Wittgenstein responds to the challenge posed most strongly by Descartes’ Meditations: having been deceived in the past, how is it that humans can know anything for certain, secure objective knowledge? In order for philosophy and science to proceed, it seems as if this challenge must be satisfied—Cartesian knowledge must be grounded on something immovable. Therefore, Descartes situates the source of knowledge in the uniformity of nature and a priori truths, all of which fall under the concept of the Cartesian rational God. If there is a God who isn’t a deceiver, then humans can know things with certainty. Descartes metaphysical presupposition is that there is a rational God; this God is the ground for the possibility of objective knowledge, and this ground falls before all experience. Only by supposing the existence of God can humans have certainty, and therefore knowledge.
Wittgenstein doesn’t take direct aim at Descartes, though. Rather, he finds a similar type of metaphysical presupposition in a most unlikely place, G. E. Moore’s philosophy. In his attempt to prove the existence of an external world, Moore makes a metaphysical presupposition when he says, “I certainly did at the moment know that which I expressed,” by holding up two hands. He presupposes that he can say meaningfully, and with certainty, the he knows a fact of the type “I have two hands.” Wittgenstein’s criticism is not that such knowledge is impossible, but rather that an utterance like “I know I have two hands” is probably nonsense. That is, Moore presupposes that he can merely, unproblematically say, “I know I have two hands.”
When philosophers use “I know…” Wittgenstein says, “I want to reply ‘you don’t know anything!’—and yet I would not say that to anyone who was speaking without philosophical intention.” This asymmetric response to different utterances of “I know…” gives a demonstration of Wittgenstein’s notion of knowledge and its attendant utterances: knowledge is heavily dependent on a context, and the sense or meaning of the utterance “I know…” depends on the context in which it is used. Moore’s use of “I know…” lacks an appropriate context, and it therefore rests on the same type of metaphysical presupposition that Descartes makes in his Meditations. Moore’s utterance lacks a context within which it would make sense; and Moore’s thinking that it does make sense presupposes a transcendent sense of meaning that must be “further back” from the beginning. For Moore, the meaning of “I know I have two hands” is pre-given and predetermined. The role of context is supposed to replace meaning’s reliance on pre-givenness and predetermination.
The major criticism that Wittgenstein levels against Moore is that he tries to refute the claim that one cannot know things about the world with the claim that he can know; and the way in which Moore makes this claim is by saying things like “I know I have two hands.” The problem with skepticism—and the realism that Moore attempts to prove in order to refute skepticism—is that the meaning of both the skeptic and the realist seems to hang in mid-air. But this is not to say that Wittgenstein’s aim is to ground knowledge. The attempt to ground knowledge is precisely what Wittgenstein tries to end. His aim seems paradoxical: he both tries to point out the groundlessness of our knowledge, and to point out the objectivity of our knowledge. Therefore, Wittgenstein’s project in On Certainty is to remove the desire for a ground to objectivity.
However, I forgot how good is Interpol. Man. This is like my second or third favorite video ever maybe.
I think I saw that the director, Italian whats-her-name, directed a film or a music video or something. She's the one that's dancing.