"I could not accept that they were human beings. I would see a child smiling at me, yet I would kill him."

This is how a Hutu man described his feelings when he slaughtered a Tutsi in Rwanda in 1994.

Such statements are shocking, yet we recognize them and hear their echoes in accounts of genocides and massacres throughout history. How is it possible for some people to believe their enemies are monsters—and thus easy to kill?

David Smith offers a compelling analysis of the philosophical and psychological roots of dehumanization, exploring its meaning as well as how and why we engage in it.

Dehumanization is deeply rooted within us. And because we are all human, we are vulnerable to manipulation by those who traffic in the politics of demonization and violence.