How can you work with a JSON value if you know nothing about it?

I have talked about the difficulty of typing certain JSON values coming from some APIs. The JSON is just very complicated. When I do that, I often get this question “how can you work with a JSON value if you know nothing about it?” The question is rhetorical. Of course you can’t do anything if you know nothing about it. But we do know a ton! We just can’t (or it’s very difficult to) encode what we know as a type.