150 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



As a guide to the more detailed expositions which are to 

 follow immediately, it will be well here to indicate the gen- 

 eral positions of the representatives of these various views. 

 Pearson and Bridgman are both positivists in their insistence 

 upon the importance of data and the unimportance of 

 knowing. For Pearson science is the mere classification and 

 shorthand description of the data; when the more highly 

 imaginative activities resulting in symbols for atoms and 

 molecules intervene the importance of these operations is 

 minimized, for the resulting symbols are themselves simply 

 devices for classification and simplified description. Bridg- 

 man' s insistence on the importance of operations does not 

 remove him from the positivist group, for the operations 

 with which he is concerned are mainly physical, i.e., they 

 are concerned with getting the data, not with knowing them; 

 hence Bridgman is essentially a positivist. 



Hobson, Poincare, and Carnap are all modified positivists 

 in their insistence that there are at least some symbols in 

 science whose meanings are determined in an important 

 sense by knowing operations, and in their conviction that 

 the operations are in some sense arbitrary, i.e., inventive. 

 Hence they all call attention to the fact that there are some 

 symbols in science which do not "apply' in any direct 

 sense to nature. For Hobson these are abstractions, obtained 

 through selective acts and therefore idealizations of the 

 data. For Poincare they are conventions, having their origin 

 in data but transformed so as to be in accord with certain 

 more or less arbitrarily set up definitions. For Carnap they 

 are formal propositions, having both meaning and truth 

 determined by the structure of the language which one 

 employs to symbolize them — a language which is, in fact, 

 simply the result of certain agreed-upon rules for the use of 

 symbols. 



Bavink is a realist. He insists both upon the importance 

 of the knowing operations, and upon the necessity for sup- 

 posing that atoms and molecules are existent entities, not 

 different in kind from stones and trees. "Our knowledge 



