And this is all that a mind is--an affair of saving and rejecting, of valuing with a system of objects of which a living body and its desires and operations, its interests, are focal and the objects marginal, for its standard. Mind, thus, is neither simple, nor immutable, nor stable; it is a thing to be "changed," "confused," "cleared," "made-up," "trained." One body, I have written elsewhere,[89] "in the course of its lifetime, has many minds, only partially united. Men are all too often "of two minds." The unity of a mind depends on its consistent pursuit of _one_ interest, although we then call it narrow; or on the coöperation and harmony of its many interests. Frequently, two or more minds may struggle for the possession of the same body; that is, the body may be divided by two elaborately systematized tendencies to act. The beginning of such division occurs wherever there is a difficulty in deciding between alternative modes of behavior; the end is to be observed in those cases of dual or multiple personality in which the body has ordered a great collection of objects and systematized so large a collection of interests in such typically distinct ways as to have set up for itself different and opposed "minds." On the other hand, two or fifty or a million bodies may be "of the same mind."
Unhappily, difference of mind, diversity and conflict of interests is quite as fundamental, if not more so, as sameness of mind, coöperation and unity of interests. This the philosophical tradition sufficiently attests. To Plato man is at once a protean beast, a lion, and an intellect; the last having for its proper task to rule the first and to regulate the second, which is always rebellious and irruptive.[90] According to the Christian tradition man is at once flesh and spirit, eternally in conflict with one another, and the former is to be mortified that the latter may have eternal life. Common sense divides us into head and heart, never quite at peace with one another. There is no need of piling up citations. Add to the inward disharmonies of mind its incompatibilities with the environment, and you perceive at once how completely it is, from moment to moment, a theater and its life a drama of which the interests that compose it are at once protagonists and directors. The catastrophe of this unceasing drama is always that one or more of the players is driven from the stage of conscious existence. It may be that the environment--social conditions, commercial necessity, intellectual urgency, allies of other interests--will drive it off; it may be that its own intrinsic unpleasantness will banish it, will put it out of mind; whatever the cause, it is put out. Putting it out does not, however, end the drama; putting it out serves to complicate the drama. For the "new psychology"[91] shows that whenever an interest or a desire or impulsion is put out of the mind, it is really, if not extirpated, put into the mind; it is driven from the conscious level of existence to the unconscious. It retains its force and direction, only its work now lies underground. Its life henceforward consists partly in a direct oppugnance to the inhibitions that keep it down, partly in burrowing beneath and around them and seeking out unwonted channels of escape. Since life is long, repressions accumulate, the mass of existence of feeling and desire tends to become composed entirely of these repressions, layer upon layer, with every interest in the aggregate striving to attain place in the daylight of consciousness.