The characteristic knowledge of our era is psychological. Even the most dramatic advances in physics and chemistry are chiefly applications of known methods of research. But the attitude toward human nature and human experience that has come in our time is new.


This attitude could not have come earlier. Before it came, there had to be long preparation. Physiology had to be a developed science; for the psychological person is also physiological. His mind, among other things, is a matter of brain tissue, of nerves, of glands, of organs of touch, smell, and sight. It was not until about 130 years ago that physiology was sufficiently developed to make psychophysical research possible, as in the laboratories of the distinguished German psychologist, William Wundt. But before physiology there had to be a developed science of biology. Since brain, nerves, glands, and the rest all depend upon cell processes, the science of the living cell had to have its intelligencizing before a competent physiology could emerge.


But before biology there had to be chemistry; and before chemistry, physics; and before physics, mathematics. So the long preparation goes back into the centuries.


There is, in short, a time clock of science. Each science has to wait until its hour strikes. Today, at last, the time clock of science strikes the hour of psychology; and a new enlightenment begins.


To be sure, the interests explored by this latest of the sciences are themselves old; but the accuracy of research is new. There is, in brief, a kind of iron logic that is in control. Each science has to wait for its peculiar accuracy until its predecessor has supplied the data and tools out of which its accuracy can be made.


Today this new psychological accuracy is bringing insights that are remaking our life. One insight in particular is of such commanding import that it may be said to be the master concept of our time. This is the concept of psychological intelligence.


We have known in a way about psychological intelligence—but vaguely and intermittently. Its full meaning now begins to dawn upon us. As it begins to dawn, we realize that the intelligence concept is central to our whole enterprise of living. This is what our past wisdoms have been leading up to. This, it would seem, is what we must now accept if we are to move forward out of the confusions and despairs of our day.


The time clock of science has struck a new hour; and a new insight begins to be at our service