The preoccupation with the choice of a mate both by male and female I regard as a continuing echo of the major selective force by which we have evolved.

Science is a tribute to what we can know, although we are fallible.

Every animal leaves traces of what it was; man alone leaves traces of what he created.

A man becomes creative, whether he is an artist or scientist, when he finds a new unity in the variety of nature. He does so by finding a likeness between things which were not thought alike before.

We have to understand that the world can only be grasped by action, not by contemplation. The hand is more important than the eye ... The hand is the cutting edge of the mind.

Science is a very human form of knowledge. We are always at the brink of the known; we always feel forward for what is to be hoped. Every judgment in science stands on the edge of error and is personal. Science is a tribute to what we can know although we are fallible.

In the moment of appreciation we live again the moment when the creator saw and held the hidden likeness.