The Logical Origin of Newton's First Law

This preprint derives Newton’s First Law (the law of inertia) purely logically from one premise: “no uncaused change”. The state of a classical point particle is defined broadly to include velocity, acceleration, jerk, all higher time derivatives of position, and any hypothetical non-kinematic variables. Causal coherence (no uncaused events) forces the entire state—including velocity—to remain constant for an inertial state, logically forcing an inertial motion to be a constant-velocity one. The proof relies on no empirical data, spacetime symmetries, geometry, or variational principles — just the requirement of a causally connected universe. It applies to point particles and extends to constituents of extended bodies. Standard explanations (empirical, symmetry-based, mathematical) are contrasted with this foundational, tautological approach.