Formal Sciences
Logic
Proof Theory
ElementScope CategorySub-ItemDefinitionProof Theory of Non-Classical Logics
1. Domain1.1 Scope of the DomainBoundariesThe range of phenomena the science includes and excludes.Studies proof systems for logics that deviate from classical principles (e.g., intuitionistic, modal, linear, relevant, paraconsistent, many-valued). Includes sequent calculi, natural deduction, tableaux, deep inference, and structural variants tailored to each logic. Excludes model-theoretic semantics except where required to validate or motivate proof rules.
ScaleThe spatial, temporal, or organizational level at which the science operates (e.g., quantum, cellular, social, cosmic).Operates at the level of proof rules, derivation structures, structural constraints (resource sensitivity, relevance conditions), modal rule schemes, and logic-specific sequent formats.
1.2 Ontological CommitmentsEntitiesThe kinds of things assumed to exist within the domain (particles, organisms, agents, fields, etc.).Non-classical sequents, labeled sequents, worlds/accessible indices (in modal systems), resources (linear/affine), relevance constraints, polarity annotations, structural-rule variants, logic-specific inference rules.
PropertiesThe fundamental attributes these entities possess (mass, charge, genotype, preference, etc.).Resource usage, polarity, accessibility, valuation multiplicity (many-valued), relevance constraints, structural-rule admissibility, normalization behavior, cut properties, context sensitivity.
CategoriesThe basic ontological types used to classify domain elements (substances, processes, relations, structures).Modal, intuitionistic, linear, affine, relevant, paraconsistent, paracomplete, many-valued calculi; labeled vs. unlabeled systems; deep vs. shallow inference; analytic vs. non-analytic rules.
1.3 State-VariablesVariablesThe measurable or definable properties that describe system conditions.World labels, resource counts, polarity markers, context configurations, accessibility relations, structural-rule availability, sequent form (single-succedent, multi-succedent), cut occurrences, valuation indices.
ParameterizationHow variables encode and represent the system’s state.Encoded using labeled sequents (w:Γ ⊢ Δ), resource-sensitive contexts (multisets, ordered structures), modal accessibility graphs, polarity annotations, relevance constraints, graded valuations.
1.4 Admissible IdealizationsSimplificationsConceptual reductions used to make the domain tractable (point masses, rational agents, perfect gases).Idealizing accessibility relations, treating resources as discrete tokens, simplifying relevance conditions, using analytic variants with subformula property, ignoring global modalities in local derivations, omitting non-local constraints when tractable.
Validity ConditionsThe limits and contexts in which idealizations hold or break down.Idealizations break down in logics with non-well-behaved modalities, nonlocal structural behavior, nonterminating normalization, unrestricted resource usage, or logics where analytic calculi cannot be recovered.
1.5 Domain AssumptionsStructural AssumptionsBackground ontological stances such as determinism, continuity, randomness, discreteness.Proofs follow the logic’s structural discipline: no weakening/contraction (linear), restricted explosion (paraconsistent), single-succedent (intuitionistic), relevance preservation (relevant logic), modality-respecting structural rules.
Implicit CommitmentsUnstated but necessary assumptions that shape the field’s conceptual structure.Assumes rule schemas are aligned with each logic’s philosophical constraints; assumes correct propagation of labels, resources, and accessibility; presumes structural coherence between sequent format and underlying logic.
1.6 Internal Coherence RequirementsConsistencyThe demand that domain concepts do not contradict one another.Rule systems must not collapse into classical logic unless intended; structural discipline must preserve each logic’s non-classical character; cut-elimination must not introduce forbidden structural behavior.
CompatibilityThe requirement that entities, variables, and assumptions fit together into a unified descriptive framework.Alignment required between structural constraints (resource sensitivity, relevance, modality), inference rules, sequent formats, normalization behaviors, and semantic motivations (e.g., accessibility, many-valued truth, paraconsistency).
2. Evidence Layer2.1 Observable PhenomenaObservablesThe aspects of the domain that can produce detectable signals accessible to measurement.Labeled-sequent transformations, modal rule applications, resource-sensitive rule usage, relevance-preserving steps, multi-valued rule firings, accessibility propagation, cut behavior in non-classical systems, normalization traces.
Detection LimitsThe boundaries of what can be resolved or sensed by current instruments or methods.Limited by complexity of non-classical proof search, undecidability of certain systems, difficulty tracking modalities or resources, branching explosion in relevant or paraconsistent tableaux, and limits of automated prover support for exotic rules.
2.2 Measurement SystemsUnitsStandardized quantifications (meters, seconds, volts, decibels, dollars, etc.) necessary for consistent comparison.Proof height, resource counts, modality depth, label-propagation steps, relevance-preservation checks, cut-rank, number of accessibility transitions, valuation degrees in many-valued systems.
InstrumentsDevices and tools (microscopes, spectrometers, sensors, surveys, detectors) used to produce measurements.Labeled-sequent proof assistants, modal proof search engines, linear-logic provers (e.g., LO types), relevant-logic tableaux generators, paraconsistent proof checkers, deep-inference tools, many-valued proof analyzers, structural-rule verifiers.
