The human species took a crucial step forward when its vocal musculature came under operant control in the production of speech sounds. Indeed, it is possible that all the distinctive achievements of the species can be traced to that one genetic change.

Science, not religion, has taught me my most useful values, among them intellectual honesty. It is better to go without answers than to accept those that merely resolve puzzlement.

A self is a repertoire of behavior appropriate to a given set of contingencies.

A person's genetic endowment, a product of the evolution of the species, is said to explain part of the workings of his mind and his personal history the rest.

The alphabet was a great invention, which enabled men to store and to learn with little effort what others had learned the hard way-that is, to learn from books rather than from direct, possibly painful, contact with the real world.

If you're old, don't try to change yourself, change your environment.

It has always been the task of formal education to set up behavior which would prove useful or enjoyable later in a student's life.