There is monism that claims that the physical world is all there is.
Then, we have dualism, a distinction between mind and matter.
Trialism is less known. In philosophy, trialism was introduced as an alternative interpretation of mind-body dualism by Descartes, keeping the two substances of mind and body, but introducing a third substance, sensation, belonging to the union of mind and body.
I would however apply the third realm to the mind of God.
According to George Cantor, there are three realms:
(1) the mind of God,
(2) the human mind, and
(3) the physical universe.
Einstein wrote about two realms, and an unbridgeable gulf between them, that separates the real world of objects, events, and tensional spacetime relations from fully abstract representations that contain information about the material world.
Isaiah 55: "For my thoughts are not your thoughts, neither are your ways my ways," declares the LORD. "As the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts.
While God has thoughts as we do, his mind and nature are in a category of their own.
I can imagine the gap of quality, the distinction that is separated by an unbridgeable gulf between the material and the human mental realm, so there is equally an unbridgeable gulf between the human mind, and God's mind.
This is maybe an as much dramatic break as between the living and non-living world and represents the second additional most dramatic and fundamental of all the discontinuities of reality.
There is a creator/creature distinction. God does not depend on any cause other than himself for his existence. He is self-existent, uncreated, eternal, the alpha and omega. He incorporates several superlatives. The first commandment is, "Thou shalt have no other gods before me." -Exodus 20:3. Put God above everything else.
So we may order the material world on the one side, man with his dual nature, matter, and spirit, in the middle, and God on the right. He transcends the physical material world, knows everything that happens in his created world, knows the mental realm of all man, and knows himself, and all dimensions above ours. Obviously, his intelligence and power far exceed what we can ever think of or imagine. His goodness is infinite, he is 100% light and love, righteousness and truthfulness, and there is no darkness in Him. He lives in perfect love in his communion of father, son, and holy spirit, and he lacks nothing. And in his all goodness, he is extends his perfect existence, offering it to his creatures - those that freely chose to know and love Him.
Other than boring, heaven will be the most awesome, awe-inspiring existence that we cannot fathom yet since it has not been fully revealed to us. But each of us will have a special place in the body of Christ - in as much as he has a plan for us here on earth, this plan extends for all eternity.
God is the precious pearl, the wealth that this world can offer is nothing in comparison. Chose wisely - chose God. He is good and has a perfect plan for each of us.