Self understanding is: the right to know who you are. But, did you know that self knowledge, and knowing yourself are two separate things?
What is active self understanding? In terms of self knowledge, it's incoming self analyzation. This means that you're not observing yourself, you're understanding self observation. This could mean you're focused on one aspect of yourself, or it could also mean you're focused on multiple. the idea is that you're observing who you relate to, as that self aspect.
What is passive self understanding? In terms of knowledge of yourself, it's outgoing self analysis. This means that you're observing yourself, and not engaged in self observation. Which means in kind, that everything that you are focused on, is happening to a you that seems separated from the aspects of self that holds your attention or attentiveness in any given moment.
Active self observation, requires an understanding of the role required of your consciousness. Whereas passive self observation