| 1. Domain | 1.1 Scope of the Domain | Boundaries | The range of phenomena the science includes and excludes. | Studies how structure influences reactivity through quantitative and mechanistic principles; excludes purely empirical synthetic outcomes lacking mechanistic or energetic interpretation. |
| | Scale | The spatial, temporal, or organizational level at which the science operates (e.g., quantum, cellular, social, cosmic). | Operates from electronic structure and transition states (quantum scale) to macroscopic kinetic behavior and thermodynamic profiles of organic reactions. |
| 1.2 Ontological Commitments | Entities | The kinds of things assumed to exist within the domain (particles, organisms, agents, fields, etc.). | Atoms, bonds, functional groups, reactive intermediates, transition states, molecular orbitals, substituent fields, charge distributions, solvent environments. |
| | Properties | The fundamental attributes these entities possess (mass, charge, genotype, preference, etc.). | Acidity/basicity, nucleophilicity/electrophilicity, charge density, resonance stabilization, polarizability, steric demand, bond strengths, solvation energies, activation parameters. |
| | Categories | The basic ontological types used to classify domain elements (substances, processes, relations, structures). | Reaction families (SN1/SN2, E1/E2, addition, rearrangement), substituent effects, kinetic regimes, thermodynamic profiles, reactive intermediate classes. |
| 1.3 State-Variables | Variables | The measurable or definable properties that describe system conditions. | Rate constants, equilibrium constants, activation energies, substituent constants (σ, σ*), solvent polarity, temperature, ionic strength, reaction coordinate position. |
| | Parameterization | How variables encode and represent the system’s state. | States described using Hammett correlations, Brønsted plots, energy surfaces, LFER models, molecular-orbital coefficients, solvation parameters, and kinetic/thermodynamic functions. |
| 1.4 Admissible Idealizations | Simplifications | Conceptual reductions used to make the domain tractable (point masses, rational agents, perfect gases). | Linear free-energy relationships, isolated-step reactions, simplified energy diagrams, neglect of minor resonance forms, idealized transition-state geometries, two-parameter substituent models. |
| | Validity Conditions | The limits and contexts in which idealizations hold or break down. | Hold under consistent substituent series, moderate solvent effects, clear rate-determining steps; break down under multistep kinetics, strong solvation, or mechanistic ambiguity. |
| 1.5 Domain Assumptions | Structural Assumptions | Background ontological stances such as determinism, continuity, randomness, discreteness. | Structure reliably predicts reactivity; substituent effects are transferable; mechanisms follow definable energy profiles governed by physical laws. |
| | Implicit Commitments | Unstated but necessary assumptions that shape the field’s conceptual structure. | Assumes additivity of substituent effects, meaningful LFER parameters, stable mechanistic classification, and interpretable transition-state structures. |
| 1.6 Internal Coherence Requirements | Consistency | The demand that domain concepts do not contradict one another. | Requires alignment among kinetics, thermodynamics, substituent effects, orbital interactions, and mechanistic interpretations across datasets and reaction families. |
| | Compatibility | The requirement that entities, variables, and assumptions fit together into a unified descriptive framework. | Demands consistency between observed reactivity trends, computational predictions, electronic structure models, and experimental activation/transition-state data. |
| 2. Evidence Layer | 2.1 Observable Phenomena | Observables | The aspects of the domain that can produce detectable signals accessible to measurement. | Reaction rates, equilibrium shifts, isotope effects, substituent-dependent changes in rate or selectivity, activation parameters, spectral signatures of intermediates, solvent-dependent reactivity. |
| | Detection Limits | The boundaries of what can be resolved or sensed by current instruments or methods. | Limited by ability to detect fast or transient intermediates, small kinetic isotope effects, subtle substituent effects, weak absorption bands, or low-concentration reactive species. |
| 2.2 Measurement Systems | Units | Standardized quantifications (meters, seconds, volts, decibels, dollars, etc.) necessary for consistent comparison. | Rate constants (s⁻¹, M⁻¹ s⁻¹), equilibrium constants (K), activation energies (kJ/mol), isotope ratios, substituent constants (σ), pKa values, ΔG‡, ΔH‡, ΔS‡, solvent parameters. |
