Can I pay any higher tribute to a man [George Gaylord Simpson] than to state that his work both established a profession and sowed the seeds for its own revision? If Simpson had reached final truth, he either would have been a priest or would have chosen a dull profession. The history of life cannot be a dull profession.

Biological determinism is, in its essence, a theory of limits. It takes the current status of groups as a measure of where they should and must be ... We inhabit a world of human differences and predilections, but the extrapolation of these facts to theories of rigid limits is ideology.

Forelimbs of people, porpoises, bats and horses provide the classic example of homology in most textbooks. They look different, and do different things, but are built of the same bones. No engineer, starting from scratch each time, would have built such disparate structures from the same parts.

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.

I dreamed of becoming a scientist, in general, and a paleontologist, in particular, ever since the Tyrannosaurus skeleton awed and scared me.

A man does not attain the status of Galileo merely because he is persecuted; he must also be right.

The absence of fossil evidence for intermediary stages between major transitions in organic design, indeed our inability, even in our imagination, to construct functional intermediates in many cases, has been a persistent and nagging problem for gradualist accounts of evolution.