Discrete Spacetime: How Einstein 1905 Refutes Einstein 1915

We present an ontology in which physical reality is constructed from discrete update events and their relations, with no continuous spatial substrate between events. From the joint application of the photoelectric effect (E = hf) and mass–energy equivalence (E = mc2), every packet of rest mass m has a characteristic minimum temporal resolution T = h/mc2; time is the discrete sequence of interaction events between energy packets. We articulate the structure of the present (here named the imperfect present) as a region with three internal components: A past-of-the-present anchor; An indivisible in-between of operation; A binary future-of-the-present. Each resolution is a quantum loop: appearance at A, disappearance, reappearance at B, with no intermediate position and no intermediate state. The structure is identified, at the level of empirical signature, with the Bohr quantum leap (Bohr 1913; Nobel 1922): the same operational object operates whether the packet is bound (atomic transition) or free (photon). Space is given an intrinsic ontology as the ephemeral operational region of an active resolution, not a persistent substrate; what classical physics calls "space between events" is, in this framework, accumulated record of completed resolutions, not currently-existing space. The constant c is the invariant ratio, in any massive observer's frame, between the spatial and temporal separations of two scars connected by a single photon quantum loop; it is the metrological signature of the loop structure, not a propagation velocity. The framework's central algebraic result derives the relativistic factor gamma = 1/sqrt(1 - beta^2) from a Pythagorean local update constraint N2 total = N2 int + N2 ext on the entity's per-cycle update budget, by two-line algebraic substitution. The internal subspace decomposes radially into three concentric layers, anchored empirically in microscopy of vesicular entities and formally in SU(3) three-color closure. Heisenberg's indeterminacy emerges as a structural consequence of the modal distinction between position (perfect past) and momentum (future of the present). Eight independent falsification conditions are stated; three open problems are declared: Duty cycle of the quantum loop; First-principles derivation of h-bar/2; Mechanism of hierarchical coordination. We conclude with four algebraic open problems on the angular structure of Hint and its consequences.