Snowflakes and fingerprints
Every kid knows that no two are the same.
The thing is, at appropriate magnification, if we’re paying attention and deciding to care, that applies to just about everything in the natural world.
Everyone is different.
It’s convenient to put people into groups and categories, and if that’s working out for you, carry on. But simply because it’s convenient to assume that people are the same doesn’t mean it’s true.