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 present world. It begins with “whole-natured forms” in which there is not as yet any distinction of sex or species.[[625]] They are composed of earth and water, and are produced by the upward motion of fire which is 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. We shall see presently how Empedokles conceived this to operate.
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.”[[626]] 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 doing. This was a favourable variation and so survived.[[627]] It should be noted that it clearly belongs to the period of Strife, and not, like the oxen with human heads, to that of Love. The survival of the fittest was the law of both processes of evolution.
117. The distinction of the sexes was an important result of the gradual differentiation brought about by the entrance of Strife into the world. Empedokles differed from the theory given by Parmenides in his Second Part ([§ 95]) in holding that the warm element preponderated in the male sex, and that males were conceived in the warmer part of the uterus (fr. [65]). The fœtus was formed partly from the male and partly from the female semen (fr. [63]); and it was just the fact that the substance of a new being’s body was divided between the male and the female that produced desire when the two were brought together by sight (fr. [64]). A certain symmetry of the pores in the male and female semen is, of course, necessary for procreation, and from its absence Empedokles explained the sterility of mules. The children most resemble that parent who contributed most to their formation. The influence of statues and pictures was also noted, however, as modifying the appearance of the offspring. Twins and triplets were due to a superabundance and division of the semen.[[628]]
As to the growth of the fœtus in the uterus, Empedokles held that it was enveloped in a membrane, and that its formation began on the thirty-sixth day and was completed on the forty-ninth. The heart was formed first, the nails and such things last. Respiration did not begin till the time of birth, when the fluids round the fœtus were withdrawn. Birth took place in the ninth or seventh month, because the day had been originally nine months long, and afterwards seven. Milk arises on the tenth day of the eighth month (fr. [68]).[[629]]
Death was the final separation by Strife of the fire and earth in the body, each of which had all along been striving to “reach its own kind.” Sleep was a temporary separation to a certain extent of the fiery element.[[630]] At death the animal is resolved into its elements, which perhaps enter into fresh combinations, perhaps become permanently united with “their own kind.” There can be no question here of an immortal soul.
Even in life, we may see the attraction of like to like operating in animals just as it did in the upward and downward growth of plants. Hair is the same thing as foliage (fr. [82]); and, generally speaking, the fiery part of animals tends upwards and the earthy part downwards, though there are exceptions, as may be seen in the case of certain shell-fish (fr. [76]), where the earthy part is above. These exceptions are only possible because there is still a great deal of Love in the world. We also see the attraction of like for like in the different habits of the various species of animals. Those that have most fire in them fly up into the air; those in which earth preponderates take to the earth, as did the dog which always sat upon a tile.[[631]] Aquatic animals are those in which water predominates. This does not, however, apply to fishes, which are very fiery, and take to the water to cool themselves.[[632]]
Empedokles paid great attention to the subject of respiration, and his very ingenious explanation of it has been preserved in a continuous form (fr. [100]). We breathe, he held, through all the pores of the skin, not merely through the organs of respiration. The cause of the alternate inspiration and expiration of the breath was the movement of the blood from the heart to the surface of the body and back again, which was explained by the klepsydra.
The nutrition and growth of animals is, of course, to be explained from the attraction of like to like. Each part of the body has pores into which the appropriate food will fit. Pleasure and pain were derived from the absence or presence of like elements, that is, of nourishment which would fit the pores. Tears and sweat arose from a disturbance which curdled the blood; they were, so to say, the whey of the blood.[[633]]
Perception.