came to deal with complex phenomena.
Thus, though he constructed a table of specific gravities--"the only
collection," says Mr. Ellis, "of quantitative experiments that we find
in his works," and "wonderfully accurate considering the manner in which
they were obtained;" yet he failed to understand the real nature of the
famous experiment of Archimedes. And so with the larger features of his
teaching it is impossible not to feel how imperfectly he had emancipated
himself from the power of words and of common prepossessions; how for
one reason or another he had failed to call himself to account in the
terms he employed, and the assumptions on which he argued. The caution
does not seem to have occurred to him that the statement of a fact may,
in nine cases out of ten, involve a theory. His whole doctrine of
"Forms" and "Simple natures," which is so prominent in his method of
investigation, is an example of loose and slovenly use of unexamined and
untested ideas. He allowed himself to think that it would be possible to
arrive at an alphabet of nature, which, once attained, would suffice to
spell out and constitute all its infinite combinations. He accepted,
without thinking it worth a doubt, the doctrine of appetites and
passions and inclinations and dislikes and horrors in inorganic nature.
His whole physiology of life and death depends on a doctrine of animal
spirits, of which he traces the operations and qualities as if they were
as certain as the nerves or the blood, and of which he gives this
account--"that in every tangible body there is a spirit covered and
enveloped in the grosser body;" "not a virtue, not an energy, not an
actuality, nor any such idle matter, but a body thin and invisible, and
yet having place and dimension, and real." ... "a middle nature between
flame, which is momentary, and air which is permanent." Yet these are
the very things for which he holds up Aristotle and the Scholastics and
the Italian speculators to reprobation and scorn. The clearness of his
thinking was often overlaid by the immense profusion of decorative
material which his meditation brought along with it. The defect was
greater than that which even his ablest defenders admit. It was more
than that in that "greatest and radical difference, which he himself
observes" between minds, the difference between minds which were apt to
note _distinctions_, and those which were apt to note _likenesses_, he
was, without knowing it, defective