For obviating this tendency to materialism, or to what may be considered almost as a species of semi-materialism in the physiology of the mind, it is of no small consequence to have accurate views of the nature of our mental identity. Above all, it is of importance, that we should be sufficiently impressed with the conviction, that absolute identity, far from excluding every sort of diversity, is perfectly compatible, as we have seen, with diversities that are almost infinite. When we have once obtained a clear view of this compatibility, as independent of any additions or subtractions of substance, we shall no longer be led to convert our simple mental operations into long continued processes, of which the last links only are mental, and the preceding imaginary links corporeal; as if the introduction of all this play of hypotheses were necessary for saving that identity of mind, which we are perhaps unwilling to abandon altogether; for it will then appear to us not more wonderful, that the mind, without the slightest loss of identity, should at one moment begin to exist in the state which constitutes the sensation of the fragrance of a rose, and at another moment should begin to exist in the state which constitutes the sensation of the sound of a flute, or in the opposite states of love and hate, rapture and agony—than that the same body, without the slightest change of its identity, should exist, at one moment, in the state which constitutes the tendency to approach another body, and at another moment in the opposite state which constitutes the tendency to fly from it, or that, with the same absolute identity, it should exist, at different moments in the different states, which constitute the tendencies to begin motion in directions that are at right angles to each other, so as to begin to move in the one case north, in the other east, and to continue this motion, at one time with one velocity, at other times with other velocities, and consequently, with other tendencies to motion that are infinite, or almost infinite.
With these remarks, I conclude what appears to me to be the most accurate view of the question of our personal, or, as I have rather chosen to term it, our mental identity. We have seen, that the belief of this arises, not from any inference of reasoning, but from a principle of intuitive assent, operating universally, immediately, irresistibly, and therefore justly to be regarded, as essential to our constitution,—a principle, exactly of the same kind, as those, to which reasoning itself must ultimately be traced, and from which alone its consecutive series of propositions can derive any authority. We have seen, that this belief,—though intuitive,—is not involved in any one of our separate feelings, which, considered merely as present, might succeed each other, in endless variety, without affording any notion of a sentient being, more permanent than the sensation itself; but that it arises, on the consideration of our feelings as successive, in the same manner, as our belief of proportion, or relation in general, arises, not from the conception of one of the related objects or ideas, but only after the previous conception of both the relative and the correlative; or rather, that the belief of identity does not arise as subsequent, but is involved in the very remembrance which allows us to consider our feelings as successive; since it is impossible for us to regard them as successive, without regarding them as feelings of our sentient self;—not flowing, therefore, from experience or reasoning, but essential to these, and necessarily implied in them,—since there can be no result in experience, but to the mind which remembers that it has previously observed, and no reasoning but to the mind which remembers that it has felt the truth of some proposition, from which the truth of its present conclusion is derived. In addition to this positive evidence of our identity, we have seen, that the strongest objections which we could imagine to be urged against it, are, as might have been expected, sophistical, in the false test of identity which they assume,—that the contrasts of momentary feeling, and even the more permanent alterations of general character, in the same individual, afford no valid argument against it; since, not in mind only, but in matter also,—(from a superficial and partial view of the phenomena of which the supposed objections are derived,)—the most complete identity of substance, without addition of any thing, or subtraction of any thing, is compatible with an infinite diversity of states.
I cannot quit the subject of identity, however,—though from my belief of its importance, I may already, perhaps, have dwelt upon it too long,—without giving you some slight account of the very strange opinions of Mr Locke on the subject. I do this, both because some notice is due, to the paradoxes,—even though they be erroneous,—of so illustrious a man, and because I conceive it to be of great advantage, to point out to you occasionally the illusions, which have been able to obscure the discernment of those bright spirits, which nature sometimes, though sparingly, grants, to adorn at least that intellectual gloom, which even they cannot irradiate; that, in their path of glory, seem to move along the heavens by their own independent light, as if almost unconscious of the darkness below, but cannot exist there for a moment, without shedding, on the feeble and doubtful throngs beneath, some faint beams of their own incommunicable lustre. It is chiefly, as connected with these eminent names, that fallacy itself becomes instructive, when simply exhibited,—if this only be done, not from any wish to disparage merits, that are far above the impotence of such attempts, but with all the veneration which is due to human excellence, united as it must ever be to human imperfection, “Even the errors of great men,” it has been said, “are fruitful of truths;” and, though they were to be attended with no other advantage, this one at least they must always have, that they teach us how very possible it is for man to err; thus lessening at once our tendency to slavish acquiescence in the unexamined opinions of others, and—which is much harder to be done—lessening also, as much as it is possible for any thing to lessen, the strong conviction, which we feel, that we are ourselves unerring.—The first and most instructive lesson, which man can receive, when he is capable of reflection, is to think for himself; the second, without which the first would be comparatively of little value, is to reject, in himself, that infallibility, which he rejects in others.
