The search for happiness is one of the chief sources of unhappiness.

One word characterizes the most strenuous of the efforts for the advancement of science that I have made perservereingly during fifty-five years; that word is failure

Never have the young taken themselves so seriously, and the calamity is that they are listened to and deferred to by so many adults.

The fear of becoming a 'has-been' keeps some people from becoming anything.

The fanatical Communist refuses to believe any unfavorable report or evidence about Russia, nor will he be disillusioned by seeing with his own eyes the cruel misery inside the Soviet promised land. It is the true believer's ability to "shut his eyes and stop his ears" to facts that do not deserve to be either seen or heard which is the source of his unequaled fortitude and constancy. He cannot be frightened by danger, nor disheartened by obstacles, nor baffled by contradictions because he denies their existence.

Every successful person has had failures but repeated failure is no guarantee of eventual success

Our achievements speak for themselves. What we have to keep track of are our failures, discouragements and doubts. We tend to forget the past difficulties, the many false starts, and the painful groping. We see our past achievements as the end results of a clean forward thrust, and our present difficulties as signs of decline and decay.