118 Species... the solution of the difficulty is to be found in the peculiar technical sense... of the
word “Species” when applied to organized Beings:^4 in which case it is always applied
(when we are speaking strictly, as naturalists) to individuals as are supposed to be
descended from a common stock, or which might have so descended; viz. which resem-
ble one another (to use M. Cuvier’s expression) as much as those of the same stock do.^5Whately expressly exempts species concepts in biology, then, from the stric-
tures of logical notions, and that, it must be observed, includes essential characters.
He notes[The fact of two organisms being the same species] being one which can seldom be
directly 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.^6So well prior to Darwin, and in a logical context, we find that the species of biology
and the species of logic are understood to be different concepts. However, Whately
expects there will be diagnostic “marks.”
A critical review of Whately’s logic entitled An Outline of a New System of Logic
was published the next year by George Bentham, who later became a noted botanist
and who was the nephew of, and was influenced by, his uncle Jeremy Bentham.^7
Bentham attacked Whately for not allowing privative classifications; oddly he
thought that was required by Aristotle, rather than by the later neo-Platonists.
However, Bentham made a crucial distinction that matches Aquinas’ material–
formal distinction. While allowing that the differentia of a (logical) species was
necessary to it, and that if the species is a universal, it is its essence,^8 that “without
which the subject would not be what it is said to be,”^9 he noted also that “the peculiar
sense in which naturalists make use of the word species... is very different from the
logical sense of the word,”^10 and he distinguished between the definition of a species
from its individuation,^11 in which “the only characteristic properties are those of
time and place, which must both be exhibited,” and essential definition applies only
in the first case.
Further, he notes that the object of specific description is to enable a learner to
recognize a species or fix the collective entity in his mind.^12 Description should thus
(^4) Elements Bk IV, ch. 5 §1. Terms like “organized beings,” “organic beings,” “natural beings,” and the
like refer to what we would now call “organisms.” Although the term “organism” had been devised in
the eighteenth century in French [Cheung 2006], the term was not introduced into English until Owen
discussed the kangaroo in 1834 [Owen 1834, 359], where he said “... if the introduction of new powers
into an organism necessarily requires a modification in its mode of development ...,” in the context of
which it is clear he means a being that has organs, or is organized.
(^5) Elements, 183. The quoted text is unchanged from the first to the ninth editions, but does not appear
in the Metropolitana volume.
(^6) Elements, 184f.
(^7) Bent ha m 1827. See Allen 2003 for discussion of his later work in botany.
(^8) Bentham, op. cit., 67.
(^9) Bentham, op. cit., 68.
(^10) Bentham, op. cit., 71.
(^11) Bentham, op. cit., 79.
(^12) Bentham, op. cit., 82.