In ACIM, we're told that we made a world, which is really spacetime, and a part of this spacetime is planet Earth. This didn't exist before the separation from God, and DEPENDS on the continuation of separation in order to take on "form".
The world itself was the idea of the opposite to everything-ness, which is the idea of nothingness. Thus the world was made as an empty shell symbolizing nothingness or a "lack of God", onto which we project meaning.
"That was the first projection of error outward. The world arose to hide it, and became the screen on which it was projected, and drawn between you and truth." (the world Earth comes between you and the truth as "emptiness" and "nothingness", and we then project ONTO the Earth)
The Earth itself is meaningless, and is nothing. Being devoid of any inherent properties of its own, like a dark shadow, it acts like a mirror, reflecting meaning given to it. You have to give it meaning because it has none. And even when you give it meaning, it still has no INHERENT meaning of its own.
"The world is nothing in itself. Your mind must give it meaning."
Because Earth is meaningless, you can project good or bad thought onto it. Thus it can REFLECT an IMAGE projected onto it. It can reflect ideas of heaven or hell, and you can see these IN it, as though a reflection once removed from the thing projected. This doesn't mean the Earth IS heaven or hell, it is neutral, but it can be INTERPRETED as REFLECTING either.
"Earth can reflect Heaven or hell; God or the ego."
"If a mind creates without love, it can create an empty shell (spacetime/Earth). This CAN be possessed by evil."
Having projected an "empty screen" AS EARTH, our egos rushed in and attempted to project ego meaning onto the Earth. It tried to focus on form and separations and differences to emphasize the separation, projecting this onto the Earth so that Earth "reflects hell."
"It represents a situation in which God and the ego "challenge" each other as to whose meaning is to be written in the empty space which meaninglessness provides. The ego rushes in frantically to establish its own "ideas" there, fearful that the void may otherwise be used to demonstrate its own unreality."
Earth, and spacetime, are a "void" of nothingness, onto which we project God or the ego. Our task then becomes to recognize that we are projecting ego/hell onto a neutral/nothing/meaningless world, and that we can instead project God/heaven onto it. This seems to project meaning and reality onto it, as well as love and peace and holiness. It then becomes possible to see IN the world, a REFLECTION of heaven.
As in "God is in everything I see". This doesn't mean the thing reflect IS LITERALLY the world or AS it, but is reflected IN it. Just as an image of your body is seen IN a mirror. This reflection is an image, and is also referred to as forgiveness. It is SYMBOLIC. It represents something once removed from itself. Just as a reflected IMAGE in a mirror is once removed from the actual object. The reflection of heaven on earth is NOT heaven ITSELF, but it appears to be LIKE heaven. And it is what you PUT THERE that is "the only reality it has."
"The only thing of value in it is whatever part of it YOU look upon with love. This GIVES it the only reality it will ever have. ITS value is NOT in itself" (it has no inherent love/value/reality) A mind which is healed translates the neutral nothingness of Earth into something that resembles heaven, interpreted with ideas of wholeness and healing, with love and peace, with light and happiness etc. This "converts" in a sense, through an inner translation, the form of the world into something that seems to mean heavenly things. Thus Earth appears to the mind to become heaven-LIKE. A REFLECTION of heaven, a symbolic DREAM of heaven. A "real world."
However, we need to be clear that this reflection of heaven on Earth IS NOT the same thing as heaven ITSELF. Heaven Itself, which is reflected ONTO the Earth through projection, is still a distinct dimensional reality created by God. Earth, as a veil of illusions, as an illusory world, as an empty screen, as a void, as a nothingness, must disappear. Part of seeing heaven in it ALSO entails seeing that the world has no attributes of its own, otherwise the reflection cannot be seen. And having no attributes, Earth is recognized as NOT REALLY THERE.
As the veil thins, the mirror dissipates, the reflection in perception (forgiven world) gives way, and parts. And now it disappears and is forgotten. Everything that entailed "the Earth" fades into the nothingness from which it came. The reflection of heaven, the real world, is gone.
"The real world still is but a dream." "Even the real world will vanish from your sight."
With the disappearing of Earth and space and time and the sun and stars, shone away BY light, because they are darkness, REPLACED by heaven, all that then remains is heaven ITSELF. An actual real created "world", not Earth in any way, not space or time, or any other such form, but the living world of light, the creations of light, the true Kingdom of God, which the nothing Earth was all this time made to CONCEAL and hide.
Heaven is first reflected in the world, seen "in the world" here, as Earth is "translated" into heaven. But then Earth ends. A translation IS once removed from the original form of something, and although our minds can see the translation the thing BEING translated is still a void of nothingness and illusions. Earth cannot remain as part of the Kingdom, it is not ACTUAL holiness, the body cannot BE holy, and all other divine attributes cannot be fused into the planet.
"As nothing, which it IS, the body cannot meaningfully be invested with attributes of Christ OR of the ego. EITHER must be an error, for both would place the attributes where they cannot BE. And BOTH must be undone, for purposes of truth."
As the world, Earth, spacetime, disappears, heaven itself, a condition of ACTUAL holiness and BEING holy, is all that remains. This is A Course in Miracles.
