to falsify or verify the theory, so in some Popperian sense the ancient theory would not be "science". But, it would be true. Or, suppose further, that the ancient thinker thought of the exact way to test his (actually true) theory that was used to test Einstein's theory, but because of the limits of technology, the ancient thinker got a negative result, thus "falsifying" his theory. But he then merely got a false negative because of the limits of technology, when in fact his theory was true. Yet, eventually an Eintsein would come along, and technology would have developed, so that a theory that was declared "false" 500 years ago becomes the new science. One could conclude that "falsifiability" (at least, present falsifiability) is not a sufficient criterion for demarcating what is worthy of scientific inquiry from what is not.

    "Science" is a process, an inquiry. Of course it is hoped that an inquiry will yield a result that can be tested and replicated. "Falsifiability" is a test of the product of that inquiry, not a standard by which to judge whether the inquiry itself is worthwhile.

    The tools of science should legitimately include statistical methods such as Bayesian analysis. We cannot hold the universe in stasis while we search for answers, relying only on deductive reasoning. We cannot roll back time to before the moment of the Big Bang (if there was one). We cannot see the Universe beyond its furthest source of light (if there is one). And we certainly cannot see the multiverse, if it exists. Deduction and inference are all we have as tools.

  • About Smolin and Unger's <i>The Singular Universe and the Reality of Time</i>; I am a fan of Smolin's background independent physics as no more falsifiable than the Standard Models, but I was horribly disappointed in 'Singular Universe'. 'Nuff said.

    About Bayesianism; Edwin Thompson Jaynes is sorely missed.

  • The progress of humanity depends on the progress of science. The progress of science is the ability to at least explain and predict observations. This makes science useful to humanity.
    Examining paradigm shifts in the past suggests the plethora of unexplained or ad hoc explanations of observations leads to new models that correspond to older models in their domains and unite several models.
    We already have such a plethora of observations. Yet, a great deal of time and money is spent of projects that are based on models that haven’t ment the first level of coordinating with existing models. I suggest the dark matter and dark energy models are in this category. Perhaps science can proceed faster if we scientists spend more effort thinking of ways to unite existing models with the problem observations. A speculation should lead to a hypothesis (test) fairly fast. If the speculation cannot yield a hypothesis, it is thinking too far ahead. Thus, the effort is probably wasted. This slows the advance of science. I put string theory (metaphysics) in this category.
    It’s time to think though the problem for a new paradigm.

  • Yes, astrology is "falsifiable", and "has been falsified". So how does that make the criterion of falsifiability ineffectual as a criterion for judging whether something is scientific or not?

  • Theory of everything (string theory or whatever) can not be a science in the classical sense of the term. Not because of technology but of ontological considerations.
    When human knowledge attempts to rise to the entire universe, it must include himself, and then it bumps into this dilemma: if its object is something real or a purely imaginary one.
    No physicist could ever circumvent or break this dilemma, because no one can empirically determine the edges of the universe ‒ "everything" is an undetermined object, non-experimentable, a purely numenal one, which can not be seen from outside.
    The only one who can help us in this discussion is Kant, with his critical solution to the four cosmological antinomies from the Critique of Pure Reason.
    Without Kant we can not get out of this epistemological dead end of modern physics.

  • In the opening paragraph, Ms. Wolchover quotes Dr. David Gross as paraphrasing a Richard Feynman quotation when he said, [physicists] "need philosophers and historians of science like birds need ornithologists,”. Wikiquote thinks this quotation is apocryphal or a misattribution . The earliest I have ever seen the quotation is in John Barrow's book THE WORLD WITHIN THE WORLD where on p. 10 [ 1988, 1st edition HC] Barrow wrote, "Philosophers of science have argued long and hard over the meaning and concept of a 'Law if Nature'. These arguments have had no discernable influence upon the practice of science: most scientists being sympathetic to the prejudice that 'THE PHILOSOPHY OF SCIENCE IS ABOUT AS USEFUL TO SCIENTISTS AS ORNITHOLOGY IS TO BIRDS' (notwithstanding the observation that some species of bird owe their continued existence to the interest of ornithologists."

  • As a non scientist I feel the need to ask what seems to be a very straightforward question of those who know.

    I continually see people saying "the word theory doesn't mean the same in science". They go on to explain "a theory is not a proposed idea, that is a hypothesis. Once there is evidence that a hypothesis is correct it becomes a theory".

    Why then do we say "string theory" not "string hypothesis" ?

    A fascinating article.

  • “If you define reality by mathematical convention, you get a conventional reality.
    But actual reality is what is, or could be, perceived.”
    Henry Bergson “Duration and Simultaneity”, 1922, p. 90

  • An excellent article. As a student of Philosophy of Science I was very happy to have come across this fine summary of an important conference. One point which I thought had emerged from the meeting was the value of hope, specially the value of collective hope in pursuing the kind of research discussed here. I think hope and confidence are some what different. One can be hopeful even when one's confidence is not particularly strong. I was delighted to see how both physicists and philosophers had identified a common platform, a well shared level playing ground to discuss such important issues. It is high time scientists stopped referring to Feynman's notorious remark and give credit to good thinking where ever it comes from.
    Thanks for giving me an opportunity to read this valuable article. With warm regards, Narasimhan.

  • Maybe instead of looking for new physics in the larger and the smaller, we should just look at the symmetry's we see over and over again. For instance if we see existence manifest itself in living organisms, governments, markets, and electrons, wouldn't we have taken a leap forward to say nature repeats herself, and that we need only look at examples we know, to construct what must be for the existence rules for many more?

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