Tacit knowledge.

While I'm procrastinating... here's a great example of tacit knowledge that I stumbled across recently. So much of our knowledge of our native language is tacit that one could play this game forever. We know how to use English properly even if we can't explain it.

I was this many years old when I learned that there is an actual list for the proper order of adjectives when using multiple ones in the same expression. Now any English speaker knows this tacitly because we tend to do it correctly when we string adjectives: "He drives a new imported bright red SUV." But we can do that without knowing that there's a rule there.

We also know when it's wrong. I actually used the wrong order for comedic effect with "golden unexpected testicles" to describe our pear tree. It should be "unexpected golden testicles" technically, but the interior rhyme of "unexpected testicles" was just way too musical sounding to pass up.

I love stuff like this. That there is so much more we know, really know, than we can express in language or numbers is one of the most important insights to understanding human behaviour, and helps to explain why markets cannot be replaced by other institutions if we want to survive and progress.