2IO THE FOUNDATIONS OF ZOOLOGY 



I cannot conceive what better basis for a philosophy of mind 

 and matter one who had seen the vibrations of a brain would 

 have than one who knows he sees, and, as a rule, sees to his 

 advantage, when he opens his eyes. 



Must we not also reflect that some of the things we see may 

 be hallucinations, or illusions, or somnambulatory dreams ? Must 

 we not ask the difficult but preeminently practical question how, 

 admitting the vibrations, we distinguish those that are in tune 

 with nature from those that are out of tune ? How, for example, 

 do the vibrations that go on as we think the thought that a stick 

 half in water is bent, differ from those that go on as we think 

 that the stick in the air is straight ? Is it not because " snap " 

 judgments about our sensible perceptions often lead us into diffi- 

 culties and tend to our physical destruction ; while rectified judg- 

 ments are beneficial ; because, for example, the savage who has 

 corrected his judgment spears his fish, while he who has not 

 loses his dinner. May not the difference perhaps prove, in ulti- 

 mate analysis, to be that adjustments that are preservative of life 

 are said to be in tune with nature, and their corresponding mental 

 states truths; while those that are injurious are said to be out of 

 tune, and their corresponding mental states errors or illusions .' 

 May it not be because our brains are the ones that have so far 

 survived the struggle for existence that we hold their normal 

 vibrations to be in tune with nature .' If this should prove to be 

 the case, would it not be due to natural selection that our brains 

 vibrate in tune with nature } If it were not for natural selection, 

 might not all seem delusion ; nothing truth ? 



No Darwinian questions the benefit of training, and practice, 

 and education, and experience ; for all this is matter of fact, 

 admitted by all. Who can ask whether a man educated is differ- 

 ent from the man uneducated ? or whether the beneficial effects 

 of nurture are anything more than might have been expected } • 



While he admits that, in some practical sense of the words, he 

 is a free agent, responsible for his thoughts and actions, and 

 able to act wisely or foolishly and to do right and wrong ; the 

 Darwinian asks whether voluntary acts are efficient causes of 

 structure, or only antecedents of the sort which we call physical 

 causes, or occasions, or stimuli; and whether they do anything 



