Unified Space-Time and Scale-Dependent Field Theory: A Conceptual Introduction

This paper introduces the Unified Space-Time and Scale-Dependent Field Theory (USSFT), a framework proposing that quantum mechanics and general relativity are emergent descriptions of a single underlying substrate: a classical microscopic field Phi(x) (the "U-field") whose coarse-grained statistical mechanics is proposed to reproduce effective quantum and gravitational phenomena. The theory is defined by an effective Lagrangian with four fundamental parameters {Phi_0, L_SRI, xi, lambda_U}, from which effective scales for hbar, G, and c are proposed to arise. This paper provides a conceptual overview: building intuition through analogy, defining the formal framework, previewing applications to quantum interference, entanglement, gravity, cosmic inflation, cosmology, and the Standard Model, and cataloguing all claims with explicit status labels distinguishing axioms, derivations, and open conjectures. Full derivations are developed in the companion Papers I-XVIII, all archived on Zenodo with cross-referenced DOIs. Paper XVIII (DOI: 10.5281/zenodo.19784680) provides the architectural synthesis and research roadmap for the complete series.