46 WHAT IS SCIENCE? 



from other steels by being rustless, we are for the first 

 time in a position to divide steels into two classes, those 

 which do and those which do not rust, and so to analyse 

 the single law implied by the use of the term " steel " 

 into two laws, one implied by the term rusting steel, and 

 the other by the term rustless steel. And so, again, when 

 we have found that steel is attracted by a magnet, we are 

 first in the position to notice that different objects, 

 hitherto all called magnets, differ somewhat in their 

 power of attracting steel ; we can break up the single 

 law, There aie magnets, into a whole series of laws 

 asserting the properties of all the various magnets 

 which are distinguished by their different power of 

 attracting steel. 



This is actually the history of scientific development, 

 so far as the discovery of laws is concerned. And now 

 we can see why it is so difficult to say what are the 

 fundamental and irresolvable laws on which science is 

 ultimately built. Science is always assuming, for the time 

 being, that certain laws are irresolvable ; the law of steel, 

 for example, in the early stages of chemistry. But later 

 it resolves these laws, and uses for the purpose of the 

 resolution laws which have been discovered on the 

 assumption that they are irresolvable. At no stage is 

 it definitely and finally asserted that the limits of analysis 

 have been reached ; it is not asserted even in the most 

 advanced sciences of to-day ; it is always recognized 

 that a law which at present appears complete may later 

 be shown to state an association which is not truly invari- 

 able. Moreover, the intermingling of the two processes 

 leads to the result that a law which is regarded as final 

 in one connexion is not regarded as final in another. 

 We use the law that there is steel to assert the law that 

 there are magnets, and at the same time use the law that 

 there are magnets to assert the law that there is steel ! 



If we attempted to describe science as a purely logical 



