"Man is a machine, but a machine in the sense that a tree is a machine. What he does, he does because of his structure, not because of some indwelling agent called a 'will.'"

"A first principle of behavior is that it is shaped by its consequences."

"The science of behavior is not interested in what goes on inside the organism, but in what the organism does."

"The world will never be saved by people who believe in free will."

"There is no such thing as a free will."