Historical Relations loi 



theory. The work in which this cosmic theory appeared, the 

 " Timaeus^ gives us a picture of the depth to which natural science 

 can be degraded by a great mind in its endeavour to give a specific 

 teleological meaning to all parts of the universe. The trend of 

 Platonism in general, and of the schools that arose from it, was 

 always away from observational science, though not unfriendly to 

 mathematical development. 



The physical philosophers of the fourth century, of whom 

 Aristotle is the greatest and most permanent type, were more 

 successful than Plato in their efforts at constructing a coherent and 

 lasting cosmic theory. We may glance at the picture of the material 

 universe presented by Aristotle. That great thinker was himself 

 an absolutely first-class naturalist. Thus the cosmic scheme that 

 he produced, unlike that of Plato, absorbed a vast mass of observa- 

 tional material, notably in the department of biology. Yet the 

 bases of the scheme were certain preconceived notions which did 

 not and could not depend upon observation. Into this scheme 

 observations had to be fitted. The difficulty of fitting them repre- 

 sents a struggle between the observational and theoretical interests 

 which IS a prototype of that so often encountered in later centuries. 



We may observe here that the general history of later Greek 

 physical philosophy presents certain features which are closely 

 parallel to that of science in the West in modern times. The 

 philosophical scheme once established becomes part of the religious 

 or semi-religious systems of thought, and any attempt to disturb 

 it is resented. An effort, too, is made to confine the activities of 

 the men of science to the adjustment of the details of the scheme. 

 An attempt, for instance, such as that of Aristarchus of Samos 

 (about 250 B.C.) to show that the earth moves round the sun is 

 denounced by the Stoic Cleanthes as impious, just in the manner 

 that Galileo was denounced by the theologians in the seventeenth 

 century. 



Let us now turn to the actual Aristotelian system oi physics. 

 That system, in a more or less modified form, was absorbed by 

 the various philosophical schools of antiquity and played a very 

 important part in the history of Christian thought. It is therefore 

 necessary to note its fundamental bases. These may be briefly 

 drawn up thus : 



{a) Matter is continuous. 



{b) All matter is somehow made up of the four elements, 



