The mind wants to know everything in a few different, limited ways: through sight, sound, hearing, taste, and smell, through feeling and through thinking. That's basically how the mind wants to know. It wants to know something as a thing.
And so the mind tries to figure out the Self as a thing. But the Self is not a thing. It can be known only when the mind is still. The Self can only be known through itself -- a direct means which is not a mental means. It knows itself because its very being is its knowing. It's not like a mind knowing an object. The Self is a knowing. But it's not a knowing of. It's simply knowing itself. But not as an object of knowledge.
This is an utterly unique way of knowing, one that is completely foreign to every kind of knowledge the mind understands.
The mind can't fathom that. It tries to put the Self into its own mental terms. And so it comes up with feelings, comes up with pictures.
When the mind is quiet the Self is experienced without the overlay of mental things that usually obscure it, but that experience is not a mental experience in the usual sense of that term. But the mind still tries to make it so. And so it analogizes.
It says: the Self is felt as a kind of vast substance holding the the mind, which is a tiny image. That the Self is "that which watches" the mind. Or that the Self is bliss or peace.
Strictly speaking, none of these are true. The Self is indescribable, except to say that it is, and that its being and its knowing are one and the same.
The mind also wants to take credit. "I know the Self," it wants to say. But the mind can never know the Self. Rather, the mind quieting itself reveals the Self which knows the Self. To whom or what is that revelation? It must be admitted: to none other than the mind. After all, the Self knows itself eternally. To itself, it cannot be "revealed" or "hidden."
But the mind "knows" the Self as the mind's own not knowing, its beyond. It knows itself as the end of its own functioning. The mind closes its eyes in the temple and is overwhelmed with awe and it calls that its experience of "knowing." It is only its experience of being utterly humbled.
The mind knows the Self as the ungraspable, the unthinkable. Only it cannot accept that.
So the mind insists on continuing to put things in its own way of knowing. Which is fine: that's the nature of mind.