128 HISTORY OF SCIENCE. 



of a new process for arriving at truth which is called the Inductive 

 Method. The principles of the inductive philosophy were not only 

 .acted upon but distinctly expressed by many authors before Bacon. 

 As we have already stated, Gilbert's treatise on magnetism is an ad- 

 mirable example of the inductive method. We have seen Palissy the 

 potter consciously practising the same method in his researches ; it 

 was by the inductive road that Copernicus obtained his results ; Tycho 

 Brahe advised Kepler "first to lay a solid foundation for his views by 

 actual observation, and then, ascending from these, to strive to reach 

 the causes of things." Leonardo da Vinci expresses clearly the neces- 

 sity of following the same method. " In treating any particular sub- 

 ject, I would first of all make some experiments, because my design is 

 first to refer to experiment, and then to demonstrate why bodies are 

 constrained to act in such a manner. This is the method we ought 

 to follow in investigating the phenomena of nature. It is very true 

 that nature begins by reasoning and ends with experiment, but it mat- 

 ters not ; we must take the opposite course ; as I have said, we must 

 begin by experiment, and endeavour by its means to discover generai 

 principles. Theory is the general, experiments are the soldiers. The 

 interpreter of the works of nature is experiment; that is never wrong. 

 It is our judgment which is sometimes deceived, because we are ex- 

 pecting results which experiment refuses to give. We must consult 

 experiment, and vary the circumstances till we have deduced general 

 rules, for it alone can furnish us with them. But you will ask, What is 

 the use of these general rules ? I answer, that they direct us in our 

 inquiries into nature and the operations of art. They keep us from 

 deceiving ourselves and others by promising ourselves results which 

 we can never obtain." We find some of the ancient philosophers dis- 

 tinctly describing inductive methods, but, as we have seen, they had 

 no idea of their importance in science. Bacon was therefore by no 

 means the first person who explained the inductive method, and, so far 

 as its use is concerned, it can easily be shown that it has been practised 

 by every human being since the world began. It is precisely this 

 mental process which is applied to the most ordinary questions of daily 

 life. The brilliant author from whose essay on Lord Bacon we have 

 already quoted a few sentences, presents this truth in an amusing way: 

 " A plain man finds his stomach out of order. He never heard Lord 

 Bacon's name ; but he proceeds in the strictest conformity with the 

 rules laid down in the second book of the ' Novum Organum,' and 

 satisfies himself that minced pies have done the^mischief. ' I ate 

 minced pies on Monday and Wednesday, and I was kept awake by 

 indigestion all night.' This is/the comparentia ad intellcctum instantia- 

 rum convenientium. ' I did not eat any on Tuesday and Friday, and I 

 was quite well.' This is the comparentia instantiarum in proximo qucz 

 natura data priv ant ur. ' I ate very sparingly of them on Sunday, and 

 was very slightly indisposed in the evening. But on Christmas Day I 



