ethical and political books, and lastly the “Metaphysics,”
which he left unfinished.
It must not be forgotten that Aristotle was not only a
philosopher in the modern restricted sense of that term.
He was a man of universal learning. There is no branch of
knowledge which did not receive his attention, and upon
which he was not the greatest expert of his time, except
perhaps mathematics. So far was he from being only an
abstract philosopher, that his natural tastes seem to have
lain rather in the field of physical science than of abstract
thought. But his design seems to have been to work over
the entire field of knowledge, thoroughly to overhaul the
sciences already in existence, rejecting what seemed false
in the work of his predecessors, and invariably adding to
the residue valuable developments and suggestions of his
own. Where there was no science already in existence, his
plan involved the foundation of new sciences wherever nec-
essary, and he thus became the founder of at least two
sciences, Logic and Zoology. He thus attained to a pre-
eminence in all branches {255} of knowledge which would
be impossible for a single man in modern times. His works
include treatises upon Logic and Metaphysics, upon Ethics,
Politics, and Art. He wrote a treatise upon the principles of
Rhetoric, another upon Astronomy, under the title “On the
Heavens,” another upon Meteorology. Several of his trea-
tises deal with the biology of animal life, in which he was
intensely interested. They include books entitled “On the
Parts of Animals,” “On the Movements of Animals,” “On
the Origin of Animals,” as well as his great treatise, “Re-
searches on Animals,” which contains an enormous mass of
facts collected from every possible source. It is true that
a large proportion of these facts have turned out to be fic-
tions, but this was inevitable in the infancy of science. It
has been calculated that Aristotle shows himself acquainted
with about five hundred different species of living beings,
though they are not, of course, classified by him in the
modern way. With these books upon animals he founded
the science of Zoology, for no one before his day had made
any special study of the subject.It has been said that everyone has either an Aristotelian
or a Platonic type of mind. As this implies that Aristotle
and Plato are opposites, it is considerably less than a half
truth. No genuine understanding of Aristotle can endorse
the opinion that his philosophical system was the opposite
of Plato’s. It would be truer to say that Aristotle was the
greatest of all Platonists, since his system is still founded
upon the Idea, and is an attempt to found an idealism free
from the defects of Plato’s system. It is in fact a develop-
ment of Platonism. What is the cause then of the popular
notion that {256} Aristotle was the opposite of Plato? Now
the fact is that theywereopposites in many important re-
spects. But there was a fundamental agreement between
them which lies deeper than the differences. The differ-
ences are largely superficial, the agreement is deep-seated.
Hence it is the differences that are most obvious, and it was
the differences, too, which were most obvious to Aristotle
himself. The popular opinion arises largely from the fact
that Aristotle never loses an opportunity of attacking the
Platonic theory of Ideas. He is continually at pains to em-
phasize the difference between himself and Plato, but says