Mark Brown Two Advantages of Punctualist

Theories of Personal Identity

Despite the evident ontological parsimony of

Punctualism and the ease with which it disentangles the problems of logical form which plague other theories of personal identity, most philosophers think that a Humean succession of numerically distinct momentary selves falls far short of a full account of personal identity. Punctualist theories of personal identity most often surface as objections to the Lockean claim that "personal identity consists, not in the identity of substance, but in the identity of consciousness". Locke’s contemporaries Joseph Butler and Thomas Reid treated the punctual nature of consciousness as a reductio of Lockean intuitions regarding the practical importance of personal identity. Among contemporary philosophers, Susan Wolfe claims that a theory of momentary selves is the one theory of personal identity known to be false and Marya Schectman argues that Punctualism reduces persons to the status of infants with time horizons which encompass little more than the specious present.

I

The purpose of this essay is to suggest that the rejection of punctualism is too quick. A punctualist theory of personal identity has two important advantages over its cross-temporal rivals. First, the reidentification question and the problems of logical form which accompany it simply evaporate if each moment in the life of a person is an individual in its own right. The transitivity of identity, for example, applies without qualification to self-identical momentary selves. The case of personal fission poses no transitivity problem for a punctualist because every pre-fission momentary person is viewed as numerically distinct from its psychological descendants whether or not it divides in the interval; every post-fission psychological descendent of an antecedent momentary self is no more and no less distinct than any other pair of momentary selves. Punctualists recognize causal and intentional linkages between successive momentary selves but since they make no identity claim with respect to the linked set, questions of failure of transitivity do not arise.

Punctualists preempt in similar fashion questions concerning the determinateness of identity. Psychological continuity theories fall afoul of the determinateness of identity because identity is a one to one, all or nothing relation, but cross temporal unity relations between person stages drawn in terms of overlapping chains of psychological connectedness hold to a greater or lesser degree. Thought experiments in which an external agent replaces the intentional states of a person stage one by one imply that no non-arbitrary distinction can be drawn between person stages which do and person stages which do not exhibit sufficient psychological continuity. In contrast, the identity of punctualist persons is wholly determinate because the gain or loss of any psychological property is sufficient to generate a distinct momentary self which may or may not be part of a series which can be treated as if it were a persisting person.

The second advantage of Punctualism over its cross temporal rivals lies in its explanatory and ontological parsimony. A punctualist theory of momentary selves which explained deeply entrenched intuitions of temporal duration without a commitment to persisting persons would be more simple than psychological continuity theories which take person stages as building blocks for larger theoretical constructs. Psychological continuity theories which link person stages to one another through some kind of unity relation treat momentary selves as self-contained units which would be persons if they were to exist on their own and not as proper parts of larger aggregates of person stages. The introduction of continuant persons, over and above the momentary selves to which these theories are already committed, would be justified only if doing so provided some explanatory gain. A punctualist theory of personal identity which explained how something as ephemeral as a momentary self could support deep seated intuitions of personal persistence could remain safely neutral with respect to the metaphysics of identity.

Most philosophers are not tempted by the logical and ontological advantages of Punctualism because they doubt that momentary selves can bear the explanatory burden of a theory of personhood. Many of the most distinctive and valuable properties of persons unfold gradually and span significant segments of time. How can a momentary self carry out long term plans or be a true friend in good times and in bad? How can a momentary self be held responsible for events which occurred before she came into existence? How can someone who will be succeeded by a freshly minted, wholly distinct self the very next minute be compensated for injuries suffered and sacrifices made? Why, indeed, should a momentary self bother to give any account of the actions of preceding momentary selves or care in a self-interested way about what happens to anybody in the future?

Punctualism is hard to believe, a liability it shares with Derek Parfit’s Reductionism. Most people are naturally disposed to accept a Non-Reductionism which depicts persons as temporally extended continuants with sharply defined, fully transitive identity conditions which underwrite widespread social practices of rational accountability and nearly universal personal policies of prudential self-concern. Intuitive judgements of this kind can be compelling, but they should not be permitted to undermine well-founded theoretical belief if they are the product of non-rational belief systems. The ethical complexities of moral responsibility are beyond the scope of this paper, but punctualists will have discharged a part of their explanatory burden if the sources of prudential self-concern can be traced to normal functions of the human mind which engender an illusion of personal persistence.

Phantom limb pain illustrates this argumentive strategy. The somatosensory cortices in concert with subcortical regions of the limbic system, hypothalamus and brain stem construct a relatively stable long term body image which under normal circumstances maps well onto the gross anatomy of the body. Amputees often experience a remarkably stable and robust body image of a missing limb for months or years after its loss. It is clear that these people are not making intellectual mistakes. They can see that their anatomy is at odds with their body image, but their observational beliefs of bodily loss do not penetrate their experiential belief in bodily wholeness, and, more to the point, their intuition of bodily integrity peacefully coexists with their theoretical belief that a limb has been amputated. Similarly, one could become convinced on a theoretical level of Reductionism, Punctualism or some other revisionary metaphysic of personal identity but still feel, and resist, the pull of Non-Reductionist intuitions rooted in experiential belief.

