Famously Einstein said if he had to choose between a beautiful theory and an ugly fact he'd take the theory every-time. Dirac remarked that he always followed beauty.

It seems to me that aesthetic considerations must play a large role in contemporary physics through being conditioned by learning the theory. Part of this maybe what physicists call physical intuition.

According to Popper scientific theories are never true but are always falsifiable. But as the theory develops these falsifying events (ie experiments) become more and more infrequent. What happens between these events? It seems to me that physics at a fundamental level must become a world unto its own (at a practical/applied level it must obviously remain involved with the world) in the same way as say mathematics is, and of course there aesthetic considerations play a large part even if they're not nominally thought of in that way.

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    I'm not sure I see the question here. What's the relation between your assumptions and the question? Yes, there might be aesthetic considerations, but does that make it art?
    – iphigenie
    Jan 7, 2013 at 19:30
  • @iphigenie: No it doesn't - I was using the word 'art' as provacative shorthand for aesthetic and also thinking of God as Artist. The point I was driving at is although aesthetic considerations may play a role in physics, its generally subordinate to its role as an empirical science - I'm trying to argue that its conceivable that it may become the sole consideration. Jan 7, 2013 at 19:40
  • Well, you can try to argue that as much as you want, if you deliberately used the word "art" provocatively, then my question is, again: What's the question?
    – iphigenie
    Jan 7, 2013 at 19:53
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    @iphegenie: Will fundamental physics become a discipline driven solely by aesthetic considerations - is that any better? Jan 7, 2013 at 20:06
  • @iphegenie: ok, I'll change my question heading. Jan 7, 2013 at 20:17

2 Answers 2


Will fundamental physics become an art?
According to Popper scientific theories are never true but are always falsifiable.
...of course there aesthetic considerations play a large part even if they're not nominally thought of in that way.

The answer bellow was before the change of the question to "...is driven solely by aesthetics?" My answer and time did not deserve this new question.

Fundamental physics has beauty as a selection criterion of a theory, and falsificationism is falsifiable.

Theories or hypotheses can only be subjected to empirical testing in groups or collections, never in isolation. The idea here is that a single scientific hypothesis does not by itself carry any implications about what we should expect to observe in nature; rather, we can derive empirical consequences from an hypothesis only when it is conjoined with many other beliefs and hypotheses, including background assumptions about the world, beliefs about how measuring instruments operate, further hypotheses about the interactions between objects in the original hypothesis' field of study and the surrounding environment, etc. For this reason when an empirical prediction turns out to be falsified, we do not know whether the fault lies with the hypothesis we originally sought to test or with one of the many other beliefs and hypotheses that were also needed and used to generate the failed prediction. It forms a criticism of methodological falsificationism.

Holist underdetermination ensures there cannot be any such thing as a “crucial experiment”: a single experiment whose outcome is predicted differently by two competing theories and which therefore serves to definitively confirm one and refute the other. Our response to the experimental or observational falsification of a theory is always underdetermined in this way. When the world does not live up to our theory-grounded expectations, we must give up something, but because no hypothesis is ever tested in isolation, no experiment ever tells us precisely which belief it is that we must revise or give up as mistaken. All of the beliefs we hold at any given time are linked in an interconnected web, which encounters our sensory experience only at its periphery.

It would be possible for us to preserve it “come what may” in the way of empirical evidence, by making sufficiently radical adjustments elsewhere in the web of belief. It is in principle open to us to revise even beliefs about logic, mathematics, or the meanings of our terms in response to recalcitrant experience; it might seem a tempting solution to certain persistent difficulties in quantum mechanics, for example, to reject classical logic's law of the excluded middle, allowing physical particles to both have and not have some determinate classical physical property like position or momentum at a given time.

Underdetermination then is when the available data do not permit us to make a decision between two or more rival theories. There are two forms of underdetermination: strong and weak. Strong tells us that there is no way to distinguish between theories with the same observable consequences – called empirical equivalence – and points to the existence of an infinity of possible theories consistent with any finite data set. We do not claim to be able to choose between empirically equivalent theories on the basis of empirical criteria, which is impossible by definition. It forms other criticism of methodological falsificationism. Moreover, it relies on an implicit separation of theory and observation: We cannot distinguish between theory and observation in a straightforward fashion, we cannot appeal to or rely on observations without theories and make a choice. All the observations that give us this problem of underdetermination are themselves theory-laden. Then strong underdetermination makes theory choice impossible because we already use theory in obtaining the observatory evidence that leads to underdetermined theories.

To the weaker underdetermination is always possible to construct alternative theories which are empirically equivalent and also choise one with many of the characteristics we desire in scientific theories: parsimony; internal consistency; beauty. Weak underdetermination is the recognition of the limits of evidentialism and falsificationism, the notion that we hold to our ideas insofar as they are supported by evidence. We do not accept or reject theories based solely on the evidence for them but also on account of many non-empirical criteria, such as parsimony; internal consistency; beauty.

