A personality alters itself through a series of self-referential experiences. We are not the same as the day before. Much as a person can never set foot in exactly the same river on any given day, we are different each day. Yesterday made us, but the past cannot contain nor restrain us. We can never mentally scroll backward and be who we used to be. We must move forward in the stream of life until the day that our life force dries up and we return to dust.