[_pius]

This reminds me of the opening to David Foster Wallace's "This is Water."

There are these two young fish swimming along, and they happen to meet an older fish swimming the other way, who nods at them and says, “Morning, boys, how's the water?” And the two young fish swim on for a bit, and then eventually one of them looks over at the other and goes, “What the hell is water?”

Of course the invention of representations like written language, equations, and graphs changed the way people think. It's just hard to see at first because you've grown up immersed in them.