An individual ant, even though it has a brain about a millionth of a size of a human being's, can learn a maze; the kind we use is a simple rat maze in a laboratory. They can learn it about one-half as fast as a rat.

One difference between ants and humans is that while ants send their old women off to war, humans send their young men.

That is the great mystery of human evolution: how to account for calculus and Mozart.

One planet, one experiment.

Humanity is exalted not because we are so far above other living creatures, but because knowing them well elevates the very concept of life.

The living environment is the biosphere, the thin layer around the world of living organisms. We're part of that. Our existence is dependent on it in ways that people haven't even begun to appreciate. Our existence depends not just on its existence, but its stability and its richness.

Human existence may be simpler than we thought. There is no predestination, no unfathomed mystery of life. Demons and gods do not vie for our allegiance. Instead, we are self-made, independent, alone, and fragile, a biological species adapted to live in a biological world. What counts for long-term survival is intelligent self-understanding, based upon a greater independence of thought than that tolerated today even in our most advanced democratic societies.