Truth-bearer (proposition as section)
A truth-bearer, in the τ-framework, is a section of a presheaf — a structural object, not a linguistic entity. Propositions are sections of the truth-functor over the worlds-presheaf; sentences and beliefs become truth-bearers only by representing such a section. Truth-makers (VII.D27, VII.D60) are the structures that make sections exist — and four canonical types are identified: inclusion, section, diagram, invariant.
τ-Definition
A truth-bearer, in the τ-framework, is a section of a presheaf — a structural object, not a linguistic entity. Propositions are sections of the truth-functor over the worlds-presheaf; sentences and beliefs become truth-bearers only by representing such a section. Truth-makers (VII.D27, VII.D60) are the structures that make sections exist — and four canonical types are identified: inclusion, section, diagram, invariant.
Categorical invariant. p is a truth-bearer ⟺ p ∈ Sect(F) for some presheaf F : World^op → Type in K_τ.
Primary registry anchor:
VII.D61
τ-Derivation Chain
-
VII.D27— Truth-Maker in Ontological — four types of truth-makers: inclusion, section, diagram, invariant. -
VII.D60— Truth-Maker in Logical — structures that make sections exist; the ground of truth. -
VII.D61— Truth-Bearer as Section — propositions are sections of presheaves; truth-bearers are structural, not linguistic. -
VII.D62— Modal Frame in τ — possible worlds as internal objects, providing the base over which the truth-bearing presheaf is defined.
Lean modules referenced:
TauLib.BookVII.Ethics.CIProof
Phenomenological Correlate
A truth-bearer is instantiated wherever something is evaluable as true or false: an empirical claim, a normative judgement, a proof-statement, a commitment-attribution. Each such evaluable item is a section over a presheaf — empirical truth-bearers over the observation-presheaf, normative over the norm-presheaf, proof-theoretic over the proof-presheaf, commitment-theoretic over the stance-presheaf. The sentence we utter is not the truth-bearer; it represents the section.
Examples:
- Empirical: 'the cat is on the mat' — represents a section of the empirical-truth presheaf assigning configurations in which 'cat-on-mat' holds.
- Mathematical: 'every prime greater than 2 is odd' — a section of the proof-truth presheaf, with truth-makers of the diagram-and-invariant types.
- Normative: 'this verdict is just' — a section of the norm-presheaf in Reg_P, with truth-makers of the section type (legitimate justificatory glue).
- Commitment-theoretic: 'the agent is committed to F' — a section of the stance-presheaf in Reg_C, with truth-makers of the inclusion type (the stance-content includes F).
Register codomain: Cross-register (each register has its own truth-presheaf; the section-structure is uniform).
Manuscript reference: manuscript-sources/book-07/part06/ch72.tex
Lean Coverage
Status: Formalized
Module: TauLib.BookVII.Ethics.CIProof
Lean kind: structure
Lean symbol: Tau.BookVII.Ethics.CIProof.TruthBearerAsSection