History followed different courses for different peoples because of differences among peoples' environments, not because of biological differences among peoples themselves

Federal elections happen every two years in this country. Presidential elections every four years. And four years just isn't long enough to dismantle all the environmental laws we've got in this country.

Bird taxonomy is a difficult field because of the severe anatomical constraints imposed by flight. There are only so many ways to design a bird capable, say, of catching insects in mid-air, with the result that birds of similar habitats tend to have very similar anatomies, whatever their ancestry. For example, American vultures look and behave much like Old World vultures, but biologists have come to realize that the former are related to storks, the latter to hawks, and that their resemblances result from their common lifestyle.

I've always been interested in a lot of things, and a lot of things at the same time, and I always tried to explain them to myself. I ask a lot of questions.

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.

People often ask, "What is the single most important environmental population problem facing the world today?" A flip answer would be, "The single most important problem is our misguided focus on identifying the single most important problem!

One way to explain the complexity and unpredictability of historical systems, despite their ultimate determinacy, is to note that long chains of causation may separate final effects from ultimate causes lying outside the domain of that field of science.