PHY.5:10 - Architectural Rationale

This method organizes the choice by physical consequence and coupling. Comparing parameter sizes alone would miss how an omitted process enters the result. Starting from the most detailed available theory can impose work that the question does not need.

Effective-theory construction supplies a useful way to retain selected influences and improve an approximation systematically. Projection and coarse-graining show why unresolved motion can remain as memory and fluctuations. The observable-specific limit shows why their adequacy is judged at the receiving physical result.

MMP.9 owns the mathematical elimination; PHY.1 uses an effective account to compare changed physical arrangements; PHY.2 uses it when constructing an analogue. The contribution here is choosing and revising the physical resolution and remaining influence of unresolved processes. The motor, chain and Brownian particle demonstrate that contribution in different comparisons.