Last night I was reading OC and (listening to Mitch Hedberg). I was struck by one passage, and that passage made me think of another.
"I want to regard man here as an animal [...] As a creature in a primitive state [...] Language did not emerge from some kind of ratiocination" (475).
"I want to conceive [certainty] as something that lies beyond being justified or unjustified; as it were, an animal" (359).
First, what is going on here? The latter, textually earlier, quotation seems prima facie to give one more way of conceiving of Wittgenstein's notion of certainty. Wittgenstein loves to obviate the need to resort to mental processes. (Thought is an epiphenomenon of action.) Consider this quotation from the PI, “[w]hat is the natural expression of an intention?-Look at a cat when it stalks a bird; or a beast when it wants to escape” (Philosophical Investigations 647). Juxtapose it with, "[d]oes a cat know that a mouse exists?" (478 OC). Wittgenstein sees in animals the perfect expression of what goes on in humans. Intention is thought to be somehow connected with the will. Look at the lengths to which Kant goes in order to try to make this connection clear. In the Groundwork for a Metaphysics of Morals Kant's examples serve to try to show a good will. That the examples are so ridiculous is supposed to isolate the will. If a shopkeeper charges a regular price, he may be said to do so out of a good will, but he may be doing so by inclination: in order to keep people coming back to his shop so that he'll make money.
The Wittgenstinian view of intention is that the shopkeeper intended to do one or the other depending on the outcome. (I think.) It seems totally external. It is the exact opposite of Kant's view of intention (and morality): That no matter what the outcome is, the intention trumps all. Wittgenstein would say--How do you know someone intends such and such? It would be discernable by the outcome. (Setting up the chessboard is part of intending to play chess.)
Since we take animals to be incapable of thought, it is perfect to look at them to give meaning to various words that don't require thought. I.e., intention. Does a cat know that a mouse exists? We would never say, 'That cat thinks a mouse exists' except in maybe one situation, where the cat was mistaken: maybe it was playing with a toy. Wittgenstein says somewhere in the 400s of OC (I cannot find it right now) that part of knowing something means being able to doubt it. If you agree with this delineation of the word 'know' then you'd have to admit a cat doesn't know anything. (If you thought cat's unable to think (therefore to doubt).)
And this is the crux of Wittgenstein's statement about treating humans here as animals. (Is the "here" important? I think it is--but this is unrelated to the point at hand.) There are certain times when a human cannot doubt, and therefore he cannot be said to know. He is certain.
I'd like to look more at this topic later in the day. Many miles to go.