Forgetting for a moment the bigger picture context, which the ego always ignores, it can seem like this world makes sense.
The body seems to be able to see the world. Becoming sick seems to be something unwanted and an attack on us. The body seems to have senses of the environment and tells us what's there. The world seems real and outside of us.
But when you reintroduce the big-picture context of what happened before this world as made, it puts everything into a completely different perspective. It give you something to contrast again, to compare, is this true, or is it an illusion?
Before this world, you had vision, the ability to see in the light. There were no obstacles. When you made the world and the body, you created a kind of bubble, populated it with objects, painted the interior walls to shut out sight of God, and then fixated on the forms.
You made a body which was designed specifically to not see God, to focus only on form, to obsess over appearances and to be completely distracted by images seeming real. You made this world and the body to BURY YOUR HEAD IN THE SAND and NOT SEE. The whole purpose of the world is to DENY GOD.
The body was given so-called sensory organs, allegedly permitting you to see and sense the world. It was given eyes to be able to seeming have sight.
But all of this is completely inside out. And the reason and purpose of it is completely backwards.
The body's sight is made to make you BLIND. It is made to PREVENT VISION, so that you will be fixated on appearances, illusions, distractions, so that you DO NOT see. The more that you gain sight of form and bodies, the more blind you become. You SEEM to be seeing "more", but you are seeing LESS.
Similarly, it seems as though sickness is something we don't want and is attacking us against our will. We seem to "not want it". But the Course tells us that in the big picture, we put sickness in place on purpose to DEFEND ourselves against life, We actually think we are defending our SELF because we have identified with a fake ego self, and that self seems vulnerable (because it is an illusion) and needs defenses. So we defend the body in order to try to SAVE OUR LIFE from the attack of truth, which attacks the body and MAKES IT SICK. So now, in the big picture context, sickness is self-attack and a WANTED attempt to die, in the name of preserving your life!
We came into the world not to experience something real, but to get away from reality. We gave our body sensory abilities so as to NOT to sense what exists, but to confuse and block the ability to sense. We created eyesight to SUBSTITUTE for being able to see. The body can't see shit.
In this world, vision is blindness, sickness is self defense, life is death, death is life, what seems it will save you destroys you, defenses are attacks, everything is backwards and inside out and upside down. Nothing is as it appears. Even "nature" is unnatural. Everything about the ego's laws are unnatural. What is "supernatural" is actually natural. Miracles are natural. When they are not happening, something has gone wrong. They are supposed to be happening ALL THE TIME.
To be free of this must entail the undoing and letting go of, dissolving of, disappearing of, all of these illusory forms and things that we MADE UP solely for the PURPOSE of avoiding God. We can repurpose them temporarily and learn from them and use them for awakening, but they are only useful teaching devices for as long as we NEED to be taught, or rather to unlearn. Then we will let them go. Who would want to keep a body which sees only an inversion of reality, blocks vision and defends against God? It is unnatural. It is not needed.