How Science Works 39 



in describing relationships between events.* In any case, 

 it is clear that they play a very important part in the de- 

 velopment of science. Perhaps one of the best ways of 

 assessing the importance or greatness of a scientist is to 

 judge him by his ability to invent useful abstractions. The 

 original idea of the gene, or even of a reflex, was essen- 

 tially an abstraction similar to the idea of mass, although 

 they are both somewhat less abstract and less general in 

 their application. 



The capacity to make useful new abstractions is with- 

 out doubt the rarest and most important capacity man 

 has. Abstractions of the generality of those given us by 

 Isaac Newton are so rare that they seem almost miracu- 

 lous. One of the really captivating qualities of some types 

 of abstractions is the ease with which they can be fitted 

 into mathematical formulas. Among other things, this saves 

 an enormous amount of time and effort in the laboratory 

 since we can try out a large number of possible cases in 

 symbolic terms before selecting the most promising ones 

 for experimental test. 



As science develops, it keeps encountering situations of 

 greater and greater complexity in which the tried and true 

 methods of dissection and isolation of variables become 

 more and more difficult to apply. Such problems underlie 

 some of the differences that separate the physical from 

 the so-called "hfe sciences" and bear on the possibility 

 of someday developing true sciences of social and political 

 behavior. We shall, therefore, say a few words about two 

 or three different kinds of complexity and the different 

 ways that have been devised for dealing with them. 



* An entirely different view of the status of abstract ideas was taken 

 by Plato and the "realist" school of medieval philosophy. It continues 

 to exist in respectable circles today, but it is not held by many scientists. 



