A New Exploration of Hegel’s Dialectics: III. The Three-Dimensional Structure gathers, concentrates, and then deliberately disperses the accumulated tensions of Hegel’s system by insisting that what most commentaries treat as parallel tracks—logic, epistemology, ontology—are not three separate rails but the self-differentiating planes of a single medium that folds back upon itself.
Deng Xiaomang names this medium the Hegelian dialectic as a unity of three, and yet he begins by worrying whether this unity is already compromised the moment it is named, since in the internal architecture of Hegel’s Science of Logic ontology appears both as replaced (by the Objective Logic) and as re-unfolded (within the Subjective Logic), such that the very gesture of “including” ontology threatens to deform the tripartite unity into a fourfold that can only be re-gathered if “the dialectical method” itself is understood not as an external technique but as the integrative factor resident within each term. In Deng’s telling, the dialectic is not a fourth coordinate hovering over logic, epistemology, and ontology; it is the unifying movement by which each domain shows itself as an event of the others, the factor doing the uniting in the unity of the three. The book’s preface frames the wager with disarming clarity and calculated risk: the “unity of four” is, when properly understood from the center of Hegel’s logical system, nothing but the tripartite unity of dialectical understanding, because what looks like a fourth is simply the methodological nerve that each of the other three already bears within itself.
This decision to think the dialectic as a unity that is more than the sum of three academic provinces brings with it an equally polemical historical claim. Deng aligns Hegel’s appropriation of the Greek logos—not merely as grammar or inference, but as the very passage from speech to law to substance—with the thesis that logic in its speculative sense is already laden with ontological and epistemological significance. Aristotle’s logic, read in this Heraclitean key, never was a sterile calculus of forms; it was an eidetic discourse in which form meant the essence of the thing. Hegel radicalizes this line by transposing logos into dialectic: the self-moving process that contains self-negation and contradiction within itself and thereby unifies logic, knowing, and being in their very motion. Deng uses this philological-conceptual archaeology to justify, but also to problematize, his claim that Hegel’s “three” can be seen neither as a neat taxonomy nor as a ladder of epistemic stages; it is the internal reciprocity by which logic becomes epistemology by transcending language, epistemology becomes ontology by transcending its own theoreticality, and ontology becomes logic by striving to articulate the essence of being as thinkability.
From this vantage, the opening movement of the volume returns to a front that Hegel’s readers alternately take for granted or dismiss as mere prolegomena: the confrontation with formal logic. Deng’s reconstruction refuses both easy apologetics and easy caricature. He sifts Hegel’s ambivalence—his genuine praise for formal logic’s power to clear the head and school abstraction, and his equally genuine critique of its poverty as a set of externally applied rules—into a stringent requirement: formal logic fails not because it is too formal but because it is not formal enough. The problem, Deng insists with Hegel, is not emptiness as such but the incomplete, fragmented character of forms that never posit their own content. What Hegel calls the absolute form is precisely a form that is its own content, the living unity of determinacies that organize themselves as an Idea—a standpoint whose method (the “highest form of the idea” in the Aristotelian sense) gathers the many scattered logical functions into an organic, self-moving whole. Deng’s account here is less a rehearsal than a redeployment: the “formal” is redeemed only when it becomes speculative, which is to say when the syllogism ceases to be a mechanical stringing-together of terms and becomes the movement of the concept through which objectivity discloses itself.
By recoding Hegel’s critique of Kant’s transcendental logic as the decisive turning-point, Deng shows that the alleged alternatives—logic as arbitrary instrument versus logic as fatalistic necessity—are both residues of a deeper failure to see that logical form must actively generate its content. Kant, on this reading, glimpsed the objectivity of categories and the synthetic unity of apperception but—taking logic as a prefabricated tool—never allowed the categories to exhibit their own self-movement. Hegel’s demand that “the finite determinateness in which the form is as ‘I’ must be shed” becomes the rubric under which logic as absolute form can be the substantial, self-positing content, the “spirit” that is the vital concrete unity of the determinations it holds together. The result is not a dismissal of the law of identity and the law of non-contradiction but their deepening: dialectical contradiction materializes as the concretion of formal contradiction, not its violation. Deng’s extended engagements—whether with analytical quibbles about the copula (“is” of attribution versus “is” of identity) or with attempts to deflate dialectical self-reference—serve this single end: to show that what looks like paradox from the standpoint of a logic of understanding is the inevitable articulation of essence once a judgment seeks to say what a thing is rather than what properties it has.
