Every philosophy major has at some point had to answer the standard challenge: “What are you going to do, teach?” It’s especially frustrating after you realize that, for someone with a humanist bent and a disinterest in worldlier things, teaching is a pretty good career choice. Unemployables in the humanities might take comfort from the fact that one of the twentieth century’s greatest philosophers, Ludwig Wittgenstein, made the same choice. He revolutionized philosophy twice, fought with shocking bravery in World War I, inspired a host of memoirs by people who knew him only glancingly—and for six years taught elementary school in the mountains of rural Austria. Biographers have tended to find this bizarre. Chapters covering the period after his teaching years, when Wittgenstein returned to philosophy, are usually called something like “Out of the Wilderness.” (That one’s from Ray Monk’s excellent Ludwig Wittgenstein: The Duty of Genius. The next chapter is called “The Second Coming.”)