136 MR. Darwin's work and 



whit more preposterous than the objections which have 

 been made to the " Origin of Species." Mr. Darwin, 

 then, had a perfect right to limit his inquiiy as he 

 pleased, and the only question for us — the inquiry 

 being so limited — is to ascertain whether the method 

 of his inquiry is sound or unsound ; whether he has 

 obeyed the canons which must guide and govern all 

 investigation, or whether he has broken them ; and it was 

 because our inquiry this evening is essentially limited 

 to that question, that I spent a good deal of time in a 

 former lecture (which, perhaps some of you thought 

 might have been better employed) in endeavom-iug to 

 illustrate the method and nature of scientific inquiry 

 in general. We shall now have to put in practice the 

 principles that I then laid down. 



I stated to you in substance, if not in words, that 

 wherever there are complex masses of phenomena to 

 be inquired into, whether they be phenomena of the 

 affairs of daily life, or whether they belong to the more 

 abstruse and difficult problems laid before the philo- 

 sopher, our course of proceeding in unravelling that com- 

 plex chain of phenomena with a view to get at its cause, 

 is always the same ; in all cases we must invent a hypo- 

 thesis J we must place before ourselves some more or 

 less likely supposition respecting that cause ; and then, 

 having assumed a hypothesis, having supposed a cause 

 for the phenomena in question, we must endeavour, on 

 the one hand, to demonstrate our hypothesis, or, oa 

 the other, to upset and reject it altogether, by testing it 

 in three ways. We must, in the first place, be pre- 

 pared to prove that the supposed causes of the pheno- 

 mena exist in nature; that they are what the logicians 



