in the market or with
patients in the hospital, we need not only to know what is true of
every human being; we must above all discover how the particular
individual is disposed and composed, or what is characteristic of
special groups, nations, races, sexes, and ages. It is clear that new
methods were needed to approach these younger problems of scientific
psychology, but the scientists have eagerly turned with concerted
efforts toward this unexplored region and have devoted the methods of
test experiments, of statistics, and of laboratory measurements to the
examination of such differences between various individuals and
groups.

But in all these new efforts the psychologist meets a certain public
resistance, or at least a certain disregard, which he is not
accustomed to find in his routine endeavours. As long as he was simply
studying the laws of the mind, he enjoyed the approval of the wider
public. His work was appreciated as is that of the biologist and the
chemist. But when it becomes his aim to discover mental features of
the individual, and to foresee what he can expect from the social
groups of men, every layman tells him condescendingly that it is a
superfluous task, as instinct and intuition and the naive psychology
of the street will be more successful than any measurements with
chronoscopes and kymographs. Do we not know how the skilful politician
or the efficient manager looks through the mind of a man at the first
glance? The life insurance agent has hardly entered the door before he
knows how this particular mind must be handled. Every commercial
traveller knows more than any psychologist can tell him, and even the
waiter in the restaurant foresees when the guest sits down how large a
tip he can expect from him. In itself it would hardly be convincing to
claim that scientific efforts to bring a process down to exact
principles are unnecessary because the process can be performed by
instinct. We all can walk without needing a knowledge of the muscles
which are used, and can find nourishment without knowing the
physiology of nutrition. Yet the physiologist has not only brought to
light the principles according to which we actually eat, but he has
been able to make significant suggestions for improved diet, and in
not a few cases his knowledge can render services which no instinctive
appetite could replace. The psychological study of human traits, too,
may not only find out the principles underlying the or