If you believe that feeling bad or worrying long enough will change a past or future event, then you are residing on another planet with a different reality system.

If any organism fails to fulfill its potentialities, it becomes sick.

Could the young but realize how soon they will become mere walking bundles of habits, they would give more heed to their conduct while in the plastic state.

A good hypothesis in science must have other properties than those of the phenomenon it is immediately invoked to explain, otherwise it is not prolific enough.

It is our attitude at the beginning of a difficult task which, more than anything else, will affect its successful outcome.

A man with no philosophy in him is the most inauspicious and unprofitable of all possible social mates.

The most ancient parts of truth . . . also once were plastic. They also were called true for human reasons. They also mediated between still earlier truths and what in those days were novel observations. Purely objective truth, truth in whose establishment the function of giving human satisfaction in marrying previous parts of experience with newer parts played no role whatsoever, is nowhere to be found. The reasons why we call things true is the reason why they are true, for to be true means only to perform this marriage-function.