Aristotle and the Metaphyics of Evolution

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Aristotle was nature's scribe, his pen dipped in mind. (1) Ancient Greek saying

Linnaeus and Cuvier have been my two gods, though in very different ways, but they were mere schoolboys to old Aristotle. (2)

Charles Darwin

I recall that in 1951 Harold Cherniss told me that Aristotle's biology was the key to his metaphysics; unfortunately I did not have the wit to interpret this Delphic utterance. (3)

J. L. Ackrill

DOES ARISTOTLE'S PHILOSOPHY rule out evolution? The short answer is "Yes, but ...!"; the long answer: "No, ... however!" Summarizing his excellent account of the reasoning which led Aristotle in book 7 of the Metaphysics to identify substance in the first place with specific form, W. K. C. Guthrie, in the final volume of his monumental history of Greek philosophy, concluded: "Doubtless this is not a satisfactory explanation of reality. For one thing it makes Darwinian evolution impossible." (4) The matter, needless to say, is not quite so simple. Two questions are immediately raised: Does the doctrine of substantial form necessarily exclude evolution? If so, is this of itself sufficient reason for us to reject form? With these questions in mind, I propose to consider some broader aspects of the relation between Aristotle's metaphysics and his biology, in order to speculate how he might respond to the modern theory of evolution.

Aristotle's metaphysics was continually nourished by his experience as a biologist; the data of Aristotle the biologist were in turn frequently illuminated by his insights as metaphysician. In our own time, biology and metaphysics are obliged to enter into dialogue regarding the theory of evolution through questions which are central to both disciplines. Evolution is viewed by some, proponents and opponents alike, as a claim for total explanation, not only of how the living cosmos came to be, but also as an exhaustive account of its ultimate origins and final purpose--or absence thereof. Such a claim is tantamount to a metaphysics of total reality. It is provoking to speculate how Aristotle would judge such a theory. While Aristotle indeed explicitly rejects evolution, I will argue that his philosophy is in many ways eminently receptive to the theory. His metaphysics, furthermore, will elucidate many of the philosophical questions encountered by any evolutionary theory. Aspects of his metaphysics which I maintain are fundamental for a theoretical consideration of evolution are his concepts of act and potency, form and finality, the nature of causation, and the explanation of chance.

It is appropriate to relate themes of biology and ontology in the work of Aristotle. It is impossible to read the famous passage from Parts of Animals and remain unmoved by the philosophic eros which it expresses: these are not just the words of a biologist but of one inspired by a loving fascination with the concrete, living individual, filled with the desire to understand it radically. (5) The passage is close to the hermeneutic of philosophy given in Metaphysics 1, which begins with the simple declaration: "All men by nature seek to know." Aristotle engaged first in exhaustive and widespread empirical observation and proceeded through reflective analysis toward a synthetic grasp of causes, in which the desire for knowledge is ultimately fulfilled. This impulse for unified comprehension is exemplified in his biology as much as his metaphysics. (6) It will be of interest to recall briefly Aristotle's significance as a biologist.

Aristotle as Biologist. Opinions vary regarding the value of the biological works of Aristotle. A longstanding problem, now thankfully a thing of the past, was that of ignorance. (7) Another was ridicule; Aristotle's biological treatises abound in risible curiosa, which suggest that they are not to be taken quite seriously; for example, men have more teeth than women (8) (perhaps neither of his wives, Pythias or Herpyllis, acquired their wisdom teeth, since he himself states that women sometimes acquire them into their eighties! …