THE SCIENCES 33 



only, their conclusions are largely of an abstract nature 

 and more simple than are the concrete realities which 

 they are thought to describe. Moreover the "laws" of 

 natural science, in which its descriptions of nature are 

 summarized, are approximate rather than exact. In / 

 the strictest sense of the phrase "exact" physical 

 sciences do not exist. 



Then too, scientific inductions, even in their own 

 sphere, are based upon very incomplete data, and have / 

 to be regarded as provisional. They are subject to 

 modification, and frequently are modified to agree with 

 newly discovered facts. A good example of this is the 

 atomic theory, which has been undergoing very impor- 

 tant modification since the discovery of certain facts 

 connected with radium — facts which appear to estab- 

 lish the existence of particles of matter much smaller 

 than atoms, and which suggest new conceptions of 

 matter and of its fundamental constitution.^ 



You will quite misunderstand the bearing of what I 

 have been saying, however, if you infer that the work 

 of physical scientists is valueless, and that the apparent 

 theological bearings of their hypotheses may safely be 

 either ignored or treated as unimportant. To revert to 

 a figure of speech previously employed in this lecture, 

 the sections of the model of nature which are examined 

 by physical and theological sciences intersect each 

 other at certain points, and the attempts to describe 



1 On the phenomena of radio-activity and the theories based upon 

 them, see R. K. Duncan, The New Knowledge; and W. C. D. 

 Whetham, op. cit., chh. vi, vii. 



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