36 THE POPULAR SCIENCE MONTHLY. 



reached it in the " Politique Positive." Be it so. That, however, is 

 a work which Mr. Harrison reproaches me with not having read. 



But if I go on in this way, meeting one by one Mr. Harrison's alle- 

 gations, I shall tire your readers before I reach the statement which I 

 think will be held conclusive. My course must be to specify those 

 idees-m^res which I have indicated to Mr. Harrison, but which he re- 

 fuses to look for, and then to show how from these the whole doctrine 

 I have set forth gradually grew. 



Omitting earlier stages, which I can trace back to 1850, I begin 

 with the essay, " Progress : Its Law and Cause," which was published 

 in 1857. On the second page of that essay I have named the general- 

 ization reached by Von Baer, that the changes undergone during the 

 development of every living thing " constitute an advance from homo- 

 geneity of structure to heterogeneity of structure." On the next page 

 I have enunciated the thesis of the essay ; namely, that " this law of 

 organic progress is the law of all progress " — not progress in a limited 

 sense, but progress inorganic as well as organic, presented throughout 

 the universe, from celestial bodies to such social products as science, 

 art, and literature. How was the evidence supporting this thesis to 

 be presented ? By taking the various groups into which all kinds of 

 phenomena are divisible, and showing that the law holds throughout 

 each group, I have arranged them in the order astronomical, geologi- 

 cal, biological, psychological, sociological. Why this order? The 

 reasons ai'e obvious. If the Cosmos has been evolved, then, in order 

 of time, astronomical phenomena preceded geological, geological pre- 

 ceded biological, biological preceded psychological, psychological pre- 

 ceded sociological. Equally was the arrangement dictated by order of 

 dependence. The existence of each of these groups of phenomena made 

 possible the existence of the succeeding group. I could not have put 

 the groups in any other order without manifest derangement. The 

 second half of the article first asks the question — -Why does this uni- 

 versal transformation go on ? and the alleged cause is that " every 

 active force produces more than one change " or effect ; the implica- 

 tion being that there is a continuous multiplication of effects, of which 

 increasing heterogeneity is a result. The rest of the article traces out 

 everywhere this multiplication of effects ; and in thus interpreting de- 

 ductively the previous inductions I was, of course, forced to follow 

 the same succession of groups of phenomena by the necessities of or- 

 derly exposition. 



Is there anything here attributable to M. Comte ? This order of 

 exposition, which arose irrespective of any classification of the sciences, 

 Comtean or other, and which governs the order in which the works 

 constituting the Synthetic Philosophy have been written, is one which 

 Mr. Harrison is courageous enough to say corresponds with Comte's 

 scheme of the sciences. He does this in face of the fact that of 

 Comte's six sciences three have no place in it ! It contains no di- 



