Likewise, if someone tries to cut in line for no good reason, or tells us the same joke three times in a row at lunch, we'll worry about which universe of discourse they're visiting us from. Common sense is a gift of history, religion, philosophy, literature and more. For example, in the United States, if you take your boat out onto the sea despite a storm warning, we'll send the Coast Guard after you, putting other people's lives at risk. In ancient Greece, you'd be left to your own foolish devices. These two common senses reflect deep understandings of what it is to be human in an inhuman world.
Common sense is a a rich gift.
Now, take our current world, viewed through common sense, and remove space and matter, and thus many of the laws of physics. Change the rules of the world and what was once common sense now makes no sense. That's why the Web is so puzzling so often. It's lacking common sense. It will take a generation to develop this new common sense, but I wonder if we're already beginning to see signs of it.