| | Instruments | Devices and tools (microscopes, spectrometers, sensors, surveys, detectors) used to produce measurements. | NMR, IR, UV-Vis, MS, calorimeters, stopped-flow equipment, temperature-jump instruments, isotopic analysis tools, kinetic spectrometers, automated reaction-monitoring systems. |
| 2.3 Operational Definitions | Definitions | Terms defined by specific measurement procedures, ensuring empirical clarity. | Mechanism defined by rate law + isotope effects + substituent effects; activation energy defined by Arrhenius/Eyring analysis; substituent effect by LFER correlations. |
| | Procedures | The explicit steps required to perform a measurement in a reproducible way. | Controlled kinetic runs, temperature variation, isotopic labeling, substituent series preparation, replicable rate-measurement protocols, consistent solvent/purity handling. |
| 2.4 Data Acquisition | Protocols | Formal processes for gathering data under controlled or standardized conditions. | Time-resolved sampling, rapid-mix experiments, multi-temperature kinetic series, systematic substituent scans, isotopic substitution studies, standardized equilibration steps. |
| | Sampling | Rules determining which subset of the domain is measured and how representative it is. | Time-series sampling for kinetics, representative substituent series, repeated measurements across temperature points, sampling across reaction progress to ensure reliable kinetic modeling. |
| 2.5 Data Character & Format | Data Types | The form raw evidence takes (time series, spectra, images, counts, qualitative records). | Kinetic curves, Arrhenius plots, Eyring plots, LFER plots, isotope-effect ratios, spectra, titration curves, computational energy surfaces, reaction-coordinate diagrams. |
| | Resolution | The granularity or precision with which data is captured. | Determined by instrument response time, spectral resolution, temperature control precision, mixing efficiency, sampling rate, and noise thresholds in isotope or substituent studies. |
| 2.6 Reliability & Calibration | Calibration | Adjustment procedures ensuring instruments produce accurate results. | Calibration of temperature probes, concentration standards, instrument baselines, isotopic enrichment measurements, spectral referencing, and kinetic instrument response. |
| | Error Characterization | Identification and quantification of noise, uncertainty, bias, and measurement error. | Identifying integration errors, fitting uncertainty, solvent effects, competing pathways, baseline drift, isotope scrambling, substituent correlation scatter, and temperature-control deviations. |
| 3. Structural Layer | 3.1 Patterns & Regularities | Laws / Relations | Stable, repeatable patterns governing how observables behave across conditions. | Linear free-energy relationships (Hammett, Taft), Brønsted catalysis laws, substituent effect trends, Hammond postulate patterns, Marcus theory parabolas, Curtius–Hammett invariance. |
| | Invariants | Quantities or properties that remain constant under transformations (symmetries, conservation laws). | Conserved substituent constants within a reaction family, invariant mechanistic classification (concerted vs stepwise), conserved electronic effects across homologous series. |
| 3.2 Causal Architecture | Mechanisms | Underlying processes or structures that produce the observed regularities. | Electron-flow pathways shaping kinetics, bond polarization patterns, transition-state stabilization, solvent-mediated rate modulation, substituent-driven energetic changes. |
| | Pathways | Organized sequences of interactions forming a causal chain or network. | Stepwise vs concerted sequences, proton-transfer chains, rearrangement trajectories, nucleophilic/electrophilic attack pathways, multi-step energy profiles with defined intermediates. |
| 3.3 Theoretical Vocabulary | Concepts | Core terms that encode the domain’s structure (force, gene, equilibrium, field). | Reactivity parameters (σ, ρ), transition state, isodesmic/homodesmotic reactions, kinetic isotope effects, activation parameters, charge development, resonance/inductive effects. |
| | Classifications | Taxonomies, categories, or typologies that organize entities and relations. | Mechanistic classes (SN1/SN2/E1/E2, addition, pericyclic), substituent-effect categories (σ, σ*, σ_R, σ_I), kinetic regimes, catalysis types (general/ specific acid/base, nucleophilic). |
| 3.4 Formal Representations | Equations | Mathematical constructs expressing laws, relations, or mechanisms. | Hammett equation, Taft equation, Brønsted relations, Arrhenius and Eyring equations, Marcus equation, LFER models, potential energy diagrams, More O’Ferrall–Jencks surfaces. |
| | Models | Structured representations—mathematical, computational, or conceptual—used to predict and explain phenomena. | Transition-state theory, Hammond/anti-Hammond models, substituent-effect models, proton-transfer models, solvent stabilization models, potential energy surfaces, More O’Ferrall diagrams. |
