Abstract

We introduce the τ-contradiction as a diagnostic tool for evaluating the coherence of metaphysical entities. Drawing on the concept of proper time (τ) from special relativity, we argue that any entity claimed to be both timeless (τ = 0) and capable of temporal functions (requiring τ > 0) harbors a logical contradiction equivalent to a round square. This framework applies to classical conceptions of God, immaterial souls, and other entities traditionally described as existing outside time while simultaneously performing temporal activities such as thinking, deciding, or creating. The τ-contradiction does not merely render such entities improbable but logically impossible. We provide a formal modal-logical derivation and discuss implications for philosophy of religion and metaphysics.