sense of “normal.” (Thompson is here developing an idea of Anscombe’s: “When we call something an acorn, we look to a wider context than can be seen in the acorn itself. Oaks come from acorns, acorns come from oaks; an acorn is thus as such generative (of an oak) whether or not it does generate an oak.”32)
One might suppose that the required non-statistical sense of normality is a normative one, and that in saying that the domestic cat (normally) has four legs we mean something like “domestic cats ought to have four legs.” Thompson thinks this is in a sense on the right track, but it fails to distinguish what we mean when we say that domestic cats ought to have four legs from what we mean when we say, for example, that mosquitoes ought to be exterminated; why does the first judgment allow us to treat having four legs as part of feline normality, while the second obviously does not allow us to treat being exterminated as part of mosquito normality? The sense in which a domestic cat “ought” to have four legs is that it needs four legs if it is to be a normal instance of its species; but this simply brings us back to the very notion of species normality we were trying to define. Nor is it of any help to gloss cats’ normally having four legs in terms of, say, their developing four legs if nothing interferes or if nothing goes wrong, because what counts as “interfering” or “going wrong” cannot be specified independently of species normality; after all, a cat will die in infancy unless its mother in some sense “interferes” by nursing it, but we would not therefore add dying in infancy to the list of natural-historical features of the domestic cat.
Yet despite our inability to give any reductive analysis of natural-historical judgments in terms of other kinds of judgments, we all know perfectly well how to use them. Thompson suggests that this is because the form of a natural-historical judgment like “The domestic cat has four legs” is simply one of the basic logical forms of judgment, as basic as the singular judgment “This domestic cat has four legs” and the universal judgment “All domestic cats have four legs.” The reason that contemporary philosophers generally find it “scandalous” that Hegel’s system of logical categories “finds a place for the concept life in it,”
32 Anscombe, The Collected Philosophical Papers of G. E. M. Anscombe, Volume Three: Ethics, Religion and Politics (Oxford: Blackwell, 1981), p. 87.
R. T. Long – Wittgenstein, Praxeology, and Frege’s Three Realms – p. 22