I'm not very knowledgeable about the whole monist/dualism debate, but I don't understand how material monism precludes the existance of a creator god. Could you elaborate on that as a logical outcome of MM?
I should qualify what I meant by God up above, sorry (I realized it soon after typing). What I meant was that a personal God is not possible in the way that God is usually conceptualized. From a material monism perspective, what we call matter/energy/spacetime is all there is. What it actually is we have no clue, but that perspective rules out the possibility of another fundamentally different substance -- say, the divine. So, everything that is consists of energy (for want of a better term) following the set laws that we call the four fundamental forces and all can be explained by that.
A personal creator God would need to have a mind in order to plan and carry out creation. For this to happen, he would need to be made of something. If he were made of energy/matter, then he could not have created energy/matter since he is composed of it. So, he must be made of something else. But material monism, as a monism, precludes any other type of substance than matter/energy. So God, a personal creator God, implies dualism if you accept the existence of matter.
How do dark matter and dark energy interact with the 4% of our universe made out of ordinary material matter? Are they assumed to be of the same type substance (i.e. monism)? I was under the impression that we know so little about them that it was reasonable to speculate that they might be made of an entirely different substance.
Not a fundamentally different substance. If dark matter and dark energy are real, and if they are accountable by the standard model, and if they interact in our universe (which they seem to do), then they are something that we already know about to some extent (like say neutrinos), or they are fallout from the standard model. It is probably the case that the standard model is wrong and we are due for a new revolution in what everything is; or it is the case that what we currently think about dark matter and energy are wrong. I'm betting that we are due for a new revolution in physics.
One of the consequences of this way of thinking is this -- we live in a universe (duh). If we accept the conservation of energy as a true maxim, then it is impossible for something like a creator God to affect the universe because his interaction would violate the law of conservation. But the law of conservation of energy only applies to closed systems. What if our universe is not a closed system? I can see two ways to think about this issue -- it is possible that there is a closed system that includes a multiverse and there are purely explainable forces from other universes that interact with our universe and which could appear to be miraculous happenings (an entity arriving purely out of the blue without seeming explanation, but if we could see from the bigger perspective of the multiverse, we could explain it). Or, it could be that there is a divine realm that exists independently of the material universe -- dualism -- that interacts with our universe (which is not a closed system) through throroughly unexplainable means (magic).
Or it could be that the law of conservation of energy is wrong ultimately since it does not apply to God.