If everyone agreed to become vegetarian, leaving little or nothing for livestock, the present 1.4 billion hectares of arable land (3.5 billion acres) would support about 10 billion people.

I think we will make it. Because one quality people have - certainly Americans have it - is that they can adapt when they see necessity staring them in the face. What to avoid is what someone once called the definition of hell: truth realized too late.

We exist in a bizarre combination of Stone Age emotions, medieval beliefs, and god-like technology.

You teach me, I forget. You show me, I remember. You involve me, I understand.

In many environments, take away the ants and there would be partial collapses in many of the land ecosystems.

If insemination were the sole biological function of sex, it could be achieved far more economically in a few seconds of mounting and insertion. Indeed, the least social of mammals mate with scarcely more ceremony. The species that have evolved long-term bonds are also, by and large, the ones that rely on elaborate courtship rituals. . . . Love and sex do indeed go together.

I believe that traditional religious belief and scientific knowledge depict the universe in radically different ways. At the bedrock they are incompatible and mutually exclusive.