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THE POPULAR SCIENCE MONTHLY. 



of this correspondence. Commencing with the lowest types of life, 

 Mr. Spencer, in successive chapters, traces up this relation of corre- 

 spondence as extending in space and time, as increasing in specialty, 

 in generality, and in complexity. It is also shown that the correspond- 

 ence progresses from a more homogeneous to a more heterogeneous 

 form, and that it becomes gradually more integrated the terms here 

 employed, in respect to the Evolution of mind, being the terms subse- 

 quently used in treating of Evolution in general. In the fourth part 

 of the work, under the title of " Special Synthesis," the Evolution is 

 traced out under its concrete form from reflex action up through in- 

 stinct, memory, reason, feelings, and the will. Mr. Spencer here dis- 

 tinctly avowed his belief that " Life, in its multitudinous and infinitely 

 varied embodiments, has arisen out of the lowest and simplest begin- 

 nings, by steps as gradual as those which evolve a homogeneous mi- 

 croscopic germ into a complex organism" dissent being, at the same 

 time, expressed from that version of the doctrine put forth by the 

 author of the " Vestiges of the Natural History of Creation." It was, 

 moreover, shown by subjective analysis how intelligence may be re- 

 solved, step by step, from its most complex into its simplest elements ; 

 and it was also proved that there is " unity of composition " through- 

 out, and that thus mental structure, contemplated internally, harmon- 

 izes with the doctrine of Evolution. 



It was at this time (1854), as I have been informed by Mr. Spencer, 

 when he had been at work upon the " Principles of Psychology " not 

 more than two months, that the general conception of Evolution in 

 its causes and extent, as well as its processes, was arrived at. He had 

 somewhat earlier conceived of it as universally a transformation from 

 the homogeneous into the heterogeneous. This kind of change which 

 Von Baer had shown to take place in every individual organism, as it 

 develops, Mr. Spencer had already traced out as taking place in the 

 progress of social arrangements, in the development of the sciences, 

 and now in the Evolution of mind in general from the lower forms to 

 the higher. And the generalization soon extended itself so as to em- 

 brace the transformations undergone by all things inanimate as well 

 as animate. This universal extension of the idea led rapidly to the 

 conception of a universal cause necessitating it. In the autumn of 

 1854, Mr. Spencer proposed to the editor of the Westminster Review 

 to write an article upon the subject under the title of " The Cause of 

 all Progress," which was objected to as being too assuming. The 

 article was, however, at that time agreed upon, with the understand- 

 ing that it should be written as soon as the "Principles of Psychology" 

 was finished. The agreement was doomed to be defeated, however, 

 so far as the date was concerned, for, along with the completion of the 

 " Psychology," in July, 1855, there came a nervous break-down, which 

 incapacitated Mr. Spencer for labor during a period of eighteen months 

 the whole work having been written in less than a year. 



