What is an Illusion?

The most effective illusion is one that is undetectably false. We are able to recognize that a perception is illusory only after having had conflicting sensations, or sensations that conflict with our clear rational understanding of what should be true, or our understanding or what is possible.

Nevertheless, illusions are sometimes very powerful, overwhelming reason or creating doubt about what we recall about what we were taught. And when we simply have conflicting sensations, we tend to pick the most powerful as if it were the most dependable; we do not always choose the correct one. It is especially important that you realize that which sensation is correct may not at be apparent.