12 THE FACTORS OF THE MIND

way to distinctions between the functions of various
cortical areas or cell-layers (indeed, the chief group-
factors so far discovered rather suggest some such basis) ;
and our distinctions between temperamental types may be
resolved into biochemical differences produced by variations
in the balance of endocrine secretions : so that in these
directions factor-analysis may turn out to be a mere make-
shift—a temporary expedient that we may conveniently
exploit while awaiting a more refined experimental tech-
nique. Since the field is highly complex, a direct advance
by non-statistical methods is bound to be slow. Meanwhile,
scientific curiosity demands at least a provisional solution ;
and the immediate needs of applied psychology call for
working hypotheses and some practical device for deter-
mining the key-characteristics of different individuals* It is
these urgent demands that factor-analysis endeavours to
meet. How far can we trust it F

Accordingly, in the opening chapters I shall confine myself
chiefly to the question of methodology. I propose first to
examine what nearly every writer on factor-analysis has
hitherto taken for granted, namely, the nature of factor-
analysis in itself as a general method of scientific inquiry,
irrespective of the particular arithmetical form which the
procedure assumes in the hands of this investigator or that,
and regardless of the particular results obtained. Only after
we have examined the logical nature of the arguments by
which factors are derived (or so at least I believe) can
we go on to decide what may be the physical or meta-
physical nature of the factors hitherto suggested.

If I am correct, the main reason for the protracted
controversies which have obscured the whole subject lies
in the fact that the opposing parties, though nominally
acknowledging the same general purposes, are interested
each almost exclusively in one purpose alone™the theor-
etical analysis of the human mind in the one case, and the
practical prediction of individual progress and develop-
ment in the other. Spearman's original concern, as the
title of his great work implies, lay in the abstract nature
of intelligence and cognition ; his aim was * to discover
the causal mechanisms of the mind and the general laws