Adulthood Rites (Xenogenesis, #2)

by Octavia E. Butler

At least, no one had been able to give him a reason why people who had excellent reasons to suppose they would destroy themselves if they did a certain thing chose to do that thing anyway. He thought he understood anger, hatred, humiliation, even the desire to kill a man. He had felt all those things. But to kill everyone… almost to kill the Earth… There were times when he wondered if somehow the Oankali had not caused the war for their own purposes. How could sane people like the ones he had left behind in Phoenix do such a thing—or, how could they let insane people gain control of devices that could do so much harm? If you knew a man was out of his mind, you restrained him. You didn’t give him power.

“A doctor who specializes in the treatment of mental illness.” She gave a bitter laugh. “The Oankali say people like me dealt with far more physical disorders than we were capable of recognizing.”