Wittgenstein and certainty

Wittgenstein’s remarks gathered in On Certainty form a bridge between the first half of the module, responding to scepticism, and the second, analysing knowledge. Though, of course, since both concern the nature and possibility of knowledge, they are connected.Wittgenstein’s remarks were prompted (possibly indirectly) by his fellow Cambridge philosopher G. E. Moore’s defence of common sense realism against scepticism. Moore’s argument was remarkably simple. He held up one hand (his own) and claimed that here was a hand. As a hand, it was a material object. Thus he knew that there was at least one material object in the world. And thus philosophical arguments against the reality of the material world were refuted.

Wittgenstein rejects that argument by suggesting that a sceptic (or idealist as such scepticism is here characterized) will say that ‘he was not dealing with the practical doubt that was being dismissed, but... a further doubt behind that one’ (§19). Moore mistakenly treats sceptical doubts as though they were practical doubts requiring practical justifications. Instead, Wittgenstein suggests a different response to scepticism, which turns on the point that: ‘a doubt about existence only works in a language game. Hence that we should first have to ask: what would such a doubt be like?, and don’t understand this straight off.’ (§24). Thus Wittgenstein’s suggestion for how to respond to scepticism is to argue that any doubt, whether practical or sceptical, requires a context to give it its meaning.

In fact the main theme of On Certainty is not the problem of scepticism but charting the context of ordinary knowledge claims and expressions of doubt. Our knowledge claims and our doubts form a system. Without this context they would not have any clear meaning.

All testing, all confirmation and disconfirmation of a hypothesis takes place already within a system. And this system is not a more of less arbitrary and doubtful point of departure for all our arguments: no, it belongs to the essence of what we call an argument. The system is not so much the point of departure, as the element in which arguments have their life. (§105)

Wittgenstein also calls this system a ‘picture of the world’, which members of a community largely share. But we do not, as individuals, arrive at such a world picture by satisfying ourselves of its correctness. ‘No: it is the inherited background against which I distinguish between true and false.’ (§94). Thus the suggestion is that in order to test or check a claim just such a background is required to provide the ground rules for empirical inquiry. Thus the background itself cannot as a whole be checked for its truth.

Insofar as Wittgenstein does directly challenge scepticism, then, he suggests what Micheal Williams terms a 'therapeutic diagnosis' that aims to show that scepticism makes no sense. So the obvious question is, if Wittgenstein is correct, why does scepticism even seem to make sense. (Contrast: “milk me sugar!” or “iggle, wiggle, piggle”)

• Wittgenstein, L. (1969) On Certainty, Oxford: Basil Blackwell extract on Blackboard.

There are only a few secondary texts on On Certainty. The first two extracts are on Blackboard. The Williams has a link to a pdf.

• McGinn, M. (1989) Sense and Certainty, Oxford: Blackwell chapter 6

• Moyal-Sharrock, D. (2007) Understanding Wittgenstein's On Certainty, Basingstoke: Palgrave chapter 4

• Williams, M. (2004) 'Wittgenstein's refutation of idealism' in McManus, D. (ed.), Wittgenstein and Scepticism. London: Routledge but also here on the web

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