10. THE SCIENCE OF PSYCHOLOGY.--Now let us come back to a science which
has to do directly with things. We have seen that the plain man has
some knowledge of minds as well as of material things. Every one
admits that the psychologist knows minds better. May we say that his
knowledge of minds differs from that of the plain man about as the
knowledge of plants possessed by the botanist differs from that of all
intelligent persons who have cared to notice them? Or is it a
knowledge of a quite different kind?

Those who are familiar with the development of the sciences within
recent years have had occasion to remark the fact that psychology has
been coming more and more to take its place as an independent science.
Formerly it was regarded as part of the duty of the philosopher to
treat of the mind and its knowledge; but the psychologist who pretends
to be no more than a psychologist is a product of recent times. This
tendency toward specialization is a natural thing, and is quite in line
with what has taken place in other fields of investigation.

When any science becomes an independent discipline, it is recognized
that it is a more or less limited field in which work of a certain kind
is done in a certain way. Other fields and other kinds of work are to
some extent ignored. But it is quite to be expected that there should
be some dispute, especially at first, as to what does or does not
properly fall within the limits of a given science. Where these limits
shall be placed is, after all, a matter of convenience; and sometimes
it is not well to be too strict in marking off one field from another.
It is well to watch the actual development of a science, and to note
the direction instinctively taken by investigators in that particular
field.