Spacetime Bounds on Consciousness

A conscious moment feels instantaneous, yet its ingredients are spread out in space, so signals take time to travel and integration must occur within a window of duration θ. In Stack Theory, Occurrence means each ingredient is true at least once within the window, while CoInstantiation means all are true together at some time. The Temporal Gap is Occurrence without CoInstantiation. Here, I show that if unity requires CoInstantiation and ingredients must exchange causal influence within window under a signal speed ceiling v, then the system diameter D satisfies D ≤ κvθ, with κ = 1 for hub exchange and κ = 1/2 for all-to-all exchange. A minimal message passing model shows fragmentation at these thresholds. Primate corpus callosum data imply size lower bounds on θ. This may rule out co-instantiated consciousness for liquid brains like ant colonies, AI on contemporary hardware, and it implies size constraints for proposed human–AI hybrids.