There is no ultimate way to distinguish what is real from what we have imagined. We may find others who agree with us, but when a particular person sees it one way and others disagree, what are we to do? Either we must turn to some imperfect, appointed authority, or we must decide for ourselves what is real and what is not.
Usually we are confident that we can judge with certainty whether an experience “actually happened” or we were “only dreaming.” However, if we can’t tell for sure, then not knowing the boundary between what is real and unreal is confusing and can be terrifying. It is understandable that we insist on continually renewing our all-or-nothing distinctions between true and false, good and bad, crazy and sane, and between dreaming and waking.
It is our responsibility to recognize what reality is for us.