c as the instrument of thought, he
introduces into it, as a fundamental feature, the ten categories. These
predicaments are the genera to which everything may be reduced, and
denote the most general of the attributes which may be assigned to a
thing.

[Sidenote: and metaphysics.]

His metaphysics overrides all the branches of the physical sciences. It
undertakes an examination of the postulates on which each one of them is
founded, determining their truth or fallacy. Considering that all
science must find a support for its fundamental conditions in an
extensive induction from facts, he puts at the foundation of his system
the consideration of the individual; in relation to the world of sense,
he regards four causes as necessary for the production of a fact--the
material cause, the substantial cause, the efficient cause, the final
cause.

[Sidenote: Temporary failure of his system.]

[Sidenote: The Peripatetic philosophy.]

[Sidenote: Substance, Motion, Space, Time.]

[Sidenote: The world.]

[Sidenote: Organic beings.]

[Sidenote: Physiological conclusions.]

But as soon as we come to the Physics of Aristotle we see at once his
weakness. The knowledge of his age does not furnish him facts enough
whereon to build, and the consequence is that he is forced into
speculation. It will be sufficient for our purpose to allude to a few of
his statements, either in this or in his metaphysical branch, to show
how great is his uncertainty and confusion. Thus he asserts that matter
contains a triple form--simple substance, higher substance, which is
eternal, and absolute substance, or God himself; that the universe is
immutable and eternal, and, though in relation with the vicissitudes of
the world, it is unaffected thereby; that the primitive force which
gives rise to all the motions and changes we see is Nature; it also
gives rise to Rest; that the world is a living being, having a soul;
that, since every thing is for some particular end, the soul of man is
the end of his body; that Motion is the condition of all nature; that
the world has a definite boundary and a limited magnitude; that Space
is the immovable vessel in which whatever is may be moved; that Space,
as a whole, is without motion, though its parts may move; that it is not
to be conceived of as without contents; that it is impossible for a
vacuum to exist, and hence there is not beyond and surrounding the world
a void which contains the world; that there co