| 1. Domain | 1.1 Scope of the Domain | Boundaries | The range of phenomena the science includes and excludes. | Includes the origin, structure, content, and evolution of the universe as a whole: expansion history, cosmic microwave background, large scale structure, dark matter, dark energy, primordial nucleosynthesis, and cosmic inflation. Excludes local astrophysical processes within single stars or galaxies except where they contribute to cosmic-scale inference. |
| | Scale | The spatial, temporal, or organizational level at which the science operates (e.g., quantum, cellular, social, cosmic). | Operates on the largest known scales from megaparsecs to the entire observable universe, and time scales from fractions of a second after the Big Bang to billions of years of cosmic evolution. |
| 1.2 Ontological Commitments | Entities | The kinds of things assumed to exist within the domain (particles, organisms, agents, fields, etc.). | Space, time, matter, radiation, dark matter, dark energy, cosmic background radiation, baryons, neutrinos, primordial fluctuations, cosmic structures, and cosmological fields. |
| | Properties | The fundamental attributes these entities possess (mass, charge, genotype, preference, etc.). | Density, temperature, expansion rate, curvature, composition fractions, fluctuation amplitude, horizon size, growth rate of structure, and redshift. |
| | Categories | The basic ontological types used to classify domain elements (substances, processes, relations, structures). | Cosmic components, epochs, large scale structures, physical processes, symmetry regimes, and matter energy partitions. |
| 1.3 State-Variables | Variables | The measurable or definable properties that describe system conditions. | Scale factor, Hubble parameter, density parameters, temperature, curvature, redshift, fluctuation spectrum, and cosmic time. |
| | Parameterization | How variables encode and represent the system’s state. | States encoded by cosmological parameter sets, expansion histories, power spectra, background radiation properties, and mass energy distributions used in cosmological models. |
| 1.4 Admissible Idealizations | Simplifications | Conceptual reductions used to make the domain tractable (point masses, rational agents, perfect gases). | Treating the universe as homogeneous and isotropic on large scales, modeling matter as perfect fluids, ignoring small scale structure, reducing complex physics to effective parameters, and simplifying early universe behavior. |
| | Validity Conditions | The limits and contexts in which idealizations hold or break down. | Valid when averaging over large scales, when small structures do not dominate dynamics, when symmetry assumptions hold, and when early universe conditions are approximated correctly; breaks down at small scales or strongly nonlinear regimes. |
| 1.5 Domain Assumptions | Structural Assumptions | Background ontological stances such as determinism, continuity, randomness, discreteness. | Assumes universality of physical laws, large scale homogeneity and isotropy, continuity of spacetime, determinism in cosmic evolution, and applicability of general relativity or alternative gravitational frameworks. |
| | Implicit Commitments | Unstated but necessary assumptions that shape the field’s conceptual structure. | Assumes dark matter and dark energy are meaningful constructs, cosmic expansion is accurately represented by metric theories, and cosmological parameters reliably reflect underlying physics. |
| 1.6 Internal Coherence Requirements | Consistency | The demand that domain concepts do not contradict one another. | Requires agreement between expansion models, radiation backgrounds, nucleosynthesis results, large scale structure observations, and gravitational theory; no contradictions among cosmological parameter sets. |
| | Compatibility | The requirement that entities, variables, and assumptions fit together into a unified descriptive framework. | Entities, variables, and assumptions must jointly support a unified description linking expansion, composition, structure growth, and radiation backgrounds into one coherent cosmological framework. |
| 2. Evidence Layer | 2.1 Observable Phenomena | Observables | The aspects of the domain that can produce detectable signals accessible to measurement. | Detectable signals include cosmic microwave background temperature and polarization, galaxy redshift distributions, supernova brightness curves, baryon acoustic oscillation features, gravitational lensing patterns, large scale structure clustering, and primordial abundance ratios. |
| | Detection Limits | The boundaries of what can be resolved or sensed by current instruments or methods. | Limited by telescope sensitivity, sky coverage, angular resolution, foreground contamination, cosmic variance, redshift accuracy, and noise in background radiation maps. |
| 2.2 Measurement Systems | Units | Standardized quantifications (meters, seconds, volts, decibels, dollars, etc.) necessary for consistent comparison. | Uses parsecs, megaparsecs, gigaparsecs, years, seconds, kelvins, redshift values, flux units, magnitudes, and energy density fractions. |
