We tend to think of dangers and uncertainties as anomalies in the continuum of life, or irruptions of unpredictable forces into a largely predictable world. I suggest the contrary: that dangers and uncertainties are an inescapable dimension of life. In fact, as we shall come to understand, they make life matter. They define what it means to be human.
Sex keeps me in shape. I don't diet, I eat what I like. I love Mars bars and I smoke and drink. But I love running off in the middle of the day to make love. It really burns up calories.