Discussion of "On Certainty"

What does it mean to be certain?

Examples of knowledge and belief contexts:

• "I know" (Moore's example) meaning "I can't be wrong"
• 106: Suppose an adult says he's been to the moon.
• "I know" my name 328
• multiplication

Wittgenstein's claims:

553: the queerness of certain "apparent" moves in a l.g.: "I know I am sitting on a chair"

51-54: basic distinction: Moore's example is not like a hypothesis in science. Moore's case plays a systemic role in a language game (as in 54) wheras scientific hyp.s are local.

111: My not having been on the moon is as sure a thing as any grounds I could give for it.

"Axioms"

1. Everything descriptive of a language game is part of its logic.
   ("there is a red patch" is part of the logic of the l.g.) (56)
2. The possibility of a l.g. doesn't depend upon everything being doubted that can be doubted (392)
3. If the true is what is grounded, then the ground is not true, nor yet false. (205)
4. 559