112 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



in a way which may be significant for each of the events; 

 if so, only the entire universe could be an isolated system. 

 For science, however, the notion of isolated system is rela- 

 tive. Scientific procedure does not demand that one start 

 with isolated situations. Isolation is "a first step in the 

 process of finding out the truth about the universe by ex- 

 amining it in chips. The first step is succeeded by a second 

 more detailed, more refined. It embraces yet a little more 

 of the changing environment as soon as it finds that its 

 initial law is not precisely fulfilled, for by that failure it 

 recognizes that the isolation was not neutral." 1 Hence 

 by a method of successive approximation one makes his 

 systems more and more inclusive. 



The isolational act which is here indicated is physical in 

 character, and refers to the actual elimination of disturbing 

 factors from the physical situation. This may involve either 

 moving the end-object into a new environment, such as a 

 laboratory, where the medium can be more or less com- 

 pletely controlled, or merely removing from the given en- 

 vironment as many as possible of the disturbing factors. 

 Often the environmental forces cannot be eliminated but 

 must be neutralized or balanced by counteracting forces. 

 But what is important here is that the isolational acts 

 here indicated are physical in character. There are also 

 selective acts which are of a biological and others which are 

 of a psychological character. 



Very important for physical science are measuring tech- 

 niques. The problem of the nature of operations of meas- 

 urement is too extensive to permit consideration here. 2 

 Measurement may be defined, in its most general sense, as 

 any technique by which numbers are correlated with events. 

 (This definition makes numbering, or counting, a special 



1 Ibid., p. 54. 



2 The problem will be considered again in Chapter XIII. Some important 

 subsidiary references are the following: W. S. Jevons, Principles of Science, 

 Book III; Norman Campbell, Physics, the Elements (Cambridge University, 1920), 

 Part II; J. Venn, Empirical Logic (London: Macmillan, 1907), Chaps. XVIII, 

 XIX; A. D. Ritchie, Scientific Method (London: Kegan Paul, 1923), Chap. V; 

 M. R. Cohen and E. Nagel, Introduction to Logic and Scientific Method (New York: 

 Harcourt, Brace, 1934), Chap. XV. 



