70 WHAT IS SCIENCE? 



is that the sun will rise and that the expectation of its 

 rising is a sound basis for the conduct of life ; he does 

 not mean something that can be made true or false just 

 as we please. It was all very well I can hear an objector 

 say to insist at the beginning of the chapter that we 

 can have no " knowledge " of future events ; it is undeni- 

 able that we have some kind of knowledge which we 

 habitually use in our practical life ; and if the only kind 

 of knowledge that science admits is a determination never 

 to be proved wrong, then we must seek elsewhere for the 

 information that undoubtedly is to be had. 



Of course, I do not deny all this ; and now I shall 

 try and show how the two points of view may be recon- 

 ciled. Men of science, though they pay no direct atten- 

 tion to prediction, are not really indifferent to the success 

 of their predictions, interpreted in accordance with the 

 plainest common sense. If their predictions always 

 failed, it would mean that each addition to experience 

 would mean a new ordering of the whole. This ordering 

 doubtless could be accomplished in some fashion, but it 

 would have no value. The achievement of science would 

 be like that of Penelope, who wove a cloth that she 

 unravelled each night and started afresh each morning. 

 If all our predictions were failures, we could, I suppose, 

 continue our task of ordering experience, but no sane 

 man would do so. Science is only worth while because 

 it does make real progress. The ordering established for 

 past experience is on the whole valid for future experience. 

 The exceptions are comparatively few, and, even when 

 they occur, it is found that the alteration of the order 

 is so slight it is often only a natural development of the 

 old order that the necessity for repeating the task is 

 not wearisome. Time unravels, not the whole web, but 

 only a few minor portions in which the shuttle has gone 

 awry. Scientific laws do predict exactly in the manner 

 which the plain man desires ; and it is really as necessary 



