132 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



be so at another. One cannot draw the limits of the given, 

 and relegate all beyond the limits to invention and fancy. 

 One of the facts which seems to be given clearly is the fact 

 that some things are given more clearly than others, and 

 one of the facts which seems to be given quite obscurely 

 is the precise location of the line separating these two 

 realms. As a result it becomes impossible to say with pre- 

 cision what the limits of a descriptive science are. If descrip- 

 tive science is defined in terms of a criterion which is itself 

 variable, the result must be a recognition that sciences are 

 not properly descriptive or non-descriptive, but more or 

 less descriptive according as they endeavor to symbolize 

 the more or less obvious data. 



This fact of the variability in the given may be clearly 

 indicated by illustrations drawn from recent and contem- 

 porary writers on the philosophy of science. The problem 

 under consideration is to determine precisely what kinds 

 of things the data of science are. About what, in other 

 words, does the scientist really talk? The question is so 

 simple that one would be led to expect a simple answer, 

 and a general agreement among investigators. But the 

 contrary proves to be the case. Hear the report, for example, 

 of an eminent scientist. "Science is in reality a classification 

 and analysis of the contents of the mind; and the scientific 

 method consists in drawing just comparisons and inferences 

 from the stored impresses of past sense-impressions, and 

 from the conceptions based upon them." x "An external 

 object is in general a construct — that is, a combination of 

 immediate with past or stored sense-impressions." 2 The 

 only events which are clearly given, therefore, are sense- 

 impressions, which are both subjective and private. All 

 else is inference and construction. But Planck is not satisfied 

 with this. It is one of the basic theorems of science, he 

 insists, that "there is a real outer world which exists inde- 

 pendently of our act of knowing." 3 This is no longer 



1 Karl Pearson, Grammar of Science, p. 52. 2 Ibid., p. 41. 



3 Where Is Science Going? (New York: Norton, 1932), p. 82. 



