Under the form of a representation of this composite art, bound together by the thread of memory, each of us ordinarily conceives his complete abiding _personality_. This idea is necessarily undergoing constant modification; and it is in comparing the present form of the representation with the past, whilst adverting to considerable alterations in my character, bodily appearance, and the like, that I sometimes say: “I am completely changed,” “I am quite another person,” though I am, of course, convinced that it is the same “I” who am changed in accidental qualities. _It is because this complex notion of my personality is an abstraction from my remembered experiences __ that a perversion of imagination and a rupture of memory can sometimes induce the so-called _“illusions or alterations of personality”_._(308) When we remember that this objective conception of the self is so dependent on the function of memory, and that the normal exercise of this faculty is in turn so dependent on the normal functioning of the brain and the nervous system,(309) we can hazard an intelligible explanation of the abnormal facts recorded by most modern psychologists concerning hypnotism, somnambulism and “double” or “multiple” consciousness.(310) Father Maher, ascribing these phenomena partly to dislocations of memory, partly to unusual groupings of mental states according to the laws of mental association—groupings that arise from peculiar physiological connexions between the various neural functionings of the brain centres,—and partly to semi-conscious or reflex nerve processes, emphasizes an important fact that is sometimes lost sight of: the fact that some section at least of the individual’s conscious mental life is common to, and present throughout, the two or more “states” or “conditions” between which any such abnormal individual is found to alternate. This consideration is itself sufficient to disprove the theory—to which we shall presently refer—that there is or may be in the individual human being a double, or even a multiple “human personality”.