What is dialectic?

I wanted to elaborate what I was beginning to get at in my post on Derrida and dialectic below. But before I do that, I have to return to the issue of dialectic itself.
What is dialectic? I have two posts below on dialectic and language that were drafts of a presentation that I made to a class on dialectic, and, after seeing how those presentations ended up, I realize it might be better to explain the dialectic in a different way.
The reflections below were motivated by a reading of dialectic that Heidegger makes in "Hegel and the Greeks:" dialectic is the process whereby thought goes through the holding-together and gathering that takes place in language, (in Greek, dia-legein) and comes to appearance that way (so that the whole is, in Greek, dia-leges-thai).
But Heidegger offers a seemingly conflicting reading of dialectic in his early course on the Phenomenology of Spirit: there, dialectic is described as the moving between the speculative and propositional sentence. It is this latter explanation that was a bit clearer to my class, so I'll explain it that way. Hopefully, though, afterwards you can see perhaps how these two explanations are not conflicting. And hopefully we will be led to a position where we can explain a "Derridian dialectic" in a later post.
So, again, what is dialectic? It seems easy to characterize at first, but after a while, you can see that no one is really clear about what it is. Gadamer makes this clear in his book on dialectic (Hegel's Dialectic: Five Hermeneutical Studies--I recommend it). Dialectic for Hegel is not just a mode of allowing thoughts to address their contradictions, like in ancient or medieval philosophy (in saying it is "not just" these, of course I am not indicating that something of the spirit of Hegel is not in them and vice versa.) Nor is it the mere play of falsity and appearance that Kant makes it out to be in his Critique of Pure Reason, though this influences heavily the sense of "phenomenology" that we find in the Phenomenology of Spirit. Hegel's sense of dialectic is more restricted. And yet, because of this restriction, it is also the most vague: divorcing himself from the tradition of dialectic to specify a really precise concept of what it does ends up making it hard to specify without going through the entire Hegelian philosophy. In fact, this is its point: it is the Hegelian philosophy insofar as this philosophy is the interrogation of negativity and its result in spirit. One cannot extract dialectic from the interrogation of which it is a constitutive movement.
But if we understand this, we can perhaps get a little more specific as to what it is, making reference to Hegel but also trying to wrest dialectic from out of Hegel. Let's begin: dialectic is not a force or power, but a result of a force or power--specifically, "the tremendous labor of the negative." That said, dialectic as a result is always being again taken up by this negative labor, so that it can never be said to merely be the sheer content and residue that this negativity deals with. That said, dialectic cannot be a form or method that experience or spirit through the labor of the negative gets processed through--Kojeve is good in showing you that it is not the form of the labor of the negative.
So, dialectic seems to merely be what we sait it was: a "constitutive movement" of a movement (of negativity and spirit) that is larger than it. This gets us nowhere. Or does it?
Understanding dialectic as a result that is not a result, that is, not a content nor a form, allows us to account for three binaries that the dialectic itself introduces in the texts of Hegel:
Immediacy/mediation
Indeterminate/determinate
Universal/particular
The first deals with how dialectic is a result or not, the second with how it is a content or not, the third with how it is a form or not.

Benjamin, German Idealism, and dialectic

Benjamin often speaks of dialectic, the logical movement powerfully confronted by German Idealism, in favorable terms: calling someone a dialectician for Benjamin is a compliment. He says of the work of Karl Kraus that it deserves respect because of its dialectical character:

"...the fact that this man is one of the very few who have a vision of freedom and can further it only by assuming the role of chief prosecutor is a paradox that most purely reveals the dialectic at work."
-"Karl Kraus (Fragment)," Selected Writings, volume 2, part 1.

But if dialectic is to be sought after as an amazingly forceful way of thinking, why would Benjamin say of German Idealists that they have a view of the world like those of Jünger who longed for a return to the militarization of World War I?

...as far as anyone could see over the edge of the trench, the surroundings had become the terrain of German Idealism: every shell crater had become a problem, every wire entanglement an antinomy, every barb a definition, every explosion a thesis; by day the sky was the cosmic interior of the steel helmet, and at night the moral law above.
-"Theories of German Fascism," Selected Writings, volume 2, part 1.

Because dialectic is able to be lifted (cf. my post on Derrida, below, as well as the writings of Althusser on Marx's "overturning" of Hegel in For Marx) from the world of German Idealists.
Dialectic is an amazing force precisely because it holds things in indeterminate (immediate) contradiction through its effort to determine (mediate) them. This holding together, this arresting and immobilizing that takes place through the negative work of dialectic (the work of the dialectic to not arrest--that is, the work of the dialectic to mediate, to mobilize, or to bring forth total-mobilization) is the most forceful element of dialectic. Why? It (that is, this holding in indeterminate, immediate contradiction) does not lend itself without distortion (that is, without determination or mediation) to the objectification of capitalism, fascism, any of the organizing political-economic structures that reduce the world to what Heidegger rightly calls (also against Jünger) a "world picture:" a world of images fully determined by technology. Given this, one needs to think of how Heidegger in his critique of the objectified world-picture really thinks dialectic too much as a process that brings this picture about, and does not think enough that dialectic's suspension and overturning of objectification in its very process of objectifying is precisely the power of it--this would be Benjamin's contention if he were to confront many of Heidegger's texts dealing with Hegel (which includes Being and Time--in fact one could argue Being and Time is Heidegger's most expansive meditation on Hegel). In other words, dialectic, while it renders everything into a world of images fully determined by technology, can also bring forth a world of images that are indeterminate with respect to technology, that use technology to bring forth these indeterminate images or immobilizations--it is not necessary to retreat from the objectification and images wholly, as Heidegger seems to think.
The world of Geman Idealism is precisley not the world of dialectic, then, for Benjamin: however (dialectically, of course) it is that world in that it utilizes its power of determination and resolving (mediation) most. German Idealism's relationship to the dialectic therefore cannot be simply overcome and the dialectic extracted from it, just like its landscape (the First World War) cannot be merely passed by or simply improved by the view that blasted it apart. In being lifted (relever) from them, dialectic is always stolen--it belongs still in a sense to those who originally owned it.

From Benjamin

Benjamin on Karl Kraus:

...His entire fire-eating, sword-swallowing philological scrutiny of the newspapers is actually concerned not with language but with justice... His linguistic and ethical quibbling is not a form of self-righteousness; it belongs to the truly desperate justice of a proceeding in which words and things concoct the most implausible alibi simply to save their own skin, and must be incessantly refuted by the evidence of one's eyes or straightforward calculation.
-Selected Writings, Volume 2, Part 1, 195-6.