I've already summarized my understanding of the authority structures in Christianity, so I'll highlight how Monism differs.
Caveat: as with any discussion of a philosophical concept, you can wind up in the weeds very fast...my superficial discussion below is based more on how various Monist concepts are influencing Western culture today than a rigorous consideration of a specific type of Monism. For example, my understanding is that most serious Buddhists from the East generally find Western interpretations of Buddhism more than a little narcissistic.
"All is one" is the basic belief of Monism. There is no fundamental separation between any god or rock or person or atom or etc. The physical and metaphysical are ontologically a single whole.
Traditional Christianity asserts that there are certain fundamental distinctions prior to creation and in the created order that must be recognized and respected. Among these are:
- God is separate from His creation, He created it volitionally (i.e., the universe is not an undirected emanation from God), He exercises authority over it, and He relates to it in a personal manner. A Monist perspective tends to deny all of this...there is no ultimate telos/purpose, there is no personal "God" ,and there is no legitimate source of authority other than an appeal to some sort of mystical knowledge. All people, animals, atoms, etc. are in a sense, "God."
- God is triune (Father, Son, Spirit). These distinctions and their roles (including the associated authority structure) are eternal. Though there's no current Monist heresy in this area (at least that I'm aware of), I think that (a) the concept of Allah in Islam (one, not triune), and (b) the egalitarian assertion that the Father-Son-Spirit authority structure is not eternal are dangerous assertions of an unbiblical oneness. More on the egalitarian perspective later.
- God is holy, humans are not (since all rebel) and are thereby separated from God, and the resulting rift between God and man is so fundamental that only the sacrifice of God in the flesh (Jesus) can repair it. Monism asserts that the apparent difference between holiness/goodness and sin/evil does not exist (e.g., Buddhism asserts they are an illusion).
- God made humans male and female. I'll address this is more detail later, but for now I'll simply note that Monism tends t0 be consistent with the belief that gender differences are superficial and fluid (i.e., not fixed) and that all possible sexual arrangements and interactions among living and non-living entities are equally valid. The degree to which this is consistent with the dominant secular ideology of Darwinism is unclear...eugenics came and went (though it's making a bit of a comeback in some circles), and it would seem that the success of sexual reproduction (vs. asexual reproduction) would resist a Monist sexuality, but that seems not to be the trend over the past couple of decades. And, genetic engineering is raising the distinct possibility of various types of reproduction: asexual (cloning), multi-sexual (a mixture of multiple males/females), and trans-species (a mixture of human and non-human). Whether God has wired the universe to make any of this impossible is not yet clear.
- God made humans to exercise stewardship authority over the rest of creation. Monism would tend to deny this, and would tend to be consistent with the more radical environmental movements that see humans as a cancer if humans are valued above other living and non-living entities. It is also consistent with a secular view that the universe was "self-created" (a logical contradiction) and with Darwinism.
I suppose the authority structures Christianity sees in the family and society (government) have not yet been as dramatically influenced by Monism (except for the husband-wife relationship...more on that later). However, it seems that this may be changing...for example, there's a growing tendency to (a) see children as autonomous (i.e., not under their parent's authority), (b) see all societal authorities as provisional at best (i.e., legitimate as long as they act in a way I think is "just") and fundamentally oppressive at worst...echoes of Marxism and other utopian frameworks that want to move the world toward some sort of blissful unity.
I guess that's more than enough for now. I'd be interested if you see other trends that are consistent with a Monist worldview.