| 3.5 Idealized Structures | Simplified Models | Purposeful abstractions that capture essential dynamics while omitting irrelevant detail. | Idealized linear substituent effects, single-step LFER applicability, isolated transition states, simplified charge distribution, symmetric TS geometries, no competing pathways. |
| | Limit Conditions | Regimes where specific models or approximations hold (classical vs. quantum, linear vs. nonlinear). | Break down under strong solvation, highly polarizable substituents, multi-step mechanisms, post-transition-state bifurcations, tight ion pairs, extreme temperatures, or nonclassical ions. |
| 3.6 Integrative Frameworks | Unifying Theories | Higher-order structures that connect disparate laws or mechanisms under a coherent whole. | Integration of kinetics, thermodynamics, substituent effects, and orbital interactions; unified reactivity models; frameworks linking energy surfaces with mechanistic patterns. |
| | Interdisciplinary Links | Points where the theory connects to adjacent sciences or larger explanatory systems. | Connects to biophysical chemistry, catalysis, organometallic chemistry, computational chemistry, electrochemistry, and reaction-dynamics theory. |
| 4. Method Layer | 4.1 Inquiry Design | Experimental Design | Structured plans for manipulating variables to test causal claims. | Controlling substituent identity, solvent polarity, temperature, ionic strength, isotopic substitution, and concentration to probe structure–reactivity relationships and mechanistic behavior. |
| | Observational Design | Systematic approaches for gathering non-manipulated data (surveys, field studies, natural experiments). | Monitoring natural reaction progression, spontaneous rearrangements, equilibrium shifts, isotope scrambling, and solvent effects without forced perturbation. |
| 4.2 Testing & Validation | Hypothesis Testing | Procedures for evaluating whether evidence supports or contradicts specific claims. | Comparing predicted LFER trends, rate laws, substituent effects, isotope effects, and transition-state structures with kinetic and thermodynamic data. |
| | Replication | The requirement that results be independently reproducible under similar conditions. | Repeating kinetic runs, equilibrium measurements, substituent series studies, isotope-effect measurements, and spectroscopic detection of intermediates across independent runs and labs. |
| 4.3 Inference & Evaluation | Statistical Inference | Rules for drawing conclusions from noisy or incomplete data. | Extracting activation parameters, substituent constants, isotope-effect magnitudes, rate constants, equilibrium constants, and correlation coefficients from noisy datasets. |
| | Model Comparison | Criteria (fit, simplicity, predictive accuracy, robustness) used to evaluate competing models. | Evaluating LFER models, substituent-effect models, transition-state models, solvent models, and energy-surface descriptions based on predictive accuracy, parsimony, and robustness. |
| 4.4 Error Management | Error Analysis | Identification and quantification of random and systematic errors. | Identifying baseline drift, temperature-control error, solvent impurities, competitive side reactions, fitting uncertainty in kinetic/regression models, and isotopic enrichment inaccuracies. |
| | Bias Control | Methods for minimizing subjective, instrumental, or procedural biases. | Ensuring consistent solvent purity, controlled temperature ramps, randomized substituent series order, standardized sampling, blinding spectral interpretation when applicable. |
| 4.5 Adjudication & Revision | Peer Scrutiny | Collective evaluation of claims through critique, review, and debate. | Independent review of mechanistic claims, substituent-effect interpretations, kinetic fits, isotope-effect analyses, and computational transition-state predictions. |
| | Theory Revision | Procedures for modifying, replacing, or discarding models based on new evidence. | Adjusting mechanistic models, revising substituent parameters, refining solvent models, updating potential energy surfaces, or changing mechanistic classifications based on new evidence. |
| 4.6 Integrity Conditions | Transparency | Requirements to disclose methods, data, assumptions, and limitations. | Full disclosure of kinetic conditions, solvent identity, temperature control methods, regression assumptions, calibration procedures, isotopic enrichment details, and computational methods. |
| | Ethical Standards | Norms ensuring responsible conduct in experimentation, data handling, and publication. | Honest reporting of deviations, uncertainties, failed runs, anomalous substituent behavior, ensuring reproducibility, and avoiding selective omission of contradictory data. |