have a principle
of motion in themselves; mathematics speculate on permanent, but not
transcendental and self-existent things; and there is another science
separate from these two, which treats of that which is immutable and
transcendental, if indeed there exists such a substance, as we shall
endeavor to show that there does. This transcendental and permanent
substance, if it exist at all, must surely be the sphere of the
_divine_--it must be the first and highest principle. Hence it follows
that there are three kinds of speculative science--Physics, Mathematics,
and Theology."--"Metaphysics," bk. x. ch. vii.]

[Footnote 717: "Metaphysics," bk. i. ch. ii.]

[Footnote 718: Aition--cause--is here used by Aristotle in the sense of
"account of" or "reason why."]

1. The Material Cause (ten ylen kai to ypokeimenon)--the matter and
subject--that _out of_ which a given thing has been originated. "From
the analogy which this principle has to wood or stone, or any actual
matter out of which a work of nature or of art is produced, the name
'material' is assigned to this class." It does not always necessarily
mean "matter" in the now common use of the term, but "antecedents--that
is, principles whose inherence and priority is implied in any existing
thing, as, for example, the premises of a syllogism, which are the
material cause of the conclusion."[719] With Aristotle there is,
therefore, "matter as an object of sense," and "matter as an object of
thought."

2. The Formal Cause (Ten ausian kai to ti einai)--the being or abstract
essence of a thing--that primary nature on which all its properties
depend. To this Aristotle gave the name of eidos--the form or exemplar
_according to_ which a thing is produced.

3. The Moving or Efficient Cause (othen e arche tes kineseos)--the
origin and principle of motion--that _by which_ a thing is produced.

4. The Final Cause (to ou eneken kai to agathon)--the good end answered
by the existence of any thing--that for the sake of which_ any thing is
produced--the eneka tou, or reason for it.[720] Thus, for instance, in a
house, the wood out of which it is produced is the _matter (yle), the
idea or conception according to which it is produced is _the form_
(eidos morphe), the builder who erects the house is the _efficient_
cause, and the reason for its production, or the end of its existence is
the _final_ cause.

[Footnote 719: Encyclopaedia Britannica, article "Aristotle;" "Post.
Analy