The third component is that some people simply have a courageous nature. Some people just don't scare easily. But even that isn't conclusive. If someone doesn't scare easily, does that mean that she has more courage than someone who has to dig deep within herself to face danger? That's why we shame people in the Army if they don't have the courage that a situation demands. Stories of combat often tell of the courage that happens because a person couldn't otherwise live with himself.
And the fourth component is that feeling lucky is a source of confidence. It can fuel courage. But don't be obsessed with luck -- that's a kind of cowardice too, where you suspect that your courage is dependent upon something outside you.
But in the end, your conclusion is that we can't really train ourselves to be courageous -- that courage remains a mystery.
One thing that helps is to read stories of courage. They make you wonder how you would have done compared with the hero of the tale, and you get very humble. You start self-querying and fantasizing about your own response, your own reaction. As the psalmist says, "You become what you behold." That's why stories of courage take you over: They are such cries of the heart.
Harriet Rubin (hrubin@fastcompany.com) is a Fast Company senior writer and author of The Princessa: Machiavelli for Women (Doubleday, 1997).