The Sensorium and the Arc of Time

Every sense perceives the past. Because every carrier of information — light, sound, drifting molecules, nerve impulses — travels at finite speed, what a sense delivers is always the state of the world at a retarded moment. This paper treats the living body as a multi-band instrument that samples the universe at many depths of time at once. It defines each modality’s lookback time (τ = d/v_sig) and lookback phase (Δθ = ωτ), tabulates the ranges across the human senses, and shows they span roughly twenty orders of magnitude — from the ~5 ms neural floor to the ~13.8-billion-year cosmic light horizon. It then pushes past the classical five: inward to the single-photon event at the floor of vision and to magnetoreception as a candidate sense built on entangled electron spins; outward to neutrinos and gravitational waves, which pierce the wall of light and let instruments observe almost to the origin of time. A corollary reframes “are we alone”: because no two separated observers can ever share a present, solitude in the present moment is structural. A closing section asks what the same arc of time implies about life, read as a temporal aperture that holds a present while the past pours through it. The work is exploratory and is written in the discipline of the “Euler Universe” series: explicit derivations, named numbers, and candid limits. The Euler phasor is used as an interpretive lens that reorganises established physics rather than replacing it, with one deliberately falsifiable prediction stated in §11. The paper is explicit that the cosmological version of the parent model is falsified and that colour-vision deficiency is not an entanglement effect.