288 THE FOUNDATIONS OF ZOOLOGY 



that our only reason for believing that the thing which we 

 expect will be the thing which comes about is our confidence that 

 nature is orderly ; and that this way of accounting for order in 

 nature brings us at last to the very point from which we set 

 out. 



Of all the strange errors that vex the mind of man, one of 

 the strangest is the opinion that our faculties would lose their 

 reality and their value if the history of man were proved to be 

 orderly, and what might reasonably have been expected, for that 

 our history cannot have the slightest bearing on the reality of 

 anything in our nature seems so obvious that it is hard to see 

 why any one should question it. 



If one knows that he is refreshed by food and drink, I fail to 

 see what bearing on this conviction any amount of anatomical 

 or physiological or historical acquaintance with his digestive 

 organs can have, even if it should enable him to deduce these 

 organs from physics and chemistry or to make others like them. 



Scientific knowledge of digestion gives valuable information 

 as to the conditions under which food and drink are beneficial, 

 and it helps us to regulate our natural appetites and to avoid 

 errors and excesses; but no one ever dreams that this is evidence 

 that these appetites are not real. 



You may perhaps find some reason to doubt whether you 

 see me in this room or hear this lecture ; for all I know, you may 

 find still more reason to doubt whether you profit by so doing; 

 but can you doubt that you see and hear, or that on the whole 

 you profit by seeing and hearing? Would you not be just as 

 sure even if you knew nothing of optics or acoustics or even of 

 eyes or ears ? For my own part I should be as sure I see 

 and hear, and see and hear to my advantage, as I am now, even 

 if my days were passed in a laboratory for the manufacture of 

 seeing and hearing beings. Since my reason began to make 

 itself known to me before I knew I had a brain, my conviction 

 that I am a rational being, like my conviction that it is good to 

 be a rational being, is independent of knowledge of the existence 

 of my brain. Since my power to draw inferences from the data 

 of sense and to profit by them is independent of acquaintance 

 with the mechanism of my brain, I fail to see why my reason 



