Our theories are wedged and controlled as nothing else is. Yet sometimes alternative theoretic formulas are equally compatible with all the truths we know, and then we choose between them for subjective reasons. We choose the kind of theory to which we are already partial: we follow 'elegenace' or 'economy'

All the higher, more penetrating ideals are revolutionary. They present themselves far less in the guise of effects of past experience than in that of probable causes of future experience, factors to which the environment and the lessons it has so far taught us must learn to bend.

There are two lives, the natural and the spiritual, and we must lose the one before we can participate in the other.

Mankind's common instinct for reality has always held the world to be essentially a theatre for heroism. In heroism, we feel, life's supreme mystery is hidden. We tolerate no one who has no capacity whatever for it in any direction. On the other hand, no matter what a man's frailties otherwise may be, if he be willing to risk death, and still more if he suffer it heroically, in the service he has chosen, the fact consecrates him forever.

The stream of thought flows on; but most of its segments fall into the bottomless abyss of oblivion. Of some, no memory survives the instant of their passage. Of others, it is confined to a few moments, hours or days. Others, again, leave vestiges which are indestructible, and by means of which they may be recalled as long as life endures.

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.

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