This shows a funny way that the word invent has shifted in meaning. Invent means “found” (almost literally “came upon” in Latin) - yet for some reason it shifted to mean “created” in a sort of “this is mine don’t steal it from me” sense. Then here we are clarifying that we literally mean the actual meaning of the word. It’s interesting that math is considered impossible to have as intellectual property, yet we think somehow that IP law is justifiable for everything else.

I understand that distinction. Russell came up with a mathematically rigorous theory for the foundations of mathematics and happened to use a very simple type system to accomplish it. He wasn't the first to formally make use of types, though he may have been the first to use that term. He also seriously pushed forward our techniques of mathematical rigor, so in some sense he "invented" many, many, many things.

To be clear, I think Russell was an amazing mathematician and inventor. I also think that the history of types is way more rich and interesting than just saying that he invented the idea. To not mention at least Frege is to miss a lot.

In my game design I've imagined two parallels to invention; discovery and identification. All three are learning about the world, but in slightly different ways.

Invention: I created that.

Discovery: I found that lying around.

Identification: I conceptualized a definition for that.

This is certainly more true. That explosion of logics I mentioned was a big movement of many authors to expand our understanding of types (among other things).