Voices carry

Chances are you will politely nod, sidle to the end of the bench, and scan the platform for another place to sit. Your reaction likely mixes pity with anxiety, because auditory hallucinations signal psychosis, and you're saddened and unnerved encountering a person unable to distinguish between reality and illusion.

The man in the subway station fades from your mind until you next attend your house of prayer, whether it be a church, synagogue, or mosque. And as the priest or rabbi or imam delivers his sermon, he refers to sacred texts that recount how Moses spoke with God at the burning bush, or how Ignatius Loyola and Martin Luther listened to the divine call, or how Mohammed was instructed by Allah to write down the suras of the Koran. As a person of faith, you venerate those who heard God's voice and translated it into wisdom for the world.

Suppose you are not a religious person but a secular humanist, committed to living an ethical and self-aware life. Then Socrates would be one of your guides. He formulated his philosophy through dialogue with the Athenians around him. But, it turns out, Socrates also regularly turned inward, listening to an inner voice that he termed his "daimonion." Rather than consult the sanctioned oracle at Delphi, he strictly obeyed the unique voice in his head.

Daniel B. Smith, in the articulate, engaging, and deeply researched "Muses, Madmen, and Prophets," wrestles with what it means to hear voices. Saint, scholar, or schizophrenic -- why do we assign differing values and valences to individuals who hear voices, and to what their voices say?