The idea that philosophy cures various sorts of mental disorder is a special case of Hobbes's bigger idea that science or philosophy ought to do people good, that it ought to improve the human condition. Superficially similar ideas have been put forward by others, in Hobbes's day and our own. Thus Descartes claimed that his own metaphysics was good therapy for the intellect. Much more recently, a certain philosophical method has been prescribed by Wittgenstein as a cure for a sickness of the understanding that afflicts us all as users of language. Hobbes's idea is closer to the Baconian one that philosophy or science can contribute to the 'relief of man's estate' - alleviate the worst features of the life of Fallen human beings. It has relatively little to do with up-to-date views of science. It has still less in common with certain current views of philosophy. For at its most distinctive and at its most philosophical, i.e., in application to ethics and politics rather than to astronomy or optics, Hobbes's science manages to be at once coercive, revisionary, and bent on pronouncing the last word. I want to conclude by indicating how this is so, and why it is no bad thing.