In a nutshell, one can divide Wittgenstein into two phases. In his first phase (Tractatus Logico Philosophicus), Wittgenstein contends that since language seems

In a nutshell, one can divide Wittgenstein into two phases. In his first phase (Tractatus Logico Philosophicus), Wittgenstein contends that since language seems to capture every facet of reality (try thinking a thought that can't be expressed in language) that language and reality must share the same logical structure. Thus what cannot be expressed in logic cannot be said to describe reality in a sensible way. The second phase (Philosophical Investigations) does away with logic as a necessary underpinning to reality and establishes ordinary language as the main constructor of reality. Thus expressions only make sense insofar as they are useful and conform to publicly agreed upon norms. Thus, for example, since we roughly agree upon usage cases for the word blue, there can be no separate meaning of blue that refers to a "private" perception of blue, which does away with a question such as "do we share the same blue?"