When we come to the course, typically we come with a pretty big bag of beliefs.
One major belief, accrued over a lifetime, is that we are separate from the world. The world is this huge thing outside us. We learned "by experience" that it does things on its own, against our will, and we do not SEEM to have any direct mental power OVER it at all.
Only a rare few have even a slight hint of what we might call "telekinesis".. mind over matter. Some bend spoons thinking it's amazing but it's barely anything.
This is what the ego set up... to be in bodies shut off from the power of the mind and *disabled* so much that we can't even use the mind DIRECTLY to make anything happen. And then we just... got used to it.
We do have SOME power over the body, even regular non ACIM folk do... like you can cause the body to change in various ways based on your experiences and moods and so on. You can choose to go into anger and make your blood pressure go up. You can manifest headaches when you don't want to go somewhere. You can develop sore throats when you didn't speak your mind. All kinds of stuff happens to the body just in normal ways as a result of the mind's power - just a little bit of power, demonstrating itself.
But beyond the body, we generally see ourselves as "cut off", disconnected, powerless, completely unable to affect anything outside of it.
Then we come to the course.
And then we hear the course saying stuff about how we need to change our perception and that what exists in the world is an outward picture of an inward condition. We REFERENCE our EXISTING BELIEF SYSTEM of "I am not connected to the world", and then try to make sense of it.
So this lead us to think, ok... My mind is not outside my body and has no power over what's out there, so this MUST MEAN, that within my own body, inside my mind inside my body, there are some false perceptions which I need to change, and this will change how I SEE the world out there... BUT, it will not actually CHANGE the world out there whatsoever.
This is because the old belief system of powerlessness, littleness, being stuck in a body, having no mental power, is still circulating as a "foundation" for what you are learning. And so you learn WITHIN that context without questioning it or thinking that it even CAN be questioned. What you learned prior to the course closed your mind, and you proved it to yourself over and over again by how many times you couldn't stop the ice-cream from falling on the sidewalk, had to suffer from the weather, or couldn't prevent an accident.
So then you learn the entire course and try to make it "fit" inside this framework, building UPON what you think you already know. This leads to GROSS DISTORTIONS of the meaning of what Jesus says. It leads to the belief that he is talking about "you in a body" when he refers to "the world you see" as being something you made up... therefore, since you believe you can only change what's INSIDE your body, which you think is all of your mind, you do not even begin to think that changing your mind would change your BODY, yet alone anything OUTSIDE OF IT. And so when Jesus says things like "the world you see", you will dilute and mangle it to fit into what it would mean INSIDE your body, therefore.. referring to your private personal misperceptions OF the world, rather than literally or directly the world.
The disconnection or rather, separation between cause and effect, between your mind and what it believes, and the out picturing of that AS body and AS THE WORLD - the physical planet - forms - bodies - people - objects - the spearation between you and that stuff seems insurmountable and too far-fetched to believe you might be able to have power over it, or that it MUST change, or that you CAN change it with your mental changes. You simply do not see, or believe, that your mind is the cause of what is literally out there.
This leads people to believe also that if they change their internal perception, housed inside the limits of their body, they will be able to become PEACEFUL and happy, IN SPITE OF, the conditions which are in the body or outside of it. They see both of them as outside of their "self" and so outside of their own mind's power or reach or control. This leads people to believe that they can a) be at peace without healing sickness, b) can be at peace with the body dying, c) can be at peace even though people continue to be able to attack their body, d) are happy to just put up with sickness because somehow, there is a way to be peaceful in spite of it.
This of course is the distortion that entirely arises because of the FOUNDATION of the thought system, which has been built up over many years, teaching us that we are CUT OFF from the world, that there is huge SEPARATION between cause (us) and effect (the world). We don't seem to have ANY mental powers at all to make objects move, to heal sick people, to stop death, to reverse suffering, or any of the rest of it. This is because our mind is BLOCKED, and we are not aware of the whole truth.
Jesus is in fact teaching us in the course that we DO HAVE THIS POWER, which is a power to LITERALLY MOVE A PHYSICAL MOUNTAIN, or even to create a planet, because this is the natural result of having CAUSAL POWER over the EFFECT which is out there. The inner picture MUST be reflected outward. So when the mind decides, hey, I am going to rearrange this entire forest but uprooting all the trees and putting them in a different assortment, that's what will happen. But we do not believe we have even REMOTELY anything near that power, because of just how radically LIMITED our mental power seems to be.
We are GROSSLY out of touch with the power of the mind. Just even being in a body seems to shut us off form being able to do this. And yet these things are miraculous. These miracles demonstrate the power the mind has OVER MATTER, because the mind that KNOWS it is CAUSE, simply knows that everything else MUST be at its effect, and so its power over it is UNLIMITED.
It is only because we believe STRONGLY that we are limited by this body, limited by the isolation of being a separate self, totally out of touch with the MIND, believing we have a mind when in fact we just have a TINY LITTLE BIT OF MIND operating as a conscious self, shut off from what we really are capable of, that we won't consider it even POSSIBLE that the Course is telling us we literally made the world, or that we can change it with our mind alone.
This is the level of resistance to miracles. This is the resistance to all ways that mind may exert its power "over matter". "That the mind can heal the body but the body cannot heal the mind is proof that the mind must be stronger than the body." ... the mind is supposed to be ABLE to COMPLETELY do whatever it wants to do with the body. No limits. "There is nothing my holiness cannot do."
But so long as we believe we are these little piddly WEAK little body-identified selves, MINDLESS, cut off from everything external, seeing no oneness or ability to join, and having no power over any forms whatsoever, we are going to just CONTINUE TO BE VICTIMS AND DIE. And that's simply because we do not recognize that we are choosing that, because we have yet to wake up to the power of the mind. We are accidentally choosing death, until we realize that we are the Son of God for whom nothing is impossible.
So there is a LOT of this resistance in the ACIM community, and even those who are on the cutting edge of opening up to the power of the mind are still like little babies in terms of the development of this power. I would sort of put myself in that category and there still seems to be so little I can actually do, definitely nothing of my own will, and even with God acting with me I am still very limited. But I am willing to be open to the possiblity that my mind, shared with God, has far more power over this world than it appears, and WAY more than I have been led to believe by the ILLUSION the ego created to make it seem I have no power at all.
We have to realize that just by being in a body, we made ourselves TOTALLY POWERLESS, victims at the effect of the world. No power whatsoever to stop things from happening. That's extremely the OPPOSITE to our natural state of miracle mindedness. We need to UNLEARN what this illusion has taught us, and reclaim the power of the mind over matter to be able to perform magnificent miracles and be free of these limitations. This is why Jesus says time and again that there is nothing you cannot do, and ALL THE POWER IN HEAVEN AND EARTH HAS BEEN GIVEN YOU. But we do not see it, or believe it, because we're so used to being blinded by this illusion of separation between what is inside me and what is outside. That must be undone.