In this article, we are firstly going to reread Lacan’s famous formula of the subject. This formula, “A signifier represents the subject for another signifier”, remains in some respects opaque to say the least. Lacan, however, will not cease to repeat it throughout his teaching. Secondly, we will read a passage in the Preface to the Phenomenology of the Spirit in which Hegel returns to the dialectic between subject and substance. In these readings, we will outline that defining the subject comes, for both authors, together with its difference from what the subject is seemingly opposed to: structure, substance, Other. This difference is central and accentuates above all an impossible relation. Nonetheless, this impossible relation does not remain silent. Instead of being simply a relation between two terms – which would amount to their difference being only something theoretical (for thought) – it is rather that, in struggling with this impossible relation, both terms become actual (wirklich) in themselves. For Lacan, the relation between subject and Other fails, which makes it ‘not to stop (not) being written’. For Hegel, the relation between subject and substance is contradictory, but this contradiction is understood as the subject itself, which is nothing but substance’s own restlessness becoming ‘in itself’.
In order to define the stakes properly, we will pass through Descartes and (Hegel’s reading of) Spinoza, whose influence on Lacan and Hegel should not be underestimated. The first part of the article investigates how Lacan’s structural formula is an attempt to write the Cartesian subject without rendering it into a thinking substance. Descartes does understand the subject as a thinking substance from the extended substance, or shortly, as thought separated from being (which has become famous as the Cartesian dualism). The second part treats how the problems with this dualism – and with Spinoza’s monism which is to be the response to these – lead Hegel to write his own topology of the subject in relation to substance. The third part is an analysis of a joke during Stalinism which helps to illustrate the impossible relation between subject and Other (Lacan) or – which we read as overlapping – Hegel’s dialectics between subject and substance.