Page:Early Greek philosophy by John Burnet, 3rd edition, 1920.djvu/257

Rh The second stage is that in which the scattered limbs are united. At first, they were combined in all possible ways (fr. 59). There were oxen with human heads, creatures with double faces and double breasts, and all manner of monsters (fr. 61). Those of them that were fitted to survive did so, while the rest perished. That is how the evolution of animals took place in the period of Love.

The third stage belongs to the period when the unity of the Sphere is being destroyed by Strife. It is, therefore, the first stage in the evolution of our world. It begins with "whole-natured forms" in which there is not any distinction of sex or species. They are composed of earth and water, and are produced by the upward motion of fire seeking to reach its like.

In the fourth stage, the sexes and species have been separated, and new animals no longer arise from the elements, but are produced by generation.

In both these processes of evolution, Empedokles was guided by the idea of the survival of the fittest. Aristotle severely criticises this. "We may suppose," he says, "that all things have fallen out accidentally just as they would have done if they had been produced for some end. Certain things have been preserved because they had spontaneously acquired a fitting structure, while those which were not so put together have perished and are perishing, as Empedokles says of the oxen with human faces." This, according to Aristotle, leaves too much to chance. One curious instance has been preserved. Vertebration was explained by saying that an early invertebrate animal tried to turn round and broke its back in so