77 o THE POPULAR SCIENCE MONTHLY. 



cases, and probably in most, passively accept the belief Mr. Mozley 

 suggests. 



Seeing this, I have felt it requisite definitely to raise the issue ; 

 and for this purpose have written to Mr. Mozley the following letter. 

 It is made long by including a general outline of the doctrine of evo- 

 lution, which it was needful to place before him that he might be in a 

 position to answer my question definitely. Perhaps I may be excused 

 for reproducing the letter in full, since ninety-nine out of a hundred 

 do not know what the doctrine of evolution in its wider sense is, but 

 suppose it to be simply another name for the doctrine of the origin of 

 species by natural selection : 



" My dear Sie : The passages from three letters of my father, 

 sent herewith one written in 1820, which was about the date referred 

 to in your account of him, one written some thirteen years later, and 

 the other twenty years later will prove to you how erroneous is the 

 statement you have made with regard to his religious beliefs. Having 

 in this case clear proof of error, you will, I think, be the better pre- 

 pared to recognize the probability of error in the statements which 

 you make concerning his philosophical ideas and the ideas which, 

 under his influence, you in early life elaborated for yourself. 



" The passage in which you refer to these gives the impression that 

 they were akin to those views which are developed in the ' System of 

 Synthetic Philosophy.' I am anxious to ascertain in what the alleged 

 kinship consists. Some twelve years ago an American friend re- 

 quested me, with a view to a certain use which he named, to furnish 

 him with a succinct statement of the cardinal principles developed in 

 the successive works I have published. The rough draft of this state- 

 ment I have preserved ; and, that you may be enabled definitely to 

 compare the propositions of that which you have called ' the younger 

 philosophy ' with that which you have called ' the elder,' I copy it out. 

 It runs as follows : 



" ' 1. Throughout the universe in general and in detail there is an unceasing 

 redistribution of matter and motion. 



'"2. This redistribution constitutes evolution where there is a predomi- 

 nant integration of matter and dissipation of motion, and constitutes dissolution 

 where there is a predominant absorption of motion and disintegration of matter. 



'"3. Evolution is simple when the process of integration, or the formation 

 of a coherent aggregate, proceeds uncomplicated by other processes. 



'"4. Evolution is compound when, along with this primary change from an 

 incoherent to a coherent state, there go on secondary changes due to differences 

 in the circumstances of the different parts of the aggregate. 



" ' 5. These secondary changes constitute a transformation of the homoge- 

 neous into the heterogeneous a transformation which, like the first, is exhibited 

 in the universe as a whole and in all (or nearly all) its details ; in the aggregate 

 of stars and nebulse ; in the planetary system; in the earth as an inorganic 

 mass; in each organism, vegetal or animal (Von Baer's law otherwise ex- 



