What is personality? Most people take it to be the complex of behavioral, temperamental, emotional, and mental attributes that characterizes us as unique individuals. We usually see personality as fixed. However, we don't have to look very hard to see that it varies radically from situation to situation. We may display care, patience, and restraint at work but not show the same patience or restraint with our families. Or we may be kind and loving with our spouse and children yet angry and impatient with employees and colleagues. When situations change, everything about us can change, too -- what we think, feel, do, how we see the world, even what we believe and understand about life.
Far from having a single personality, we are like the shards of a shattered mirror, each piece reflecting a different picture of the world. Yet we think of ourselves as the same person, a single entity that is consistant throughout the day. We are largely unaware that we are acting on the basis of the reflections of one shard in one moment, and another shard in the next.
What would life be like if we approached life, our world of experience, consistently -- that is, with a single personality, rather than as a collection of shards?
I use the term awake here instead of the more commonly used word, enlightened. Enlightened implies a state of being based on an idealized conception of human perfection -- an enlightened person as opposed to an unenlightened one. Awake is probably more appropriate, because it points to an experience, not a state.
This is, in essence, the definition of subpersonality theory. We are many selves, each one of them with their own worldview, feelings, thoughts, preferences, and so on. But we also have an awake "center," what Hal and Sidra Stone call the Aware Ego, or what Richard Schwartz calls the Self. This is, essentially, our Buddha Nature.
The foundation of Buddhist practice, even if it does not recognize the term subpersonalities, is devoted to transcending all these separate selves. Where Western psychology becomes valuable is in explaining how these selves function, where they come from, and how to quiet their insistent voices so that we can transcend them and have better access to the Awareness within us -- our True Nature.
An integrated methodology, using both Buddhist meditation practice and Western psychology is the best way to work with subs and to learn how to access the Awareness within that sees these subs as merely shards in a transient self.