What distinguishes Deng’s exposition, however, is not precision alone but his insistence that Hegel’s speculative logic is inseparable from a corresponding transformation in our grasp of experience. Drawing on Hegel’s own tactical “defamiliarization,” Deng argues that the Logic is not a replacement for experience by calculus but experience raised into thought: a lived, reflexive apprenticeship in which concepts are not mute operators but powers felt in their self-negation, their passage into otherness and back. Hence the insistence that the Logic’s forms cannot be stabilized by spatial figures, algebraic symbols, or a calculus without losing the very thing those crutches were meant to catch; the concept must be encountered as a living immediacy that mediates itself. If this seems to echo phenomenological and hermeneutic intuitions, Deng’s point is more stringent: speculative logic is the discipline by which spirit becomes conscious of the logical nature that already animates it, extracting from the instinctive weave of categories a freedom that is no longer blind. The Logic is thus the pedagogy of experience—not in the empiricist sense, but as the acquisition of a plastic receptivity fit for the movement of the concept.
Consequently, the first axis of the book’s “three-dimensional” field—logic—arrives at its epistemological resonance without leaving its own terrain. Deng’s central claim here is that dialectical logic is itself a learning-experience of the object: not an external organ that mediates knowing but the very truth of knowing as self-mediating movement. Knowing unfolds as a development of logical form, and this development is already the growth of cognition from abstract immediacy into concrete comprehension. Hegel’s language of the concept as free actuality—the principle of all life—is not rhetorical flourish; it names the concrete universality in which logical forms are the living spirit of the actual, the condition under which “truth” is no longer a matter of the correspondence of thought to being but of being’s conformity to the concept. On this inverted epistemological map, error attaches to being that does not yet rise to the concept, whereas the pure or concrete concept is ipso facto true. Deng’s recasting of this “agreement of dialectical logic with epistemology” quietly undoes the habitual division of labor: epistemology is not a second-order theory about methods of access; it is logic in its self-producing passage into truth.
Yet the second axis—epistemology in the ordinary sense—does not disappear; it is transformed. Deng’s chapters on the implications of dialectical reason and the dialectical development of knowing never settle for a generic gradient from ignorance to knowledge. They instead track the way acts of knowing internalize their own failure as the motor of advance, how each purportedly adequate stance negates itself by revealing the insufficiency of its determinacy, and how “reflection” becomes both the structure of conceptual movement and the lived character of experience. What results is not a staged march through familiar stations but an account of how the form of inference (syllogism) grows thick with content and how even those “syllogisms of necessity” that formal logic exposes as circular regain epistemic value when transposed into the dialectical medium in which necessity is nothing but the self-unfolding of the concept. In this sense, epistemology is the name of logic’s self-feeling, the phenomenology latent within speculative science.
The third axis—ontology—enters, in Deng’s reconstruction, not as the belated application of prior results but as a conversion of the very standpoint of the Logic. Hegel’s doctrine of subject-substance is approached here neither as a slogan nor as a metaphysical hyphen; Deng demands to know on what grounds conceptual substance claims to be the substance of everything, and how the conceptual subject becomes substance in its own right. To answer, he pivots both backward and forward: backward, to the Phenomenology of Spirit, where the dialectic of consciousness is said to establish “objective thought” as the absolute content; forward, to the Philosophy of Nature, where the passage from mechanism through chemism to organism traces an ontological pathway by which objectivity shows itself as the process of the subject’s becoming objective. The point, characteristically, is double-edged. On the one hand, Hegel’s proof that the true must be grasped as both substance and subject drives beyond Spinoza by injecting freedom and self-movement into the heart of being. On the other, Deng takes seriously Marx’s counterclaim that Hegel’s absolute spirit is a metaphysically disguised human, a conceptualization that risks converting living practice into an abstract “universal I” whose positing power elevates knowing into being. The resulting tension is not resolved by fiat; it is the pressure that makes the ontology think.
