A Course in Miracles has some basic structure to it. The very simplest of these is the contrast between reality and illusions. e.g.
God, reality, awakening, light, creation, eternity, wholeness, permanence, heaven, truth, the Kingdom of God, etc... these all represent THE ONE TRUTH. This is "really big picture stuff". Only the Holy Trinity is real.
Illusions, separation, ego, denial, unconsciousness, death, dreaming, attack, murder, sickness, suffering, unawareness, darkness etc... these all represent THE EXACT OPPOSITE TO that one truth.
This produces what you could either think of as "two boxes", or as a container within a container.
Box A: Heaven, God, Creation etc
Box B: World you made, illusions, ego etc
as in "Earth, heaven's opposite in every way"
Larger container: Heaven, God, Reality etc
Smaller container inside it: ego, illusions etc
as in "you are safe in God, dreaming of exile"
You as a being, with a mind, are able to seem to "be in" either one of these two states. You can be in reality, or in illusions. You can be in heaven, or on Earth. You can be out of a body, or in a body. You can be having eternal life, or seeming to suffer and die.
In every case, there is a clear distinction between the "box" of reality and the box of illusions. Because in truth, the box of illusions does not really exist. There really IS only reality, and the "illusory fearful world" isn't real.
"Life has no opposite, for it is God."
Jesus describes this:
"If perfect love casts out fear, and if fear exists, then there is NOT perfect love. But only perfect love really exists. Therefore, if there is fear, it creates a state which does not exist"
Your experience of "where you are" and "what you are", is determined by whether you believe that Actual Reality is REAL, or whether an ILLUSION is real. If you believe illusions are real, you will substitute reality for it, BLOCKING your awareness of reality, and you will believe that illusions are reality. This is the ego at work. Being deceived by things which don't exist.
When this happens, you seem to find yourself WITHIN the "context of" which of the two boxes you believe is reality. Either heaven seems real, or earth seems real. Either God's Kingdom is reality, or "the world you made in dreaming" seems real. And if the world you made is your reality, you will believe you are LOCATED inside of it.
Now, there are things which ACIM states about reality, which is true in the biggest possible picture. For example, "Reality is a constant state", "Nothing real can be threatened", "Nothing unreal exists." In this CONTEXT, it might correctly identify that, from the perspective of reality, "the body is a dream" - "the body is clearly a device for separation and therefore does not exist" - "God did not create the body."
These are statements made FROM the context of reality. BUT, in the same Course, Jesus might go on to start talking about the body. He might talk about your USE of it. He might talk about what it pictures or symbolizes. He might talk about how to heal it, and about sickness of the body. These statements are made WITHIN or inside of the context of assuming that "the illusory body seems to exist."
So Jesus then is dipping inside of the "illusions" box, and starting to talk about the body as if it matters. But then later he might jump out of that box again and talk about it as though it is nothing and doesn't exist. He might say "The mind, being sane, heals the body." This is squarely within the context or box of "IF the body exists." We are ASSUMING here that we're talking about the body AS IF it is real. And so now Jesus talks about how to heal or change its condition.
But then Jesus might go on to say, "The body cannot stay without illusions" - "the body is a limit" "therefore it does not exist" etc. And this means he has stepped OUT of the context of the illusion box, into the BIGGER truth. The big truth now reveals that sick bodies and healthy bodies are EQUALLY ILLUSIONS.
What happens then is, if people don't RECOGNIZE which box Jesus is speaking FROM, what the CONTEXT is, what is assumed or accepted for the sake of description, mistaken conclusions will be drawn.
If you don't realize that there even ARE these two "levels" or contexts, you might read the entire course thinking it is describing ONE single context or state. And this will produce significant confusion and contradiction, because he isn't talking that way. What this then means is that you are "confusing the levels" because you are not clearly recognizing the context he's talking in.
So you might say, as if on the same level, "Jesus says sick bodies are the same as healthy bodies"... and "therefore, there's no point healing them." Do you see the subtle shift between contexts? It suddenly went from a "big picture" context, took that "level" of truth, and then shifted into the small picture context, and tried to make the big-picture truth apply equally at that level. This is a mistake in reasoning.
It leads to things like "there's no point changing the world", "there's no point healing bodies", "there's no point working miracles for others" etc. It also leads to "I'm not really a body so I should stop eating", "the world is not real so why bother having relationships", and all kinds of other nonsense. Confusing the levels leads to false conclusions. It also leads to sickness.
