[In the following excerpt, Burnet examines Anaximander's scientific system in relation to later ancient and early modern cosmological models.]

[The] generation of the Milesian school [after Thales] is represented by Anaximander. We are on surer ground with regard to his doctrines; for he wrote a book which was extant in the time of Theophrastos and later. It is probable that it was the first Greek book written in prose, and it may be noted here that Ionic prose was the regular medium of philosophical and scientific writing. Two Greek philosophers, Parmenides and Empedokles, wrote in verse at a later date, but that was quite exceptional, and due to causes we can still to some extent trace. Anaximander was also the first cartographer, and this connects him with his younger fellow-citizen Hekataios, whose work formed, as has been said, the text of Anaximander's map.

Anaximander seems to have thought it unnecessary to fix upon "air," water, or fire as the original and primary form of body. He preferred to represent that sim ply as a boundless something … from which all things arise and to which they all return again. His reason for looking at it in this way is still in part ascertainable. It is certain that he had been struck by a fact which dominated all subsequent physical theory among the Greeks, namely, that the world presents us with a series of opposites, of which the most primary are hot and cold, wet and dry. If we look at things from this point of view, it is more natural to speak of the opposites as being "separating out" from a mass which is as yet undifferentiated than to make any one of the opposites the primary substance. Thales, Anaximander seems to have argued, made the wet too important at the expense of the dry. Some such thought, at any rate, appears to underlie the few words of the solitary fragment of his writing that has been preserved. He said that things "give satisfaction and reparation to one another for their injustice, as is appointed according to the ordering of time." This conception of justice and injustice recurs more than once in Ionic natural philosophy, and always in the same connexion. It refers to the encroachment of one opposite or "element" upon another. It is in consequence of this that they are both absorbed once more in their common ground. As that is spatially boundless, it is natural to assume that worlds¹ arise in it elsewhere than with us. Each world is a sort of bubble in the boundless mass. Our authorities attribute this view to Anaximander, and no good reason has been given for disbelieving them. It is obviously an idea of the greatest scientific importance; for it is fatal, not only to the theory of an absolute up and down in the universe, but also to the view that all heavy things tend to the same centre. It was, in many ways, a misfortune that Plato was led to substitute for this old doctrine the belief in a single world, and thus to prepare the way for the reactionary cosmology of Aristotle. The Epicureans, who took up the old Ionic view at a later date, were too unscientific to make good use of it, and actually combined it with the inconsistent theory of an absolute up and down. We are told that Anaximander called his innumerable worlds "gods." The meaning of that will appear shortly.

The formation of the world is, of course, due to the "separating out" of the opposities. Anaximander's view of the earth is a curious mixture of scientific intuition and primitive theory. In the first place, he is perfectly clear that it does not rest on anything, but swings free in space, and the reason he gave was that there is nothing to make it fall in one direction rather than in another. He inferred this because, as has been observed, his system was incompatible with the assumption of an absolute up and down. On the other hand, he gives the earth a shape intermediate between the disc of Thales and the sphere of the Pythagoreans. He regarded it as a short cylinder "like the drum of a pillar," and supposed that we are living on the upper surface while there is another antipodal to us. His theory of the heavenly bodies shows that he was still unable to separate meteorology and astronomy. So long as all "the things aloft" … are classed together, that is inevitable. Even Galileo maintained that comets were atmospheric phe nomena, and he had far less excuse for doing so than Anaximander had for taking the same view of all the heavenly bodies. Nor was his hypothesis without a certain audacious grandeur. He supposed that the sun, moon, and stars were really rings of fire surrounding the earth. We do not see them as rings, however, because they are encased in "air" or mist. What we do see is only the single aperture through which the fire escapes "as through the nozzle of a pair of bellows." We note here the beginning of the theory that the heavenly bodies are carried round on rings, a theory which held its ground till Eudoxos replaced the rings by spheres. We are also told that Anaximander noted the obliquity of these rings to what we should call the plane of the equator. Eclipses were caused by stoppages of the apertures.

With regard to living beings, Anaximander held that all life came from the sea, and that the present forms of animals were the result of adaptation to a fresh environment. It is possible that some of his biological theories were grotesque in detail, but it is certain that his method was thoroughly scientific. He was much impressed by the observation of certain viviparous sharks or dogfish, and evidently regarded them as an intermediary between fishes and land animals. His proof that man must have been descended from an animal of another species has a curiously modern ring. The young of the human species require a prolonged period of nursing, while those of other species soon find their food for themselves. If, then, man had always been as he is now he could never have survived.

Notes

¹ I do not use the term "world" for the earth…. It means everything within the heavens of the fixed stars. From our point of view, it is a "planetary system," though the earth and not the sun is its centre, and the fixed stars are part of it.