CONCEPT
The Laplacean Limit
Prigogine's name for the boundary that deterministic computation cannot cross: the physical impossibility, in far-from-equilibrium systems, of predicting which branch of a bifurcation a system will enter—and what this implies for AI forecasting and the irreducibility of human judgment at moments of genuine historical contingency.
Laplace's demon was the thought experiment that founded determinism: an intelligence that knew all forces and all positions at a given instant could calculate every future state with perfect certainty, for such an intelligence nothing would be uncertain, and the future, like the past, would be present before its eyes.
Ilya Prigogine spent his career demonstrating that the universe Laplace described—deterministic, time-reversible, the future fully inscribed in the present state—is not the universe we inhabit. At
bifurcation points in
far-from-equilibrium systems, the indeterminacy is not a product of insufficient information but a physical fact: the fluctuations that tip the system toward one branch or another are thermodynamically random in a sense that no complete specification of the prior state can circumvent. The future of the system at a bifurcation is not determined; it is constrained by the past without being entailed by it. This is the Laplacean Limit: the