66 THE HISTORY OF BIOLOGY 



neo-Platonists were as opposed to the men of antiquity as their Christian 

 contemporaries. The founder of the school, Plotinus, was ashamed of pos- 

 sessing a body, while its last great thinker, Proclus (411-485), lived as a 

 hermit; he dwelt in a cave, avoided wine, meat, and women, and saw visions 

 of supernatural things. For to be uplifted into the supersensible by means 

 of ecstatic rapture was to the neo-Platonists not only the whole object of 

 life, but also the very foundation of science. With all its fantastic specula- 

 tion this school nevertheless developed human thought in one important 

 sphere; it discussed the idea of infinity as none of its predecessors had been 

 able to do. To the ancient atomists infinity was really only an unlimited 

 extension in time and space, akin to the custom of children and wild men, 

 who when they are weary of counting, call the remainder "much" or 

 "many." To the neo-Platonists, again, the infinite was equivalent to the 

 inexpressible and the unknowable, that which exceeds all limitations and 

 measures. And though their endeavour to attain to this infinity by way of 

 ecstasy was naturally of no scientific value, there was nevertheless an in- 

 disputable truth to be gained as a result of their endeavours, seeing that 

 the impotence of the power of knowledge in face of the infinite was estab- 

 lished once and for all. The natural-research work of our time is based on 

 the realization of the limitation of knowledge in face of the infinity of 

 existence — a limitation which only unscientific dilettantism thinks it pos- 

 sible to override. 



Destruction of the old culturt 

 There were, then, among the thinkers of this period ideas which pointed 

 beyond the limitations by which the ancient conceptions of existence had 

 been surrounded. It is impossible to estimate how these aims might have 

 developed in happier external circumstances. For as a result of the fall of 

 the Roman Empire the external, purely material preconditions for the con- 

 tinuance of scientific research and for the progress of culture in general no 

 longer existed. As early as the latter half of the imperial epoch the pros- 

 perity of those nations which formed the Roman Empire steadily declined 

 as a result of misgovernment, civil war, and the inroads of neighbouring 

 peoples. In the fifth century the world empire collapsed entirely owing to 

 the invasion of the Germans, and a state of dire distress, economic, politi- 

 cal, and moral, ensued. The new kingdoms which were founded by barbar- 

 ous nations had great difficulty in firmly establishing themselves, and their 

 rulers' utter lack of culture rendered impossible any kind of ordered system 

 of government and, consequently, any high standard of prosperity. How- 

 ever, the inhabitants of western Europe gradually co-operated in reviving 

 culture on a national basis. During the last hundred years of the Roman 

 Empire, Gaul had been the most civilized country in the Empire, with 

 numerous institutions founded for the study of classical learning. During 



