@Cyracuz,
First: "Experiencing experiencing experiencing" (This is not my idea. Wish I could remember the source in which I originally read the phrase.) So what does it mean?
On one level imagine a sentence that has a subject an active verb and an object. Like John sees a tree. Now this sentence can be interpreted the same way. Who or what subject is experiencing? Answer: Experiencing is experiencing. What is experiencing doing? Experiencing is experiencing. What is experiencing experiencing? Answer: Experiencing. Now you can see the meaning of the sentence by uttering it that way. I mean "Experiencing experiencing experiencing." Subject verb object.
Now here is the real problem. Understanding that sentence is not possible without being the experiencing experiencing experiencing. The only way I can explain it (I know I am being repetitive - excuse me) is to imagine the line drawing of a curve. You can look at one of the squares as being forward in the figure. Then you can, through an act of will, try to see the other square as forward and the one that was forward now in the rear. Then after you try for a few seconds - suddenly - it changes. So it is with experiencing experiencing experiencing. First you must look out of your eyes and try to "see" experience that way. Then after a time, perhaps, just as suddenly as a cube changes sides, it happens. And you must see then that that is what "Being" is. Being is being. It is a kind of verb. Time... or better "time-ing" is fundamental to it. And you will wonder how you could ever have not seen it. But in a while you will no longer be able to see it that way except you will remember it and know its meaning.
It is not enough to understand what I am saying you have to see it. You have to look up from the words at the room around you and try to see what I mean. If you do it will unlock philosophy.
The idea of "substance interacting" is not correct. There is no interaction at the foundation of reality. It is a monism and the nominal case which is the essence of what substance refers to merges with the verb. There are not two substances "consciousness" and "reality" - in fact there is no substance only experiencing. And in fact it turns out that even in the objective interpretation there is only one substance. It is achieved by nihilating or removing the notion of perceptions from the interpretation of the thing. It is not my seeing a rock. It is the rock. And the rock is over there not where the seeing is. The seeing is over here in my head separated by the distance between me and it. And that seeing is not substantive. That is why people identify consciousness with the brain and why they say rocks are independent of consciousness. Because there is no other substance there! And if "to be" is only "to be something" to "be substantial" to "be concrete" rather that to be a "mere abstraction" then consciousness is really nothing. That is the objective interpretation.
The notion of substance is a valid interpretation of the nature of reality and within that interpretation there is a notion of the being of substance. But this only a natural entity posited. A kind of constancy is required for its validity. Above all it is an interpretation of the natural world. It is not an interpretation of existing itself. The fact that the natural world is objective is an accidental property of existing itself.
We do identify with our brains in the objective interpretation, but our brains are, like all other objects, merely a fact. They are not essential to existing. You can see this by imagining that the world kind of melts in front of you. Colors kind of swirl and you try to look down at your body but there is no possibility as there is only swirling color then the color goes monochromatic.
That is a logical possibility. But saying it "could happen" ignores the result of natural science which says we are our brains and there are these things which are interacting in space etc. and were your brain to melt you would cease to experience. Natural science excludes the logical possibility that I just described. Says it won't happen. And it doesn't. At least it hasn't in recorded history or in my experience.
That natural science however is true only based on existence - that is based on experiment which is incapable of completely removing the possibility. But it is true in that sense - within that limit. It is undeniable. Look around you. Even within relativity and quantum mechanics it is to a large extent true. This is the source of a lot of the frustration that materialists feel when they confront descriptions of existence. The objective world is right there. You are looking at a computer. Do you know see that? Materialism expresses a lot of the nature of our experience and even, to the extent that an assembly of of molecules into a brain causes experience in the material sense of causality it describes the *fact* of our existence. For example I was born on a certain day at a certain place. This is a very valid assertion.
Of course I am saying that this is merely a "fact" and so is subject to observation and in fact the normal materialist view of naive realism is compromised by quantum mechanics and the theory of relativity. Technically the naive form is unscientific. But that does not mean that a large part of objectivity doesn't survive in these theories. Sorry for the long post.