METAPHYSICAL STATUS OF FACTORS 231

experience or training that we assume to be superimposed
upon them.

This artificial subdivision of the mind into independent
components greatly simplifies the task of prediction ; yet,
unless we continually remember that our predictions can
never yield more than probabilities and first approxima-
tions, we shall make the fatal mistake of treating the
individual's potentialities as far more rigidly fixed than is
actually the case. In educational work the doctrine of an
innate general factor of intelligence has, I believe, been on
the whole helpful rather than harmful. But, as applied to
adults rather than to children, it involves great dangers.
With both, the notion of innately limited abilities needs to
be employed with far more caution than hitherto ; and the
identification of temperamental factors with such concrete
physiological influences as physical types or endocrine
secretions, over which the individual has no control,
though full of suggestive and neglected possibilities, has
led both factorial and non-factorial writers to rash specula-
tions, and has often proved a needless obstacle to proper
clinical treatment.

Nevertheless, I would not be so pedantic as to banish
causal terms altogether from the psychologist's vocabulary.
The physicist, who would never mention causes in a book
on quantum physics, would not scruple to use the word in
chatting over a practical problem with an engineer.
Similarly, in practical or applied psychology, where, for
example, we are canvassing the history and the handling of
subnormal cases, the language of causation is not only
convenient, it is almost unavoidable, if we are. to remain
comprehensible.

As a practical psychologist, then, though not as a theor-
etical psychologist, I should consider myself licensed to talk
in terms of causal factors—abilities, temperamental tenden-
cies, acquired habits, and the like, just as a modern astrono-
mer is still free to talk of sunrise and sunset. And I should
certainly prefer to express these causes in genetic, physio-
logical, or biochemical terms, were only our knowledge
sufficiently advanced. Since it is not, I have to give my
causes mental rather than material labels, and speak of