Animals and plants.
190. Living creatures arose from the earth, doubtless under the influence of heat. Their souls, of course, were air, and their differences were due to the various degrees in which it was rarefied or condensed (fr. [5]). No special seat, such as the heart or the brain, was assigned to the soul; it was simply the warm air circulating with the blood in the veins.
The views of Diogenes as to generation, respiration, and the blood, belong to the history of Medicine;[[1016]] his theory of sensation too, as it is described by Theophrastos,[[1017]] need only be mentioned in passing. Briefly stated, it amounts to this, that all sensation is due to the action of air upon the brain and other organs, while pleasure is aeration of the blood. But the details of the theory can only be studied properly in connexion with the Hippokratean writings; for Diogenes does not really represent the old cosmological tradition, but a fresh development of reactionary philosophical views combined with an entirely new enthusiasm for detailed investigation and accumulation of facts.
III. Archelaos of Athens
Anaxagoreans[Anaxagoreans].
191. The last of the early cosmologists was Archelaos of Athens, who was a disciple of Anaxagoras.[[1018]] He is also said to have been the teacher of Sokrates, a statement by no means so improbable as is sometimes supposed.[[1019]] There is no reason to doubt the tradition that Archelaos succeeded Anaxagoras in the school at Lampsakos.[[1020]] We certainly hear of Anaxagoreans,[[1021]] though their fame was soon obscured by the rise of the Sophists, as we call them.
Cosmology.
192. On the cosmology of Archelaos, Hippolytos[[1022]] writes as follows:—
Archelaos was by birth an Athenian, and the son of Apollodoros. He spoke of the mixture of matter in a similar way to Anaxagoras, and of the first principles likewise. He held, however, that there was a certain mixture immanent even in Nous. And he held that there were two efficient causes which were separated off from one another, namely, the warm and the cold. The former was in motion, the latter at rest. When the water was liquefied it flowed to the centre, and there being burnt up it turned to earth and air, the latter of which was borne upwards, while the former took up its position below. These, then, are the reasons why the earth is at rest, and why it came into being. It lies in the centre, being practically no appreciable part of the universe. (But the air rules over all things),[[1023]] being produced by the burning of the fire, and from its original combustion comes the substance of the heavenly bodies. Of these the sun is the largest, and the moon second; the rest are of various sizes. He says that the heavens were inclined, and that then the sun made light upon the earth, made the air transparent, and the earth dry; for it was originally a pond, being high at the circumference and hollow in the centre. He adduces as a proof of this hollowness that the sun does not rise and set at the same time for all peoples, as it ought to do if the earth were level. As to animals, he says that when the earth was first being warmed in the lower part where the warm and the cold were mingled together, many living creatures appeared, and especially men, all having the same manner of life, and deriving their sustenance from the slime; they did not live long, and later on generation from one another began. And men were distinguished from the rest, and set up leaders, and laws, and arts, and cities, and so forth. And he says that Nous is implanted in all animals alike; for each of the animals, as well as man, makes use of Nous, but some quicker and some slower.
It is not necessary to say much with regard to this theory, which in many respects contrasts unfavourably with its predecessors. It is clear that, just as Diogenes had tried to introduce certain Anaxagorean ideas into the philosophy of Anaximenes, so Archelaos sought to bring Anaxagoreanism nearer to the old Ionic views by supplementing it with the opposition of warm and cold, rare and dense, and by stripping Nous of that simplicity which had marked it off from the other “things” in his master’s system. It was probably for this reason, too, that Nous was no longer regarded as the maker of the world.[[1024]] Leukippos had made such a force unnecessary. It may be added that this twofold relation of Archelaos to his predecessors makes it very credible that, as Aetios tells us,[[1025]] he believed in innumerable worlds; both Anaxagoras and the older Ionians upheld that doctrine.