2.3 Operational DefinitionsDefinitionsTerms defined by specific measurement procedures, ensuring empirical clarity.Derivability defined relative to logic-specific rule sets; modal accessibility defined by labeled transitions; resource usage defined via structural constraints; relevance defined by syntactic connection; valuation levels defined in many-valued calculi.
ProceduresThe explicit steps required to perform a measurement in a reproducible way.Running logic-specific proof search, verifying accessibility paths, checking resource compliance, enforcing relevance constraints, executing cut-elimination in non-classical settings, performing normalization sensitive to modality or resource structures.
2.4 Data AcquisitionProtocolsFormal processes for gathering data under controlled or standardized conditions.Standardized modal proof construction, resource-sensitive derivation protocols, relevance-preservation verification, multi-valued rule application sequences, canonical labeled-sequent workflows, systematic cut-elimination tests.
SamplingRules determining which subset of the domain is measured and how representative it is.Selecting representative modal depths, resource-sensitive derivations, relevance-constrained proof patterns, canonical many-valued derivation cases, typical normalization paths across non-classical variants.
2.5 Data Character & FormatData TypesThe form raw evidence takes (time series, spectra, images, counts, qualitative records).Labeled sequents, modal derivations, resource-annotated contexts, relevance-constrained proof trees, many-valued tableaux, normalization graphs, accessibility transition logs, structural-rule usage traces.
ResolutionThe granularity or precision with which data is captured.Determined by granularity of label tracking, resource annotation precision, fidelity of accessibility graphs, number of valuation levels (finite or infinite), and detail level in modal or relevance-based normalization sequences.
2.6 Reliability & CalibrationCalibrationAdjustment procedures ensuring instruments produce accurate results.Validating modal accessibility rules, verifying resource-discipline implementation, checking relevance constraints, ensuring correctness of many-valued rule schemas, calibrating deep-inference systems, validating normalization procedures across logics.
Error CharacterizationIdentification and quantification of noise, uncertainty, bias, and measurement error.Misapplied modal or resource-sensitive rules, incorrect label propagation, faulty relevance tracking, rule-schema misalignment with logic’s semantics, normalization failures, implementation errors in non-classical proof assistants.
3. Structural Layer3.1 Patterns & RegularitiesLaws / RelationsStable, repeatable patterns governing how observables behave across conditions.Modal accessibility propagation rules, resource-sensitive rule interactions (linear/affine), relevance-preservation constraints, paraconsistent non-explosion patterns, many-valued rule behaviors, intuitionistic single-succedent structure, cut-reduction laws adapted to each logic.
InvariantsQuantities or properties that remain constant under transformations (symmetries, conservation laws).Accessibility invariants in modal systems, resource invariants in linear/affine logics, relevance invariants, polarity preservation, valuation invariants in many-valued systems, preservation of constructive content in intuitionistic logics, cut-rank monotonicity across non-classical calculi.
3.2 Causal ArchitectureMechanismsUnderlying processes or structures that produce the observed regularities.World-label propagation (modal logics), resource consumption/production (linear), relevance-filtering mechanisms, non-explosive inference mechanisms (paraconsistent), valuation propagation in many-valued systems, constructive introduction/elimination rules.
PathwaysOrganized sequences of interactions forming a causal chain or network.Modal rule chains (□/◇ introduction–elimination sequences), resource-tracking derivation paths, relevance-preserving proof flows, paraconsistent derivation branches avoiding triviality, many-valued proof propagation chains, intuitionistic constructive proof pathways.
3.3 Theoretical VocabularyConceptsCore terms that encode the domain’s structure (force, gene, equilibrium, field).Accessibility, resource sensitivity, relevance, paraconsistency, paracompleteness, polarity, valuation degrees, linearity, constructivity, modality depth, single-succedent structure, analytic/non-analytic rules.
ClassificationsTaxonomies, categories, or typologies that organize entities and relations.Modal (K, T, S4, S5), intuitionistic (LJ variants), linear/affine (LL, MILL), relevant logics (R, RW), paraconsistent calculi (LP, da Costa systems), paracomplete logics, many-valued logics, labeled vs. unlabeled systems, deep inference vs. sequent calculus.
3.4 Formal RepresentationsEquationsMathematical constructs expressing laws, relations, or mechanisms.Modal accessibility equations (wRu), resource-balance equations, polarity equations, many-valued truth-transform equations, permutation conversions adapted to non-classical constraints, specialized cut-reduction equalities.
ModelsStructured representations—mathematical, computational, or conceptual—used to predict and explain phenomena.Labeled-sequent derivation trees, Kripke-style proof structures, resource-annotated proof graphs, relevance-filtered tableaux, many-valued tableaux, deep-inference derivation networks, intuitionistic proof trees.
