Aristotle's biology

held that the material and moving causes yield no adequate conception of the organism, so biology today incLnes to hold that no adequate description of the living organism can be framed in categories of matter " and " energy." Phrases change; and thinking takes a new direction from the new phrase and seems to flow in untried channels. The old phrase be- comes an alien. Few of us today could bring ourselves to accept eo nomine the xj/vrjx^ — ^^^ soul or, if one will, the organic life in its ascending scale, — as the entelechy, to wit, " the form or actuality of a natural body having in it the capacity of life." More specifically, the xj/yvn is the first entelechy," or actuality, standing as knowledge stands to the exercise of knowledge in speculation. This " soul " is the formative principle of the body and the body's end or final cause, even as speculative activity ( to Qewpeiv ) is the soul's final end. Such statements are not of our time. Yet perhaps they are not so far from our intel- lectual purposes. Do we not think that all the sciences, including those having to do with organisms, contribute to the soul which is life,

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