It should be obvious to anybody who knows a little about physics and programming that it's technically possible to have an accurate-enough physics simulation of the matter and energy in a brain, even if it would require more resources than are available, and therefore strong AI is theoretically possible, right? Unless someone believes a human brain requires some supernatural component that operates outsode of the known laws of physics, in which case there's no point discussing the matter with them. Otherwise I don't see how that argument could be legitimately refuted.