Devavan in the idea of A Course in Miracles about our choice for safety and a consistency of perception seeing with our whole Mind. It starts with this choice and offers us the understanding of the impossibility of two worlds.

As indicated in the Lessons 130 of the Workbook of ACIM:
"Perception is consistent. What you see reflects your thinking. And your thinking but reflects your choice of what you want to see. Your values are determiners of this, for what you value you must want to see, believing what you see is really there. No one can see a world his mind has not accorded value. And no one can fail to look upon what he believes he wants.... Fear has made everything you think you see.

It is impossible to see two worlds which have no overlap of any kind. Seek for the one; the other disappears. But one remains. They are the range of choice beyond which your decision cannot go. The real and the unreal are all there are to choose between, and nothing more than these. ... "

- with introductory video on YouTube by DevAvan: https://youtu.be/YrvedwNlLJg