Our paper Hegel and Modern Topology fails to address the third great part of Hegel's Logic, the one dedicated to Concept (Begriff) and its unfolding into Idea. Here we give just a few vague hints on how the theory of Concept might be mirrored in formal logic, mathematics and science. Besides the direct interest to the interpretation of Hegel we believe that such investigations may be of interest to formal approaches to phenomenology and dialectics and shed light on the problem of formal models of consciousness.
Of course Hegel states explicitly that all such formalization will pertain to the strictly finite exterior domain of the understanding and as thus be inadequate. We reply that modern developments present us with formalisms which embody multidimensional, dynamic, modal, meta-theoretical and self-referential aspects which were not evident in mainstream 19th-century logic and science. So we will at least give it a try.
Our letimotiv is that a central role will be played by paraconsistent logics and with the phenomena of self-reference and the reflection of metatheoretical properties of a system within the system itself. Other key concepts will be self-similarity (Hegel in the Encyclopedia Logic writes of Object that it is a division into distinct beings each one of which is the totality), process philosophy and teleology.
Let us start with the subjective logic, with Hegel's initial discussion of the concept. The following analogy occurs to us: the universal is like a group $G$, the particular is like a particular representation of $G$ on some vector space $V$ and individuality is a a concrete totality (not, Hegel points out, an immediate concrete perceived individual) - and this can only be the monoidal category of all representatiins of $G$. For certain kinds of monoidal categories the group can be extracted from the category just as the category is generated from the group by considering its representations. This expresses the flowing forth between the universal, particular and individual.
Consider a category $C$. Then the consideration of the objects as objects corresponds to the Logic of Being wherein morphisms connecting objects appear a something both necessary and external. The Logic of Essence corresponds to considering morphisms as morphisms wherein their source and target objects are implicit. The identity morphism $id_A$ corresponds to the principle of identity, etc. The transitions might be understood in a 2-categorical context. In more advanced stages one considers diagrams into $C$. Finally the Logic of Concept corresponds to considering the whole category $C$. The logical aspect is the internal logic of the category $C$. In more advanced stages we can consider the presheaf category or sheaves over a site defined with $C$ and finally come to the category of categories or other considerations from homotopy theory. Maybe the particular can be seen to correspond to slice categories.
Hegel's critical treatment of judgment and inference is curious and in particular his distinction between judgment and proposition (which might be given some justification in modern type theory) and his introduction of ontological and subjective considerations into formal logic (cf. the apple is red, the apple is edible, the rose is a plant, the rose is beautiful). This might suggest a geometric interpretation in which we distinguish for instance between accidental properties of a space (relating to fiber bundles and connections), relational properties such a cobordism and more intrinsic properties such a homotopy and cohomology. Hegel's critique of formal logic recalls that of René Thom. Also we could examine topological accounts of teleology given by the concept of attractor (or even organizing center) in dynamical systems theory. There is also a passage of subjective Concept in the Enclyclopedia Logic which discusses a dualism in the formula "the individual is the universal" which suggests an alteration between the discrete or chaotic topologies. Either we trivially assert the individual is the individual or else were must assert and and indefinite number of assertions "the individual is not A, not B, not C, ...".
From the point of view of our Analyticity, Computability and the A Priori, there does not seem to be any clear reason to reject paraconsistent logic anymore than for rejecting a game because a player's piece can end up both on a white and a black square. Paraconsistent logic would seem to be a step towards formalizing Hegelian Reason (and, be it mentioned, furnishing a simple solution to the sorites paradox). Maybe an analysis of Fichte's Wissenschaftslehre might furnish a few clues: the ego posits the non-ego and we have $A \wedge \sim A$. From a Hegelian and dialetheistic perspective it seems reasonable to opt for the presentation of paraconsistent logic which discards the negative syllogism $A\vee B, \neg A \vdash B$ as disjunction introduction (or the disjunctive syllogism) seems to be given a more favorable view.
But reading the last sections of the Encyclopedia Logic we are lead to propose that the ultimate expression of the Hegelian Concept, the Idea, can only be a formal system which can reflect its own metatheoretical properties as well as of weaker systems and which can reflect its own proof theory, it can internalize the very process by which the external subject acquires metatheoretical knowledge in the system: the great example being due to Gödel or in general the classical semantic paradoxes of self-reference and truth. "This sentence is false" can be given a Hegelian interpretation. On the immediate level this expression is a subjective, spontaneous, free, immediate positing "I am freely positing that what I am saying is false" and thus in the aspect of its immediacy and positedness it is true, because it only expresses a free choice and finite determination as such (cf. omnis determinatio negatio). However by reflection and return-to-self this determination dissolves itself, its determination, its truth-claim is the seed of its own overcoming.
Can type theory and category theory encompass this kind of reflection? Are there categories or generalizations of categories whose internal logic is paraconsistent? Or do we need to break free from type restrictions and alter some fundamental logical assumptions to be able to encompass things like Girard's Paradox (or the Burali-Forti paradox)? Saying that $\vdash U: U$ is an expression of the Hegelian Idea. $U$ remains the same in all its particularizations.
The Hegelian Idea is a kind of dynamic synthesis between Sextus' Pyrrhonian dialectics and Kantian criticism - but perhaps even closer to neoplatonic dialectics. Dialectics as the life of the nous which unfolds, divides itself, circulates through itself then reunites and integrates itself within itself.

