May I ask a question about philosophy of physics?
You can ask any such question of me.
Is it permitted or not or frowned upon?
From moderator David Z's response, it looks like such questions are frowned upon. For myself, I think that if you can't ask physicists about this stuff, and if instead you're sent away to some philosophy forum with a flea in your ear, that's not right.
But I hope you'd rather see discussions about "what is physics?" and "falsifiability" (and some of the stuff that Smolin complains about) here among physikers, than in a purely philosophy-bent forum.
I would. I view Sean Carroll's stance on falsifiability with alarm.
Can we ask in the Physics.SE about whether or not the following is science or is still philosophy: 1.string theory, 2.M theory, 3.multiverse? Just curious.
Grateful for any response, including downvotes.
Maybe you can't ask on Physics.SE, but while we're on the subject, let me say this: there's no evidence for string theory or M-theory. And none for the multiverse. These hypotheses remain speculative even after many decades. Moreover the M-theory "brane-leak" claim as to why gravity is so weak contradicts GR, and the Goldilocks multiverse "just right" claim contradicts running constants. On top of that these speculations can never be disproven, and as such they're on a par with religious promises and claims. They aren't science. What they are is pseudoscience popscience masquerading as science.