“In any given culture at any given moment,” Foucault wrote in The Order of Things, “there is always only one episteme that defines the conditions of possibility of all knowledge, whether expressed in a theory or silently invested in a practice.”12 An episteme is a set of rules telling people in that culture (I would say society) how to gain knowledge about their world and put that knowledge to use. By the same token, an episteme is a set of constraints on what people can possibly know. Must we take Foucault’s epistemes as he found them? I think not. The first two he evoked brilliantly. The third is, in my view, misrepresented. A fourth he failed to identify at all.
Foucault has framed the Renaissance episteme as a world of “things visible and invisible,” among which its inhabitants routinely made associations.13 Knowledge is the methodical accumulation of similarities. Metaphor, analogy and repetition make the dissemination of knowledge no less methodical. Only in this epistemic space of inexhaustible resemblances was it possible for Renaissance humanists to situate themselves in relation to the ancients, find an alternative to cyclical or apocalyptic interpretations of the past and undermine the temporal unity and moral authority of medieval universalism.14
Resemblance was, however, not only a way for Renaissance minds to turn their experience of the world into knowledge about the world. Adjacency plays its part; things “come sufficiently close to one another to be in juxtaposition.” Yet we should not think of adjacency as a geometric relation. Things are adjacent when “their edges touch, their fringes intermingle, the extremity of the one also denotes the beginning of the other.”15 Even less does it imply that cause is an abstract relation between things. Instead adjacency links proximity and familarity, valorizes what is convenient and customary in everyday life, smooths out the discontinuities that odd resemblances might suggest and produces local knowledge.
On Foucault’s account, the classical episteme no longer limits thinking to similarities. Differences come to the fore because each thing has a nature uniquely its own. Yet things do not differ in every ascertainable property, and they can be sorted by the kinds of properties they have in common with some other things. Moreover, the relations among things can also be sorted by what they have in common, the ways in which they are identical. Even the relation between properties and relations has fixed properties. What we can know depends on how we represent the relation of things in relation. The Archaeology of Knowledge uses the term representation in a spare and not very helpful way: representations are “signifying elements referring to contents.”16 Throughout The Order of Things, the text associates representation and order.
Order lends itself to formal expression, most obviously as geometry. For the classical mind, nature has an order that we cannot appreciate directly but nevertheless can make sense of by ordering things and their relations. Yet classical order is neither order for its own sake nor order for practical purposes. It is an attempt to explain how the world works in the most general terms, on the assumption that the great classical thinkers of antiquity had the same ambition.
Foucault’s understanding of the modern episteme is harder to convey. “History displaces order as the fundamental mode of being of empiricities.” History is not simply “a compilation of factual successions or sequences”; it “givesplace to analogical organic structures, just as Order opened the way to successive identities and differences.” In the classical episteme, identities and differences succeeded each other as spatially imagined wholes. The modern episteme took analogy out of the Renaissance world of appearances and deployed it in time. By invoking development, evolution and dialectical reasoning, modern thinkers could bring together “totalities of elements without the slightest visible identity.”17
The “empiricities” of history are the objects and events to which modern sciences applies its analytic procedures—an “analytic of fini- tude”18 (see Dillon in this volume). Positivist methodology starts by isolating these things and measuring their properties. Only then can observers make causal inferences about the relations of things. Reduction displaces representation in the methodical pursuit of knowledge. When things are related with enough complexity to resist analysis, we often call these complex things organisms or, more abstractly, systems, to which we impute structure and make inferences about their functions. Modern physics and biology exemplify the possible trajectories of modern science.
The modern episteme developed a discontinuity, first manifest in the theory of evolution and on full display by 1900. Yet Foucault seems never to have acknowledged it. Many other scholars have paid it a great deal of attention as the modernist movement in arts and letters. I believe Foucault’s resistance on this point stems from his close attention to the preoccupation with organisms and their functioning in the early nineteenth century. Foucault may not have seen a discontinuity develop later in the century because of its functional orientation. Or he may have read subsequent modernist functionalism, with its emphasis on adaptive differentiation, back into earlier investigations of organisms and the totality of their functional relations.
In any event, modernism issued science a methodological mandate: get below the surface of things, and not, as modern science demands, below some thing to the things beneath. Thus motivated, modernists instituted a new set of sciences: political science, sociology, psychology and anthropology. Insofar as modernist thought and the social sciences reaffirm “human finitude” and thus “the strange figure of knowledge called man,” they remain, for Foucault, within the confines of the modern episteme. Thus, the imminent “disappearance of man” would mark the appearance of an entirely new post-modern episteme, and not merely a post-modernist moment.
For each episteme, there is a before and after, a pair of discontinuities, none of them easily identified. Foucault found these discontinuities in different “domains” of knowledge. Domain (domaine) is a conveniently loose metaphor, which we find Foucault having deployed in many contexts. Domains of knowledge are “discursive formations” or “unities”—Foucault used both formulations repeatedly. Treating such unities methodically, “what we discover is neither a configuration, nor a form, but a group of rules that are immanent in a practice.”19
Do domains of knowledge, each defined by its own ensemble of rules, have common features when considered together? Foucault inveighed against “totalitarian periodization.”20 Yet discontinuities within discursive formations must have common features—a “totality” of cross-domain continuities—if they are to constitute an epistemic rupture. Foucault contradicted himself on this issue.21 I suspect he was unsure as to whether some ensemble of rules unified the rules constituting each episteme and then at some point these meta-rules changed, or each ensemble of domain rules more or less paralleled the others in reaching a breaking point and losing their coherence. Here’s how Foucault finessed the issue in The Archaeology of Knowledge:
The idea of a single break suddenly, at a given moment, dividing all discursive formations, interrupting them in a single moment and reconstituting them in accordance with the same rules—such an idea cannot be sustained. The contemporaneity of several transformations does not mean their exact chronological coincidence: each transformation may have its own particular index of temporal “viscosity”.22