December 6, 1895.] 



SCIENCE. 



773 



though I cannot admit that this was an unhappy 

 selection. 



To the correspondent who asks me (p. 287) why 

 I cannot conceive that the image on my retina 

 is upside down, I can give no answer ex- 

 cept that I am made so, although I admit that I 

 have no right to speak for others, and that I 

 should not have used the editorial we in the 

 statement referred to. 



I find many of the truths of science inconceiv- 

 able, and while my intellect apprehends the 

 logic of the evidence that the sun is more than 

 a million times as big as the earth, I am abso- 

 lutely unable to conceive this stupendous 

 fact, or to reconcile it with my experience. 



It seems to me that my co?iceptions of nature 

 are pretty strictly regulated by my pe»'ceptious ; 

 and, while I have no desire to measure the 

 minds of others by my own limited powers, I 

 must ask the ' Psychologist ' whether this cor- 

 respondent has not failed to discriminate be- 

 tween apprehension of the evidence for a fact, 

 and conception of the fact itself. 



While I suppose every one admits that 

 knowledge of the chemistry and physics of the 

 organism is a necessary condition for progress 

 in biology, I hope Professor Gage will improve 

 every fitting occasion to tell the ' mechanical 

 physiologists ' that the problems of life are not 

 yet reduced to physics and chemistry, and that 

 consciousness is not yet proved to be 'a proj)- 

 ertj' of protoplasm.' 



I shall gladly second him to the best of my 

 ability as often as he insists that no progress in 

 our knowledge of vital actions can be hojied for 

 unless the organic machine is studied as a living- 

 being; but I must point out the fact that none 

 of the passages he quotes (p. 590) have any 

 bearing whatever on the problem of the origin 

 of vital phenomena except so far as they show 

 that it is as yet unsolved. This is a very differ- 

 ent matter from proof that the problem is insolu- 

 ble; and a schoolboy who believes that what his 

 teacher has not yet explained is ' not explica- 

 ble ' may be making a most grievous blunder. 



We are all of us schoolboys in knowledge of 

 nature, and our admission of ignorance is 

 not dogmatism but caution. I, for one, do not 

 dare to say any natural event is ' not explicable ' 



by means of the data of physical science; al" 

 though I am sure all who have studied with 

 me will confirm my statement that I have neg- 

 lected no opportunity to insist that we have 

 not yet made the slightest approximation to 

 such an explanation of the phenomena of life. 



I am, however, equally confident that I know 

 of no approximation to any other explanation; 

 nor do I believe that any one has any moral 

 right to believe in one unless he is prepared to 

 give evidence for it. 



W. K. Brooks. 



Baltimore, November 19, 1895. 



SCIENTIFIC LITER ATUBE. 

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