We may immediately call it right and intelligible so far as it posits a past time with past thoughts or selves contained therein—these were data which we assumed at the outset of the book. Right also and intelligible so far as it thinks of a present self—that present self we have just studied in its various forms. The only question for us is as to what the consciousness may mean when it calls the present self the same with one of the past selves which it has in mind.
We spoke a moment since of warmth and intimacy. This leads us to the answer sought. For, whatever the thought we are criticising may think about its present self, that self comes to its acquaintance, or is actually felt, with warmth and intimacy. Of course this is the case with the bodily part of it; we feel the whole cubic mass of our body all the while, it gives us an unceasing sense of personal existence. Equally do we feel the inner 'nucleus of the spiritual self,' either in the shape of yon faint physiological adjustments, or (adopting the universal psychological belief), in that of the pure activity of our thought taking place as such. Our remoter spiritual, material, and social selves, so far as they are realized, come also with a glow and a warmth; for the thought of them infallibly brings some degree of organic emotion in the shape of quickened heart-beats, oppressed breathing, or some other alteration, even though it be a slight one, in the general bodily tone. The character of 'warmth,' then, in the present self, reduces itself to either of two things,—something in the feeling which we have of the thought itself, as thinking, or else the feeling of the body's actual existence at the moment,—or finally to both. We cannot realize our present self without simultaneously feeling one or other of these two things. Any other fact which brings these two things with it into consciousness will be thought with a warmth and an intimacy like those which cling to the present self.
Any distant self which fulfils this condition will be thought with such warmth and intimacy. But which distant selves do fulfil the condition, when represented?
Obviously those, and only those, which fulfilled it when they were alive. Them we shall imagine with the animal warmth upon them, to them may possibly cling the aroma, the echo of the thinking taken in the act. And by a natural consequence, we shall assimilate them to each other and to the warm and intimate self we now feel within us as we think, and separate them as a collection from whatever selves have not this mark, much as out of a herd of cattle let loose for the winter on some wide western prairie the owner picks out and sorts together when the time for the round-up comes in the spring, all the beasts on which he finds his own particular brand.
The various members of the collection thus set apart are felt to belong with each other whenever they are thought at all. The animal warmth, etc., is their herd-mark, the brand from which they can never more escape. It runs through them all like a thread through a chaplet and makes them into a whole, which we treat as a unit, no matter how much in other ways the parts may differ inter se. Add to this character the farther one that the distant selves appear to our thought as having for hours of time been continuous with each other, and the most recent ones of them continuous with the Self of the present moment, melting into it by slow degrees; and we get a still stronger bond of union. As we think we see an identical bodily thing when, in spite of changes of structure, it exists continuously before our eyes, or when, however interrupted its presence, its quality returns unchanged; so here we think we experience an identical Self when it appears to us in an analogous way. Continuity makes us unite what dissimilarity might otherwise separate; similarity makes us unite what discontinuity might hold apart. And thus it is, finally, that Peter, awakening in the same bed with Paul, and recalling what both had in mind before they went to sleep, reidentifies and appropriates the 'warm' ideas as his, and is never tempted to confuse them with those cold and pale-appearing ones which he ascribes to Paul. As well might he confound Paul's body, which he only sees, with his own body, which he sees but also feels. Each of us when he awakens says, Here's the same old self again, just as he says, Here's the same old bed, the same old room, the came old world.
The sense of our own personal identity, then, is exactly like any one of our other perceptions of sameness among phenomena. It is a conclusion grounded either on the resemblance in a fundamental respect; or on the continuity before the mind, of the phenomena compared.
And it must not be taken to mean more than these grounds warrant, or treated as a sort of metaphysical or absolute Unity in which all differences are overwhelmed. The past and present selves compared are the same just so far as they are the same, and no farther. A uniform feeling of 'warmth,' of bodily existence (or an equally uniform feeling of pure psychic energy?) pervades them all; and this is what gives them a generic unity, and makes them the same in kind. But this generic unity coexists with generic differences just as real as the unity. And if from the one point of view they are one self, from others they are as truly not one but many selves. And similarly of the attribute of continuity; it gives its own kind of unity to the self—that of mere connectedness, or unbrokenness, a perfectly definite phenomenal thing—but it gives not a jot or tittle more. And this unbrokenness in the stream of selves, like the unbrokenness in an exhibition of 'dissolving views,' in no wise implies any farther unity or contradicts any amount of plurality in other respects.
And accordingly we find that, where the resemblance and the continuity are no longer felt, the sense of personal identity goes too. We hear from our parents various anecdotes about our infant years, but we do not appropriate them as we do our own memories. Those breaches of decorum awaken no blush, those bright sayings no self-complacency. That child is a foreign creature with which our present self is no more identified in feeling than it is with some stranger's living child to-day. Why? Partly because great time-gaps break up all these early years—we cannot ascend to them by continuous memories; and partly because no representation of how the child felt comes up with the stories. We know what he said and did; but no sentiment of his little body, of his emotions, of his psychic strivings as they felt to him, comes up to contribute an element of warmth and intimacy to the narrative we hear, and the main bond of union with our present self thus disappears. It is the same with certain of our dimly-recollected experiences. We hardly know whether to appropriate them or to disown them as fancies, or things read or heard and not lived through. Their animal heat has evaporated; the feelings that accompanied them are so lacking in the recall, or so different from those we now enjoy, that no judgment of identity can be decisively cast.
Resemblance among the parts of a continuum of feelings (especially bodily feelings) experienced along with things widely different in all other regards, thus constitutes the real and verifiable 'personal identity' which we feel. There is no other identity than this in the 'stream' of subjective consciousness which we described in the last chapter. Its parts differ, but under all their differences they are knit in these two ways; and if either way of knitting disappears, the sense of unity departs. If a man wakes up some fine day unable to recall any of his past experiences, so that he has to learn his biography afresh, or if he only recalls the facts of it in a cold abstract way as things that he is sure once happened; or if, without this loss of memory, his bodily and spiritual habits all change during the night, each organ giving a different tone, and the act of thought becoming aware of itself in a different way; he feels, and he says, that he is a changed person. He disowns his former me, gives himself a new name, identifies his present life with nothing from out of the older time. Such cases are not rare in mental pathology; but, as we still have some reasoning to do, we had better give no concrete account of them until the end of the chapter.
This description of personal identity will be recognized by the instructed reader as the ordinary doctrine professed by the empirical school. Associationists in England and France, Herbartians in Germany, all describe the Self as an aggregate of which each part, as to its being, is a separate fact. So far so good, then; thus much is true whatever farther things may be true; and it is to the imperishable glory of Hume and Herbart and their successors to have taken so much of the meaning of personal identity out of the clouds and made of the Self an empirical and verifiable thing.