Formal Sciences
Logic
Set Theory
ElementScope CategorySub-ItemDefinitionDescriptive Set Theory
1. Domain1.1 Scope of the DomainBoundariesThe range of phenomena the science includes and excludes.Studies definable sets of reals in Polish spaces; includes Borel sets, analytic/coanalytic sets, projective hierarchies, regularity properties (measurability, Baire property), classification by definability and complexity. Excludes arbitrary subsets of reals unless considered relative to axioms extending ZFC (e.g., determinacy).
ScaleThe spatial, temporal, or organizational level at which the science operates (e.g., quantum, cellular, social, cosmic).Operates at the definability and topological scale: Polish spaces, σ-algebras, pointclasses, hierarchies (Borel, projective), Wadge reducibility, determinacy levels.
1.2 Ontological CommitmentsEntitiesThe kinds of things assumed to exist within the domain (particles, organisms, agents, fields, etc.).Reals, Borel sets, analytic sets, projective sets, Polish spaces, continuous maps, trees, pointclasses, equivalence relations, scales, norms, determinacy games.
PropertiesThe fundamental attributes these entities possess (mass, charge, genotype, preference, etc.).Definability level, measurability, Baire property, perfect set property, complexity (Borel rank, projective level), reducibility degrees, regularity properties under determinacy.
CategoriesThe basic ontological types used to classify domain elements (substances, processes, relations, structures).Borel hierarchy, projective hierarchy, Wadge degrees, pointclasses (Σ, Π, Δ levels), equivalence relation complexity classes, definable sets under determinacy axioms.
1.3 State-VariablesVariablesThe measurable or definable properties that describe system conditions.Definability parameters, ranks of sets, codes for trees, game positions, Wadge degrees, equivalence relation classes, norms/scales on sets.
ParameterizationHow variables encode and represent the system’s state.Encoding states via Borel codes, projective levels, Wadge degrees, tree representations, definability predicates, determinacy game lengths.
1.4 Admissible IdealizationsSimplificationsConceptual reductions used to make the domain tractable (point masses, rational agents, perfect gases).Treat Polish spaces as canonical; treat definability as absolute under continuous reductions; assume standard hierarchies; ignore pathologies from arbitrary sets of reals unless considering determinacy extensions.
Validity ConditionsThe limits and contexts in which idealizations hold or break down.Break down when choice is too strong (destroying regularity), when determinacy is absent at higher levels, in non-Polish spaces, or in models without appropriate regularity properties.
1.5 Domain AssumptionsStructural AssumptionsBackground ontological stances such as determinism, continuity, randomness, discreteness.Assumes ZFC (or ZF + DC + determinacy in stronger contexts), classical topology of Polish spaces, definability hierarchies, closure under continuous preimages, basic regularity principles.
Implicit CommitmentsUnstated but necessary assumptions that shape the field’s conceptual structure.Assumes definability reflects genuine structural complexity; hierarchies behave monotonically; determinacy (when used) provides canonical regularity; topological structure informs logical classification.
1.6 Internal Coherence RequirementsConsistencyThe demand that domain concepts do not contradict one another.Requires consistent interaction among definability hierarchies, regularity properties, reducibility relations, and determinacy assumptions; hierarchies must not collapse arbitrarily.
CompatibilityThe requirement that entities, variables, and assumptions fit together into a unified descriptive framework.Requires alignment of Borel/projective ranks, Wadge reducibility, measurable/Baire properties, determinacy levels, and coding systems across all definable sets and Polish spaces.
2. Evidence Layer2.1 Observable PhenomenaObservablesThe aspects of the domain that can produce detectable signals accessible to measurement.Borel ranks, projective levels, Wadge degrees, definability behavior in Polish spaces, regularity properties (measurability, Baire property, perfect set property), game outcomes under determinacy.
Detection LimitsThe boundaries of what can be resolved or sensed by current instruments or methods.Limits of first-order ZFC in classifying projective sets, inability to detect arbitrary non-definable sets, failure of regularity properties under full Choice, expressive limits of reducibility frameworks.
2.2 Measurement SystemsUnitsStandardized quantifications (meters, seconds, volts, decibels, dollars, etc.) necessary for consistent comparison.Borel rank, projective level, Wadge degree, tree rank, norm lengths, scale complexity, descriptive complexity.
