Using textual evidence, How well does Hamlet know himself?

I don't think he really understands himself until the end of the play. Hamlet is a bit of an existential hero figure. He understands that he, like all of us, is destined to die. He is satisfied that he has done his due diligence before exacting revenge for his father.

Not a whit. We defy augury. There's a special providence in the fall of a sparrow. If it be now, 'tis not to come. If it be not to come, it will be now.