Twenty-five hundred years ago it might have been said that man understood himself as well as any other part of the world. Today he is the thing he understands least.

Old age is rather like another country. You will enjoy it more if you have prepared yourself before you go.

But restraint is the only one sort of control, and absence of restraint isn't freedom. It's not control that's lacking when one feels 'free', but the objectionable control of force.

That's all teaching is; arranging contingencies which bring changes in behavior.

The simplest and most satisfactory view is that thought is simply behavior - verbal or nonverbal, covert or overt. It is not some mysterious process responsible for behavior but the very behavior itself in all the complexity of its controlling relations.

A disappointment is not generally an oversight. It might just be the best one can do the situation being what it is. The genuine error is to quit attempting.

The strengthening of behavior which results from reinforcement is appropriately called 'conditioning'. In operant conditioning we 'strengthen' an operant in the sense of making a response more probable or, in actual fact, more frequent.