I do agree that a society capable of nuclear power or space travel can be considered implausible. A similar thought experiment might be, "how technological coul

I do agree that a society capable of nuclear power or space travel can be considered implausible. A similar thought experiment might be, "how technological could a prior species have become before we'd notice?" Animals today, from dolphins to chimps, can be found using tools. Is there any reason to believe this didn't happen in the age of the dinosaurs? Then you can expand beyond simple sticks and stones to other primitive technologies. Maybe we weren't the first to figure out fire, or agriculture, or animal husbandry. Or maybe any brain capable of fire + agriculture + animal husbandry will eventually be so successful that nuclear power and space travel are inevitable. I'm not arguing in favor of any of this: it's just fun to think about.