You never know how much you really believe anything until its truth or falsehood becomes a matter of life and death to you. It is easy to you believe a rope to be strong and sound as long as you are merely using it to cord a box. But suppose that you had to hang by that rope over a precipice. Wouldn't you then first discover how much you really trusted it? … Only a real risk tests the reality of a belief.

A Grief Observed (1961)