A Crisis At The Edge Of Physics

[C C]

http://www.nytimes.com/2015/06/07/opinio...ysics.html

EXCERPT: DO physicists need empirical evidence to confirm their theories? You may think that the answer is an obvious yes, experimental confirmation being the very heart of science. But a growing controversy at the frontiers of physics and cosmology suggests that the situation is not so simple.

A few months ago in the journal Nature, two leading researchers, George Ellis and Joseph Silk, published a controversial piece called “Scientific Method: Defend the Integrity of Physics.” They criticized a newfound willingness among some scientists to explicitly set aside the need for experimental confirmation of today’s most ambitious cosmic theories — so long as those theories are “sufficiently elegant and explanatory.” Despite working at the cutting edge of knowledge, such scientists are, for Professors Ellis and Silk, “breaking with centuries of philosophical tradition of defining scientific knowledge as empirical.”

Whether or not you agree with them, the professors have identified a mounting concern in fundamental physics: Today, our most ambitious science can seem at odds with the empirical methodology that has historically given the field its credibility.....

[Magical Realist]

The problem with verifying our scientific theories with evidence now is that theories now concern states and conditions not subject to experimental verification. Take string theory. It is dealing with units so small that we cannot now and maybe never will detect them. Is this a lesson in how far scientific theorizing should be allowed to go? Or is it an argument in favor of the purely mathematical validation of these new theories? Is it even science anymore when we are just using math to create our models? I'd like to think science will always be about empirical evidence, but maybe those days are over with. New forms of verification involving predictability, computerized models, statistics, and topology may be taking over from here on.

[Yazata]

DO physicists need empirical evidence to confirm their theories? You may think that the answer is an obvious yes, experimental confirmation being the very heart of science. But a growing controversy at the frontiers of physics and cosmology suggests that the situation is not so simple.

A few months ago in the journal Nature, two leading researchers, George Ellis and Joseph Silk, published a controversial piece called “Scientific Method: Defend the Integrity of Physics.” They criticized a newfound willingness among some scientists to explicitly set aside the need for experimental confirmation of today’s most ambitious cosmic theories — so long as those theories are “sufficiently elegant and explanatory.” Despite working at the cutting edge of knowledge, such scientists are, for Professors Ellis and Silk, “breaking with centuries of philosophical tradition of defining scientific knowledge as empirical.”

What Ellis and Silk seem to be talking about sounds to me like the distinction between physics and metaphysics.

A great deal depends on what the word 'explanatory' is taken to mean. Explanatory of what, exactly? Presumably what's happening here is that 'higher' levels of theory are being used to unify lower-level theories that address real world observables and to give some account of why those empirical theories take the forms they take.

That doesn't seem all that bad... until we imagine that maybe multiple inconsistent higher-level theories can do the same work. If the choice between them doesn't have any real-world empirical implications, how could we ever determine which one was true?