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.

Science can't tell us what our life means ethically. It can't tell us what we are meant to do as moral creatures. But, insofar as science can understand what we're made of, and what we're related to, the Darwinian revolution completely revised our ideas about who we are and what we're related to and how long we've been here and why we're on this Earth.

Wind back the tape of life to the early days of the Burgess Shale; let it play again from an identical starting point, and the chance becomes vanishingly small that anything like human intelligence would grace the replay.

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.

What an odd time to be a fundamentalist about adaptation and natural selection - when each major subdiscipline of evolutionary biology has been discovering other mechanisms as adjuncts to selection's centrality.

We cannot win this battle to save species and environments without forging an emotional bond between ourselves and nature as well - for we will not fight to save what we do not love.

The essence of Darwinism lies in its claim that natural selection creates the fit. Variation is ubiquitous and random in direction. It supplies raw material only. Natural selection directs the course of evolutionary change.