xxiii.] THE USE OF HYPOTHESIS. 509 



The irony of fate will probably decide that the most 

 original and valuable . part of Mill's System of Logic is 

 irreconcilable with those views of the syllogism and of 

 the nature of inference which occupy the main part of 

 the treatise, and are said to have effected a revolution 

 in logical science. Mill would have been saved from 

 much confusion of thought had he not failed to observe 

 that the inverse use of deduction constitutes induction. 

 In later years Professof Huxley has strongly insisted 

 upon the value of hypothesis. When he advocates the 

 use of " working hypotheses " he means no doubt that 

 any hypothesis is better that none, and that we cannot 

 avoid being guided in our observations by some hypo- 

 thesis or other. Professor Tyndall's views as to the 

 use of the Imagination in the pursuit of Science put the 

 same truth in another light. 



It ought to be pointed out that Neil in his Art of 

 Eeasoning, a popular but able exposition of the principles 

 of Logic, published in 1853, fully recognises in Chapter 

 XI. the value and position of hypothesis in the discovery 

 of truth. He endeavours to show, too (p. 109), that 

 Francis Bacon did not object to the use of hypothesis. 



The true course of inductive procedure is that which 

 has yielded all the more lofty results of science. It 

 consists in Anticipating Nature, in the sense of forming 

 hypotheses as to the laws which are probably in opera- 

 tion; and then observing whether the combinations of 

 phenomena are such as would follow from the laws 

 supposed. The investigator begins with facts and ends 

 with them. He uses facts to suggest probable hypotheses ; 

 deducing other facts which would happen if a parti- 

 cular hypothesis is true, he proceeds to test the truth 

 of his notion by fresh observations. If any result prove 

 different from what he expects, it leads him to modify 

 or to abandon his hypothesis ; but every new fact may 

 give some new suggestion as to the laws in action. 

 Even if the result in any case agrees with his anticipa- 

 tions; he does not regard it as finally confirmatory of his 

 theory, but proceeds to test the truth of the theory by new 

 deductions and new trials. 



In such a process the investigator is assisted by the 

 whole body of science previously accumulated. He may 



