Te best class I took in college was on the philosopher Ludwig Wittgenstein. Until that point, I had avoided philosophy of language as simply being too esoteric and hermetic to be of use. David Pears, a prodigious yet modest and approachable figure visiting from Oxford, changed my mind. In large part because of Pears’ instruction, Wittgenstein’s philosophy has been directly relevant to my thinking about computer science, artificial intelligence, and cognitive science. When other scholars were thinking that language and thought could be reduced to a universal, logical language, Wittgenstein turned the matter to practical questions and raised incredibly inconvenient questions that gained traction in artificial intelligence in the 1970s, 40 years after he was working on them.