Learning is a struggle against “the illusions of commonsense perception” (Maria Popova). When it was obvious that the Earth stood still and the Moon moved, Kepler wrote a novel about traveling to the moon and meeting a civilization who believed, based on their commonsense perception, that the Moon stood still and the Earth moved. If a person can imagine the perspective of a moon-based being, maybe they can see that their belief is tied to their Earthbound context.
The phrase “That’s common sense,” like “That’s obvious,” means “I believe this, and the people I trust all believe this, and I can’t explain it.”
Many people in America have a commonsense notion: “Men have penises and women have vaginas.” It’s all they’ve personally seen. Can you imagine someone with a different perspective? an intersex person, even if you don’t know that you’ve met one?

This frame is self-fulfilling. Any one who is intersex ain’t gonna tell you about it, when you are sure that’s not a thing. Common sense shapes our perspective of the world in multiple ways: in what we can perceive, and in what people show us.
Especially if you have power! Then people extra show you what you want to see and nothing else. Power inhibits perception.
Common sense is contextual. In the Midwest, obviously everybody drives. (Scientifically, it’s incredibly dangerous.) In embedded device drivers, obviously you test your software thoroughly, and statically typed languages are superior. In web apps for ad campaigns, obviously that’s all a waste of time. Can we imagine situations where people have different perspectives?
If you imagine someone with a different perspective, then you can gain insight into your own perspective. You might get more accurate theories — be able to predict eclipses, which a lifetime of seeing the moon come up at night can’t prepare you for. You might see that your perspective isn’t true everywhere, and that you could move — maybe not to the moon, but to a city where there’s a community of queer or genderfluid people (and maybe even public transport). Or to a team that treats testing differently, where you can expand your experience.
But this kind of imagination takes work. Was it useful to the average human in 1600 to know that the Earth revolves around the sun? Heck, is it to the average person today? It isn’t directly relevant to my daily life, but I believe it by default, because everyone around me does. Most of the commonsense beliefs we grow up with aren’t worth questioning.
It takes effort, research, emotional energy and brainspace to adopt new frames. We can’t all do it for everything. Some of us learn that the gender binary is nonsense. Some of us learn many programming languages. Some of us study astronomy.
When you meet a person who still holds an outdated notion, it doesn’t mean they’re an idiot. It means they haven’t taken the effort to break this one yet. We can’t all understand everything. And most of the time we don’t need to. It’s a bonus when someone does break out of the default beliefs.
When you do gain new understanding and alter the beliefs you started with, it stays with you forever. Wisdom comes with age, or with accumulation of shattered assumptions.
Kepler understood this, and he worked to make it easier for people to understand that maybe Earth isn’t the only place in the universe, and therefore not the center of the universe. Thank you to people who share their stories, lowering the effort it takes me to realize that a belief that’s been good enough for this long, is not good enough for everyone.