Similarly, social transformations may upset the stable and familiar. Wars, revolutions, and migrations make the conditional nature of everything taken for granted evident once again.
Internal transformations are just as likely to introduce instability.
The hormonal changes and new social demands of adolescence may likewise transform the happy and reasonable child into a depressed and hostile teen-ager. The ever-expanding human capacity for abstract thinking, for example, appears to be a consequence of evolutionary, social and individual forces, working synergistically. The unknown has become permanently contaminated with death, for Homo sapiens. Our great transpersonal cognitive power, however, has not yet rescued us from the valley of the shadow of death.