Concept
Philosophical Investigations (Philosophische Untersuchungen) is a work by the philosopher Ludwig Wittgenstein, published posthumously in 1953. Philosophical Investigations is divided into two parts, consisting of what Wittgenstein calls, in the preface, Bemerkungen, translated by Anscombe as "remarks". A survey among American university and college teachers ranked the Investigations as the most important book of 20th-century philosophy. In its preface, Wittgenstein says that Philosophical Investigations can be understood "only by contrast with and against the background of my old way of thinking". That "old way of thinking" is to be found in the only book Wittgenstein published in his lifetime, the Tractatus Logico-Philosophicus. Many of the ideas developed in the Tractatus are criticised in the Investigations, while other ideas are further developed. The Blue and Brown Books, a set of notes dictated to his class at Cambridge in 1933–1934, contains the seeds of Wittgenstein's later thoughts on language and is widely read as a turning point in his philosophy of language. Norman Malcolm credits Piero Sraffa with breaking the hold on him of the notion that a proposition must literally be a picture of reality by means of a rude gesture on Sraffa's part, followed by Sraffa's question, "What is the logical form of that?" In the Introduction to the book written in 1945 Wittgenstein said Sraffa "for many years unceasingly practiced on my thoughts. I am indebted to this stimulus for the most consequential ideas in this book. Wittgenstein develops this discussion of games into the key notion of a language-game. For Wittgenstein, his use of the term language-game "is meant to bring into prominence the fact that the speaking of language is part of an activity, or of a life-form." A central feature of language-games is that language is used in context and cannot be understood outside of that context.