Death does not trouble me. I have no fear of supernatural punishments, of course, nor could I enjoy an eternal life in which there would be nothing left for me to do, the task of living having been accomplished.

If the world is to save any part of its resources for the future, it must reduce not only consumption but the number of consumers.

It is not a question of starting. The start has been made. It's a question of what's to be done from now on.

A first principle not formally recognized by scientific methodologists: when you run into something interesting, drop everything else and study it.

Behavior is shaped and maintained by its consequences

To say that a man is sinful because he sins is to give an operational definition of sin. To say that he sins because he is sinful is to trace his behavior to a supposed inner trait. But whether or not a person engages in the kind of behavior called sinful depends upon circumstances which are not mentioned in either question. The sin assigned as an inner possession (the sin a person "knows") is to be found in a history of reinforcement.

Those who have had anything useful to say have said it far too often, and those who have had nothing to say have been no more reticent.