There is a planet in the Solar System where the people are so stupid they didn’t catch on for a million years that there was another half to their planet. They didn’t figure that out until five hundred years ago! Only five hundred years ago! And yet they are now calling themselves Homo sapiens.
Dumb? You want to talk dumb? The people in one of the halves were so dumb, they didn’t have an alphabet! They hadn’t invented the wheel yet!