P-Theory (Planckian Crystallization Theory - PCT) proposes a comprehensive framework for discussing fundamental problems in quantum mechanics and cosmology based on a minimal five-dimensional extension, in which the fifth dimension is interpreted as world time T , orthogonal to four-dimensional spacetime. The central idea is to describe physical reality as a process of becoming, governed by an order parameter Φ(T ) and a two-stage crystallization dynamics: stochastic inception and subsequent deterministic drift. Within Stage-1 (current level), P-Theory proposes a mechanism from which, under five conditions P1–P5 (following from axioms A1–A8), Born’s Rule emerges as a conditional theorem via ergodic averaging; the detailed five-step derivation and verification of the absence of logical circularity are provided in the monograph [1], §4.2–4.3. The universal temperature dependence of decoherence τdecoh ∝ T−1 is derived from the structure of two-stage crystallization and serves as a testable prediction (tests F1–F3, 2026–2031). The P-Theory mechanism also enables the formulation of a series of testable consequences for cosmology and particle physics. The article presents preliminary numerical results of Stage-1 for the cosmological constant Λ, the anomalous magnetic moment of the muon (g − 2)μ, and the stability of the physical vacuum, as well as indicates pathways for their independent verification through molecular interferometry, cosmological data, and KK-spectrum analysis. Detailed derivations and calculations belong to the Stage-1 monograph materials [1]; here we provide their overview and physical interpretation.Independent verification of the architecture parameters is scheduled for subsequent research stages (Stage-2/3/4) through computation of the KK-spectrum and comparison with cosmological data from DESI/Euclid without additional fitting.