Is the self all that can be known to exist?

[Edwardo Piet]

The self is not what is known; but rather, it is the means by which we know.

The self is a known knower. It's not the entirety of what we know but it's certainly part of it.

Identity, A=A, is what we know. Knowing ourselves is a subset of that because that's self-identity. We can't have "I think therefore I am" without "I am what I am" and "I think what I think" or A=A.