This is a simple logical premise deeply rooted in the Course. Heaven was all that existed, and WE MADE UP an opposite to Heaven. And that opposite is ALWAYS opposed to Heaven, totally UNLIKE Heaven in every way, and is the idea of HELL, no matter how you perceive it or look at it or think about it. An opposite to heaven DOES NOT EXIST. Therefore there is no world - Earth, as Heaven's OPPOSITE, does not exist.
Below are a selection of quotes, which all highlight that Earth and Heaven are OPPOSITE. They will NOT EVER BE "one thing", or the "same thing". Earth was made to OPPOSE the one possibility of Heaven in every way. "The world was made as an attack on God." In no way, at no time, will the Earth merge with Heaven. "Love, which is all encompassing, HAS NO OPPOSITE", and so the opposite to Heaven, which is Earth, shall simply disappear into the nothingness from which it came.
You are either "in heaven", without an opposite, or you are "in hell" (Earth) with an opposite. If you are in the Earth, Heaven must then HAVE an opposite, Earth is now hell, and there is no escape from duality.
Perception has nothing to do with that fact. Perceiving hell in a heavenly way is only a temporary state in order to prepare you for the reality that Heaven is the only reality and THERE IS NO WORLD. Earth, as Heaven's total opposite, CANNOT CONTINUE being "Earth" in any recognizable way, which is MADE OF OPPOSITION (which is attack), while also being "equated" with or identical to Heaven. Heaven HAS no opposite. Earth DOES NOT EXIST.
"For THIS WORLD IS THE OPPOSITE OF HEAVEN, having been made to BE its opposite. And EVERYTHING here takes a direction EXACTLY OPPOSITE to what is true."
"Heaven remains your one ALTERNATIVE to this strange world YOU MADE and all its ways; its shifting patterns and uncertain goals, its painful pleasures and its tragic joys. 2 God made no contradictions. 3 What denies its own existence and attacks itself is not of Him. 4 He did NOT make two minds, with Heaven as the glad effect of one, and EARTH the other's sorry outcome WHICH IS HEAVEN'S OPPOSITE IN EVERY WAY."
"FOR THIS WORLD IS THE OPPOSITE OF HEAVEN, being MADE TO BE ITS OPPOSITE, and everything here takes a direction EXACTLY OPPOSITE of what is true. 7 In Heaven, where the meaning of love is known, love is the same as union. 8 Here, where the illusion of love is accepted in love's place, love is perceived as separation and exclusion."
"It applies to everything that God created, and ONLY what He created is real. It is beyond learning because it is BEYOND TIME AND PROCESS. It HAS NO OPPOSITE; no beginning and no end. It merely is."
"How could the Son of God make time to take away the Will of God? 3 He thus denies himself, and contradicts what HAS NO OPPOSITE. 4 HE THINKS HE MADE A HELL OPPOSING HEAVEN, and believes that HE ABIDES IN what DOES NOT EXIST, while Heaven is the place he cannot find."
"From knowledge and perception respectively, two distinct thought systems arise which are OPPOSITE IN EVERY RESPECT. In the realm of knowledge no thoughts exist apart from God, because God and His Creation share one Will. The WORLD OF PERCEPTION, however, is MADE BY THE BELIEF IN OPPOSITES AND SEPARATE WILLS, in PERPETUAL CONFLICT with each other and with God. What perception sees and hears appears to be real because it permits into awareness only what conforms to the WISHES of the perceiver. This leads to a WORLD OF ILLUSIONS, a world which needs constant defense precisely BECAUSE IT IS NOT REAL."
"In this world Heaven is a choice, because here we believe there are ALTERNATIVES to choose between. We think that all things have an OPPOSITE, and what we want we choose. If Heaven exists there must be HELL as well, for contradiction is the way we make what we perceive, and what we THINK is real."
"CREATION KNOWS NO OPPOSITE. 2 But here is OPPOSITION part of being "real." 3 It is this strange perception of the truth that makes the choice of Heaven seem to be the same as the relinquishment of hell. 4 It is not really thus." (because hell doesn't exist)
"For truth is true, and NOTHING ELSE is true. 7 THERE IS NO OPPOSITE to choose instead. 8 There is no contradiction to the truth."
"IN DEATH ALONE ARE OPPOSITES resolved, for ending OPPOSITION is to die. 4 And thus salvation must be seen as death, for LIFE IS SEEN AS CONFLICT. 5 To resolve the conflict is to end your life as well."
"In me is love perfected, fear impossible, and joy established WITHOUT OPPOSITE. 4 I am the holy home of God Himself. 5 I am the HEAVEN where His Love resides."
"Now the light has come: ITS OPPOSITE HAS GONE WITHOUT A TRACE. 9 Where evil was there now is holiness. 10 What is the ego? 11 What the evil was. 12 Where is the ego? 13 In an EVIL DREAM that but SEEMED REAL WHILE YOU WERE DREAMING IT."
"The OPPOSITE OF SEEING through the body's eyes is the vision of Christ, which reflects strength rather than weakness, unity rather than separation, and love rather than fear. The OPPOSITE OF HEARING through the body's ears is communication through the Voice for God, the Holy Spirit, which abides in each of us."
"The Holy Spirit uses logic as easily and as well as does the ego, except that His conclusions are not insane. 5 They take a direction EXACTLY OPPOSITE, pointing as clearly TO HEAVEN as the ego points to darkness and to death (earth)."
"What could you choose between but life or death, waking or sleeping, peace or war, your dreams or your reality? 2 There is a risk of thinking death is peace, because THE WORLD EQUATES THE BODY WITH THE SELF WHICH GOD CREATED. 3 Yet a thing can NEVER BE ITS OPPOSITE. 4 AND DEATH IS OPPOSITE TO PEACE, because it is the OPPOSITE OF LIFE."
"The perception of goodness is NOT knowledge, but the denial of the OPPOSITE of goodness enables you to recognize a condition in which OPPOSITES DO NOT EXIST."
"The Thought of peace was given to God's Son the instant that HIS MIND HAD THOUGHT OF WAR. 2 There was no need for such a Thought before, for peace was given WITHOUT OPPOSITE, and merely was."
"From here we give salvation to the world, for it is here salvation was received. 2 The song of our rejoicing is the call to all the world that freedom is returned, that time is almost over, and God's Son has but an instant more to wait until his Father is remembered, DREAMS ARE DONE, ETERNITY HAS ****SHINED AWAY THE WORLD**** , and ONLY HEAVEN NOW EXISTS AT ALL."
"There is NO LIFE OUTSIDE OF HEAVEN. 2 Where God created life, there life must be. 3 In any state APART from Heaven LIFE IS ILLUSION. 4 At best it SEEMS LIKE LIFE; at worst, like death. 5 Yet both are judgments on what is NOT LIFE, equal in their inaccuracy and lack of meaning. 6 LIFE NOT IN HEAVEN IS IMPOSSIBLE, and what is not in Heaven is NOT ANYWHERE. 7 Outside of Heaven, only the conflict of illusion stands; senseless, impossible and beyond all reason, and yet PERCEIVED as an eternal barrier to Heaven. 8 Illusions are BUT FORMS (life forms). 9 Their content is never true."