THEORIES OF SCIENTIFIC CONCEPTS 165 



complex body of operations associated with the invention 

 and use of language. 



The justification for this interpretation of logical pos- 

 itivism may be found in the writings of Carnap. Attention 

 must be called, first, to the more positivistic aspects of his 

 system. 'Science is a system of statements based on direct 

 experience, and controlled by experimental verification. . . . 

 Verification is based upon 'protocol statements,' a term . . . 

 understood to include statements belonging to the basic 

 protocol or direct record of a scientist's (say a physicist's or 

 a psychologist's) experience. Implied in this notion is a 

 simplification of actual scientific procedure as if all experi- 

 ences, perceptions, and feelings, thoughts, etc., in everyday 

 life as well as in the laboratory, were first recorded in writ- 

 ing as ' protocol ' to provide the raw material for a subsequent 

 organization." x A protocol statement would therefore de- 

 scribe what Pearson called sense-impressions, and what we 

 have called in the course of this discussion the most clearly 

 given data. Statements in the scientific language which 

 are not protocol statements, can, in general, be verified by 

 the technique of deducing from them statements which are 

 protocol. This is the indirect method of verification which, 

 for Hobson, constitutes the test of the applicability of 

 idealizations and abstractions. 



But science, in the broadest sense of the word, contains 

 more than this. "Scientific research may be concerned with 

 the empirical content of theorems, by experiment, observa- 

 tion, by the classification and. organization of empirical 

 material; or again it may be concerned with establishing 

 the form of scientific statements, either without regard for 

 content (formal logic) or else with a view to establishing 

 logical connections between certain specific concepts." 2 Ev- 

 ery scientific statement, in other words, may be considered 

 either in its 'material' mode, i.e., as asserting about 

 "objects," and "states of affairs," or in its "formal" mode, 

 i.e., as referring only to linguistic forms. To logic and 



1 Ibid., pp. 42-43. 2 Ibid., p. 33. 



