J. B. Kennedy argues that Plato's dialogues have an unsuspected musical structure and use symbols to encode Pythagorean doctrines. The followers of Pythagoras famously thought that the cosmos had a hidden musical structure and that wise philosophers would be able to hear this harmony of the spheres. Kennedy shows that Plato gave his dialogues a similar, hidden musical structure. He divided each dialogue into twelve parts and inserted symbols at each twelfth to mark a musical note. These passages are relatively harmonious or dissonant, and so traverse the ups and downs of a known musical...