The Two Strata: Observation and Reality on the Spiral

A companion paper in the Euler Universe series. The logarithmic spiral e^((lambda+i)theta) is used as an interpretive lens over established decoherence physics to laminate the questions of observation and reality. Measurement is read as the i-to-lambda handoff of the exponent: pure unitary evolution is the imaginary (rotation) part, and measurement is where the real (dilation) part switches on, draining the off-diagonal coherence of the reduced density matrix. A fact is identified with the Fubini-Study quarter-turn of pi/2 to a distinguishable state, and facthood is shown to resolve into two independent graded axes: distinguishability and irreversibility. These span a "facthood plane" whose accessible region is a triangle, with the quantum eraser at its decoupling corner and the Schrodinger cat as its extrapolated macroscopic limit. One edge of the plane is anchored to measured thermal-decoherence data for C70 fullerenes. The Schrodinger cat paradox is dissolved by separating the question of whether a macroscopic superposition persists (answered) from the question of why a single outcome is experienced (untouched). Wigner's friend is resolved completely in its realistic form and reduced, in its idealised Frauchiger-Renner form, to the open definite-outcome problem, whose location below the reduced density matrix is stated exactly. The parent cosmology of the series remains falsified by four independent tests; the lens is retained only as a way of looking, and no new number is claimed. Claude (Anthropic) was used as an analytical and writing tool, not credited as an author