Neti-neti
An approach to self-knowledge is the "neti-neti". Going for "exclusion" you want to get to know yourself. I'm neither the perceptions nor the one who perceives them. I'm the "unknown thing" that knows (all). But in fact, if you go through the course of the neti-net you come to understand that you are both perceptions and the one who perceive them.
That "unknown thing" is unknown in the sense that one cannot know it as the human mind knows.
That "unknown thing" cannot be described to a person through concepts and words. And as I cannot describe it to someone, I cannot describe it to "me" because we are abused to know things through concepts and words.
You try to understand a feeling in the same way as you try to explain it to another person.
But to know that feeling I should not use the words with myself as if I were an "other"! I should not need the words! I just know that feeling in percieving it!
In this sense I can not know the mysterious thing that is "behind the perceptions and who perceives them".
But it's not a distant thing we do not have access to. It's the closest thing and the only one we've always had access to, but we have no way of describing it (in its entirety) to ourselves with the words.
So it is not really unknown. It is not something to find behind the perceptions or behind the one who perceives.
It is exactly what it takes the form of perceptions and of the one who perceives. It's as if in a universe made of clay we are looking for clay.
In the beginning, I surely see vases and statues, I do not find any clay. The clay I imagine is informe, muddy, gray etc.
When I understand the nature of that universe (and of the clay so) I understand that while I look at statues and pots I'm just looking at clay, while looking at my body I'm looking at clay, my sensations will be made of clay.
So from neti-neti (I'm not the vase, I'm not the statue etc) one MUST arrive to "I'm the vase I'm the statue" etc.
Everywhere I look there is clay, even if i close my eyes there is clay, whatever I do or will not do I'll always see/percieve just clay! I'm THAT (clay) Everything is That (clay)
I have words to describe only statues and pots and I can not describe clay! But who cares to describe it!?!
So maybe I do not "know"it even in being clay?
I know it. I know just it. I can know just it. I'm it. There is just it. (Monàs)