InstrumentsDevices and tools (microscopes, spectrometers, sensors, surveys, detectors) used to produce measurements.Borel codes, trees, continuous reductions, Wadge tests, equivalence-relation reducibility tools, determinacy games, scale-construction machinery.
2.3 Operational DefinitionsDefinitionsTerms defined by specific measurement procedures, ensuring empirical clarity.Definitions of Borel/analytic/coanalytic/projective sets, pointclasses (Σ, Π, Δ), Wadge reducibility, equivalence-relation reducibility, scales and norms.
ProceduresThe explicit steps required to perform a measurement in a reproducible way.Constructing Borel codes, forming analytic sets via projections, computing ranks, running infinite games, building scales, performing Wadge reductions, analyzing canonical Polish-space encodings.
2.4 Data AcquisitionProtocolsFormal processes for gathering data under controlled or standardized conditions.Generating hierarchy levels, constructing tree representations, building reductions, testing definability across Polish spaces, exploring determinacy consequences (when allowed).
SamplingRules determining which subset of the domain is measured and how representative it is.Selecting representative definable sets at each hierarchy level, sampling equivalence relations, testing reducibility behavior on canonical examples, examining definable families under parameter variation.
2.5 Data Character & FormatData TypesThe form raw evidence takes (time series, spectra, images, counts, qualitative records).Borel codes, trees, Wadge diagrams, definability hierarchies, scale sequences, norm data, equivalence-relation complexity tables, determinacy game trees.
ResolutionThe granularity or precision with which data is captured.Determined by granularity of Borel rank, depth of projective hierarchy, precision of Wadge degrees, fidelity of tree codings, and strength of determinacy assumptions used.
2.6 Reliability & CalibrationCalibrationAdjustment procedures ensuring instruments produce accurate results.Verifying correctness of Borel codes, checking well-foundedness of trees, validating reducibility results, confirming rank computations, ensuring determinacy rules match payoff sets.
Error CharacterizationIdentification and quantification of noise, uncertainty, bias, and measurement error.Misranked sets, incorrect tree encodings, faulty reductions, non-well-founded trees, misidentified Wadge degrees, determinacy misapplications, incorrect complexity classification.
3. Structural Layer3.1 Patterns & RegularitiesLaws / RelationsStable, repeatable patterns governing how observables behave across conditions.Borel and projective hierarchy laws; closure properties under continuous preimages; regularity patterns (measurability, Baire property, perfect set property); stability of Wadge reducibility; determinacy-driven structural regularities.
InvariantsQuantities or properties that remain constant under transformations (symmetries, conservation laws).Borel rank, projective level, Wadge degree, equivalence-relation complexity class, tree rank, scale invariants, classification invariants under continuous reductions.
3.2 Causal ArchitectureMechanismsUnderlying processes or structures that produce the observed regularities.Tree representation mechanisms; projection mechanisms generating analytic sets; game-theoretic mechanisms producing determinacy outcomes; continuous-reduction mechanisms creating Wadge order; scale-construction mechanisms under determinacy.
PathwaysOrganized sequences of interactions forming a causal chain or network.Borel hierarchy progression, projective hierarchy steps, iterative Wadge reduction paths, determinacy game progressions, scale-refinement pathways, tree refinement processes.
3.3 Theoretical VocabularyConceptsCore terms that encode the domain’s structure (force, gene, equilibrium, field).Borel, analytic, coanalytic, projective, Polish spaces, pointclasses, Wadge reducibility, equivalence-relation reducibility, trees, norms, scales, determinacy, regularity properties.
ClassificationsTaxonomies, categories, or typologies that organize entities and relations.Borel hierarchy, projective hierarchy, Wadge hierarchy, equivalence-relation complexity classes, definability classes (Σ/Π/Δ), determinacy-based classifications of definable sets.
3.4 Formal RepresentationsEquationsMathematical constructs expressing laws, relations, or mechanisms.Rank equations for Borel sets; projective recursion equations; Wadge reduction formulas (A \leq_W B); definitions via tree projections; scale inequalities; hierarchies expressed as ordinal-indexed sequences.
ModelsStructured representations—mathematical, computational, or conceptual—used to predict and explain phenomena.Polish-space models; tree models of analytic sets; hierarchy models; determinacy-model frameworks (e.g., (AD)-based universes); Wadge-order models; equivalence-relation complexity models.