"The world stands like a block before Christ's face. But true perception looks on it as nothing more than just a fragile veil, so easily dispelled that it can last no longer than an instant. It is seen at last for only what it is. And now it cannot fail to disappear, for now there is an empty place made clean and ready. Where destruction was perceived the face of Christ appears, and in that instant is the world forgot, with time forever ended as the world spins into nothingness from where it came."
"YOU DO NOT WANT THE WORLD. The only thing of value in it is whatever part of it YOU look upon with love. This GIVES it the only reality it will ever have. ITS value is NOT in itself" (notice how you GIVE it reality/love, it does not HAVE it itself)
"The world is nothing in itself. Your mind must give it meaning. And what you behold upon it are your wishes, acted out so you can look on them and think them real." (wishes can be unholy or holy, but they're still GIVEN and not inherent)
"This interpretation of the body will change your mind entirely about its value. Of itself it has NONE."
"But what is truth to him must be brought to the last comparison that he will ever make; the last evaluation that will be possible, the final judgment upon this world. It is the judgment of the truth upon illusion, of knowledge on perception; IT HAS NO MEANING AND DOES NOT EXIST." (the Earth mirror does not exist, spacetime has no meaning of its own)
"Creation cannot even be conceived of in the world. It has no meaning here. Forgiveness is the closest it can come to earth." (forgiveness is an earthly symbolic form of heaven's love)
"The body no more dies than it can feel. IT DOES NOTHING. Of itself, it is neither corruptible nor incorruptible. IT IS NOTHING." (this is literal, the physical body is nothing at all, it has no reality).
"It is still true that the body has no function of itself."
"The test of EVERYTHING on earth is simply this: "What is it FOR?" The answer makes it what it IS for you. It has NO meaning of itself, yet you can GIVE reality to it, according to the purpose which YOU serve." (it has NO MEANING of itself, Earth has NO MEANING of itself. You have to GIVE it TEMPORARY meaning)
"Darkness is lack of light. It does not have unique properties of its own." (Earth is like a shadow, a lack of light, the absence of God - world made as an attack on God/light etc)
"All these attributes are given it by you. The world is meaningless in itself." (Earth has no inherent attributes)
"In the world you, can become a spotless mirror, in which the holiness of your Creator shines forth from you, to all around you. You can REFLECT HEAVEN here. But no reflections of the images of other gods must dim the mirror that would hold God's reflection in it. Earth can reflect Heaven or hell; God or the ego." (Just the fact Earth can reflect VARIABLE things means NEITHER is permanent)
"Those who have learned to offer ONLY healing, because of the reflection of holiness in them, are ready at last for Heaven. There, holiness is not a reflection, but rather the ACTUAL CONDITION of what was but reflected TO them here. God is no image, and His creations, as part of Him, hold Him in them in truth. They do not merely REFLECT the truth, for THEY ARE truth." (notice how reflecting holiness on earth makes you READY to go to heaven, cus you're not there yet. IN heaven, holiness is a condition not a reflected image)
"Yet forgiveness is the means by which I will recognize my innocence. It is the reflection of God's Love on earth. It will bring me near enough to Heaven that the Love of God can reach down to me and raise me to my home." (again, bringing heaven to earth to REFLECT here, gets you ready to LEAVE)
"As I begin to see, I recognize His reflection on earth."
"Forgiveness, truth's reflection, tells me how to offer miracles, and thus escape the prison house in which I think I live."
"All the world shines in reflection of its holy light, and I perceive a world forgiven at last."
"Reflect the peace of Heaven HERE, and bring this world to Heaven. For the REFLECTION of truth draws everyone TO truth. And as they enter INTO it, they leave ALL reflections behind. In Heaven, reality is SHARED, and not reflected" (again a distinction between reality being shared (communion) in heaven, vs reality being REFLECTED on earth (communication))
"What they have felt in them they look upon, and see Its sure reflection everywhere."
"A sleeping mind must waken as it sees its own perfection mirroring the Lord of Life so perfectly it fades into what is reflected there. And now it is no more a mere reflection. It becomes the thing reflected, and the light which makes reflection possible. No vision now is needed. For the wakened mind is one that knows its Source, its Self, its Holiness." (again moving out of the reflected heaven on earth, INTO heaven proper, leaving the world behind)
"We do not see the ego's shadow on the world today. We see the light, and in it we see Heaven's reflection lie across the world." (heaven's REFLECTION, not heaven itself)
"the world he made. In error it began. But it will end in the reflection of his holiness." (the world ENDS when heaven is reflected in it, it doesn't go any further or enter INTO heaven)
"Where this Child shall go is holy ground. It is His holiness that lights up Heaven, and that brings to earth the pure reflection of the light above, wherein are earth and Heaven joined as one." (one means similar, not singular. also heaven is above the earth and they are not the same thing)
"God's laws do not obtain directly to a world perception rules, for such a world could not have been created by the Mind to which perception has no meaning. Yet are His laws reflected everywhere. ******NOT that the world where this reflection is, is real at all.*******" (The place where heaven is reflected on earth IS NOT REAL AT ALL - Earth is not real at all!! The reflection appears to be a real-like IMAGE, but is not heaven itself. Earth is never heaven but can appear heaven-like through translation.)