Recent work in the cognitive sciences suggests that the natural disposition to feel prudential concern for a future self resides in two continuously reactivated sets of representations: An autobiographical memory system on the basis of which the social identity and personal history of a human being can be reconstructed and revised repeatedly, and a continuously updated, relatively stable long term body schema which imparts to the anticipation of experience its distinctive affective quality. On this view, momentary selves are neurally constructed from the ground up so continuously and consistently that each succeeding self never suspects it is being remade unless something goes wrong in the rebuilding. This constant reactivation of updated autobiographical and biological self-representations generates the stable sense of self which acts as the backdrop against which gradual shifts in intentional content and biological condition are experienced as external perturbations in the life of a persisting person. In the next two sections of this essay I sketch the rationale for a Punctualist explanation of self-concern along these lines, first with respect to autobiographical memory and then with regard to the affective quality of anticipation.

II

Punctualism strikes many philosophers as implausible in part because they are implicitly committed to a Lockean memory theory in which the content of episodic memory replicates and indexes previous experiences, rather like a photo album or videotape. If momentary selves had access only to isolated Lockean fragments of a personal past, torn like pages from a novel, then they would be cast adrift in time like an infant or an animal as Schectman suggests, but it is clear that human episodic memory functions within an autobiographical memory system in which episodic memory is located inside a four-dimensional interpretative context. Just as a copy of Dickens’s David Copperfield exists as a unit at a time, autobiographical memory reconstructs for the benefit of the present self a narrative of events in which current experience is understood as the culmination of the past and the foreshadowing of the future. Each moment autobiographical memory releases to punctual consciousness a new edition of the story of a self depicted as unchangingly self-identical and engaged in myriad time spanning activities. Intuitions of personal persistence emerge naturally from momentary self-representations all of which are built upon a generally stable structure of lifetime period memory and emblematic episodic memories of routine behavior, turning points and peak experiences.

The content of autobiographical memory shifts as people revise the past to satisfy their present concerns and reflect current knowledge. The earnest, unquestioning faith of the ten year old choirboy cannot be replicated by the skeptical philosophy professor; the fourteen year old’s confidence in high school basketball glory cannot be recreated by the graduating senior painfully aware of athletic failure; first love cannot be re-lived from the perspective of a man nursing emotional scars from a failed marriage. Each episode is understood in terms which could not possibly have been known at the time. These experiences can be remembered, but they cannot be revived; they can be woven into an intelligible narrative but they cannot be restored, replayed or re-experienced. The retrospective reconstruction of memory comes to the forefront at times of crisis, when the events of a lifetime demand wholesale reinterpretation. A woman discovers the habitual philandering of her husband and what was once remembered as innocent banter between her mate and a female friend now is recalled as infidelity and betrayal; an adolescent learns of his parents’ long planned divorce and comes to remember family holidays, vacations and birthdays as forced exercises in pretended civility; a father struggling to come to terms with the tragic death of a child remembers their last conversation quite differently before and after he hears the news.

Frequently rehearsed memories normally are recalled with a high degree of confidence, a confidence which almost always is misplaced. Remembrance of an event is itself an experience to be logged into the same repository which encoded the original experience. Each time the event is rehearsed, a reconstructed version of the memory is superimposed upon the initial engram, interfering with its efficient retrieval, introducing new engrams and altering the inferential patterns which control subsequent recollections. Episodic memories are consolidated in long term memory as amalgams of engrams of the original experience and engrams of subsequent recollections, with all of the reconstructive components of each rehearsal overlaid upon the original. In short, people don’t remember the past, they remember the last time they remembered the past.

Autobiographical memory elicits Non-Reductionist intuitions because it excludes from self-awareness any form of self-represented personal identity in which person stages are united by continuity relations. Memories of the personal past are assimilated within an autobiographical narrative within which the most notable experiences are consolidated as fused episodic memories and more mundane experiences submerged within general event memory. The earnest choirboy has disappeared within the skeptical philosophy professor; the young lover is buried under layers of broken romantic entanglements; the limitless energy of the aspiring athlete has dissipated within the tired and sick old man. The temporally unified self-representation autobiographical memory presents to consciousness appears unanalyzable because each new self-representation appropriates old self-representations within a continually updated narrative which presents itself as the true story of one’s life.

