I think people really like charts and graphs, which is why my entry on narrative was the surprise hit of the summer with the thread picked up by both Steve and Dennis. We are artists and love to think visually. To answer Dennis' question..I think I'll say "yes"..discourse is both a cloud of condensation, and precipitation...that's sort of the nature of clouds after all. But I also have a great wikipedia passage to crib and some images that may shed some light on just what this whole "discourse" deal is all about. The irony gods will appreciate this discourse on discourse. I'll get to nature and its obscenities later.
According to Foucault, discourse can't be reduced to an ideological reflexion, it is to be thought as itself a Kampfplatz or battlefield. Against Kant's conception, Foucault argues that truth is not the objective bounty that the winners can take; truth is not an absolute, it is on the contrary produced in this battle with strategic aims. This conception of truth may be related to Althusser's theory on the "epistemological break" between science and ideology (the "epistemological break" is not an event, but a process; "science" always has to fight for its truth against ideology, which keeps coming back). Since knowledge and power are intrinsically related, according to Foucault, he can thus say that power relations are immanent to discourses, whereas in the classic marxist conception, the discourse is conceived as the ideological superstructure - which, of course, interacts with the base, as Marx wrote, but this does not impede the power relations being essentially located in the economic base, afterward reflected in the superstructure.