Philosophers as radicals

The association between philosophy and radicalism is an ancient one and in some ways a natural one. Philosophy is in one sense an intrinsically revolutionary activity, simply because its goal is to put received authority into question. Its interrogatory approach—or, as philosophy’s victims say, its methods of interrogation—and its adherence to the standards dictated by the bar of reason quickly ride roughshod over the sensibilities and sentiments of the day. And, of course, philosophers sometimes offer detailed emendations of received authority, describing what a state of affairs based on reason would look like.

Plato’s Republic supplies the model in the Western tradition, but any truly philosophical tradition is bound to offer similar paradigms. We automatically characterize resistance to philosophy’s needling questions as mere prejudice, close-mindedness, and irrationality. We do this because we are...