From the perspective of autobiographical memory, the Self has no dissociable parts; it is a single numerically identical enduring entity. Non-Reductionists are so impressed by this sense of temporal extension that they reject all attempts to reduce personal identity to a relation other than numerical identity on the grounds that no empirical property entails the identity of the person whose future I anticipate or the identity of the person whose past I recall. Only identity can justify self-concern, Non-Reductionists claim, because only identity guarantees that I am the person I care about.

This objection is sometimes called The Extreme Claim: Psychological continuity theories, whether Reductionist, Punctualist or Four-Dimensionalist, provide no reason, or at least no special reason, for the present self to care about its own future. Self-concern is without foundation; and if not irrational, then non-rational, dispensable and arbitrary. The Extreme Claim seems plausible because the egocentric desire that my life go well is cut loose from its experiential foundation when subjective autobiography is superimposed upon objective biography. The self-evident importance this life story once had now seems mysterious. What good, objective reason do I have to care about a future self any more than I care about my friends, lovers and children? What reason do I have to sacrifice now for a future self with whom I may have little in common? My life is not worth more than theirs; my future doesn’t matter more than their present. From the point of view of objective biography, the Extreme Claim seems inevitable.

III

From a subjective point of view, the Extreme Claim is nearly unintelligible. I can sympathize with my friend’s tale of her unhappy marriage without a hint of prudential self-concern, empathize with my child’s fear of a medical checkup without anticipating the prick of the needle and share my brother’s excitement as his wedding approaches without expecting to share in his honeymoon, but let these roles be reversed, and feelings of frustration, fear and lust come to the forefront of consciousness. Ordinarily, there is an enormous affective difference between anticipating an experience and imagining someone else having the very same experience. Attempts to understand a situation from another person’s point of view are sheer guesswork compared to the immediacy with which anticipation elicits bodily sensations and emotional responses to situations. I feel a twinge of fear when thinking about my upcoming eye operation, relish the thought of meeting old friends and feel nauseous at the prospect of yet another vertigo inducing ride at the County Fair because when I imagine myself having these experiences I represent my bodily state as it would be in such circumstances. The associated feelings transform an intellectual model of a projected scenario into a surrogate form of lived experience which has far greater impact than stand alone representations.

Anticipation on this view arises out of the juxtaposition of an imagined scenario of future events with a dynamic body schema which modulates the emotional content of experience. The cognitive content of imagined states of affairs interact with representations of the bodily landscape to initiate the sensations which give anticipation its distinctive quality. Normal processes of education and socialization solidly pair subtly discriminated sensations with categories of situations, whether directly experienced or created in imagination. Affective responses arising out of alterations in the organism’s body schema are connected, by learning, to predicted future outcomes of certain scenarios. When one anticipates having an experience, the somatosensory cortex organizes itself in the explicit activity pattern it would have assumed had the imagined scenario actually occurred. This is why people in general anticipate only experience represented as their own: The affective quality of anticipated experience is evoked by scenarios associated only with representations of their own bodily states. Since body transfer thought experiments remain hypothetical, no one has had occasion to link at the level of experiential belief imagined futures of someone else’s body. Empathetic identification falls short of anticipation because imagining someone else’s experiences evokes neither an altered body schema nor the associated bodily sensations.

Anosognosia provides some indirect evidence for these claims. As a result of stroke or other forms of damage to the somatosensory cortices, some people appear unable to update their internally generated body image. Their representation of their bodies relies on old information, growing older by the minute. Ill-founded experiential beliefs crystallized in frozen body schemas routinely override well-founded theoretical beliefs. The entire left side of the subject’s body may be paralyzed, but since he relies on an image of his body that is now out of date, he will sincerely deny that it is damaged in any way. When confronted with compelling evidence of paralysis, he may accede to an objective point of view only to have the intuition of bodily wholeness return with full force a moment later. The absence of updated body signals often leads to a lack of self-concern in situations normal people would find alarming. The news that he is suffering from invasive brain cancer, for example, might be greeted with gallows humor but not with panic, despair or anger. Emotional responses are flat, planning for the future profoundly impaired and normal self-concern absent entirely.

The brains of healthy human beings generate a continuous succession of momentary states which present the self as if it were a single individual who extends into the past in memory and into the future in anticipation. Punctualists argue that these representations are sufficient to explain without further metaphysical commitment the sense of temporal duration most people experience. All that exist are successive states of the human organism, each neurally represented anew, moment by moment, each anchoring an equally momentary intuition of temporal duration. Body schemas generate the affective quality of anticipation through dynamic, newly instantiated, on-line representations of a transitory emotional state; autobiographical memory endlessly reactivates and reinterprets narratives designed to serve current needs and desires. Self-concern itself emerges as an adaptive but ultimately non-rational feature of human mental life. Human persons are naturally disposed to believe on an experiential level that they extend into the past and the future. Perhaps they do. But if self-concern can be explained by an appeal to a natural belief in persistence without commitment to persistence itself, philosophers have one less reason to neglect the punctualist alternative.