ARISTOTLE AND THE EARLIER PERIPATETICS vol.I by Eduard Zeller, B.F.C.Costelloe 1897

THE PHILOSOPHY »F ARISTOTLE 179
in a thing is only its essence as thought in the idea of
it, and that all else is actual ' ' only in so far as it
partakes of that ideal essentiality. Yet, whereas to
Plato this ' Essential Being ' was a thing existing by
itself, which he relegated to a separate ideal world
beyond the world of experience, his follower recognises
the truth that the Idea, as the essence of things, could
not stand separate from the things themselves. Therefore
he seeks to present the Idea, not as a Universal
existing for itself apart, but as a common essence of
things indwelling in the particular things themselves.
In lieu of the negative relation to which the sundering
of ideas and phenomena had led with Plato, he posits
rather the positive relation of each to the other and
their mutual dependence. Therefore he calls the sensible
element the Matter, and the insensible essence the
Form. He puts it that it is one and the same Being,
here developed into actuality, there undeveloped and
lying as a mere basis. So it comes that, for him,
Matter must, by an inner necessity, strive upward to
Form, and Form equally must present itself in Matter.
In this transformation of Plato's metaphysic, it is easy
to recognise the realism of the natural philosopher
whose aim is the explanation of the actual. Just this
is his strongest and ever recurrent charge against the
Ideal Theory, that it leaves the world of phenomena,
the things of Becoming and Change, unexplained. For
his own part, he finds the very root-definitions of his
metaphysic in his treatment of those processes wherein
is the secret of all genesis and all change, whether by
.nature or by art.
180 ARISTOTLE
Yet Aristotle, too, is barred from completing his
philosophy in these directions by just that dualism of
the philosophy of Ideas which he inherited from Plato.
Hard as he tries to bring Form and Matter together,
still to the last they always remain two principles, of
which he can neither deduce one from the other, nor
both from a third. Fully as they are worked out
through the range of finite things, still the highest
entity of all is nothing but the pure Spirit, left outside
the world, thinking in itself—as the highest in
man is
that Reason which enters into him from without, and
which never comes into any true unity with the individual
side of his being. In this way, Aristotle is at
once the perfection and the ending of the Idealism of
Socrates and Plato : its perfection, because it is the
most thorough effort to carry it throughout the whole
realm of actuality and to explain the world of phenomenal
things from the standpoint of the ' Idea '
; but
also its ending, since in it there comes to light the impossibility
of ever holding together the Idea and the
Phenomenon in any real unity, after we have once
posited, in our definition of the ultimate basis of the
world, an original opposition between them.
If we follow out the development of these principles
in the Aristotelian system, and seek for that purpose to
take a general view of the divisions
he adopted, we are
met at once with the unfortunate difficulty that, neither
in his own writings nor in any trustworthy account of
his method, is any satisfactory information on that point
to be found. 1 If we should trust the later Peripatetics
1
Cf. for what follows : Eitxeb, iii. 57 sqq. ; Erandis, ii. b, 130
n 2