There are times where Jesus speaks highly of the world. In its forgiven state, He suggests it is the loveliest thing you'll ever see. How there is nothing but holiness reflected in it. That it's practically like heaven on earth. This is within the context of "inside the illusion box". It's under the ASSUMPTION that we're accepting that "the world seems to exist."
But Jesus then goes on to talk about how the world is NOTHING, the "sorry outcome" of a split mind, a world made by minds driven mad by guilt, an attack on God, a picture of the crucifixion of God's son. That eternity will shine away the world, and even the forgiven world will spin into nothingness. He even goes so far to as imply that in comparison to Heaven's reality, IT IS UGLY.
"This little step, so small it has escaped your notice, is a stride through time into eternity, and beyond all **ugliness**, into beauty that will enchant you, and will never cease to cause you wonderment at its perfection."
So at one moment he is speaking seemingly very highly of this world. Speaking of the highest possible way that you can look upon whatever it is, as if he's putting it on a pedestal and worshipping it. Then the next, he jumps OUT of that context of "the illusory world forgiven" and reminds us of how in the BIG picture, everything he just said so amorously about he world is dashed to the rocks and thrown into oblivion.
Because in the bigger picture, in that CONTEXT, there literally IS NO WORLD. Describing the world then as an illusion, false, unreal, hell, temptation, lack, darkness, the world of sin etc, is a CORRECT and truthful perspective when regarding the world from the LARGER perspective of reality. And this SEEMS now to be a "negative" tone, not at all praising the world or "sounding loving". Yet it is true.
This could cause a lot of confusion if you think that there are no levels or "structure" in the course. Many people, me included, read the course thinking that everything it says is all one ONE level and applies to everything. But believing this, one must be fundamentally confused by what it says. Jesus must sound contradictory. And what He says is likely to be only PARTIALLY accepted.
In this way, we will gravitate towards parts that we find acceptable or "sounding" more lovely, and will likely reject the parts that "sound negative". One part of the course will be pitted against another part and held up as defense against what the other part says.
It is vital to realize that there ARE levels because there IS a significant difference, TOTAL OPPOSITION, between reality and illusions. Which means effectively there are TWO WORLDS. The Kingdom God created, and the one you made to OPPOSE it. And the one you made in dreaming is totally opposite to God's.
"Earth, heaven's OPPOSITE in EVERY way."
You find yourself on earth in a body because of the fact you don't want to be IN the CONTEXT of heaven. Each of these two major contexts are not just concepts. Each one is a thought system. Each has produced an entire REALM of existence. And each is its own WORLD.
When you are IN the context of reality, you are NOT in this world. When you are IN the context of illusions, you are in THIS world. You cannot be in THIS world, this context, and be free of illusions. "The body cannot stay without illusions." "Indeed, you cannot remain in the world with this knowledge." "God cannot enter a body, nor can you join him there." "Those who perceive still need healing". etc.
So there are two major contexts, two worlds, two realms in which to find yourself, two thought systems, two "universes", and only one of them is totally true. The other seems true ONLY WITHIN its own context of "it seems to exist." If the world is accepted as existing, there IS something to be done to help others in the world. There is a curriculum to learn. There are miracles to perform. Bodies and minds need healing.
"The Soul never loses its communion with God. ***Only the mind and body need Atonement.*** The miracle joins in the Atonement of Christ by placing the mind in the service of the Spirit. This establishes the proper function of mind, and abolishes its errors."
Outside of the context of "I am in this world", being OUTSIDE the illusion box, you exist in Heaven with God. In Heaven there is absolute reality, permanence, truth, certainty, communion, creation, eternal life, holiness, omnipresence, immortality, constancy. "Outside" heaven in the dream world, none of these things are possible because the illusory world DENIES all of them.
So beware when you read ANYTHING in the Course, try to discern WHAT level it's on. What context is it being said within. And watch even for shifts in context/levels mid-sentence. Creating in your mind a crystal clear distinction between the two levels, assigning appropriate things to EACH BOX, will go a really long way to clarifying what Jesus MEANS and what he's referring to.
There are some extremely lofty beautiful things He says which are STILL squarely within the realm of illusions. And there are things which don't sound beautiful at all which are actually coming from a HIGHER level. "There is no world" isn't a damning condemnation of this world. It's just being honest about this illusion, from the perspective of the big picture. It actually should be cause for celebration.
"Forget not the Kingdom of God for anything the world has to offer. The world can ADD nothing to the power and the glory of God and His Holy Sons, but it can blind the Sons to the Father if they behold it. You cannot behold the world and know God. Only one is true."