The Mirror-Zero Hypothesis proposes that the mathematical point traditionally represented as “zero” can be split into two distinct but symmetrical boundaries: –0 and +0. Between them lies a finite, navigable interval — a “liminal nexus” — representing immediate potential. This reframing treats zero not as a single, indivisible point, but as a bounded space that can be addressed and traversed before resolution into either state. The hypothesis explores parallels in physics (vacuum fluctuation, time asymmetry, phase transitions) and cognitive science (decision-making dynamics, potential states), suggesting that the same underlying structure may describe both physical and mental processes. This work presents conceptual number lines at macro and micro scales to illustrate the idea, and discusses possible implications for modelling choice, symmetry, and boundary conditions.