"Can you explain a bit how ACIM describes or references the concept of consciousness? I realize this is a fairly big issue, so if you can hit the highlights, I will follow up with more detailed questions if necessary. Thank you!"
In A Course in Miracles, there are certain terminologies used and each has a distinct meaning. The term "awareness" is different to the term "consciousness".
At the highest level, in Spirit, where there is no separation in the One mind, there is pure awareness. This isn't a state of there being a separate thing to be aware of, or an observer who looks upon at thing believing it is separate from themselves.
The awareness can be equated with light, truth, presence, oneness etc. It is an awareness of what is. The awareness is itself aware of the awareness, so to speak. It's a little hard to clearly explain that state of being because there is no separation in it and no division between something being aware and what it is aware of. There is only a oneness. A presence.
In contrast to this, following the illusion of the separation from God, there came into being an idea of a split in the mind, or a division between Self and True Self, and between Self and God. This split in the mind appeared to cause there to be more than one mind. The mind, by choosing to believe in separation, believed that it contained separation, and had become separated from itself as well as from God.
This act of separation, if it were real, is essentially an "attack" on Self and on God. The attack is the attempt to push God away and to reinforce the idea of some kind of difference between Self and God, and between Self and self. So the mind then has this kind of war going on with itself, a self-attack, and a state of inner conflict.
This split in the mind created a state of mind where it seemed like some parts of mind were one identity, and other parts of mind were another. Some kind of illusion of a difference seemed to distinguish the parts from each other.
Mainly, one part of the mind remained the "conscious mind" which houses the persona - an illusionary identity which comprises all of the aspects of Self that you want to keep or emphasize, and an "unconscious mind" which houses the shadow - an illusory identity which comprises everything that the conscious mind wants to get rid of.
In order to create the illusion of separate selves, and of being less than whole, the conscious persona mind attempts to isolate various aspects of the mind and deny them, hide them, reject them, or at least creates an illusion that this is possible. It shoves guilt and sin and darkness and self-hate into that unconscious part of the mind to try to get rid of it, creating the illusion that the conscious mind-self remains good and innocent and guiltless. It's a coping mechanism and an attempt to pretend i.e. deny the guilt that arose from believing in the separation from God.
So in a typical split mind, there's at least two major parts, and usually many more sub-divisions and parts. Either way, this contrast between one part of the mind being separated off and identified with or kept in awareness, while another part is relegated to unconsciousness, creates "consciousness". In other words, consciousness in Course terms means the state of mind where the mind is split in half and therefore, there is now an observer and an observed, an object and a subject, or what appears to be a separate viewpoint or perspective looking upon everything that it believes it is not - the unconscious mind, as though it is "not self".
So the persona part of the mind basically disassociates from the rest of the mind and experiences the rest of the mind as though it is "not myself". This makes it unconscious but also makes the mind believe that this other stuff is not inside of it, and thus is external to the conscious self. This belief that the unconscious mind is separate from and external to the conscious mind, causes the conscious mind to experience the unconscious as "the external world". All of this is taking place within the whole mind, of course, but the little bit of mind that remains conscious thinks it is the whole of "self", while the vast expanse of the unconscious is perceived as "not me".
When you think of this in the big picture, in terms of Christ's mind doing this, then you would find that the retained conscious self is the "sonship" and everything that was denied and believed to be "not me" turned into the physical universe. The entire physical universe is now experienced as being outside of the many fragments of conscious self - which show up in bodies, surrounded by the protective shell of the physical body, outside of which appears to be "everything that is not myself" i.e. the unconscious mind.
So now you have the inner and the outer, the little me that hides in the body behind the defenses it provides, and the big unconscious mind which is estranged and not-myself, outside of it. The body is a device for separation within the whole, standing between the inner and outer self. This literally is how the world was made within the scope of the whole mind of the Son of God. It is all happening inside the mind, and this whole physical universe including the conscious selves is the content of the larger one mind of the Son of God dreaming of exile.
