This book is the third stage of a continuous research programme and is not intended to be read in isolation. To understand its premises and dependency structure, readers should first read The Necessity of Structure, followed by The Necessity of Quantum Structure. Across eight interdependent volumes spanning more than 1,800 pages, The Admissibility of Natural Physics asks how far modern physics can be reconstructed without simply assuming its familiar ingredients from the outset. Taking the previously established single-system quantum framework as its starting point, it develops a step-by-step account of composite systems, interaction, identical particles, locality, quantum fields, gauge structure, particle sectors, physical parameters, gravity, and cosmology. At every stage, the work distinguishes what is genuinely derived from what is measured, assumed, conditional, representational, or still unresolved. It culminates in a unified master constraint and a frozen prospective empirical testing protocol, while insisting that unsupported conclusions must remain open rather than being forced into an artificially complete theory.