It seems like the Course is saying we shouldn't change the world, or the body, or our lives, and therefore we should only change our mind.
And this leads people to believe that the world, and the body, are going to continue being filled with war and conflict and disease, but that somehow we are going to find some kind of 'peace' or safe-haven within ourselves which allows us to not be upset about it.
But this really is an ego perspective. The ego has made the world be filled with war and disaster and disease. The ego has created the perspective that causes and power are outside of you beyond yourself. The ego has made it seem like it is natural for us to go around having the world do stuff to us, and that we just need to find a way to let it do stuff to us without it upsetting us. We are so used to the world being broken that we don't know what it could be like.
What we don't realize is that the only reason the world or our body seem to contain war and disease is precisely because we are at war with ourselves, and are attacking ourselves, and are using the projected dream of suffering against ourselves. And we are the ones who are putting it out there. We, with our powerful minds, are projecting a world of suffering.
So I think it's a gross mistake to say, well, if I just recoil from this harsh world and go into hiding and be a nice well-behaved Course student and keep to myself and be forgiving, then I will be able to *survive* better, which is really part of the ego's survival strategy.
We don't realize that all the stuff out there in the world, and all of the things wrong in the body, are ALL COMING FROM US.
So if we truly change, if we truly take back our power, if we truly access and accept the mind's CAUSAL POWER over everything, recognizing that we are the dreamer of this fricking dream, this allows us to STOP making a world of disease, to STOP creating sickness, to STOP war, and to stop making the world real.
We have made the world seem real through mistaken perceptions, and then we are reacting to those mistaken perceptions with an effort of being forgiving or trying to find peace, all the while keeping those perceptions of the world being real intact. So then we think, well, it seems like the Course is telling us to just focus on changing our mind and this won't have anything to do with the world.
Is sure as fuck will have something to do with the world because the world is coming from YOU. You are expressing the world. You are contributing to the world. As Jesus says in the urtext (edited out), your mind is powerful enough to create planets. Planets! And who do you think made this one? ;-)
So no. It's not our job to figure out how we can stay INSIDE an illusion of the world existing objectively on its own, in such a way that it has power and causality over us, while simultaneously trying to be at peace. It is not our job to learn to live with sickness. It is not our job to try to be okay with suffering and war and conflict.
How can anyone accept death, as though it is real and allowed and normal and natural? Death is a state of non-acceptance. It is the physical expression of not accepting the truth. You can't be IN it at the same time as accepting the truth. You can't be IN it at the same time as being all nice and peaceful and detached. Try it!
If you want true peace, you need to realize that you are POWERFUL, that you are not at the effect of a DREAM WORLD that is not only not even real, but is itself ONLY an effect and not a cause. There is NO CAUSE in this world at all, and you are the ONLY cause, so how exactly does that add up to tolerating sickness, allowing the body to continue to suffer?
If you are masterful you don't care what's going on in the dream, or in the body, or whether there's sickness, as such, because you know it's not real. And it's not affecting you. But as Jesus says, until every single brother has been woken up, your awakening is INCOMPLETE. We need to ALL wake up and all be causal and all come to agree that the world does not exist, and then it will literally disappear, because it does not have the power to stop us.
There is nothing you cannot do. There is nothing your power, shared with God, cannot accomplish. This is the only way that you can have freedom. Freedom means there are no limitations. This is the freedom that God has given you forever. Freedom from all limitations. Freedom from death. Freedom from sickness. Freedom even from a DREAM of death. Freedom from a world of death. Freedom in all ways at all levels.
Masterfully you could allow sickness to seem to remain in the body, but only in the knowing that you put it there, on purpose, and that it is only there because you say so, and you do not suffer from it because you have mastery over it, and you know it is not real. But that doesn't mean you will therefore just 'put up with' sickness remaining in the body, or that you can't do anything about it.
Many people who have woken up have experienced instantaneous healing of all sicknesses that their body exhibited before, things for which there was no known cure. Why do you need sickness? Why do you need to keep it around when you're done with buying into the ego completely? It cannot stay when it has no purpose. As Jesus says, sickness will disappear when the purpose for which you needed it no longer exists. What purpose can it serve other than to defend against the truth? And if you're not defending against the truth, how are you going to create or sustain sickness?
You are immortal.