The aim of this short work is to introduce the serious student of philosophy to the work of the late Wittgenstein and to encourage some critical ways of tackling the central philosophical themes dealt with in On Certainty.

Some of Wittgenstein’s central problems in On Certainty are couched in the context of his arguments against G.E. Moore’s ‘common-sense' conception of the world. We shall look at this theme with special regard to the theory of sense data and truth.

In his paper, 'Wittgenstein on Certainty', first delivered in a lecture in 1973, and published in 1974, A.J Ayer broaches a number of particular philosophical issues concerning sense data that we shall focus on in this introductory text.