Foucault’s preface to The Order of Things (1966), translated by Routledge (anonymously!), referring to Borges’s story “The Analytical Language of John Wilkins”:
This book ﬁrst arose out of a passage in Borges, out of the laughter that shattered, as I read the passage, all the familiar landmarks of my thought — our thought, the thought that bears the stamp of our age and our geography — breaking up all the ordered surfaces and all the planes with which we are accustomed to tame the wild profusion of existing things, and continuing long afterwards to disturb and threaten with collapse our age-old distinction between the Same and the Other. This passage quotes a “certain Chinese encyclopedia” in which it is written that “animals are divided into: (a) belonging to the Emperor, (b) embalmed, (c) tame, (d) sucking pigs, (e) sirens, (f) fabulous, (g) stray dogs, (h) included in the present classiﬁcation, (i) frenzied, (j) innumerable, (k) drawn with a very ﬁne camelhair brush, (l) et cetera, (m) having just broken the water pitcher, (n) that from a long way off look like flies”. In the wonderment of this taxonomy, the thing we apprehend in one great leap, the thing that, by means of the fable, is demonstrated as the exotic charm of another system of thought, is the limitation of our own, the stark impossibility of thinking that.
But what is it impossible to think, and what kind of impossibility are we faced with here? Each of these strange categories can be assigned a precise meaning and a demonstrable content; some of them do certainly involve fantastic entities — fabulous animals or sirens — but, precisely because it puts them into categories of their own, the Chinese encyclopedia localizes their powers of contagion; it distinguishes carefully between the very real animals (those that are frenzied or have just broken the water pitcher) and those that reside solely in the realm of imagination. The possibility of dangerous mixtures has been exorcized, heraldry and fable have been relegated to their own exalted peaks: no inconceivable amphibious maidens, no clawed wings, no disgusting, squamous epidermis, none of those polymorphous and demoniacal faces, no creatures breathing ﬁre. The quality of monstrosity here does not affect any real body, nor does it produce modiﬁcations of any kind in the bestiary of the imagination; it does not lurk in the depths of any strange power. It would not even be present at all in this classiﬁcation had it not insinuated itself into the empty space, the interstitial blanks separating all these entities from one another. It is not the “fabulous” animals that are impossible, since they are designated as such, but the narrowness of the distance separating them from (and juxtaposing them to) the stray dogs, or the animals that from a long way off look like ﬂies. What transgresses the boundaries of all imagination, of all possible thought, is simply that alphabetical series (a, b, c, d) which links each of those categories to all the others.