Take the case of courage: no quality has ever so much addled the brains and tangled the definitions of merely rational sages.
Courage is almost a contradiction in terms: it means a strong desire to live taking the form of a readiness to die. "He that will lose his life, the same shall save it", is not a piece of mysticism for saints and heroes. It is a piece of everyday advice for sailors or mountaineers. It might be printed in an Alpine guide or a drill book. This paradox is the whole principle of courage; even of quite earthly or quite brutal courage. A man cut off by the sea may save his life if he will risk it on the precipice; he may get away from death by continually stepping within an inch of it. A soldier surrounded by enemies, if he is to cut
his way out, needs to combine a strong desire for living with a strange carelessness about dying. He must not merely wait for death, for then he will be a suicide and will not escape. He must not merely cling to life, for then he will be a coward, and will not escape. He must seek his life in a spirit of furious indifference to it: he must desire life like water and yet drink death like wine.
No philosopher, I fancy, has ever expressed this romantic riddle with adequate lucidity, and I certainly have not done so. But Christianity has done more; it has marked the limits of It in the awful graves of the suicide and the hero, showing the distance between him who dies for the sake of living and him who dies for the sake of dying. And it has held up ever since above the European lances the banner of the mystery of chivalry: the Christian courage, which is a disdain of death; not the [Oriental] courage, which is a disdain of life.
... Gilbert Keith Chesterton, Orthodoxy [1909]
