Book excerpt: An engaging and often hilarious survey of the far-from-fusty extra-curricular activities of some of philosophy’s finest practitioners Philosophers Behaving Badly examines the lives of eight great philosophers—Rousseau, whose views on education and the social order seem curiously at odds with his own outrageous life; Schopenhauer and Nietzsche, two giants of the 19th century whose words seem ever more relevant today; and five immensely influential philosophers of the 20th century, Russell, Wittgenstein, Heidegger, Sartre, and Foucault.