String theory isn't physics. There's no experimental confirmation, or even the slightest physical evidence, for anything stringy. String theorists now say that there will never be any experimental evidence, and many string textbooks are being published in newer editions with previous predictions reworded or completely removed after having been ruled out by LHC (fucking kek). There's even one string theorist who runs a blog and has said for at least 17 years that string theorists don't give a fuck about experiments or any empirical confirmation of their ideas, as they are "above" experimentalists.

On the other hand, it's also not mathematics. Fuck off about mirror symmetry, Calabi-Yau manifolds, Witten's Fields medal, etc. There is absolutely NO proofs of any of the mathematics in string theory. It's maths that is "physically based" like how most physicists do their weaksauce maths, except that even the physical basis of stringy maths isn't actually empirically verified (see previous paragraph). Witten didn't even give a rigorous proof of the positive energy theorem which is why he won the fields, he had to have mathematicians fill in all the gaps. Weak.

So if it's not physics, and it's not mathematics, and all the hundreds of redundant textbooks are being rewritten and removing all past (failed) predictions and not giving any new predictions because they don't fucking have any, which is really just a laughably hardcore historical revisionism, when what the fuck is string theory? Religion?