The opinion of Locke, with respect to personal identity, is, that it consists in consciousness alone; by which term, in its reference to the past, he can mean nothing more than perfect memory. As far back as we are conscious, or remember; so far and no farther, he says, are we the same persons. In short, what we do not remember, we, as persons, strictly speaking, never did. The identity of that which remembers, and which is surely independent of the remembrance itself, is thus made to consist in the remembrance, that is confessedly fugitive; and, as if that every possible inconsistency might be crowded together in this simple doctrine, the same philosopher, who holds, that our personal identity consists in consciousness, is one of the most strenuous opponents of the doctrine, that the soul always thinks, or is conscious; so that, in this interval of thought, from consciousness to consciousness,—since that which is essential to identity is, by supposition, suspended, the same identical soul, as far as individual personality is concerned, is not the same identical soul, but exists when it does not exist.
“There is another consequence of this doctrine,” says Dr Reid, “which follows no less necessarily, though Mr Locke probably did not see it. It is that a man be, and at the same time not be, the person that did a particular action.
“Suppose a brave Officer to have been flogged when a boy at school, for robbing an orchard, to have taken a standard from the enemy in his first campaign, and to have been made a General in advanced life: Suppose also, which must be admitted to be possible, that when he took the standard, he was conscious of his having been flogged at school; and that when made a General, he was conscious of his taking the standard, but had absolutely lost the consciousness of his flogging.
“These things being supposed, it follows, from Mr Locke's doctrine, that he who was flogged at school is the same person who took the standard; and that he who took the standard is the same person who was made a General. Whence it follows, if there be any truth in logic, that the General is the same person with him who was flogged at school. But the General's consciousness does not reach so far back as his flogging, therefore, according to Mr Locke's doctrine, he is not the person who was flogged, Therefore the General is, and at the same time is not, the same person with him who was flogged at school.”[51]
But it is needless to deduce consequences, from this very strange paradox; since its author himself has done this, most freely and fully, and often with an air of pleasantry, that, but for the place in which we find it, as forming a part of a grave methodical essay on the understanding, would almost lead us to think, that he was himself smiling, in secret, at his own doctrine, and propounding it with the same mock solemnity with which the discoverer of Laputa has revealed to us all the secrets of the philosophy of that island of philosophers.
He allows it to follow, from his doctrine, that, if we remembered at night, and never but at night, one set of the events of our life; as, for instance, those which happened five years ago; and never but in the day time, that different set of events, which happened six years ago; this, “day and night man,” to use his own phrase, would be two as distinct persons, as Socrates and Plato; and, in short, that we are truly as many persons as we have, or can be supposed to have, at different times, separate and distinct remembrances of different series of events. In this case, indeed, he makes a distinction of the visible man, who is the same, and of the person who is different.
“But yet possibly it will still be objected,” he says, “suppose I wholly lose the memory of some parts of my life, beyond a possibility of retrieving them, so that perhaps I shall never be conscious of them again; yet am I not the same person that did those actions, had those thoughts that I once was conscious of, though I have now forgot them? To which I answer, that we must here take notice what the word I is applied to; which, in this case, is the man only. And the same man being presumed to be the same person, I is easily here supposed to stand also for the same person. But if it be possible for the same man to have distinct incommunicable consciousness at different times, it is past doubt the same man would at different times make different persons; which we see is the sense of mankind in the solemnest declaration of their opinions; human laws not punishing the mad man for the sober man's actions, nor the sober man for what the mad man did, thereby making them two persons: which is somewhat explained by our way of speaking in English, when we say such an one is not himself, or is beside himself; in which phrases it is insinuated, as if those who now, or at least first used them, thought that self was changed, the self-same person was no longer in that man.”[52]