444 



SCIENCE. 



[N. S. Vol. III. No. 64. 



can see no better logical warrant for attribut- 

 ing to me the opinion that I can conceive of the 

 retinal image, but not of its inversion ; for, most 

 assuredly, I have said nothing of the sort, and 

 I find all the physiological antecedents to vision 

 equally inconceivable. 



If something in the minds of certain writers 

 leads them to believe that I adhere to an obso- 

 lete and worthless hypothesis of vision I am 

 helpless, for while I have the right to demand 

 that my words shall pass at their face value I 

 have no way to defend this right except an ap- 

 peal to unprejudiced readers. 



I cannot conceive of the antipodes, and if 

 C. L. F. infers that I accept the astronomy of 

 Homer I must bear up as well as I can. 



Both the rotundity of the earth and the in- 

 version of the retinal image are proved by am- 

 ple evidence, but apprehension of the proof of 

 a truth is a very different thing from conception 

 of the truth itself, and no one who is not totally 

 destitute of imagination could confuse the one 

 with the other ; although it may be well to re- 

 mind C. L. F. that I have nowhere said that 

 ' there is anything which needs explanation in 

 the fact that the image on the retina is inverted,' 

 and that it is because the evidence is conclusive 

 that I made use of the inversion to illustrate 

 that great law of logic that ' the test of truth is 

 evidence and not conceivability. ' (Science, Oct. 4, 

 1895.) 



If any reader cares to ask what has called 

 forth all this criticism, which has occupied the 

 pages of Science for more than six months, he 

 may be surprised to find that my statement about 

 the retinal image was nothing more than an in- 

 cidental illustration of less than a dozen words in 

 an article in Science, October 4, 1895, in which 

 I tried to show that ' ' the mental vice to which 

 we are most prone is our tendency to believe 

 that lack of evidence for an opinion is a reason 

 for believing something else." 



The correspondence which this illustration 

 has excited seems to show that I should have 

 done well to state this truth in a more general 

 form, and to point out that the mental vice to 

 which we are most prone is our tendency to in- 

 terpret a negation as an aflftrmation of some- 

 thing else. 



W. K. Bkooks. 



certitudes and illusions. 



To the Editor of Science: In my first 

 article on ' Certitudes and Illusions,' I cited 

 two illustrious examples of persons who had 

 lapsed into reification, namely, Spencer in his 

 'First Principles,' where he reifies force, and 

 Hegel in his Logic where he reifies idea or com- 

 prehension ; but I did not attempt to exhibit 

 Spencer's reification of force or Hegel's reifica- 

 tion of idea. In that article I tried to set forth 

 the nature of the subject-matter of a series of 

 articles which I had planned and promised the 

 editor. 



Fichte has seized upon certain of Kant's 

 reifications and those of others and reasoned 

 about non-existent abstractions or pure proper- 

 ties of mind, and in his presentation has naively 

 reduced the whole method of reasoning to an 

 absurdity ; but he died a disappointed and sad 

 man because he had not consciously discovered 

 that he had murdered his own methods. Hegel 

 seems to have discovered this and to have char- 

 acterized pure abstraction in no unmeasured 

 terms, notwithstanding which he finally fell in- 

 to the same vice and reified idea. In my first 

 article Hegel's illusion was not set forth, but 

 only reference made to the matter for the pur- 

 pose of calling attention to the subject-matter 

 of which I wish to treat. I shall not ignore or 

 underestimate Spencer's contribution to the 

 biology of the lower animals nor his contribu- 

 tion to psychology. In the same manner I 

 shall not underestimate Hegel's acute reasoning 

 in his system of logic, but I shall attempt to 

 show that Hegel accepts Kant's doctrine of 

 antinomies and develops this doctrine into a 

 logic of contradiction and by its use reifies idea 

 and ends as an absolute idealist. Now, Mr. 

 Editor, permit me to say this word in reply to 

 Prof. Royce, whose letter is in every way kind, 

 but whose error consists in supposing that I 

 attributed to Hegel all of the reifications men- 

 tioned in my article. 



If he will take down the Phanomenologie des 

 Geistes and read in the first chapter what Hegel 

 has said about the demonstratives, and then read 

 what I have said about them, he will discover 

 to what I had reference in the treatment and 

 use of these demonstratives, and maybe he will 

 further discover that I have a purpose in speak- 