3.5 Idealized StructuresSimplified ModelsPurposeful abstractions that capture essential dynamics while omitting irrelevant detail.Canonical trees for analytic sets; idealized Borel codes; simplified Wadge chains; toy determinacy games; stripped-down Polish spaces illustrating definability phenomena.
Limit ConditionsRegimes where specific models or approximations hold (classical vs. quantum, linear vs. nonlinear).Collapse of regularity properties under AC; breakdown of determinacy at high projective levels without additional axioms; non-well-founded trees; inability to classify arbitrary sets of reals in ZFC.
3.6 Integrative FrameworksUnifying TheoriesHigher-order structures that connect disparate laws or mechanisms under a coherent whole.Borel and projective hierarchy theory; determinacy as a unifying framework for regularity; Wadge theory unifying reducibility; scale and norm theory unifying projective structural behavior.
Interdisciplinary LinksPoints where the theory connects to adjacent sciences or larger explanatory systems.Links to topology (Polish spaces), real analysis (regularity properties), logic (determinacy, large cardinals), computability theory (degree structures), and ergodic theory (measurability structures).
4. Method Layer4.1 Inquiry DesignExperimental DesignStructured plans for manipulating variables to test causal claims.Varying definability parameters, modifying codes or representations of sets, altering topological structures (within Polish limits), manipulating reduction frameworks (e.g., switching reductions from continuous to Borel) to test definability and complexity.
Observational DesignSystematic approaches for gathering non-manipulated data (surveys, field studies, natural experiments).Observing Borel/projective behavior without altering axioms; tracking Wadge degrees, determinacy game outcomes, tree well-foundedness, or equivalence-relation complexity in natural settings.
4.2 Testing & ValidationHypothesis TestingProcedures for evaluating whether evidence supports or contradicts specific claims.Testing whether a set is analytic, coanalytic, or projective; checking Borel rank; verifying reducibility relations; determining correctness of tree representations; validating determinacy-induced regularity.
ReplicationThe requirement that results be independently reproducible under similar conditions.Reproducing tree codings; re-testing reducibility using multiple reductions; recomputing Borel/projective ranks; repeating determinacy games; verifying equivalence-relation classifications across models or Polish spaces.
4.3 Inference & EvaluationStatistical InferenceRules for drawing conclusions from noisy or incomplete data.Logical analogues: analyzing distribution of definability levels, comparing Wadge-degree frequencies, assessing regularity prevalence under determinacy, evaluating complexity spectra of equivalence relations.
Model ComparisonCriteria (fit, simplicity, predictive accuracy, robustness) used to evaluate competing models.Comparing definability hierarchies across Polish spaces; comparing models with/without determinacy; evaluating differences under large cardinal assumptions; comparing reducibility frameworks and their structural strength.
4.4 Error ManagementError AnalysisIdentification and quantification of random and systematic errors.Detecting mis-coded Borel sets, incorrect projective classification, faulty tree constructions, misapplied reductions, incorrect determinacy assumptions, errors in equivalence-relation complexity assessments.
Bias ControlMethods for minimizing subjective, instrumental, or procedural biases.Avoiding selective sampling of “nice” definable sets; preventing bias toward low-level Borel structures; ensuring non-biased choice of reductions; avoiding cherry-picking canonical representations to force desired complexity.
4.5 Adjudication & RevisionPeer ScrutinyCollective evaluation of claims through critique, review, and debate.Community evaluation of definability proofs, rank computations, reducibility arguments, determinacy results, equivalence-relation complexity claims, and tree or scale constructions.
Theory RevisionProcedures for modifying, replacing, or discarding models based on new evidence.Revising pointclass definitions, adjusting reducibility frameworks, updating determinacy assumptions, refining scale theory, modifying tree constructions, or redefining equivalence-relation hierarchies after counterexamples.
4.6 Integrity ConditionsTransparencyRequirements to disclose methods, data, assumptions, and limitations.Full disclosure of coding methods, reducibility assumptions, determinacy reliance, regularity hypotheses, game definitions, and topological constraints.
Ethical StandardsNorms ensuring responsible conduct in experimentation, data handling, and publication.Honest reporting of definability failures, accurate treatment of determinacy limitations, avoidance of overstated complexity claims, and correct attribution of classification results and game-theoretic techniques.