Freewrite. Prompt: I know

For some hours now, I have been thinking on something to write on I know. It seems very easy enough and yet very difficult, maybe because of the simplism in it, I don't know. But there are a lot of things that I know or I think I know, or I know about "I know".

Like now, I know that I have been thinking for some couple hours on what I should write on I know. And I have been asking myself questions like: Should I write on what I know or "I know" itself?
Because if it were that I should write on I know itself, maybe focusing on its syntax would be more relevant and appropriate.
But if it were writing on what I know then maybe I will never finish or even start writing.
Because I know what I know and I do not know what I know or what I have known. Since there are some things I know I know but I don't know and there are many things I think I have known but I don't anymore.
I am confused.