In the text the author tries to investigate Wittgenstein’s notions of action, practice and pragmatism in his book On Certainty. An attempt is made to sketch the criterion of Wittgenstein’s analysis of certainty and to define the crucial concepts such as world-picture, practice, certainty and justification. The analysis shows that Wittgenstein applies a specific form of pragmatic solution to the problem of justification, which after all, can and should be called a kind of pragmatismus. This is the subject of the (...) first and the second part of the text. The third part shows the application of this pragmatic theory of justification to Wittgenstein’s refutation of scepticism. The author suggests that his pragmatic analysis of certainty presents an adequate means for the refutation of scepticism. However, his anti-scepticism is situated in the tradition of common sense and ordinary language philosophy and epistemology (Moore, Chisholm, Lehrer, Austin, Grice, Strawson, etc.). In the conclusion the author applies this anti-sceptical solution to the so called rule-following problem (as stated in Kripke’s work) and shows that there are some far reaching consequences of this interpretation of Wittgenstein’s later work to his position on language, learning, ontology and knowledge. (shrink)