It is an all-too-familiar phenomenon in philosophy: something that seems undeniably true turns out to be false. For example, philosophers used to believe that space has Euclidean structure and that we can discern this structure from an armchair. But then Einstein demonstrated that an entirely different structure is not only possible but (almost certainly) actual. Some philosophers, such as George Bealer, think that since actual physics can never expand the realm of possibility, these examples show that our pre-theoretical intuitions about physical possibility were flawed all along.
Now another example of something that exists despite seeming a priori to be physically impossible: auxetic materials. These puzzling substances don’t get thinner when they are stretched, Continue reading “Another Failure of A Priori Physics”