Transitional forms are generally lacking at the species level, but they are abundant between larger groups.

The equation of evolution with progress represents our strongest cultural impediment to a proper understanding of this greatest biological revolution in the history of human thought.

Any human being is really good at certain things. The problem is that the things you're good at come naturally. And since most people are pretty modest instead of an arrogant S.O.B. like me, what comes naturally, you don't see as a special skill. It's just you. It's what you've always done.

At a minimum, in explaining evolutionary pathways through time, the constraints imposed by history rise to equal prominence with the immediate advantages of adaptation.

In what I like to call the Great Asymmetry, every spectacular incident of evil will be balanced by 10,000 acts of kindness, too often unnoted and invisible.

Few tragedies can be more extensive than the stunting of life, few injustices deeper than the denial of an opportunity to strive or even to hope, by a limit imposed from without, but falsely identified as lying within.

All interesting issues in natural history are questions of relative frequency, not single examples. Everything happens once amidst the richness of nature. But when an unanticipated phenomenon occurs again and again—finally turning into an expectation—then theories are overturned.