Abstract

In 1929, Wittgenstein made use of river imagery to convey the supposedly inexpressible thesis that all is in flux. However, he rejects this extreme thesis in manuscripts from the early 1930s and drafts of the Philosophical Investigations, affirming that one can step twice into the same river. His later discussion of the “stream of life” involves a return, in certain respects, to the river analogy, albeit in a very different key. Examining Wittgenstein’s changing use of this image casts light on the continuities and discontinuities in the development of his philosophy. Wittgenstein’s argument that a private definition is impossible because ostension always depends on a “technique of use”, and his rejection of a positive theory of mind is clarified by examining some unusually explicit notes for a public lecture on private language. This material shows how the treatment of training and practice in the opening sections of the Philosophical Investigations is the basis for the subsequent discussion of both rule-following and privacy.