But, this doesn't really grasp what an illusion is. It's not just some word you can replace other words with.
The definition of an illusion is something appearing tobe something it is not, designed to deliberately deceive and block awareness of the truth. It is a device that lies to you and tricks you into believing something that isn't true. But in order to even KNOW that it is an illusion, you have to have enough awareness of what it's like to NOT be deceived by the illusion. You have to be aware of how the illusion works, what it's actually 'doing' to portray an appearance, how it is distracting you, and basically to 'see through it'.
Overlooking illusions is forgiveness. This means being aware of all of the 'tricks' that the illusion attempts to perform, but seeing through them and past them and not being fooled by them. And this is an entirely different state of consciousness and awareness, than to simply stay IN the ego illusion and start labeling it 'illusion'. That's like just switching out the term "planet earth" for "planet illusion". That doesn't really reveal HOW it deceives you.
So the big problem we have is that we do NOT realize how the illusion is an illusion. We do not recognize it AS an illusion. We do not see through it, or past it. We are fooled by it. We are made unconscious by it. It's like being hypnotized or put into an unconscious stupor, in which we take the illusion seriously, at face value, and listen to its appearance as if that is reality. Mistaking an illusion for reality is our only mistake.
Here's an example of an illusion. You are in the dark. The room is unlit. In the room there are objects. One of the objects you touch and it feels really strange and it seems to move as you touch it, and this makes you suddenly afraid that there's maybe a person in the room, and you scream. So you've fallen for the illusion, the impression, that there is something serious and frightening happening. But what happens when you switch the light on, suddenly you have MORE INFORMATION. You are now aware of more parts and pieces that you couldn't even see before, and were not aware of at all. Suddenly you realize that the thing you touched was in fact just a large house plant which you brushed up against, and it's completely safe and not scary at all. You feel relieved, right?
This is what it means to see through the illusion. It means, you have seen the truth, which has revealed to you, by shining a light of increased awareness, ALL of what is present, rather than only a narrow context or portion of what is present. When things are taken out of context they become a nightmare. Meaning becomes distorted. Reality becomes disjointed. We start to hallucinate that things might be happening that aren't really happening. This is how someone experiences insanity - losing touch with the bigger picture and becoming fixated on something whose relationship to real meaning has been distorted and blocked, such that you can no longer tell what anything really is and everything becomes frighteningly animated and motivated by bizarre nonsense forces that you don't understand.
The physical world, in the form that it appears, is an illusion. This does not mean that the physical world of form is being seen 'correctly' and fully, by seeing objects as they are. Or like, you become more aware of how all the objects contain beauty or contain God etc. That isn't seeing through the whole illusion. What you do not realize, because you have forgotten what it means to be NOT DELUDED AT ALL, is that the physical world of forms is, in its entirety, designed to block and distract away from the awareness of the presence of God. Even if you awaken to some 'stage' in which you see God in all things, if you are still seeing forms you are still deluded by the illusion.
"Nothing so blinding as sight of form" - ACIM
"Everything the body's eyes can see is a mistake, an error in perception, a distorted fragment of the whole without the meaning that the whole would give." - ACIM - "T-22.III.4."
Also.. "T-22.III.5. 3 The body's eyes see only form. 4 They cannot see beyond what they were made to see. 5 And they were made to look on error and not see past it. 6 Theirs is indeed a strange perception, for they can see only illusions, unable to look beyond the granite block of sin, and stopping at the outside form of nothing. 7 To this distorted form of vision the outside of everything, the wall that stands between you and the truth, is wholly true. 8 Yet how can sight that stops at nothingness, as if it were a solid wall, see truly? 9 It is held back by form, having been made to guarantee that nothing else but form will be perceived." - ACIM
What you may not realize is, this entire physical universe is a holographic projection, designed SPECIFICALLY and INTENTIONALLY, to distort and block all trace of the nature of God. It is deliberately designed to obfuscate, distort, give an opposite appearance to, and completely make it appear, that God does not exist at all. The form that it takes is DELIBERATELY designed by the ego to show you something that looks nothing like God, has no properties of God, completely diffuses and blocks God's character, and makes you completely BLIND to God. The body's eyes then can only see this form, the appearance of the absence of God, and cannot see past it TO God. The entire physical universe is a DECEPTION!
The way this works is, every 'form', every object, presents to your awareness the idea that all things are different. It presents the idea that all objects are separate from each other, none of them share anything at all including the same space or time, none of them truly are equal or perfectly alike, and all of them are in conflict. Does that sound like a picture of God? No. That's intentional. Form, the form of error, was deliberately made make God not apparent, and to make it seem to your awareness that God does not exist at all anymore. That's the ego's wish. That's why it made this illusion.