The underdetermination is inductive, but science can believe in entities that are not directly observable, such as electrons. Not only the observables are relevant to believing a scientific theory. Simplicity, explanatory power or some other feature of a theory is criterion for it over its rivals.

  • in your terms I'm asking how one can navigate the infinite number of empirically equivalent theories - which is where I'm placing the role of aesthetics here Jan 7, 2013 at 23:36

It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong. Richard P. Feynman (http://www.brainyquote.com/quotes/quotes/r/richardpf160383.html#745dv0Bufc8kAcDX.99

In contrast to philosophy and mathematics, physics deals with the real world, which happens to be as it is regardless of our perceptions of it's beauty (or lack thereof). I think that any preference of "art" and "beauty" would significantly decrease the scientist's ability to understand this world and learn about it.

Einstein is actually a prime example of this problem: After developing General Relativity in 1915 he set out to find the "complete theory of the universe" and that was the main goal for the rest of his life. Given his indisputable genius and skill he might actually have had a good shot at it. However, he was doomed to fail from day one by his rejection of quantum mechanics. It violated his sense of how the universe should work (quote: "God doesn't play dice") and he rejected it based on religious/aesthetics/philosophical concerns. He spend a lot of time trying to prove it wrong or incomplete and also in finding an alternative: with no success whatsoever.

For example he proposed the Einstein-Poldolsky-Rosen experiment in an attempt of "reductio ad absurdum", i.e. showing that the consequences of Quantum Mechanics would violate one of the most basic assumptions about the universe: locality http://www.physicsoftheuniverse.com/topics_quantum_nonlocality.html. This violation was termed by Einstein "spukhafte Fernwirkung" or "spooky action at a distance". At the time Bohr and Heisenberg defended Quantum Mechanics by simply stating that Einstein could not come up with an experiment where locality vs. non-locality makes any difference, so it ended up as a tie (sort of). In the 1960s John Stuart Bell actually came up with a modification that should produce measurable difference http://www4.ncsu.edu/unity/lockers/users/f/felder/public/kenny/papers/bell.html and in the 1990s the experiment was actually performed (most notably by Alain Aspect). It turns out that Bohr was right and Einstein was wrong.

So the lesson here is that philosophical prejudice can significantly hinder even the most capable scientist. The current Standard Model is the best model of the world we have. Personally I think it's a horrible mess, applicable but not understandable, but that doesn't make it any less real. Whether we like it or not, the universe appears to be non-local (spooky action at distance) and based entirely on unpredictable randomness (god does indeed role the dice) and any predictability is only based on the statistics of large numbers.

To qualify this: it is absolutely desirable describe the same physical theory or fact in as simple or elegant terms as possible. The original form Maxwell's equation is almost unreadable but Heinrich Hertz managed to rewrite them into four simple lines. Schroedinger found a much simpler formulation to Heisenberg's horribly convoluted matrix mechanics. However, in either case the underlying physics are the same, just the description has been beautified.

[sorry, I had to disable most links, because I'm only allowed to post two].

  • Feynman said that if all scientific knowledge was forgotten in the future and he was allowed to tell them one thing, he would say that everything was made out of atoms. He didn't acknowledge that this had already been 'discovered' by greek, jain & buddhist philosophers over 2 millenia ago. Yes, schrodinger did make it easier for 19C physicists brought up in the classical mould to digest Quantum Mechanics, but its also true that it was Dirac that moved QM forward by assimilating matrix mechanics. Jan 7, 2013 at 14:51
  • Maxwell equations can now be written in two equations. This doesn't mean that the underlying physics remain the same. To some degree it does, but rewriting it in another formalism means that new potentialities are possible. The exterior calculus allows the equations to be written for an arbitrary curved manifold. It allows the mathematical expression of string theory whether one agrees with it or not. Jan 7, 2013 at 14:54
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    @MoziburUllah: somewhat important to Feynmann's "one idea to be passed on" is something that the Greeks never postulated: that heat is due to the motions of the atoms. Of course, it's wonderful that someone was able in antiquity not only to postulate a theory of atoms, but that the fact that it was postulated was preserved to the present day; it no doubt influenced research directions in physics. But it is not clear that it was a "discovery" until someone was able to provide experimental support. Jan 7, 2013 at 15:41
  • Epicurus had some interesting things to say about the movement of atoms. He postulated that all atoms must curve when they fall. His thought was, that if atoms fell in a straight line, then no atoms would ever interact. Since it seems as those atoms and the composites made of them do interact, he inferred that atoms couldn't fall in a straight line and must curve as they fall. Not directly relevant, but an interesting factoid these comments reminded me of.
    – Dennis
    Jan 7, 2013 at 16:26
  • @Dennis: I think it's more than curve, unless you're using the word differently to what I imagine. Lucretious wrote about clinamen the unpredictable swerve of atoms. It's interesting that the epicurean school had conceived that random motion must play a part in physics well before Einstein declared that 'God does not play with dice'. Jan 7, 2013 at 19:12

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