CORRESPONDENCE 



To THE Editor of " Science Progress " 



MATHEMATICAL PHILOSOPHY 



From HON. BERTRAND RUSSELL, F.R.S. 



Sir, — The review of my Introduction to Mathematical Philosophy by the late 

 P. E. B. Jourdain, in the April number of Science Progress, contains some 

 statements which I cannot pass by in silence. 



In the first paragraph, on p. 673, Mr. Jourdain repeats his complaint 

 that I ignored his attempted proof of the multiplicative axiom. In actual 

 fact, I took endless pains over it. At first, I told him where I thought it 

 faulty ; he then sent me a new version, altering other parts, but leaving 

 the vital point unchanged. This process occurred repeatedly. I consulted 

 all competent people whom I could get hold of, and they all agreed with 

 me in thinking the proof invalid. I have read his proof with minute care 

 in its various successive forms ; I have written to him over and over again 

 explaining where I thought it faulty ; but on this point it has not changed. 

 Mr. Jourdain was a friend of many years' standing, for whom I had both 

 affection and respect, and I was reluctant to enter into public controversy 

 with him. Therefore when I did not think well of his work I did not mention 

 it. Neither in connection with the multiplicative axiom, nor in any other 

 connection, had I any other motive for not referring to him. This applies 

 in particular to the matter mentioned in the second paragraph of p. 673. 



In conclusion, I must entirely repudiate the statement at the top of 

 p. 672 : " Mr. Russell acknowledged the justice of the present writer's stric- 

 tures in the Cambridge Review on a crop of similar errors, but said they were 

 all due to Dr. Whitehead." This odious accusation must be based upon 

 some conversation of ten years ago, and I can only base my denial upon the 

 certainty that that is not the sort of thing I should do. 



Yours, etc., 

 Bertrand Russell. 

 April 20, 1920. 



To THE Editor of " Science Progress " 



THE ICE-AGE QUESTION 



I 



From A. H. BARLEY 



Dear Sir, — I am looking forward to the answer of astronomers to the 

 question propounded in Major Marriott's very temperate reply to Mr. H. 

 Spencer Jones's letter in the July number. It seems hardly likely I am alone 

 in this, for the present period is one in which " authority " is viewed with 

 disfavour except in so far as it justifies its position through the appeal to 



loi 