So the 'illusion' is, that forms present an image to you which is not the truth, which is extremely deceptive, and which you fall for easily. For example, consider problems. The ego presents to you a specific problem which is usually limited to a handful of forms. It tells you that only these forms are a problem, so you need to solve it. You solve it, but this has no effect on the 50 billion other problems in the world. The ego's solution to problems only seems to apply to a tiny portion of the world, and has no transfer value to other problems.
The ego absolutely hates the idea of it being possible to solve ALL problems with ONE solution - that is the Holy Spirit's attitude. It does not want that at all. So it keeps you focussed on looking at objects as being very DIFFERENT to each other. A dog is not a cat. A car is not a house. An attack by a coworkers is not an attack by a neighbor. The ego makes it all APPEAR different and separate. THAT is how it deceives you. Because in truth, there is only ONE problem and ONLY solution resolves the entirety of it completely.
The abstraction needed to SEE and to RECOGNIZE that all forms are THE SAME THING, the same illusion, takes some significant forgiveness and awakening. Being able to look at all forms and recognize, every single one of the deceptions and temptations that every one of these forms is trying to SHOW me, to try to convince me that they are TRUE, is the SAME LIE, and they are all using the SAME STRATEGY. Ultimately, the entire world is the same ONE illusion, presented by the ONE ego, using ONE set of seemingly diverse and apparently highly fragmented deceptions. Each time that you fall for one of its deceptions and think, hey, yes, this illusion is real and this problem is separate from others, and this object is not one with other objects, and that person is separate from this person etc... that's you FAILING to see through the illusion. That's you FALLING FOR THE TRICK!
So yes, there is a way of seeing, which doesn't just overlook illusions but which is AWARE ONLY OF GOD. There is a way of recognizing everything that is false for what it is - false. There is a way of no longer believing a single thing that any appearance of object or form or separation or expression of fragmentation/multiplicity suggests to you in any way. There is a way of COMPLETELY IGNORING what the senses are shown via external signals. There is a way of absolutely not listening to a single shred of ego consciousness whatsoever. And there is a way of SEEING GOD DIRECTLY AND FULLY. And guess what? God does not look ANYTHING like how the physical world looks, and they have nothing in common at all.
In revelation, the entire world disappears. The entire illusion disappears. All physical objects disappear and are replaced with brilliant bright light and total awareness of love. That is all. This is reality. This is an experience of no illusions. Compare that to the PURPOSE of the world that the ego made, and recognize that forms looks like forms FOR A REASON, and separate objects appear to be separate FOR A REASON, and separate problems appear to be distinct and unique FOR A REASON, and all temptations and deceptions are designed to distract you and lead you into unconsciousness FOR A REASON.
The ego's use of the world is NOT that it is neutral. The ego's use of the world is to create a 'veil', an illusion, a huge TRICK, a distortion of consciousness, a BLOCK to awareness, over your awareness, so that you can no longer fully experience God or recognize His nature. God is the same everywhere. God is in all parts equally. All of God is in every part of God. When you are presented with objects which appears to only contain distinct separate parts in each part and there is no sign of any sharing or oneness whatsoever, in form, THAT is the illusion that there is no God. You have to learn NOT TO BELIEVE YOUR EYES!
This is what illusion means. You have to get out of the illusion to know that it is an illusion. You have to awaken to a greater reality in which you are aware of how God is everywhere, God shares everything, God is in everything fully, all of God is in all parts of existence, there is no separation, and all appearances are a LIE. Lies are not meant to be paid attention to, you are meant to discern that they are lies and not listen to them and not take what they present to you seriously or as though it is even real. Recognize the entire physical universe was made to SHUT OUT GOD, and not just in terms of you having a separate perception OF the world that has errors in it, but that the world ITSELF is an error and has taken on a multitude of forms to completely deceive your comprehension of 'what is'. We fall for this every single day and every time we believe in any kind of differences whatsoever.
There are no forms in God, not even forms that seem like they have God in them. NO FORMS. Complete formlessness. Forms are separation and separation is not real.
Every time we think one thing is not something else. Every time we think one object is not another object. Every time we experience separate problems and separate solutions. Every time we believe that we are separated from other people by bodies. Every time we don't recognize that there is only ONE problem, and only ONE solution is needed once and for all to solve them all, permanently. Every time we fall for this grand illusion and can't find a vantage point in awareness from which we can see 'the whole', the one, we fall for the ego's deception. Truly this world is not just a 'thing' and not just a 'place', it is a mechanism for reality distortion, consciousness obstruction, enforced unconsciousness, fragmentation of mind, and loss of life. This is what we have to see past and not believe what our senses are saying is out there.
"There is no world. This is the central thought the Course would attempt to teach." - ACIM - think about that deeply, the entire physical world is a magic trick aimed at stopping Creation, stopping awareness, and stopping God.
We are immortal Spirit. We are God's creation. We are infinite and unlimited by form. We are equal everywhere. And we are real. And we have no differences. And we are not separate objects. And we are not limited by space or time.
"I cannot see in darkness but in light" - "I am not an illusion but a reality." - ACIM