With the rise of chiefdoms around 7,500 years ago, people had to learn, for the first time in history, how to encounter strangers regularly without attempting to kill them.

Why did human development proceed at such different rates on different continents for the last 13,000 years?

With the MacArthur grant, I realized that people have high expectations of me, that they were placing me in this group of achievers. I compared what Id actually achieved in my life with what I would like to achieve and what other people have achieved, and I found that comparison depressing.

No government is here forever. And there are other forces - the most potent force in our society, in fact, big business - doing good for the environment.

Science is often misrepresented as "the body of knowledge acquired by performing replicated controlled experiments in the laboratory." Actually, science is something broader: the acquisition of reliable knowledge about the world.

Twelve thousand years ago, everybody on earth was a hunter-gatherer; now almost all of us are farmers or else are fed by farmers. The spread of farming from those few sites of origin usually did not occur as a result of the hunter-gatherers' elsewhere adopting farming; hunter-gatherers tend to be conservative.... Instead, farming spread mainly through farmers' outbreeding hunters, developing more potent technology, and then killing the hunters or driving them off of all lands suitable for agriculture.

All of our current environmental problems are unanticipated harmful consequences of our existing technology. There is no basis for believing that technology will miraculously stop causing new and unanticipated problems while it is solving the problems that it previously produced.