584 ON CONCEPTION.
the reasons and causes of what he does, and adds why he does it ; although that cause, ' cujus gratia/ and the reason ' for the sake of the good and fair/ are joined rather to the works of nature than to those of art."
" The end/' he elsewhere says/ " is this ' cujus gratia' (for whose sake), as health is the thing for the sake of which we walk. For why does a man walk ? We answer, for the sake of his health ; and when we have thus said, we think we have given a ' cause ;' and whatever else is further interposed, by means of another agent, is done for the sake of this end, as dieting, or purging, or drugs, or instruments, are all for the sake of health ; for all these are for the sake of the end." Again, " It is our business always to seek the primary cause of everything, For instance, a man builds a house because he is a builder, but he is a builder by reason of the art of building ; this then (the art) is a prior cause ; and so in all things." Hence it is that he asserts 2 " that the cause which first moves, and in which the ' reason' and c form' lie, is greater and more divine than the ' material cause.' "
In all natural generation, therefore, both the " matter" out of which and the " efficient cause" by which (namely, A, the thing which is moved, and B, the thing moving) are alike for the sake of the animal begotten or to be begotten ; for that which moves and is not itself moved, viz. C, is in (inest) both. For both those (viz. A and B) are at the same time capable of motion, and are moreover moved, viz. the thing fecundating, B, (which both moves and is moved) and the thing fecundated, A, the " matter," viz. or ovum, which is moved and changed only. Wherefore if no moveable thing is actually moved, unless the thing which moves is present, so neither will " matter" be moved, nor the "efficient" effect anything, unless the first mov- ing cause be in some way present; and this is the "form" or- " species" which is without matter, and is the prime cause. "For the efficient and generating," according to Aristotle, 3 " in so far as they are so, belong to that which is effected and generated." The following syllogism, therefore, may be framed out of these first and necessary predicates :
1 Physiologia, lib. ii, tract. 3. z De Gen. Anim. lib. ii, cap 1
3 Ibid. can. 4.
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