What is the world? What is the knower of the world?
Any "thing" is only apparently so from the perspective of senses - from the perspective of eyes and touch the rock is a solid thing - yet from a microscope we find the elements, maybe molecules which are atoms - atoms are empty space described by an orbiting electron - pulsing energy - energy behaving in certain patterns. This commonality is the same for any "thing" essentially. At this point all so-called "things" are particular patterns of energy or emptiness. Emptiness behaving in particular ways.
We know this even at the level of the senses - water is ice, liquid and vapor - why is it so? Isn't the essence water in all cases? The form we see is different but the essence remains the same. We aren't fooled by the form-ation because we know it's water appearing as ice, water appearing as liquid, water appearing as vapor or fog or mist.
But water is hydrogen atoms and oxygen atoms - a combination of atoms creating a particular form-ation, a particular appearance. We look upon water in its various forms and overlook the reality that it is both hydrogen and oxygen atoms. Those atoms are a movement of energy - the behavior of emptiness itself. Is it not so? We don't walk around thinking this way but nevertheless it's true. Our reality is shaped in terms of our taking the resulting form-ation as true and overlooking the essence.
In other words, we take a relative appearance AS absolute reality. This is called maya. A veil made up only of inattention, only of conceptual reality, of ignoring what IS in preference for what appears.
Yet we can also say that what appears IS what is, only the resulting form-ation is relied upon for the picture of reality. Therefore the rock is a separate entity. The ice cube is a separate "thing". And this is mainly from the perspective of a knower. To ME it is separate. From MY perspective it is separate, yes?
So what is the reality or essence of the knower? The body is part of the world - it is a form-ation - it is made up of the elements - carbon, hydrogen, oxygen, etc. The make-up of the body is the elements - elements are atoms - atoms are once again emptiness - intelligence-energy - behaving in a way as to appear, like the rock, as a separate form, a thing among things -but only from the perspective of the knower of the body.
Ultimately there is a knower of all forms - a knower that isn't appearing as part of the known. That knower is also intelligence - you are intelligent - you are present. So you are a fact yet you cannot find yourself among these form-ations. However we can never divide or separate or assert a separate intelligence anywhere. That emptiness, that intelligence-energy is no different from the intelligence-energy from which the world appears.
That intelligence is what IS - that intelligence is all. We can say it is knowing only in reference to the known. When it is only knowing itself, even knowing must fall away as the final duality and what IS remains indescribable yet the most real, unbound from the relative form-ations and dualistic equation of seer and seen.
What IS, when described in terms of the resultant form-ation, is only relatively true - the absolute (concept) is undefinable and ineffable yet is the most real.
You are that.