Deng’s detailed analysis of “substance as ontological ground” and “the subject as substance coming into being” turns this pressure into method. When Hegel’s Doctrine of Concept moves from subjective concept to objectivity, the ensuing analysis of mechanism, chemism, and organism is not a zoology of categories but the disclosure that objectivity, even in its “spiritual” mechanics, retains the mark of externality the concept must sublate. The ontological proof, in this light, is not an argument in the courtroom of the understanding but the concept’s self-transition into externality as the site where it recognizes itself. Deng uses this to stage, rather than to suppress, the divergence between a conceptual ontology (in which the concept universalizes itself as the being of beings) and a practical ontology (in which the subject’s sensuous, purposive activity is primary). The dialectical core Hegel bequeaths—self-negation, reflection, mediated immediacy—operates in both, but the direction of priority is inverted: for Hegel, practice is a moment of concept; for Marx, consciousness is a moment of practice. Deng’s exposition neither collapses nor canonizes this distinction; it mines it to clarify what is at stake when we say that ontology “agrees” with logic.
The culminating claim of the volume—the agreement of dialectical ontology with logic—thus names less a correspondence thesis than a structural identity: subject and object are logically unified in practical activity, and it is through practice that logic realizes itself as history. Deng’s discussion of modern semantic reconstructions of Hegel (notably Fulda), while acknowledging their analytic finesse, rebukes their tendency to extract the logical form from the unity of thinking and being; when dialectic is reduced to a general theory of meaning, what remains is an abstract framework divorced from the object, an “unchanging logic” without use. Against this evacuation, Deng re-inscribes practice—not as an extra-logical supplement but as the inmost pulse of dialectical logic—so that the so-called “syllogism of action” can be seen as the hinge on which theory becomes a material force by “grasping the root of things,” that is, the person itself in its social-historical determinacy. Logic realizes itself as history where it is enacted, and history becomes intelligible as logic where its movement is read as the concept’s own.
Here, then, the volume’s Marxist horizon is not an addendum; it is the proof-case of the three-dimensional thesis. The principle of the agreement of logic with history, Deng argues, is the philosophical source of inspiration for historical materialism—not because Hegel prefigures Marx’s positions, but because Hegel’s dialectic, in discovering the unity of the three, produces the only standpoint from which the mutual transformation of thought and life, cognition and production, freedom and necessity, can be articulated without remainder. To say that logic becomes epistemology as it transcends mere language is to say that knowing is the form of life by which the concept lives; to say that epistemology becomes ontology as it transcends its theoreticality is to say that being is not a mute substrate but a process that thinks; to say that ontology becomes logic is to say that the essence of being is to be intelligible as self-movement. Deng’s bridge to Marxism is built not by analogy but by pressure: the dialectic in its Hegelian exposition pushes itself until its speculative identity with practice either becomes legible or breaks—and Deng wants us to see both the legibility and the risk.
One consequence of pursuing this pressure consistently is that Deng’s “book description” refuses the comfort of a linear précis. Instead, he reenacts Hegel’s own style of exposition—Darstellung as dialectical choreography—by allowing each surface to flip into depth. The terrain of formal logic reappears as the threshold of speculative life; the chapter on experience turns out to be the meta-logic of reception without which no concept could move; the excursus on semantic vagueness yields the result that what appears “fuzzy” from the standpoint of everyday sense is precise from the standpoint of a concept observed in motion. Even the famous Hegelian provocations (“being is nothing,” “determination is negation”) are recast not as linguistic games but as the only expressions adequate to a content that will not be held still. Deng says this without adornment: the Logic is the science of absolute form, in which the living content is not in the forms but is the self-movement of form itself.