| | Instruments | Devices and tools (microscopes, spectrometers, sensors, surveys, detectors) used to produce measurements. | Instruments include space based telescopes, microwave background observatories, ground based survey telescopes, radio arrays, spectrographs, gravitational lensing survey systems, and cosmic ray detectors. |
| 2.3 Operational Definitions | Definitions | Terms defined by specific measurement procedures, ensuring empirical clarity. | Quantities such as redshift, luminosity distance, power spectrum amplitude, density parameters, and expansion rate are defined through standardized observational and survey procedures. |
| | Procedures | The explicit steps required to perform a measurement in a reproducible way. | Procedures include sky scanning, spectral line fitting, multi band photometry, microwave background mapping, weak lensing shape measurement, survey calibration routines, and large scale clustering extraction. |
| 2.4 Data Acquisition | Protocols | Formal processes for gathering data under controlled or standardized conditions. | Data gathered through long integration times, repeated sky scans, multi wavelength surveys, uniform exposure patterns, spectroscopic follow up, and cross calibration across instruments. |
| | Sampling | Rules determining which subset of the domain is measured and how representative it is. | Sampling rules include wide area sky coverage, redshift binning, magnitude limited selection, random sampling of survey fields, and repeated measurements to suppress noise. |
| 2.5 Data Character & Format | Data Types | The form raw evidence takes (time series, spectra, images, counts, qualitative records). | Data appears as full sky maps, power spectra, redshift catalogs, photometric catalogs, supernova light curves, lensing shear maps, clustering statistics, and primordial abundance measurements. |
| | Resolution | The granularity or precision with which data is captured. | Determined by detector sensitivity, telescope aperture, spectral dispersion, time sampling, scanning speed, and pixelization in sky maps. |
| 2.6 Reliability & Calibration | Calibration | Adjustment procedures ensuring instruments produce accurate results. | Calibration uses standard stars, wavelength references, flux standards, beam profile calibration, atmospheric models, detector noise mapping, and inter survey consistency checks. |
| | Error Characterization | Identification and quantification of noise, uncertainty, bias, and measurement error. | Errors arise from instrumental noise, calibration drift, sample variance, foreground contamination, redshift uncertainties, sky coverage limitations, and modeling assumptions in data reduction. |
| 3. Structural Layer | 3.1 Patterns & Regularities | Laws / Relations | Stable, repeatable patterns governing how observables behave across conditions. | Stable patterns include cosmic expansion laws, redshift distance relations, temperature evolution of the cosmic microwave background, large scale clustering behavior, nucleosynthesis abundance ratios, and consistent growth patterns of structure. |
| | Invariants | Quantities or properties that remain constant under transformations (symmetries, conservation laws). | Invariants include conservation of energy momentum under cosmological models, stable large scale isotropy, statistical uniformity of the cosmic microwave background, preserved abundance ratios from primordial nucleosynthesis, and fixed functional forms of large scale power spectra. |
| 3.2 Causal Architecture | Mechanisms | Underlying processes or structures that produce the observed regularities. | Mechanisms arise from gravitational collapse, cosmic expansion, dark matter structure formation, radiation matter decoupling, baryon acoustic oscillations, inflation driven primordial fluctuations, and feedback from galaxies and clusters. |
| | Pathways | Organized sequences of interactions forming a causal chain or network. | Pathways include inflation seeding fluctuations, recombination producing the cosmic microwave background, formation of first structures, hierarchical buildup of halos, galaxy formation, and long term evolution under dark energy driven expansion. |
| 3.3 Theoretical Vocabulary | Concepts | Core terms that encode the domain’s structure (force, gene, equilibrium, field). | Core terms include scale factor, redshift, horizon, inflation, dark matter, dark energy, cosmic microwave background, baryon acoustic oscillation, large scale structure, and cosmic variance. |
| | Classifications | Taxonomies, categories, or typologies that organize entities and relations. | Classifies models by curvature type, energy content, expansion history, inflation type, structure growth regime, and galaxy or cluster formation pathways. |
| 3.4 Formal Representations | Equations | Mathematical constructs expressing laws, relations, or mechanisms. | Uses equations for expansion dynamics, density evolution, radiation temperature evolution, structure growth, nucleosynthesis yields, and statistical power spectra of cosmic fluctuations. |
| | Models | Structured representations—mathematical, computational, or conceptual—used to predict and explain phenomena. | Includes standard cosmological models, inflationary models, dark matter halo models, structure formation simulations, nucleosynthesis models, and simplified phenomenological models. |
