“The fox knows many things, but the hedgehog knows one big thing.” Perhaps by now, invoking Isaiah Berlin's famous distinction risks banality, but it is more than just an interesting contrast. Philip Tetlock, in his wonderful book Expert Political Prediction, has shown that it has a genuine basis in different cognitive styles. Overall, and of course with many important exceptions, moral, social, and political philosophy is the clash of the hedgehogs. Often political philosophers actually characterize themselves as defending one supreme value – “I'm an egalitarian” or “I'm a libertarian.” But even when hedgehogosity is not quite so blatant, moral, social, and political philosophy is often the clash of well-defined schools with well-defined programs: Aristotelians, virtue theorists, perfectionists, Kantians, Humeans, utilitarians, deontologists, expressivists, realists, intuitionists, naturalists, moral sense theorists, and on and on. And when philosophers are dissatisfied with the current state of philosophy and seek to advance a new view, they almost always see the need to ensure that it qualifies as a fully fledged hedgehog view. Thus many moral philosophers who have been impressed by the need to take empirical evidence seriously go on to insist that moral philosophy really is simply cognitive psychology. One experimental moral philosopher once objected to me: “I have no idea what people are talking about when they invoke the idea of rationality.” All that old rationality talk is out, and now it is just the study of cognitive processes. Philosophy as the clash of the hedgehogs is central to our pedagogy.