DEFINE “KNOW”?
As far as I know (as far as I am aware) it can only mean ‘aware of’. One’s assessment of the truth or falsehood is quite different. The test of that truth or falsehood is something else. The truth or falsehood should we possess perfect knowledge is something else entirely.
So we can know something.
We can know something is false.
We can know something is not false.
We can know something is difficult to be other than true.
Knowing of WHAT.
Most philosophical questions are actually just grammatical sophisms.