EVIDENCE OF INORGANIC EVOLUTION 5 8 5 



The Arguments from Classification 



The fact that the groups of organisms fall naturally into a certain 

 classification is in itself evidence of their origin by evolution. 3 Now, 

 the most salient characteristic of this classification is a division into 

 groups, and a subordination of groups within groups. 



There is a breaking up into groups and sub-groups, and sub-sub-groups, 

 which do not admit of being placed in serial order, but only in divergent and 

 re- divergent order. . . . The Alliances are subdivided into Orders, and these 

 into Genera, and these into Species. 4 . . . The conception finally arrived at, is, 

 that of certain great subkingdoms, very widely divergent, each made up of 

 classes much less widely divergent, severally containing orders still less divergent, 

 and so on with genera and species. 5 



If we examine the characteristics of the Periodic classification, we 

 shall find there the same peculiarities as have been observed in zoological 

 classifications. Thus, there are the nine groups of elements, each quite 

 distinct from the others, and each, as we have shown, very probably 

 having a distinct plan of atomic structure common to all the members 

 of the group. These nine groups correspond to the twelve phyla of 

 organisms. Each group, again, is divided into two families, corre- 

 sponding to the classes into which organic phyla are divided. That we 

 have no further subdivisions corresponding to those in the organic clas- 

 sification is doubtless due to the circumstance that the number of ele- 

 ments is extremely small as compared with the number of species of 

 animals. When we remember that even with this small number of ele- 

 ments, the Periodic classification presents many irregularities — as forc- 

 ing into the same family elements with widely different properties (e.g., 

 the copper family) ; creating a group of " transitional elements " dif- 

 ferent in the principle of its arrangement from the other groups; the 

 breaking of the periodic sequence by argon, which is greater in atomic 

 weight than potassium, yet precedes it in the series, and by tellurium, 

 which bears a similar relation to iodine; and the irregularities pre- 

 sented by the rare earths — when these facts are considered, it can 

 scarcely be doubted that if the number of the elements were at all 

 comparable to that of organic species, the classification of the ele- 

 ments would necessarily present a subdivision of group within group 

 as extensive, perhaps, as that found among organisms. Moreover, 

 the periodic relation would probably be largely obscured by the great 

 number of its irregularities and contradictions. 



Since the classification into which organisms are naturally arranged, 

 of group subordinated to group, is regarded as an indication of evolu- 

 tion, as previously stated; the fact that a similar arrangement is found 

 in the classification of the elements suggests (when we consider also 



3 For a detailed discussion of this point, which can not be given here for 

 lack of space, see Spencer, "Principles of Biology," Vol. I., pp. 356-359. 



4 Spencer, loc. cit., p. 297. 

 6 Spencer, loc. cit., p. 358. 



YOL. Lixxn.- 40. 



