Tutorial #17. Skepticism And "Proof of an External World". G.E.Moore

G.E. Moore (1939). “Proof of an External World.” Proceedings of the British Academy 25.

Certain Keypoints in the argument:

1. According to Moore, to prove that he was holding up his hands would require him, as Descartes pointed out, to prove (not just know) that he isn’t dreaming, which Moore doesn’t think he can do.
2. Moore thinks you can know things you can’t prove.
3. It has been a common view among philosophers, however, that you can’t know things you can’t prove–you can only take them on faith.
4. A test to see if a conclusion is different from a premise (or, if two propositions are different) is to see if one could be true while the other false.
5. To say that something might be proven to exist (or be true) is to say that that thing might be certain to exist or be true.