Believing in the reality of error or illusion, which makes it real in your own mind, though not in reality. More specifically, believing in the reality of other people's mistakes, which makes those mistakes seem like sins. The ego's plan of forgiveness (followed by the unhealed healer) is to then try to forgive or dispel these "real" errors, but this is impossible, for reality cannot be dispelled. "To perceive errors in anyone, and to react to them as if they were real, is to make them real to you" (T-9.III.6:7). The ego also tries to make real the separation, sickness, nothing, guilt, the past, the unholy relationship, the ego's goals, the body, dreams.