Double Truth

The "doctrine of the double truth" names a medieval epistemological principle — associated with Averroist scholasticism — according to which a proposition can be true in theology (the order of faith and final ends) while simultaneously false in philosophy (the order of rational demonstration), and vice versa. Lacan invokes this doctrine in Seminar XIII not as a historical curiosity but as a structural precursor: the medieval split between truth and knowledge anticipates, in pre-modern form, the constitutive non-relation between vérité and savoir that modern science inherits but represses. Where medieval thinkers explicitly maintained the gap between these two registers as doctrine, post-Cartesian science proceeds as though knowledge can absorb and eventually replace truth entirely, foreclosing the very division that the double-truth doctrine acknowledged.

For Lacan, Dante's Divine Comedy functions as a poetic-topological witness to this split. The poet projects cosmological knowledge — the medieval savoir of the heavens — into the field of "final ends," which is precisely the field of truth (what the subject will have been, eschatologically). In doing so, Dante inadvertently maps the edge-topology that links the word-in-the-Other to the emergence of the objet petit a, specifically as gaze. The conjunction of the liar and the counterfeiter in Hell is a concrete literary articulation of the antinomy: the liar subverts truth while the counterfeiter subverts knowledge/coin (medium of symbolic exchange), and their co-damnation figures the impossibility of collapsing the two registers into one. The "double truth" thus operates in Lacan's argument as the medievals' own (inadvertent) testimony to the Real gap between the Symbolic order of knowledge and the register of truth — a gap that psychoanalysis, unlike science, refuses to suture.

In jacques-lacan-seminar-13-1 (p. 93), the "doctrine of the double truth" appears as a hinge concept within Lacan's extended reading of Dante. The concept's primary canonical anchor is Knowledge (savoir): the doctrine stages, avant la lettre, the Lacanian axiom that "Knowledge and Truth have no relation with one another." Where the Knowledge synthesis notes that modern science operates as "self-accumulating knowledge structurally severed from truth," Lacan here retrojects that structural severance into a medieval theological controversy, suggesting the split is not merely a Cartesian event but a permanent feature of the subject's relationship to the symbolic order. The "double truth" names the moment when the non-relation was still visible and named as such — before science's foreclosure of the question.

The concept is also closely linked to the Gaze and Extimacy canonicals. The gaze, as objet petit a of the scopic field, is precisely what inhabits the visual-topological edge that Dante's poem maps: an interior-exterior object, extimate to both knowledge and truth. The doctrine of the double truth thus functions as a theoretical precursor to extimacy — the medieval form of the insight that what is most intimate to the subject (truth, final ends, salvation) is simultaneously located outside, in the Other. Within the source's argument, the concept is neither a primary theoretical construction nor a mere allusion; it is a structural relay that allows Lacan to historicize the knowledge/truth split while using Dante as a topological demonstration of the same antinomy that psychoanalysis addresses through the concept of objet petit a.

Seminar XIII · The Object of Psychoanalysis (alt. translation)Jacques Lacan · 1965 (p.93)

this thematic of the opposition between truth and knowledge is inscribed throughout the whole development of medieval thinking in what is called the doctrine of the double truth

The phrase "inscribed throughout the whole development of medieval thinking" is theoretically loaded because it frames the truth/knowledge opposition not as a marginal heresy but as a structural constant of an entire episteme — exactly paralleling Lacan's claim that this non-relation is constitutive rather than accidental. The word "inscribed" further resonates with the Lacanian Symbolic: the opposition does not merely occur in medieval thought, it is written into it, prefiguring the way the split between vérité and savoir is always already marked in the structure of the subject's relation to the Other.