The 693 numbered paragraphs that comprise the Investigations constitute what is perhaps the most important philosophical work of the 20th century. The Investigations calls into question the classical theory of language and hence “truth”:  “individual words in language do not name objects” in the world “outside” language; rather, the “meaning of a word is its use in the language.” Indeed, “there are no thoughts outside of language”; we communicate with others because we learn what ordinary words like “two,” “blue” or “pain” mean in their particular context. In practice, this new philosophy of “language games” has changed our thinking about everything from information science to aesthetic discourse.