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You could check All Ravens Are Black by: 1. seeking out all ravens and checking their colour, or 2. seeking out all things that are not black and checking the
by learnstats2 12y ago
You could check All Ravens Are Black
by:
1. seeking out all ravens and checking their colour, or
2. seeking out all things that are not black and checking they are not ravens.
Looking at an apple constitutes evidence, in that it contributes to the second case, and that's not in doubt here. But you're really checking that the apple is not a raven.
If you believe that apples are not ravens (perhaps by definition), then checking an apple no longer contributes to the probability at all.
- learnstats2 12y agoAlternative point of view, separated for clarity: "seeking out all things that are not black and checking they are not ravens." This statement seems a faintly ridiculous idea. Our mental model holds an infinite number things that are "not black", so there are still an infinity to check. Checking one thing should not change our internalised probability at all. Even if you disagree that there are an infinite number of things, checking all apples contributes 0% towards this case - and is surely no easier than checking every raven.
- indrax 12y agoYou can't be sure you're gotten all ravens unless you check everything in the universe to see if it is a raven.
- crimsonalucard 12y agoThis is why it's impossible to prove anything in science. Science is the art of falsification.
- learnstats2 12y agoWell, not necessarily. It depends on the definition of raven. If you define 'raven' as a current resident of Earth, that simplifies things for you - it's meaningless to check things off Earth.
- wongarsu 12y agoGiven that earth seems to be just a random planet in the universe that happens to have developed life, or more specifically ravens, it stands to reason that any random planet has a non-zero (but extremely small) chance of developing life which evolves into ravens. Given an infinite and reasonably uniform universe there should be infinitely many planets where life formed which evolved into ravens, and where at least one raven is alive right now. It follows that both the number of objects in the universe and the number of ravens in the universe are infinite. Alternatively we can stay on earth. The number of ravens on earth is finite, but so is the number of objects on earth.