46 ESSAYS SCIENTIFIC AND PHILOSOPHICAL. 



species, instead of showing how species came to 

 be. If a cat and a dog are different in kind, so 

 are a man and a monkey, whatever view we may 

 take of the genetic relations of the pairs. But this 

 is not what Mr. Romanes means by different in kind. 

 In a footnote to page 3, he says that difference 

 of kind means difference of origin, and accuses 

 Professor Sayce of "confusion" for saying that 

 " differences of degree become in time differences 

 of kind." We seem to remember a greater than 

 Professor Sayce teaching us that the categories of 

 quantity and quality disappear in " measure." 

 And if this sounds to Mr. Romanes a trifle meta- 

 physical, we might remind him that whenever 

 science has shown that differences of kind, con- 

 sidered genetically, are differences of degree, no 

 one dreams of supposing that they are any the 

 less differences of kind. The question of origin 

 has nothing to do with it. Only apparently Mr. 

 Romanes is fighting against some one who explains 

 the difference in kind between human and brute 

 psychology by a difference of origin. If this is 

 the view of Mr. Wallace, or Mr. Mivart, or Pro- 

 fessor Quatrefages, we must leave them to defend 

 it. And if Mr. Romanes is defending the unity of 

 origin for man and brute, he need not be afraid 

 of theological opposition. Christianity knows of 

 only one origin for all things, however widely they 

 differ in kind. If of man it is said that God 



