We have seen that in certain respects operant reinforcement resembles the natural selection of evolutionary theory. Just as genetic characteristics which arise as mutations are selected or discarded by their consequences, so novel forms of behavior are selected or discarded through reinforcement.

...not everyone is willing to defend a position of 'not knowing.' There is no virtue in ignorance for its own sake.

Problem-solving typically involves the construction of discriminative stimuli

The problem of far greater importance remains to be solved. Rather than build a world in which we shall all live well, we must stop building one in which it will be impossible to live at all.

Science is a willingness to accept facts even when they are opposed to wishes.

A fourth-grade reader may be a sixth-grade mathematician. The grade is an administrative device which does violence to the nature of the developmental process.

I will be dead in a few months. But it hasn't given me the slightest anxiety or worry. I always knew I was going to die.