
points. Each could offer a plausible explanation for why this occurs. But
the simplest explanation may be that the design process of man’s systems,
like man himself, passes through three stages of life: youth, maturity, and
old age.
In the youthful stage, people are full of vigor. They are the new kids on
the block; they exude vitality, crave attention, and show lots of potential. As a
person passes from youth to maturity, he or she becomes more useful to the
world. Careers take shape. Long-term relationships develop. Influence widens
in worldly affairs. The person makes an impact—good, bad, or otherwise. By
the time old age sets in, the person has