92 REPLIES TO CRITICISMS. 



Taking other of Prof. Bain s objections, not in the order 

 in which they stand but in the order in which they may be 

 most conveniently dealt with, I quote as follows : 



&quot;The law of the radiation of light (the inverse square of the 

 distance) is said by Mr. Spencer to be Abstract-Concrete, while the 

 disturbing changes in the medium are not to be mentioned except 

 in a Concrete Science of Optics. We need not remark that such 

 a separate handling is unknown to science.&quot; 



It is perfectly true that &quot; such a separate handling is un 

 known to science.&quot; But, unfortunately for the objection, it 

 is also perfectly true that no such separate handling^ is pro 

 posed by me, or is implied by my classification. How Prof. 

 Bain can have so missed the meaning of the word &quot;concrete,&quot; 

 as I have used it, I do not understand. After pointing out 

 that &quot;no one ever drew the line,&quot; between the Abstract- 

 Concrete and the Concrete Sciences, &quot;as I have done it,&quot; 

 he alleges an anomaly which exists only supposing that 

 I have drawn it where it is ordinarily drawn. He appears 

 inadvertently to have carried with him M. Comte s concep 

 tion of Optics as a Concrete Science, and, importing it into 

 my classification, debits me with the incongruity. If he 

 will re-read the definition of the Abstract-Concrete Sciences, 

 or study their sub-divisions as shown in Table II., he will, 

 I think, see that the most special laws of the redistribution 

 of light, equally with its most general laws, are included. 

 And if he will pass to the definition and the tabulation of 

 the Concrete Sciences, he will, I think, see no less clearly 

 that Optics cannot be included among them. 



Prof. Bain considers that I am not justified in classing 

 Chemistry as an Abstract- Concrete Science, and excluding 

 from it all consideration of the crude forms of the various 

 substances dealt with ; and he enforces his dissent by saying 

 that chemists habitually describe the ores and impure mix 

 tures in which the elements, etc., are naturally found. Un 

 doubtedly chemists do this. But do they therefore intend 



