But living that life as an animal — an insensate brute, incapable of reason, abstraction, perhaps even feeling? Unthinkable. Yes, yes, the animals don’t recognize the difference, and neither would you. If you’re a goat, you possess the knowledge of a goat, and that can’t be much. But there’s more to it than that.

Human beings have always had something of a bipolar relationship with the millions of other species with which we share the planet. We are fascinated by…