3 ms·

So he proved "if x then y", then later proved "!x"

• knzhou 7y ago
  Well, perhaps, but in physics we like to think of our field as containing many separate, logically independent models of reality. Yes, "x" probably isn't true in our universe, but it is true in an exceptionally good model for our universe, and that's what makes it an important result. It's like how the round Earth is wrong, but way less wrong than the flat Earth.
• nightcracker 7y ago
  No. x -> y && !x does not give !y, it just gives nothing. He proved y under some set of assumptions, and then later !y under another set of assumptions. So he proved a -> y && b -> !y.
  • xamuel 7y ago
    But, given x->y, if you prove !y, you can conclude !x, so in a sense kibibu is right (possibly requiring "proved" to be read as "indirectly proved"), and we should give them the benefit of the doubt.
    • pdonis 7y ago
      > given x->y, if you prove !y, you can conclude !x But given x -> y, if you prove !x, you can't conclude anything. And kibibu said !x, not !y.
      • kibibu 7y ago
        Yeah, I interpreted: > quantum fields near the horizon can violate some of the assumptions that are required for the area theorem as !x