74 WHAT IS SCIENCE? 



very pedestrian talents of energy and application. But 

 we are simply following in the footsteps of our masters. 

 In Chapter III we noticed that there were standard 

 forms of laws ; there are many laws, all quite distinct and 

 ordering quite different groups of fact, which are yet 

 obviously all of the same form. The laws asserting the 

 properties of a substance provide a notable example ; 

 there are many substances, but the laws which assert 

 that there are such substances have all the same form. 

 The properties of hydrogen, which are asserted by the 

 law that there is such a thing as hydrogen, are quite differ- 

 ent from the properties of iron, asserted by the law that 

 there is such a thing as iron ; yet the laws are of the same 

 form. Now once we have got the idea that there are laws 

 of this form, it is a comparatively simple problem, which 

 can be solved more or less according to fixed rules, to 

 establish the laws of a new substance or, by finding new 

 properties, to alter or augment an old one. And we 

 do know now that laws of this particular form are among 

 those to which nature will conform, and which can be 

 usefully applied in prediction. The stroke of genius was 

 that of the man who first suggested a law of that form ; 

 once he had suggested it and showed that such a law is 

 permanently valid, it was easy enough for others to take 

 up the work and find others of the same form. 



The discovery of the laws of substances is hidden in 

 the darkness of the past ; they are among the ideas which 

 we take over from common sense, and were invented by 

 the unknown giants who laid the basis of human know- 

 ledge. But advances quite as important, the discovery 

 of other forms of laws which have been used by the 

 humbler folk who do the spade-work of science, such 

 advances have occurred in historic times. Certain great 

 men are recognized as the founders of certain branches 

 of science, and if we inquire why they are so regarded, 

 we shall usually find (but another reason will be found in 