This appears to create consciousness, whereby you as a separate fragment of mind look out upon the vast expanse of the disassociated external world, and so now little people in little bodies look upon a big wide world believing it is not themselves. "Others" show up in bodies in this world also, really additional portions of conscious self that have been split off into a multitude of selves, all disassociated from each other and dwelling within the confines of the larger mind which shows up as an illusory universe.
So really consciousness is not just a matter of a person in a human body being aware of stuff outside of them, or a confusion about whether animals are conscious etc. Quite obviously absolutely everything within the confines of this dream world is a part of consciousness, and therefore must retain some portion of awareness, because it is all part of the mind. What is within the mind must have a mind, and so all forms of so-called life in the world have a mind with some conscious awareness, even rocks and planets.
But really on the larger scale, this entire universe is still an illusion which is based in separation, and all of the "consciousness" that expresses it is not really representative of a whole mind. Consciousness does not mean wholeness, it means separation. It means somehow you are looking upon some portion of your own self as though it is not yourself. It means no longer being whole or one, and thus when you look out upon a world and see it is as not yourself, you are in a split mind - i.e. state of consciousness.
Really, you could substitute the word "consciousness" for UNconsciousness, because as soon as a split is introduced into the mind, there is a reduction in awareness and so the mind is falling asleep. It sounds completely backwards to say this, but, consciousness means unconsciousness, and by "becoming conscious" you actually are gaining unconsciousness. Consciousness is a decoy. It is not all it's cracked up to be, and that's a pun in more ways than one.
What you really should be interested in is awareness. Awareness is the opposite of consciousness. Consciousness is what you get when there is separation in the mind and the mind cannot see all of itself or be aware of oneness. Awareness is what you get when the mind is aware of its wholeness and oneness and it doesn't have a persona or a shadow or any other fake identities within it. Cultivation of awareness leads to "awakening" to a state of the awareness of Love's presence i.e. God.
Consciousness is highly overrated, in that regard, and placed on a pedestal and worshipped as some kind of crowning glory of mankind's amazing abilities or advancement. Really we are transcending consciousness and returning to awareness - a state of mind without division in which there isn't a separate self looking out upon a "not self" world, disassociated from itself and believing that it has multiple personalities. Consciousness means multiplicity and duality. Awareness means wholeness and oneness and singularity.
The persona part of the mind - the conscious mind, needs to be canceled out by being brought into contact with the unconscious mind - the shadow - whereby the whole mind sees that both of these parts of mind are actually a part of Self, and not distinct personalities. Whatever separations exist between them or in whatever way they have a story or an identity based on differences, those differences must be recognized as illusions and as not true.
The whole mind needs to be able to step outside of the partial mind, seeing that both the persona and its enemy the shadow, are both "within" it, and therefore are both a part of Self, and cannot therefore be separate of really different from each other. Whatever differences the parts of the mind exhibits must be illusions.
The persona's enemy, the shadow, has really just been the whole mind using the shadow to attack the persona. And the shadow, which sees the persona as an enemy, is really just the whole mind using the persona to attack it. This is all a game of self-attack, masquerading as though both sides of the attack are actually different parties. They are not. They are both being manipulated and controlled by the one whole mind. The one whole mind needs to become aware of this so that it will literally stop attacking itself.
This is why the secret to salvation is that you are doing this all to yourself. All of your conflicts and wars are really playing out within the confines of your own mind, not out in an external world. It's all about you and what you are doing to yourself, what your persona is doing to your shadow, what your shadow is doing to your persona, and how you are playing them off of each other as part of your self attack. You are not a multiple-personality consciousness, you are a unified awareness.
If you would realize that you have been using one part of your mind to attack another part, in the name of believing in separation, you would perhaps stop doing so. And then the awareness that would dawn on the mind that ALL parts of the mind are part of Self or Identity, would cancel all of those splits and the mind would return to wholeness - awareness. This would be the end of consciousness (and unconsciousness), and the restoration of awareness. Both the conscious self and the unconscious self are illusions within the greater awareness. Subject and object are illusions of consciousness within awareness.
You do not need consciousness in order to exist, or in order to have a mind, or in order to be aware. You only need awareness, and awareness is of the One Spirit, shared with God.