The pedagogical posture that follows from this is exacting. To read Hegel with Deng is to undergo a disciplining of attention in which plastic receptivity becomes the condition of understanding. One cannot import an alien “method” into the Logic; the method is the Logic’s final vista because only at that height can one see that every prior determination was already a moment of the absolute form. This is why Deng’s narrative oscillates between close logical reconstruction and staged encounters with misreadings—analytic, formalist, or historicist. What those misreadings share is a failure to let form posit content—or, more pointedly, a refusal to let content show itself as only intelligible in the absolute form. Deng’s response is not to lecture but to perform the conversion: formal rules are retained, yes, but as lower-level rules serving lower-level ends, subordinated within a movement that concretizes them and thereby liberates them from their own narrowness.
If the volume’s argumentative center is the triune unity, its rhetorical center is a set of asymmetries Deng refuses to flatten. He affirms Hegel’s anti-Kantian certainty that “absolute knowing” brings the movement of consciousness to the standpoint of science, yet he exposes the speculative assertiveness that rides along with that certainty and shows why Marx could diagnose in Hegel a transposition of human sensuous practice into conceptual sovereignty. He draws from Aristotle to certify the ancient unity of logic and being, yet he insists that only a logic that internalizes contradiction can rise to the level of modern science’s dynamism. He adapts semantic analysis to clarify dialectical terms, yet he warns that meaning-modification without subject-object unity is a form without world. These asymmetries are not defects; they are Deng’s way of preserving the initiative of the dialectic itself.
As the final installment of a trilogy, the book does more than complete an arc; it tests the series’ own premise by forcing the reader to decide whether the “unity of three” is a conceptual economy or a living structure. Because Deng continuously juxtaposes Hegel’s speculative logic with the “practical ontology” emphasized by Marx, the reader must learn to inhabit both optics: to see how the concept universalizes itself as being without erasing the embodied, historical practice that gives the concept any purchase; to see how practice concretizes the concept without reducing thinking to instrumentality. The reward of this double inhabitation is twofold. First, Hegel’s thought is rescued from traditional caricatures—either as pan-logistic fatalism or as mere word-alchemy—by being read at the level where logical life and lived logic are the same phenomenon. Second, Marx’s historical materialism is seen not as a negation of speculative reason but as one of its most stringent embodiments: the place where the agreement of logic with history becomes operative in the syllogism of action.
In the end, Deng presents The Three-Dimensional Structure as a book less to be summarized than to be entered, because what it offers is not a doctrine alongside Hegel’s but a re-composition of Hegel’s composition. To say that logic, epistemology, and ontology are one is not to claim that they share a border; it is to claim that each is the way the other two reveal themselves, and that the dialectical method is the immanent identity of this mutual revelation. In this sense, Deng’s “fresh understanding” of Hegel is not the novelty of thesis but the renewal of a classical demand: that philosophy be equal to life in its capacity to negate itself and thereby to preserve itself. That is why the book closes not with a slogan but with an orientation: if modern thought seeks to overcome the oppositions of subject and object, of thinking and being, it will either pass through Hegel’s unity of the three—or else it will reinvent it unawares at a cost of confusion it could have spared itself. Deng wagers that the former route is both more honest and more fruitful, because it recognizes in Hegel’s speculative logic not an archaism but the still-unexhausted resource of a thinking that dares to say of being only what being can say of itself.
This volume concludes Deng’s three-part exploration of Hegel’s dialectic, first published in English by Routledge in 2022 (transl. Wu Lihuan and Chad Austin Meyers) as part of the China Perspectives series, with the explicit aim of presenting leading Chinese scholarship to international readers; its framing as the culmination of a trilogy is integral to its argumentative density and its insistence that the “unity of three” be seen as the revolutionary development of logic, epistemology, and ontology in the history of Western philosophy and as a decisive philosophical wellspring for Marx’s materialist conception of history. If one were to compress Deng’s work into a single problematic sentence—against the spirit of the project but in fidelity to its drive—it might be this: the dialectic is the unity of three because only a unity in which logic is epistemology, epistemology is ontology, and ontology is logic can make good on the promise that thinking, as living form, is adequate to a world whose truth is its own self-movement. The rest is the labor of reading—and with this book, that labor becomes its own reward, because the form of the book is the movement it describes.
Simon Gros 
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