| 3.5 Idealized Structures | Simplified Models | Purposeful abstractions that capture essential dynamics while omitting irrelevant detail. | Idealizations include homogeneous and isotropic universes, perfect fluid matter content, simplified inflation potentials, linear structure growth, and minimal dark sector interaction assumptions. |
| | Limit Conditions | Regimes where specific models or approximations hold (classical vs. quantum, linear vs. nonlinear). | Valid when averaging over large scales, in the linear regime of structure growth, when deviations from isotropy are negligible, and when small scale baryonic effects do not dominate cosmic dynamics. |
| 3.6 Integrative Frameworks | Unifying Theories | Higher-order structures that connect disparate laws or mechanisms under a coherent whole. | Includes frameworks linking gravity, particle physics, thermodynamics, and statistical structure formation into the standard cosmological picture; unifies early universe physics with late time expansion. |
| | Interdisciplinary Links | Points where the theory connects to adjacent sciences or larger explanatory systems. | Links to particle physics, nuclear physics, astrophysics, gravitation theory, statistical physics, and computation at the scale of cosmic simulations. |
| 4. Method Layer | 4.1 Inquiry Design | Experimental Design | Structured plans for manipulating variables to test causal claims. | Direct manipulation of cosmic variables is impossible; instead, cosmologists design tests by selecting survey targets, redshift ranges, wavelengths, and specific cosmic tracers to probe causal relationships in expansion, structure formation, and energy content. |
| | Observational Design | Systematic approaches for gathering non-manipulated data (surveys, field studies, natural experiments). | Uses wide area surveys, deep field imaging, all sky mapping, multi wavelength observations, time domain surveys, and natural experiments such as gravitational lensing, cosmic expansion, and cluster formation. |
| 4.2 Testing & Validation | Hypothesis Testing | Procedures for evaluating whether evidence supports or contradicts specific claims. | Tests compare observed power spectra, supernova distance curves, clustering statistics, abundance ratios, and cosmic microwave background features with predictions from cosmological models. |
| | Replication | The requirement that results be independently reproducible under similar conditions. | Replication requires confirming signals across multiple telescopes, surveys, wavelengths, independent data reduction pipelines, and repeated measurements of the same cosmic structures. |
| 4.3 Inference & Evaluation | Statistical Inference | Rules for drawing conclusions from noisy or incomplete data. | Methods include fitting cosmological parameters, extracting power spectra, computing likelihoods, analyzing noise and variance, reconstructing density fields, and estimating uncertainties in expansion or structure growth. |
| | Model Comparison | Criteria (fit, simplicity, predictive accuracy, robustness) used to evaluate competing models. | Models compared based on predictive accuracy for expansion history, cosmic microwave background features, structure growth patterns, baryon acoustic oscillations, and consistency across independent datasets. |
| 4.4 Error Management | Error Analysis | Identification and quantification of random and systematic errors. | Errors arise from instrumental noise, foreground contamination, calibration drift, cosmic variance, redshift uncertainty, incomplete sky coverage, and modeling assumptions used in data extraction. |
| | Bias Control | Methods for minimizing subjective, instrumental, or procedural biases. | Bias reduced through blind analysis, cross surveying, standardized calibration, removal of foreground contamination, independent verification pipelines, and consistent treatment of selection effects. |
| 4.5 Adjudication & Revision | Peer Scrutiny | Collective evaluation of claims through critique, review, and debate. | Findings evaluated through peer review, cross survey comparison, conference critique, comparison with simulations, and reconciliation with particle physics and gravitational theory constraints. |
| | Theory Revision | Procedures for modifying, replacing, or discarding models based on new evidence. | Theories revised when new data contradict predicted expansion rates, clustering patterns, cosmic microwave background features, or nucleosynthesis yields, requiring updated models of dark matter, dark energy, or early universe physics. |
| 4.6 Integrity Conditions | Transparency | Requirements to disclose methods, data, assumptions, and limitations. | Requires full disclosure of survey strategy, calibration steps, foreground removal techniques, data reduction procedures, uncertainty ranges, and modeling assumptions. |
| | Ethical Standards | Norms ensuring responsible conduct in experimentation, data handling, and publication. | Requires accurate reporting, avoidance of selective data use, responsible release of survey catalogs, clear uncertainty communication, and adherence to professional standards in cosmological research and data analysis. |