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There is one circumstance which ought to be noticed, as having probably contributed not a little to foster this error: I mean the peculiar technical sense of the word “Species” when Technical applied to organized Beings. It has been laid cies when down in the course of this work, that when resized several individuals are observed to resemble each other in some point, a common name may be assigned to them denoting that point,--applying to all or any of them so far forth as respects that common attribute,and distinguishing them from all others; as, e. g. the several individual buildings, which, however different in other respects, agree in being constructed for men's dwelling, are called by the common name of “House:” and it was added, that as we select at pleasure the circumstance that we choose to abstract, we may thus refer the same individual to several different species, according as it suits our purpose; and the same in respect of the reference of Species to Genus: whence it seems plainly to follow that Genus and SpeScies are no real things existing independent of our thoughts, but are creatures of our own minds. Yet in the case of Species of organized Beings, it seems at first sight as
τόδε τι σημαίνειν, όταν είπη, άνθρωπος, ή ζώον» ΟΥ ΜΗΝ ΓΕ ΑΛΗΘΕΣ· αλλά μάλλον ποίον τι σημαίνει: κ. τ. λ. Aristotle, Categ. $ 3.
if this rule did not hold good; but that the Species to which each individual belongs, could not be in any degree arbitrarily fixed by us, but must be something real, unalterable, and independent of our thoughts.
Cæsar or Socrates, for instance, it may be said, must belong to the Species Man, and can belong to no other; and the like, with
individual Brute, or Plant. On the other hand, if any one utters such a proposition as “ Argus was a mastiff,” to what head of Predicables would this Predicate be referred ? Surely our logical principles would lead us to answer, that it is the Species; since it could hardly be called an Accident, and is manifestly no other Predicable. And yet every Naturalist would at once pronounce that Mastiff is no distinct Species, but only a variety of the Species Dog. This however does not satisfy our inquiry as to the head of Predicables to which it is to be referred.
The solution of the difficulty is to be found in the consideration of the peculiar technical
sense of the word “Species” when applied to Species dis. organized Beings : in which case it is always Naturaliais applied (when we are speaking strictly, as
naturalists) to such individuals as are supposed to be descended from a common stock, or which might have so descended; viz. which resemble one another (to use M. Cuvier's
expression) as much as those of the same stock do. Now this being a point on which all (not merely Naturalists) are agreed, and since it is a matter of fact, that such and such in- Questions of dividuals are, or are not, thus connected, it questions of follows, that every question whether a certain individual Animal or Plant belongs to a certain Species or not, is a question not of mere arrangement, but of fact. But in the case of questions respecting Genus it is otherwise. If, e.g. two Naturalists differed, in the one placing (as Linnæus) all the Species of Bee under one Genus, which the other subdivided (as later writers have done) into several genera, it would be evident that there
no question of fact debated between them, and that it was only to be considered which was the more convenient arrangement; if, on the other hand, it were disputed whether the African and the Asiatic Elephant are distinct Species, or merely Varieties, it would be equally manifest that the question is one of fact; since both would allow that if they were descended (or might have descended) from the same stock, they were of the same Species, and if otherwise, of two: this is the fact, which they endeavour to ascertain, by such indications as are to be found.
For it is to be further observed, that this fact being one which cannot be directly
Mark by which a
known, the consequence is, that the marks by which any Species of Animal or Plant is known, are not the very Differentia which constitutes that Species. Now, in the case of unorganized beings, these two coincide; the
marks by which a diamond, e. g. is distine percebes hot guished from other minerals, being the very Differentia. Differentia that constitutes the Species Dia
mond. And the same is the case in the Genera of organized beings likewise : the Linnæan Genus “felis,” e. g. (when considered as a Species, i. e. as falling under some more comprehensive class) is distinguished from others under the same Order, by those very
marks which constitute its Differentia. But in the Infimæ Species (according to the view of a Naturalist) of plants and animals, this, as has been said, is not the case; since here the Differentia which constitutes each Species includes in it a circumstance which cannot be directly ascertained (viz. the being sprung from the same stock), but which we conjecture from circumstances of resemblance; so that the marks by which a Species is known, are not in truth the whole of the Differentia itself, but indications of the existence of that Differentia ; viz. indications of descent from a common stock.*
There are few, and but a few, other Species to which the same observations will in a great degree apply: I mean
Hence it is that Species, in the case of organized beings, appears to be something real, and independent of our thoughts and language; and hence, naturally enough, the same notions have been often extended to the Genera also, and to Species of other things: so that men have an idea of each individual of every description truly belonging to some one Species and no other; and each Species in like manner to someone Genus; whether we happen to be right or not in the ones to which we refer them.
Few, if any indeed, in the present day avow and maintain this doctrine; but those who are not especially on their guard, are perpetually sliding into it unawares.
Nothing so much conduces to this as the transferred and secondary use of the words
»* “one and the same," “ identical,” Ambignity of &c. when it is not clearly perceived and care- same;" fully borne in mind, that they are employed
in which the Differentia which constitutes the Species, and
other homicide by circumstances of preparation, f:c., which are not in reality the Differentia, but indications of the Differentia; i. e. grounds for concluding that the malice did exist.
See Appendix, No. I. art. Same.