Halloween has become a veritable carnival in the U.S. and those countries within its sphere of cultural influence. Children and adults dress up as witches, ghosts, monsters, and even politicians (some of whom are positively scary —if not in appearance, at least in their policies).
Children visit various homes in their neighborhood, and when the door opens, blurt out “Trick or treat!” The resident is then obliged to offer the visitors some candy, or face the possibility of being on the receiving end of a prank.
Even though some costumes can be truly spectacular, it is virtually inconceivable that the residents will actually believe that they have been visited by real ghosts and goblins. Used to these annual festivities, we know without a doubt that under those strange clothes and frightening make-up there is a child, a human neighbor, who will don other clothes and have a different appearance tomorrow.
However, in our daily lives we have the tendency to accept the costume (observed appearances) as if they were real and permanent. We come to believe that this being is a friend, and the other an enemy; this one is young, the other old; this one is good, the other bad; and so on.
Daily appearances are only masks and costumes. Ordinary existence is a carnival.