Carter makes the point that all mental states, including thoughts, feelings, perceptions, and sensations, may occur consciously as well as unconsciously. So far, despite continuous research, consciousness is still difficult to explain. Hypotheses abound. It could be that there are two basic aspects of consciousness—a physical aspect and a phenomenal one. It is possible that the stream of consciousness is produced by constantly shifting brain states, most of which are themselves unconscious and are produced by an antecedent brain state that gives us an illusion of consciousness, directing its own course. It may be possible that consciousness really does create itself, by affecting the physical states from which it emerges.