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Show 162 DAR TV IN IAN A. most unlimited manner. He is not peculiar in this regard. Mr. Agassiz tells us. that the convic~ion is "now universal, among well-mformed naturalists, that this globe has been in existence for innumerable ages and that the length of time elapsed since· it first beca'm e inhabited cannot be counte d 1. n years ; " p·IC - tet that the imagination refuses to calculate the imm~ nse number of years and of ages during which the faunas of thirty or more epochs have succeeded one another, and developed their long succession of generations. Now, the reviewer declares that such indefinite succession of ages is" virtually infinite," "lacks no characteristic of eternity except its name," at least, that " the difference between such a conception and that of the strictly infinite, if any, is not appreciable." But infinity belongs to metaphysics. Therefore, he concludes, Darwin supports his theory, not by scientific but by metaphysical evidence; his theory is" essentially and completely metaphysical in character, resting altogether upon that idea of 'the infinite' which the human mind can neither put aside nor comprehend." 1 And so a theory which will be generally regarded as much too physical is transferred by a single syllogism to metaphysics. Well, physical geology must go with it : for, even on the soberest view, it demands an indefinitely long time antecedent to the introduction of organic life upon our earth. A fortiori is physical astronomy a branch of metaphysics, demanding, as it does, still larger "instalments of infinity," as the reviewer calls them both as to time and number. Moreover, far the ' t North American Review, .loc. cit., p. 48'7, et passim. DAR WIN AND HIS REVIEWERS. 163 greater part of physical inquiries now relate to molecular actions, which, a distinguished natwal philosopher informs us, "we have to regard as the results of an in.fonite number of in.fonitely small material particles, acting on each other at infonitely small distances " -a triad of in:fini ties-and so physics becomes the most metaphysical of sciences. Verily, if this style of reasoning is to prevail- "Thinking is but an idle waste of thought, .And naught is everything, and everything is naught." The leading objection of Mr. Agassiz is likewise of a philosophical character. It is, that species exist only "as categories of thought "-that, having no material existence, they can have had no material variation, and no material community of origin. Here the predieation is of species in the subjective sense, the hlference in the objective sense. Reduced to plain terms, the argument seems to be: Species are ideas; therefore the objects from which the idea is derived cannot vary or blend, and cannot have had a genealogical connection. The common view of species is, that, although they are generalizations; yet they have a direct objective ground in Nature, which genera, orders, etc., have not. According to the succinct definition of J ussieu-and that of Linnams is identical in meaning-a species is the perennial succession of similar individuals in continued generations. The species is the chain of which the individuals are the links. The sum of the genealogically- connected similar individuals constitutes the species, which thus has an actuality and ground of dis- |
