52 Introduction 



cialization than by showing that all those twigs belong to the same tree, 

 the old tree of knowledge, which stood in the garden of Eden? And 

 how best can we show that than by describing the growth of the tree? — 

 Now the growth of that tree, that is the history of science. 



We remarked that that history is much more than the sum of special 

 histories; it is also much less. The special histories are, of necessity, far 

 more technical, while in the general history, the humanistic and social 

 elements are much stronger; for that history deals not only with every 

 branch of science and with their various interrelations and mutual reper- 

 cussions but also with the impact of all the social and philosophical in- 

 fluences to which they are all submitted. Every great discovery over- 

 flows its original field in many ways. The history of instruments implies 

 the history of physics and chemistry, irrespective of their uses. The 

 microscope is built by physicists and used by biologists, physicians, crys- 

 tallographers, chemists, etc. The chemical revolution was also a physio- 

 logical revolution. The development of thermodynamics did not simply 

 affect the physical sciences, it influenced deeply our philosophy. The 

 theory of evolution dominates the whole of modern thought. The de- 

 velopment of, say, photographic or statistical methods concerns all the 

 sciences. This list might be extended endlessly. There are, it is true, 

 discoveries which are so small that they cause no stir outside of their 

 own little field; they may be abandoned to the historian of that field; 

 such discoveries do not affect the tree but only a few twigs; the historian 

 of science may safely overlook them. 



From this point of view there are interesting resemblances and dif- 

 ferences between the history of science, on the one hand, and the history 

 of religion, on the other. The last-named discipline was unsectarian 

 from the beginning; in fact, its purpose was more often anti-sectarian 

 than pro-sectarian. The first historians of religion were anxious to study 

 religion per se as a general attribute and desire of the human spirit al- 

 ways and everywhere. This led naturally to the study of what was 

 called comparative religion, and for the most scholarly minded it led 

 also to impartial history. On the other hand, each religion developed 

 very much within its own field; Buddhism was not influenced by Chris- 

 tianity, nor Parseeism by Islam. The situation is very different from 

 that of science, for every science may influence willy-nilly all the others, 

 and the synthesis is unavoidable. Visit the great laboratories and ob- 

 servatories, and you will find scientists of many kinds working together, 

 needing one another. In a modern observatory, there are, of course, 

 astronomers but also mathematicians, physicists, chemists, and some- 

 times biologists and geologists are called in consultation. 



The arts grow together, too, but they are not bound together as 

 closely as the sciences. Their integration is tangible enough in a cathe- 

 dral the building of which required the collaboration of architects, sculp- 

 tors, painters, and decorators, while fulfillment of the offices and rites 

 called for musicians and stage managers. In spite of that, the arts 

 developed, to a large extent, independently and each is autonomous. 

 Hence, one may study the past of one of them very profitably, say, the 



