Philosophy as Bad Science?
Somewhere along the line many physicists have come to believe that it must be possible to formulate a theory without observational input, based on pure logic and some sense of aesthetics. They must believe their brains have a mystical connection to the universe and pure power of thought will tell them the laws of nature. But the only logical requirement to choose axioms for a theory is that the axioms not be in conflict with each other. You can thus never arrive at a theory that describes our universe without taking into account observations, period. The attempt to reduce axioms too much just leads to a whole “multiverse” of predictions, most of which don’t describe anything we will ever see….
I cringe every time a string theorist starts talking about beauty and elegance. Whatever made them think that the human sense for beauty has any relevance for the fundamental laws of nature?…
A theory might have other uses than describing nature. It might be pretty, artistic even. It might be thought-provoking. Yes, it might be beautiful and elegant. It might be too good to be true, it might be forever promising. If that’s what you are looking for that’s all fine by me. I am not arguing that these theories should not be pursued. Call them mathematics, art, or philosophy, but if they don’t describe nature don’t call them science.
The foregoing is an excerpt from “Does the Scientific Method Need Revision?“, an essay by Sabine Hossenfelder, assistant professor at the Nordic Institute for Theoretical Physics with a particular interest in the phenomenology of quantum gravity. In the essay, she raises concerns about physicists being led astray by philosophers (Richard Dawid is mentioned as an alleged culprit; he’s interviewed here) into thinking that observation and testability through experimentation can be dispensed with. According to her, it may be alright for mathematicians and philosophers to pontificate about the structure of the universe without experimentation, but that, she says, is not what scientists should be doing.
Philosophers and historians of science, care to chime in?
(art: detail of Fall by Bridget Riley)
Philosophy as such is not concerned with what Socrates would call “material speculations”. Why a ball falls to the ground when we drop it is not the domain of philosophy; whether we can know a definite reason for its fall or not — or if that reason necessitates the ball dropping in the future, are questions best left to philosophers though.
A similar idea, in the context of philosophy rather than physics, is argued in Dennett’s ‘Higher-order truths about chmess’.
In my experience, theoretical physicists are more likely than philosophers of science to take beauty and elegance to be non-empirical guides to the truth about the physical world, and those philosophers who do defend such a view tend to bolster their views by quotations from well-known physicists.
It is perhaps worth noting that, though his primary focus is currently philosophy, Dawid’s formal training, including his Ph.D., is in theoretical physics. So, his case doesn’t fit neatly into the mold of philosopher leading physicists astray.
This is a pretty strange point to raise as a criticism of string theory, in my opinion. Because we don’t actually have a consistent theory that agrees with the whole body of experimental knowledge and covers the domain of quantum gravity that string theory aims to describe. This means that if the string theory program succeeds, the resulting theory will have considerable empirical advantages over our best current theories. Unlike the standard model, it will predict gravity. Unlike general relativity, it will predict quantum phenomena and the electromagnetic and nuclear forces.
I am also one of those people who believe that elegance confers at least a bit of justification to a theory (not sure I would say it makes the theory “more likely to be true” in any sense independent of our epistemic practices, but the same goes for inductive reasoning too). But I don’t think you need to go as far as I’m inclined to go to defend string theory from this sort of criticism.
Sabine knows that the new anti-empiricism originates not with philosophers but with physicists (Sean Carroll, Leonard Susskind, et.al). Dawid just articulates more nakedly what they think, namely that in the absence of empirical results one must accept the confidence of theorists in their theories as a justification for further research. I don’t think that anyone, philosophers or otherwise, is very impressed by this argument; but neither do I pretend to know how research should be funded. Sabine’s main beef is with the funding going to theoreticians rather than experimentalists. I trust her instincts.
I agree with the demand of testability but I find Sabine’s formulation very vague, which is probably a good thing as making it more precise would make it more dogmatic and more one-sided. “Non-empirical facts” or qualitative considerations have always been a part of scientific method construed in the widest sense, and Einstein famously was indifferent to “verification by little effects”. Sabine argues effectively that observation is in fact present all the time, so why insist on a particular type of obsevation as an absolute necessity? Qualitative considerations could be sufficient observational fit for very abstract, very general theories that comply with non-empirical constraints as well.
Surely the requirement of testability is not valid in itself, but rather as part of the more general requirement of realism, of actually describing the world. Some of Sabine’s formulations conflate too easily these two requirements, e.g. “The whole point of physics is to select axioms to construct a theory that describes observation”. A realist would say the whole point is to describe the world, and confrontation with observation is one way to test this. She also talks about describing nature, but it is not obvious that this is the same as describing observation. Some observation at least is erroneous or misleading, being based on false theories, and will have to be corrected or even jettisoned.
So I would reformulate this text’s concern as the increasing tendency to idealism in modern physics, and that this idealism underlies a certain indifference to testability. I don’t think Einstein’s indifference, insofar as it existed, was based on such idealism, but more on time considerations, i.e. that “good” verifications take time especially when the theory is very abstract. Relying on aesthetic criteria in this case would not be an absolute, but an interim measure necessitated by the fact that observations can sometimes lag behind theory.
The worry would then be that a properly interim measure could come to be taken as a permanent definition of science. This would lead to a new form of dogmatism, not so much of the content of a particular theory but a methodological dogmatism where mathematical speculation reigns unchecked. On the other hand, no time limit to interim speculation can be specified in advance, as sometimes we don’t even know how to go about getting the necessary observations. Close fit to readily accessible observations can also be considered to be an interim measure, adapted to some phases of a science but not to all.
I think Sabine is basically right on this particular issue, but think she doesn’t appreciate “philosophy” enough overall. In discussions at her FB page, we are mulling over this very issue of philosophy in science. Here are some of what I wrote there so far:
Philosophy is a background to thinking, period, and includes the contexting and semantics that allows logic to *intelligibly refer* to whatever it deals with, to the extent it can. It is unavoidable in the hardest of science, ethics or no. It is a tragedy IMHO that more people do not appreciate that.
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Neil Bates In a separate pure sense, if the contents are interchangeable elements of sets as sheer abstractions – eg, numbers. But despite the pretense that we can use syllogisms etc “for anything”, actual use of terms of reference and description requires appreciation of the epistemological ground, what our terms really mean, all that good stuff. F = ma is just crude simple math by itself, but what each of those “means” and refers to is more subtle.
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Neil Bates The logic that people are taught is based on a pretense of utterly given and understood elements to manipulate with the set theory, which is not what we actually can do with the real world.
Yes, when I say “describing nature”, I mean “describing observations.”
I have no “beef” with funding going to theoreticians rather than experimentalists, but that the middle is being left out, the middle being phenomenology, that what connects the math and/or philosophy (no description of observation) with observations that either have been made, or are proposed to be made by experimentalists. There are some areas of physics where this middle is basically non-existent and the theory is more or less disconnected from experiment. Quantum gravity is an example. The multiverse another one. Many discussions in quantum foundations are.
(Besides this, I’m vegetarian, and don’t normally have beef.)
Thanks for your thoughts, it has been an interesting read that makes me realize where I have to be more careful.
I have a longer reply on my blog here: http://backreaction.blogspot.com/2015/01/is-philosophy-bad-science.html