Before the separation, there was only the truth of God. God's Kingdom was the only reality. Everything in it was directly known and cognized. There was no interpretation, no judgement, no evaluation, and no decisions about what things mean. It was a very direct unified experience and everything was a given.
In this state of perfection, we knew that only God's truth was true. That only God's laws applied. There was nothing else to oppose this. There was, you could say, a recognition, that only the truth is true, AND that only the false is false. But you also knew that the false means nothingness and non-existence - that nothing is false. So there was no experience of the false, only of the true, and love had no opposite.
Let's then consider the tiny mad idea, BEFORE you believed in it. Let's imagine the idea has only just formed and you are considering what it is. The idea is that there is an opposite to God, as an opposite to what has no opposite. It's the idea of an opposite to the truth, which had to be nothing like the truth in order to BE opposite. We made-up in our minds an imagined notion of what it might be like it God were completely opposed, and something completely different were to exist. But note at this point you had not "gone into it" with belief or conviction.
This mad idea was an idea filled with opposites to God's nature. It was an idea of that which is false, untrue, unreal, impossible, non-existing, murderous, deadly, vulnerable, weak, powerless, unloving, impermanent, corrupt, distorted, deceptive, valueless, meaningless, nothingness, evil and every other notion that opposes some quality of God.
If you would have remained in your right mind, examining this idea, you would not have given it a moment's belief. It would have been completely obvious to you how impossible and unbelievable it is. You would have had no faith in it, on trust in it, and it would appear to be you be completely nothing. You would see no value in it, no merit to it, and would not want it at all. You would turn away from it instantly knowing that it was so profoundly false, you could not help but laugh at it.
Let's now say that you, nevertheless, chose to start to entertain the idea, began to persuade yourself that it was possible and true, and listened to it. You gave it a second thought and started to take it more seriously. What this meant is that you suddenly began to lose touch with what is objectively real. You lost touch with God's reality, and started to enter into a subjective reality. A reality which seemed to be different for you than for others, where reality was unstable.
This subjective position was what we call "perception", which put you into a slightly removed mode of "reading into" what you saw. A slight delay or gap was introduced between what was there and what you knew, producing a sense of space and time, and also removing you a little from the direct experience. Your mind began to twist and distort, it began to lose touch with context, it began to hallucinate, it entered into doubt and lost track of meaning. It started to interpret everything according to what it thought it might mean, making up meanings, and judging everything to try to assess what it was. And this was also a hallucinatory experience.
By believing that there was some truth to what was false, the mind began to swap the true and the false. Perception acted like a layer of interpretation overlaid on top of the clarity that the true and the false were completely opposite. That the false didn't even exist. Truth and reality was given to the false, combining with it into a blurred soup of meaninglessness and confusion. And similarly aspects of the false were incorrectly associated with the truth, further distorting your view of reality and driving you insane.
This process continued in the "descent into hell", whereby all things true were confused with all things false, and vice versa. This eventually produced a complete inversion of the facts. All true things were believed to be false, and all false things were believed to be true. This produced a completely upside down viewpoint. Whereas we might say truth was above and the false was below, the true was now placed below and the false above. This backwards perception was overlaid on top of the actual arrangement of the facts or levels.
The state of false perception turns everything into its opposite. So we also perceived from a vantage point of believing that unreality was real, the false was true, the impossible was possible, death was life, suffering was salvation, hell was heaven, and god was non-existent. It was this combination of the false and the true which was the state of false perception in the mind, and it was this which as projected out AS THE PHYSICAL WORLD. A world where everything is backwards, the impossible happens, and everything is insane.
The world therefore took on a nature which is completely impossible and contradictory. It appeared to be in some ways both true and false. In it the impossible seemed to always be happening, as though it were possible. Death could occur even though this is not possible. It gives only to take away. There was a cost to everything. And since there was this overlaid blend of true and false, everything in the world was something other than what it appeared to be on the surface.
False perception therefore looks upon a false unreal world, riddled with impossibilities, and believes it to be real and true. It in a sense sees heaven in it, but not through recognizing heaven as it it. Instead by believing that something that is NOT heaven is heaven. The world itself was made on this basis. The body was made on this basis. And the body's eyes now look out upon the unreal world and make it seem real.
