For me the important thing to realize about Lacan is that he already had a whole career in Psychoanalysis before he started his own school though his writings. When Structuralism came along he realized that he could reinterpret Freud via structuralism and semiotics and thus started on his journey of pursuing his esoteric reinterpretation of Freud. Prior to that he was friends with Dali and other surrealists and had listened to Joyce read parts of Ulysses in Paris. So he was fairly far out as an intellectual already before all this work of reinterpretation of Freud. Also he took along with everyone else the Hegel course of Hyppolite. http://en.wikipedia.org/wiki/Jean_Hyppolite Due to the lack of substance in Freud’s work Lacan had to appeal to Hegel in order to have any depth in his critique of Freud. Lacan was also very influenced by Heidegger, and knew him personally. Since it is clear that Heidegger had appealed to Hegel’s phenomenology in Being and Time in order to get some distance from the Phenomenology of Husserl and because Heidegger says himself that Dasein is Geist, then you could read at some level Hegel and Heidegger as being the same despite Heidegger’s critiques of Hegel. Being and Time begins and ends with Hegel. Basically we can see Heidegger’s Being and Time as a thinking though Husserlian Phenomenology based on Hegel’s Phenomenology with an appeal to Aristotle’s kinds of knowledge as a foundation. If Episteme is present-at-hand theoretical knowledge then techne stands between Episteme and Phroness (Judgement). Thus the root of techne (as skill and arte) is phroness. So Phroness becomes the ready-to-hand circumspective concern. Techne exhibits totality while Episteme exhibits unity. But the root in Phroness which is attributed to Dasein. Technology then at the interface between Episteme and Phroness becomes the source of nihilism.
Lacan famously has three registers Symbolic, Real, Imaginary.
Episteme is Symbolic = Present-at-hand = Theory = Pure Being
Technology is Imaginary = Synthesis = Synthetic Apriori
Phroness is Real = Ready-to-hand = Circumspective Concern = Process Being
Dasein is in Hegel’s logic the first determination after the positing of the difference between Being and Nothing (explicitly Buddhist Emptiness). Heraclitian Flux is the synthesis of these two opposites and the first determination, i.e. next level thesis is Dasein.
So notice that Flux is Process Being. But the episteme gives us the difference between Being and Nothing as mixed in the flux. Thus the first determination is Dasein which is the German technical word for Existence used by Hegel. We might call it determinate being. So Dasein is the first determinate Being and thus we stand Hegel’s logic on end so that we can see that from determinate being comes the process being of Heraclitian flux in which as practice phronesis rules and then the episteme where we distinguish the distinction between Being and Emptiness (aka Nothing).
Heidegger says that Kant first had Imagination as an independent faculty in the first version of the Critique. Heidegger uses that as his gateway into the comprehension of Dasein. Dasein is the source of the projection of the synthetic apriori, which is the basis for the projection of the world.
So in a way we can see Eptisteme and Phronesis coming out of Techne as the production of synthetic wholes by craft.
When we distinguish between Symbolic, Imaginary and Real, the source is the Imaginary as the upwelling of a priori synthesis. What is symbolic is what we can understand in language that is conventional. What is real is the whole problem of True names in Plato’s Cratylus (i.e. what is really out there that is indicated by language but not captured by it).
As I have shown previously in various answers here on Quora the distinction between Rede, Verstehen, and Befindlichkeit which have their core of Sorge comes from Parmenides three ways:
Rede = Talk = Being = Symbolic = Present-at-hand = Episteme = Reason
Verstehen = Understanding = Appearance = Imaginary = Techne
Befindlichkeit = Discoveredness = Non-Being = Real = Phroneses = Experience
For Kant Understanding was the intersection between Reason and Experience. Reason on its own being caught up in the antinomies and unable to create anything but illusory metaphysical dogmas.
So from this we can see that there is in Lacan’s registers a homeomorphism between the insights that Being and Time is based on coming from Aristotle’s kinds of knowledge which goes all the way back to Parmenides three ways.
Once we have this fundamental philosophical framework in place then it is just a matter of using the approaches of semiotics and structuralism to read Freud anew through the lens of Hegel/Heidegger and to my mind that is precisely what Lacan did.
Zizek then comes back and treats the real Lacan as the later Lacan who he sees as identical to Hegel. And because Lacan’s work is derived from Hegel via Heidegger and the Hyppolite course then this is not only possible but it does little violence to Lacan and allows Zizek to systematize Lacan, and then use that as a basis for cultural critique as well as the critique of Derrida and Deleuze the last generation of famous French philosophers with the most depth.
Zizek’s own contribution is in the deconstruction of the Dialectic by producing the anti-dialectic of the Parallax Views and the Anagogoic Swerve between them that jumps over the discontinuities. This turns Hegel’s “System” into a Meta-system. Cf. Plotnitsky In the Shadow of Hegel and Complementarities.
Language is the Unconscious is the axiom of Lacan. Language is symbolic. But when read from beneath, i.e. from the point of view of techne and phronesis it turns into a meta-system, i.e. the deconstructed dual of the system. In that case we dive into the metaphorical basis of language and all that is implicit in those metaphors.
Bourdieu says that practice is a black box in Logic of Practice, but de Certu says that in our practice of language we can see something of what is happening inside practice, and that it is really a gray box because we use the practices of language in our stories about what happened in our practices. Stories are the interface between theory and practice, and stories are the imaginary use of language. So the narrative is the techne that mediates between the conceptual content of the story, and the tropes by which we tell the story and make it interesting linguistically.
The story of who we are hides and also displays everything about us through our semiotic practices. Lacan focuses on those. And what is surprising is how much Lacan’s work resembles that of Jung. Lacan worked with Jung in his residency. I see Lacan as a more sophisticated version of Jung even though as far as I know Lacan never mentions Jung explicitly. I think Jungian and Lacanian psychology is basically the same thing just using a different vocabulary for exploring the collective unconscious, i.e. the immersion in the Mitsein.