CLASSICAL ANTIQUITY, MIDDLE AGES 43 



way — breed worms which give rise to eggs, as, for instance, insects, whose 

 pupas Aristotle regarded as eggs, whereas the true insect eggs were unknown 

 to him. His descriptions of animal development contain a mass of extraor- 

 dinarily sound details; as always, it is marine animals that interest him most. 

 His account of the breeding of sharks is especially well known, while the 

 pairing and growth of ink-fish are also described with a thorough knowledge 

 of his subject. Embryology, too, he discusses in great detail, chiefly the 

 development of the hen's egg, which Hippocrates had also studied; in particu- 

 lar the evolution of the heart and the first blood-vessels is carefully explained. 

 Various speculations on colour-variations, change of teeth, and other prob- 

 lems of development complete Aristotle's work on the reproduction of 

 animals, which, more than any other of his biological works, testifies to 

 both his greatness and his limitations. 



H/s evolution theory really dogmatic 

 Aristotle's great contribution to the development of biological science 

 lies, as has already been pointed out, not so much in the sphere of discoveries 

 as in the thought-system, embracing all the phenomena of life, which he 

 created and consistently worked out in all its details. The finest merit of this 

 system of thought lies in the fact of its being based on an evolution subject 

 to rigid laws and proceeding from the lower to the higher. But as this theory 

 of evolution is, as has been shown above, primarily based on a predominant 

 guiding intelligence, it acquires a dogmatic arbitrariness; the subjection to 

 law is not an act of nature itself, but rather a product of divine wisdom, or, 

 in other words, human speculation. This could, then, it is true, solve with 

 abstract catchwords all the problems against which Democritus' atomic 

 theory was powerless, but any such method of solution failed to stimulate 

 thought to continued search; on the contrary, it induced a feeling of self- 

 complacent satisfaction with the limited cosmogony produced out of unreal 

 systems of thought. Thus it came about that Aristotle, the founder of sys- 

 tematic biology, became at the same time the father of the scholastic philoso- 

 phy of the Middle Ages; that the man who was the first to introduce and 

 logically to apply to the conception of the entire universe a theory of evolu- 

 tion from the lower to the higher appeared fifteen centuries later as the 

 founder of a system of stagnation and obedience to authority. What the 

 whole of this long period lacked was a conception of nature which would 

 have associated Aristotle's theory of subjection to law with Democritus' 

 theory of the dominance of necessity in nature. Subjection to law caused by a 

 personal, guiding will, and necessity with pure chance as its driving force: 

 the choice lay between these two alternatives until, through Galileo and 

 Newton, the impersonal, law-bound force, operating by natural necessity, 

 was made the basis on which to interpret the course of events in the universe. 

 For the fact that such a long time should have elapsed before this conception 