3.5 Idealized StructuresSimplified ModelsPurposeful abstractions that capture essential dynamics while omitting irrelevant detail.Analytic calculi with logic-specific subformula properties, restricted structural rules, simplified accessibility relations, compressed resource annotations, idealized relevance constraints, finite-valued truncations of many-valued systems.
Limit ConditionsRegimes where specific models or approximations hold (classical vs. quantum, linear vs. nonlinear).Breakdown under non-well-founded accessibility, infinite-valued logics, nonterminating normalization, systems lacking analytic reformulations, resource-sensitive logics without contraction/weakening, modal logics requiring non-local structural rules.
3.6 Integrative FrameworksUnifying TheoriesHigher-order structures that connect disparate laws or mechanisms under a coherent whole.Generalized cut-elimination across non-classical families, proof-theoretic semantics, labeled-sequent meta-frameworks, deep inference as unifier of structural variation, category-theoretic unification for resource/logical structure.
Interdisciplinary LinksPoints where the theory connects to adjacent sciences or larger explanatory systems.Links to Kripke semantics, category theory (monoidal categories for linear logic), type theory (polarity and constructivity), computational complexity of non-classical proof search, modal/temporal semantics, substructural logics in computer science.
4. Method Layer4.1 Inquiry DesignExperimental DesignStructured plans for manipulating variables to test causal claims.Manipulating modal rules, altering accessibility constraints, adding/removing resource-sensitive structural rules, restricting or permitting relevance conditions, adjusting truth-degree rules in many-valued systems, toggling contraction/weakening, and modifying succedent structure to observe effects on derivability and normalization.
Observational DesignSystematic approaches for gathering non-manipulated data (surveys, field studies, natural experiments).Observing how derivations evolve under fixed logic-specific constraints: tracking modal accessibility propagation, resource accounting, relevance preservation, non-explosion behavior, multi-valued propagation patterns, and constructive proof evolution without modifying the calculus.
4.2 Testing & ValidationHypothesis TestingProcedures for evaluating whether evidence supports or contradicts specific claims.Testing admissibility of non-classical structural rules, verifying preservation of modality or resource conditions, determining whether cut-elimination holds in each system, checking relevance or paraconsistency constraints, testing equivalence between labeled and unlabeled proofs.
ReplicationThe requirement that results be independently reproducible under similar conditions.Reproducing modal or linear derivations across independent calculi, verifying accessibility paths, replicating resource-sensitive proofs, cross-running cut-elimination procedures, validating consistency across different proof assistants for the same non-classical logic.
4.3 Inference & EvaluationStatistical InferenceRules for drawing conclusions from noisy or incomplete data.Analyzing frequency distribution of rule applications (modal, resource-sensitive, relevance-based), complexity of proof search under constraints, data on normalization lengths, cut-rank changes, and multi-valued propagation patterns across representative proof families.
Model ComparisonCriteria (fit, simplicity, predictive accuracy, robustness) used to evaluate competing models.Comparing logics by normalization strength, cut-elimination feasibility, analytic vs. non-analytic rule behavior, rule schema simplicity, proof-length bounds, modal-depth growth, resource sensitivity, relevance enforcement, and computational complexity of proof search across systems.
4.4 Error ManagementError AnalysisIdentification and quantification of random and systematic errors.Identifying mispropagated labels or modalities, resource miscounts, broken relevance constraints, incorrect many-valued rule applications, invalid structural transformations, failed normalization sequences, and flawed rule schemas in non-classical proof implementations.
Bias ControlMethods for minimizing subjective, instrumental, or procedural biases.Avoiding structural bias in rule ordering, preventing over-reliance on classical heuristics in non-classical proof search, ensuring neutral treatment of modal depth, controlling implementation bias in relevance checking or resource tracking, and standardizing multi-valued evaluation strategies.
4.5 Adjudication & RevisionPeer ScrutinyCollective evaluation of claims through critique, review, and debate.Reviewing derivations across modal/linear/relevant/paraconsistent calculi, evaluating normalization and cut-elimination arguments, critiquing rule schemas, verifying equivalence between different formulations (e.g., labeled vs. unlabeled), and meta-theoretic scrutiny of logic-specific proof properties.
Theory RevisionProcedures for modifying, replacing, or discarding models based on new evidence.Updating accessibility rules, adjusting resource constraints, modifying relevance conditions, refining many-valued rule schemas, altering sequent formats, strengthening or restricting structural rules, repairing failures in normalization or cut-elimination, and reformulating systems to better match semantic motivations.
4.6 Integrity ConditionsTransparencyRequirements to disclose methods, data, assumptions, and limitations.Full disclosure of modal rules, accessibility frameworks, resource annotations, relevance constraints, valuation schemes for many-valued systems, normalization steps, cut-elimination details, and implementation documentation for proof assistants.
Ethical StandardsNorms ensuring responsible conduct in experimentation, data handling, and publication.Honest reporting of logic-specific inference behavior, avoiding hidden semantic assumptions in rule definitions, ensuring reproducible non-classical proof experiments, documenting structural constraints clearly, and maintaining principled handling of non-classical derivability claims.