Constitutive descent from the observer's causal diamond

Wheeler proposed that acts of registration constitute classical reality through the formation of records. Taking the proposal literally requires a structure that turns what a finite observer can distinguish into persistent classical facts, and a condition that makes many local facts one spacetime. Such a structure is proposed on the observer's causal diamond. Quantum field theory and general relativity are unchanged. A record is a settled classical fact, formed when which-outcome information leaves the diamond. A central postulate is the record rule, which fills unrecorded content from the vacuum, conditioned on the existing records. Constitutive descent, the compatibility of nesting in time with gluing across space, is then proposed to join local records into one shared world. A framework is presented together with its consequences. First, gravity responds only to what has been recorded. Two masses that have been recorded, but whose positions remain in superposition, still attract, yet classically mediated gravity cannot entangle them, a prediction testable by tabletop experiments. Second, records are irreversible and only accumulate, and their accumulation carries an arrow, proposed here as the arrow of time. Third, the structure yields candidate values for quantities usually taken as inputs, including three generations, four spacetime dimensions (d = 4), the rate λ = 3/(16π²) at which recording resolution fails per logarithmic scale, the transfer g = 1/d and the Higgs bare quartic λ₀ = 1/8. Companion papers apply the same recording geometry to cosmological observables and to Standard Model mass ratios. No-go results show that local recording cannot fix absolute amplitudes or favour one allowed branch over another. Absolute scales must therefore be set by measured values, and amplitudes and branch selection are proposed to close through Wheeler's self-excited circuit, in which records fix the geometry that defines the observer. Shared reality is thus built from the records settled on each observer's causal diamond, joined by constitutive descent.