ABSTRACT
An understanding of geological time was necessary for framing a theory of evolution. Similarly, a better understanding of the role of timing in ontogenetic processes may be a prerequisite for a general theory of development, something we urgently need. That time is at the center of any concept of development is so obvious that we tend to take it for granted. We have gradually come to realize that it is more than simply the dimension within which events unfold, a yardstick or reference scale for the description of differences. So long as development was viewed in global terms as a unitary process by which disparate elements were gradually put together or through which discrete responses grew out of mass action behaviors, time simply served to chart progress or define stages. Environmental events, particularly traumatic ones, if they occurred at early points on this time scale, were thought to disturb development primarily through arresting the unfolding process at the stage when they occurred, so that full maturation of a given functional system did not take place. But as more careful empirical studies were done, in the 1960s and 1970s, more and more observations just did not fit these assumptions, and researchers were forced into new ways of thinking.
