On Monday, June 27, 2016 at 12:10:21 PM UTC+5:30, Marko Rauhamaa wrote: > Steven D'Aprano : > > > Naive empirical falsification can, at best, be considered as a > > best-practice rule: if you have no way of falsifying something even in > > principle, then it's not scientific. But it doesn't really give you > > much in the way of practical guidance. What counts as falsification? > > We cannot get any information on black holes proper because black holes > cannot come into existence according to the very theory that predicts > black holes. It will take infinitely long for an event horizon to form. > Speculating on what happens to an astronaut falling in is not much > different from speculating what happens after the end of the world. > > > We have no way of seeing what goes on past the black hole's event > > horizon, since light cannot escape. But we can still see *some* > > properties of black holes, even through their event horizon: their > > mass, any electric charge they may hold, their angular momentum. > > If an event horizon cannot come into existence, you can only see > properties of almost-black-holes. Even though there probably is > virtually no difference between the two astronomically, it relieves > physicists from answering some awkward questions on the goings-on inside > an event horizon. > > > We can test the proposition that a black hole that forms from hydrogen > > is no different from one which forms from uranium. We can look for > > variations in randomness in the Hawking radiation emitted, we can test > > that the event horizon is where we expect, etc. An electrically > > neutral black hole with a magnetic field would likely falsify a lot of > > theories about what goes on inside the event horizon. > > If an event horizon cannot ever form, you can't really test any of that > stuff.
I am reminded of an argument I once had with a colleague about infinite, lazy data-structures I said that for the Haskell list [0..] [0..] ++ [-1] == [0..] ++ is like python's list append + This could equally apply to a Python generator like: def nats(): i=0 while True: yield i i += 1 He said (in effect) yes that -1 would not be detectable but its still there! -- https://mail.python.org/mailman/listinfo/python-list