On Conjectures (De coniecturis) is Nicholas of Cusa’s philosophical-theological treatise on the nature, scope, and limits of human knowing. It is designed to complement and extend the argument of On Learned Ignorance. Its governing claim is that exact truth is God and therefore exceeds the capacity of finite minds; as a result, all human knowledge is conjectural. A conjecture, in Nicholas’s technical sense, is not a provisional empirical hypothesis or a mere guess. It is a positive assertion that participates in truth, but only “with otherness”: it is true without being exact, and it can always be revised to become a more faithful likeness of what it partially captures. The treatise therefore develops an ars coniecturalis, an art of forming, comparing, and correcting conjectures about God, the universe, and the human mind.
The work is organized in two books. The first book lays the epistemological and metaphysical foundation. Nicholas argues that the human mind is made in the image of God and is genuinely creative in its knowing: it measures, compares, and constructs likenesses of reality rather than simply receiving exact copies of things. Because the mind knows by proportion and symbol, its concepts are conjectural. Mathematical symbols—especially unity and number—serve as privileged models, since the mind generates them from itself and can use them to image the relation between the one and the many. The first book distinguishes absolute unity, which is God, from the contracted unity of the created order and from the unity of the human mind. It insists that all names and concepts of God are conjectural: they affirm something true, but their finite otherness prevents them from grasping God as God. Learned ignorance is thus not abandoned; it becomes productive.
The second book applies the art of conjecture to the universe and to God. Nicholas treats the created universe as a finite, contracted expression of divine unity—a conjectural likeness of God rather than an exact duplicate. The cosmos is one and many, a ordered harmony of unity and difference, and human accounts of it remain true but revisable. The treatise ascends from cosmological conjecture to theological conjecture, using finite symbols to speak of the triune God and of God’s relation to creation. Because God is absolute oneness, every name and image both reveals and conceals; every theological assertion is a conjecture that points beyond itself. The work closes with the ideal of the wise person who knows that his knowledge is conjectural, and who therefore holds his assertions with humility and openness to correction.
Throughout, Nicholas is concerned with the dignity as well as the limits of human knowing. Conjecture is not a defect to be overcome in this life but the proper mode of finite intelligence. The mind’s conjectural activity is a creative participation in truth, and the recognition that all human constructions are conjectures is itself a form of learned ignorance. The treatise is thus a philosophical theology of the approximate: it explores how finite symbols, mathematical proportions, and theological names can truthfully image what they can never exhaust.
A further theme of the treatise is the graded character of conjectural knowledge. Mathematical conjectures are comparatively precise because the mind generates them from its own unity and can compare them with itself; cosmological conjectures are more remote because they concern a contracted order whose unity is always mixed with otherness; theological conjectures are the most remote from exactness yet the most necessary, since they use finite symbols to intend the infinite. This hierarchy keeps the art of conjecture from collapsing into either dogmatism or skepticism: the mind can form true likenesses, but it can never convert likeness into identity.
The book also presents conjecture as an activity of the mind’s assimilation to what it knows. Knowing is not a passive reception of exact species but a constructive measuring, comparing, and proportioning; the mind becomes like its object by forming symbols and proportions that participate in the object’s intelligibility. Because the human mind is an image of God, this constructive activity has a genuine dignity, but because it is an image marked by otherness, its constructions remain conjectural. The recognition of this condition is itself part of the art: the wise conjecturer compares conjectures with one another, corrects them, and refers them beyond themselves to the absolute truth that measures all things while remaining unmeasured by them.
The treatise’s treatment of unity and otherness is central to this project. Absolute unity is God; finite unity is always unity in otherness, a contracted harmony of the one and the many. The created universe is therefore a conjectural expression of divine unity rather than an exact duplicate, and human accounts of it must remain plural, revisable, and open to correction. In this way the book joins negative theology with a positive symbolic theology: finite names and images truly reveal, but only by also concealing, and every theological assertion is an icon that must not be mistaken for the infinite reality it signifies. The significance of On Conjectures lies in its sustained attempt to make learned ignorance productive—to show that conjecture is not a provisional defect of finite knowing but the proper form of creaturely intelligence, and that the disciplined awareness of one’s own conjectural condition is itself an intellectual virtue.
