it read as if they were mere lecture notes. There are many
interpolations. The same characteristics are to be observed in
Aristotle's other writings, though in a less degree. It seems probable
that they were not intended, in their present state, for publication.
Final revision and finishing touches are lacking. In spite of these
defects, the writings are voluminous and clear enough to enable us to
trace out the whole of the main positions of Aristotle's thought.

We saw, in the case of Plato, that, as his literary activity lasted
over a period of half a century, during which his philosophy was in
constant development, it became important to trace this development in
the {254} order of his Dialogues. The same thing is not true in the
case of Aristotle. The whole of his writings, or rather those that
have come down to us, seem to have been written during his last
thirteen years, while he was at Athens, that is to say, after he had
passed his fiftieth year. His system was then complete, mature, and
fully developed. The question of the order in which they were written
has no great importance. The result of critical investigations,
however, is to show that he probably began with the various works upon
logic, composed next the treatises upon physical science, next the
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 necessary, 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
includ