19 Aug. 1814

Logic

2

Ch. Division

'. Synthesis and Analysis

correspond not

8

In this supposed case, for every species there is one individual, and no more; for every individual, one species, and no more.

But as, within the extent of one species, an indefinite number of individuals may be, and habitually are, contained, so from any one individual, much more from a greater number of individuals, an unlimited number of species may be deduced.

No new species, it is true, can be formed, except so far as in description it is capable of being rendered different from every species which had been described, before it had ever been described. But, in regard to any of the observable species of natural bodies, taken as they come out of the hands of nature, this is a condition, of the failure of which no reasonable probability seems to present itself. Take, for instance, the 40,000 different species of plants, that having, some years ago, been said to be the number of those species already known to be in existence. Of these, there exists not any one which has not some property, or aggregate of properties, which is not to be found in any of the others, and which constitute that difference, or say differential character, whereby it stands distinguished from every other. Of these differences, the ideas were respectively formed in the mind by the process of abstraction. They were formed from the observations made of some individual plant or plants, which, at the time of observation, were respectively considered as belonging to those same species. On this occasion, in the formation of any such species, what was done was, not to take for the character, or essence of the species, every mark whereby the individual in question, the individual, or individuals, then and there observed, was seen to differ from all individuals that had ever been observed before, but only some one or other small number of these marks. For, in all the different species of plants that have thus been formed, take any one whatsoever: answerable to the description, how ample and particular soever of that one species, will be found individuals in a multitude absolutely inexhaustible, no two of them so perfectly similar but that, upon a simultaneous comparison, differences, perceptible and describable differences, between them might be found.

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