proportionate to the amount of food eaten), sometimes with the work
done by human beings and their steam-engines, and shows it to be due
ultimately to the sun's heat. It would never occur to a reader of his
pages that a social force proper might be anything that acted as a
stimulus of social change,--a leader, for example, a discovery, a book,
a new idea, or a national insult; and that the greatest of "forces" of
this kind need embody no more "physical force" than the smallest. The
measure of greatness here is the effect produced on the environment,
not a quantity antecedently absorbed from physical nature. Mr. Spencer
himself is a great social force; but he ate no more than an average
man, and his body, if cremated, would disengage no more energy. The
effects he exerts are of no nature _of releases_,--his words pull
triggers in certain kinds of brain.

The fundamental distinction in mechanics between forces of
push-and-pull and forces of release is one of which Mr. Spencer, in his
earlier years, made no use whatever. Only in his sixth edition did he
show that it had seriously arrested his attention. In biology,
psychology, and sociology the forces concerned are almost exclusively
forces of release. Spencer's account of social forces is neither good
sociology nor good mechanics. His feeble grasp of the conception of
force vitiates, in fact, all his work.

But the task of a carper is repugnant. The "Essays," "Biology,"
"Psychology," "Sociology," and "Ethics" are all better than "First
Principles," and contain numerous and admirable bits of penetrating
work of detail. My impression is that, of the systematic treaties, the
"Psychology" will rank as the most original. Spencer broke new ground
here in insisting that, since mind and its environment have evolved
together, they must be studied together. He gave to the study of mind
in isolation a definitive quietus, and that certainly is a great thing
to have achieved. To be sure he overdid the matter, as usual, and left
no room for any mental structure at all, except that which passively
resulted from the storage of impressions received from the outer world
in the order of their frequency by fathers and transmitted to their
sons. The belief that whatever is acquired by sires is inherited by
sons, and the ignoring of purely inner variations, are weak points; but
to have brought in the environment as vital was a master stroke.

I may say that Spencer's controver