As Jesus states in the course "The world is false perception." This means that so long as your mind is backwards and confused, having swapped the true and the false, it will perceive what we call the physical world. And this way of perceiving will line up with the world's nature. When the mind is in false perception, ie upside-down belief, or backwards cause-and-effect, everything in the world seems natural and makes sense and seems like the only reality.
So long as the mind remains in false perception it will see the physical world, along with its seeming laws and its insane ways, because it is a projection of madness. False perception sees all false things as if they are true, all illusions as if they are real, and buys into all the impossible things that seem to happen. It falls for temptation and is deceived.
The way out of such a world is through true perception. The only thing that is needed to move into true perception, is to reverse the upside-down inverting lens of perception. Remember this is a layer of interpretation overlaid on top of the facts. False perception turns the truth upside down and associates it with the false, and true perception corrects this and lines up the filter of truth with the actual truth. Now both the actual truth and the perceived truth are on the top, lined-up, and the actual false and the perceived false are on the bottom.
True or "accurate" perception now very closely matches knowledge, in which you are much more directly and accurately recognizing what things are. That which is false is now clearly recognized AS false, instead of believing it has truth to it. The false world, which includes Earth, is no longer given value and belief, and instead it is recognized as unreal and untrue. It is seen as nothing, which causes it to become transparent to your perception. You see through it because you see through the lie.
True perception therefore focuses on the actual real truth of the real world, or of heaven, and lines up with it. It wants to see it because it values it. And in order TO see it, it denies that the false world has any reality. The world you see in false perception is completely denied, because seeing it shuts out awareness of the real world. You deny the physical world - anything not of God - and this steers your perceptual reality filter towards the right-side-up truth.
Heaven is then perceived through the lens of perception, because the truth in belief now lines up with the actual truth. It becomes so close to it and so alike its nature that it can "accurately interpret" reality. It forms reality contact and recognition, which is also enlightenment. The true is recognized as all that is true, and the false is recognized as completely false. The false world is recognized as nothing, and disappears, as the face of Christ - symbol of the real truth, appears to your vision.
While some amount of perception remains, and while you seem to still have a false body, the body still continues to see WITH totally false perception. It is worth noting this because this does not change. The body still continues to send images of a false world to the mind, and all the things it sees are still JUST AS false as they ever were. The mind has to learn that they ARE false and categorize them as unreal. This doesn't stop the mind seeing them, until the most advanced state, so it has to learn that everything the body shows it is unreal. And this acutely conflicts with its growing awareness of reality.
Also at the same time, true perception (vision) is developing. Note that false perception manifests through physical sight, and true perception manifests through a spiritual non-physical sight - the spiritual eye or mind's eye. While the mind is still looking at the false world temporarily, yet from a very healed state, it is seeing from a vantage point that is very filled with truth. It is very heaven-like, operating in a loving and forgiving manner. This loving sight looks upon the false unreal world and forgives it, and also even loves it. But it is not a special love of attachment and still does not want it.
The vantage point of true perception comes from a mind that has lined itself up with God and the soul. And so it is itself a reflection of heaven. And therefore what it projects is a reflection of heaven, still within perception. And this "glosses over" the false world's falseness and sees love "in" it, seeing God's reflection in it. Not because the false world contains God but because God is there in spite of and beyond the false images. This is how the reflection of heaven is seen in the world. This doesn't change the world's nature either, but it does see it in a beautiful way.
The real world, or heaven, looks away from and beyond the forgiven world, beyond spacetime, beyond form and matter and bodies, and looks to the light of reality. It's the minds desire to value only reality and to accept the truth (atonement). It therefore becomes able to see the real world, ie reality's reflection in perception, as a kind of "perception of heaven", as though outside of heaven peering in slightly removed from it. You see the real world, in which everything shines forever, and this is just prior to your total movement INTO the Kingdom.
Once this point is reached, all perception ends and its re-purposing is done, because it has now lined up with reality as much as is possible. Perception vanishes, the physical world vanishes, the real world vanishes, and all that remains is heaven. You wake up in reality knowing that you never left, and that you merely slept a while, and now you continue co-creating with God as though nothing ever happened. Your mind has been restored to knowledge and the direct cognition of the Kingdom.