“What is it about the study of modern philosophy that tends to make brilliant minds stupid?"

“What is it about the study of [modern] philosophy that tends to make brilliant minds stupid when it comes down to what are known as actual cases? Consider Martin Heidegger, Bertrand Russell, Jean-Paul Sartre, and Ludwig Wittgenstein ... four great names in twentieth-century philosophy: the first was a Nazi, the second died certain that America was responsible for all the world’s evil, the third was a Stalinist long after any justification for being so could be adduced, and the fourth lived on the borders of madness most of his life. Contemplation of the lives of philosophers is enough to drive one to the study of sociology.”

~ Joseph Epstein from his Essays in Biography [hat tip Stephen Hicks]