234 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



for the formulation of the problem or for the illustrative 

 solutions which are presented in the following pages. What 

 is offered is merely a proposal. The attempt has been made 

 to define the problem in a way which will make intelligible 

 the many writings on the subject. A common conception 

 of the task is, I believe, discernible in the mass of material, 

 though the authors themselves are not always clearly con- 

 scious of its character ; the general problem and the outlines 

 of its solution seem to be implicitly rather than explicitly 

 recognized. The proposed formulation may be examined 

 immediately. 



GENERAL CHARACTER OF PROBLEM 



The terminology in which the problem is expressed is 

 unfortunate. Properly speaking, the question is not merely 

 one of concepts but one of propositions as well. Science is 

 based not only upon unexamined ideas but on uncriticized 

 beliefs. Hence the problem is to determine not merely what 

 the concepts of science mean but what the justification is 

 for the mass of assumptions about an external world, a 

 uniform nature, the existence of causes, and so on. Con- 

 cepts, of course, are neither true nor false; the only legitimate 

 problem in connection with them is one of meaning. But 

 propositions, or judgments, are both meaningful and either 

 true or false; hence questions of both kinds may arise in 

 connection with this type of symbol. 



But from a more general point of view the differences 

 between these two types of problem are not great. For both 

 meaning and truth are determined by essentially the same 

 techniques. A concept is meaningful and a proposition is 

 both meaningful and true either extensionally, i.e., by refer- 

 ence to the realm of events, or intensionally, i.e., by refer- 

 ence to other symbols. Hence the problem is primarily one 

 of establishing the relationships which any given symbol 

 (concept or proposition) bears, on the one hand, to events, 

 and, on the other, to symbols. 



A recognition of this common feature seems to place the 



