"The way in which we think about the causes of human behavior has changed in a way that suggests that we are at an early stage of a scientific revolution."

"I deny that I have ever attacked anyone's dignity. I have attacked the concept of dignity as a causal agent."

"The environment not only goads or releases, it selects."

"The baby is an exquisite instrument, and we must learn to play it properly."

"No one asks how to motivate a baby. A baby naturally explores everything it can get at, unless restraining forces have already been at work. And what is true of the baby is true of the scientist."