If one cannot state a matter clearly enough so that even an intelligent twelve-year-old can understand it, one should remain within the cloistered walls of the university and laboratory until one gets a better grasp of one's subject matter.

Sometimes, instead of helping people to advance, a discovery or an invention holds them back.

When human beings have been fascinated by the contemplation of their own hearts, the more intricate biological pattern of the female has become a model for the artist, the mystic, and the saint. When mankind turns instead to what can be done, altered, built, invented, in the outer world, all natural properties of men, animals, or metals become handicaps to be altered rather than clues to be followed.

An occupation that has no basis in sex-determined gifts can now recruit its ranks from twice as many potential artists.

We — mankind — stand at the center of an evolutionary crisis, with a new evolutionary device — our consciousness of the crisis — as our unique contribution.

The way in which each human infant is transformed into the finished adult, into the complicated individual version of his city and his century is one of the most fascinating studies open to the curious minded.

Female animals defending their young are notoriously ferocious and lack the playful delight in combat which characterizes the mock combats of males of the same species. There seems very little ground for claiming that the mother of young children is more peaceful, more responsible, and more thoughtful for the welfare of the human race than is her husband or brother.