Mathematical philosophy, a study of fate and freedom; lectures for educated laymen, by Cassius J. Keyser.

LECTURE XVIII
The Mathematics of Psychology
BACKWARDNESS OF THIS AND OF THE PSYCHOLOGY OF
MATHEMATICS-THE LAW OF WEBER AND FECHNER
REEXAMINED-SOME OF THE LAW'S UNNOTICED IMPLICATIONS-THOUGHT AS INFINITELY REFINED
SENSIBILITY.
Two of the subjects that this course should include
are the mathematics of psychology, and the psychology
of mathematics. The two things, though closely related,
are distinct-they interpenetrate but neither includes the
other; it is one thing to mathematicize psychology, and
a very different thing to psychologize mathematics; the
aim of the former is to express psychological relations in
mathematical terms; that of the latter is to study those
aspects of mathematics which are psychological as distinguished from logical; both enterprises are immense
and important; neither one is far advanced, and the reasons are evident-the tasks are difficult, requiring special
preparation, while psychologists have not been mathematicians and the latter have not been psychologists. But
psychologists have done as much to mathematicize their
subject as mathematicians have done to understand the
psychology of theirs, though the former task is perhaps
the harder of the two.
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