The growth of the human mind is still high adventure, in many ways the highest adventure on earth.

The sense of paralysis proceeds not so much out of the mammoth size of the problem but out of the puniness of the purpose.

The main trouble with despair is that it is self-fulfilling. People who fear the worst tend to invite it. Heads that are down can't scan the horizon for new openings. Bursts of energy do not spring from a spirit of defeat. Ultimately, helplessness leads to hopelessness.

The tragedy of life is in what dies inside a man while he lives - the death of genuine feeling, the death of inspired response, the awareness that makes it possible to feel the pain or the glory of other men in yourself.

To talk about the need for perfection in man is to talk about the need for another species. The essence of man is imperfection. Imperfection and blazing contradictions-between mixed good and evil, altruism and selfishness, cooperativeness and combativeness, optimism and fatalism, affirmation and negation.

What was most significant about the lunar voyage was not that men set foot on the moon but that they set eye on the earth.

Laughter is a form of internal jogging. It moves your internal organs around. It enhances respiration. It is an igniter of great expectations.