Islands of Coherence (Metaphor)
In describing discursive formations, Foucault provides a metaphor for what he does not advocate we study:
Such an analysis would not try to isolate small islands of coherence in order to describe their internal structure; it would not try to suspect and to reveal latent conflicts; it would study forms of division. Or again: instead of reconstituting chains of inference (as one often does in the history of the sciences or of philosophy), instead of drawing up tables of differences (as the linguists do), it would describe systems of dispersion. (41)
Here, the “island of coherence” would suggest that a statement is completely independent, and that its meaning can be found all by itself. Instead, Foucault is interested in the “exteriority” of the statement, which means how forces beyond the statement governed the shape the statement took. To extend the metaphor, Foucault is more interested in the ocean than in the island.
Grids of Specification (Metaphor)
In Chapter 3 of Part 2, Foucault outlines how to describing the formation of objects. The final step involves showing how different objects are related to one another within a discourse:
We must analyze the grids of specification: these are the systems according to which the different ‘kinds of madness’ are divided, contrasted, related, regrouped, classified, derived from one another as objects of psychiatric discourse. (46)
Here, “grid” is a metaphor for a system of organization. It is not that objects can actually be mapped like coordinates on a graph. But it is important to map out, conceptually, how objects are close to or a part of other concepts. The “grid” is Foucault’s term for a description of these relations.
Sciences as Organisms (Simile)
In his opening discussion of “unity” in discourse, Foucault goes through a list of possible ways to unify documents, each of which he rejects. One of these rejected strategies is to use disciplines to organize discourse into different but ultimately comprehensive fields of study like economics or biology. He explains how others might approach this task:
In ‘sciences’ like economics or biology, which are so controversial in character, so open to philosophical or ethical options, so exposed in certain cases to political manipulation, it is legitimate in the first instance to suppose that a certain thematic is capable of linking, and animating a group of discourses, like an organism with its own needs, its own internal force, and its own capacity for survival. (39)
Here, a discipline acts like an organism, controlling and regulating all its documents in a closed circuit. In contrast, Foucault thinks documents cannot be so neatly bounded into a single organism. It is instead necessary to see how statements cut across different disciplines or, to extend the simile, across different bodies. Here, statements would be more like the air that different disciplines breathe rather than the blood that circulates exclusively inside each one.
Objects as Words (Simile)
Toward the end of his discussion of object formation in discourse, Foucault warns against a few false steps one might take in such an analysis. Of particular importance is not thinking that objects have a referent in the world prior to discourse:
It would be quite wrong to see discourse as a place where previously established objects are laid one after another like words on a page. (47)
When we put words on a page, we already have a concept to which they refer. When I write down, “I see a tree,” for instance, there is already an “I” and a “tree” that exist before being written down. In contrast, Foucault thinks the formation of objects in discourse often creates the very thing it describes. The phenomenon named by an object is produced by being named.
