North American Philosophical Publications PSYCHOLOGICAL CONTINUITY AND THE NECESSITY OF IDENTITY Author(s): Robert Francescotti Source: American Philosophical Quarterly, Vol. 47, No. 4 (OCTOBER 2010), pp. 337-349 Published by: University of Illinois Press on behalf of the North American Philosophical Publications Stable URL: http://www.jstor.org/stable/25734160 . Accessed: 28/07/2014 17:44 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . University of Illinois Press and North American Philosophical Publications are collaborating with JSTOR to digitize, preserve and extend access to American Philosophical Quarterly. http://www.jstor.org This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions American Philosophical Quarterly Volume 47, Number 4, October 2010 PSYCHOLOGICAL CONTINUITY AND THE NECESSITY OF IDENTITY Robert Francescotti I In attempting to understand personal identity, it is common practice to imagine a person existing at some time t (x at t) and a person existing at a time t* (y at t*), and then to ask, What does it take for person x at t to be the same person as person y at t*? The Psychological Continuity Approach (hereafter PC A) answers: there is a relation, R, of psychological continu ity such that person x at t is the same person as person y at t* if and only if x at t bears R toy att*.1 But maybe the question above is not the right one to ask when trying to understand personal identity. Olson (1997, p. 25) calls this the narrow question of personal identity, which he distinguishes from the broad ques tion: What does it take for person x at t to be the same individual as y at t*? One reason Olson focuses on the broad ques tion is that it leaves open whether a person can continue to exist without being a person.2 We should not preclude at the outset the possibil ity of our having once existed without any person-making psychological features (e.g., as a fetus at some sufficiently early stage) or of a person continuing to exist after the loss ?2010 by the Board of Trustees of the University of Illinois of those features (e.g., in a vegetative state). So, Olson concludes, when inquiring about our persistence conditions, the broad question is the one we should ask. And as a response to the broad question, PCA tells us that there is a relation, R, of psychological continu ity such that person x at t is the same individual as y at t* if and only if x at t bears R to y at t* which allows that a person might have existed at an earlier time or might exist at a later time without being a person at that time. It is not necessary here to decide which of these two questions is the more important one to ask when thinking about personal identity. The worry presented here for PCA arises whether the account is meant to answer the broad question or intended only to answer the narrow question. So long as "same" in our formulation of PCA means "numerically identical," the problem presented in this es say remains. Of course, in its most historically influen tial version, PCA already faces well-known objections. Thanks to Locke, psychological relation R is most commonly understood in terms of memory. Suppose that a person at one time is able to remember many of the thoughts and actions of a person at some earlier time, and remember them as thoughts and actions of herself. Then, on a memory construal of relation R, PCA gives the result This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions 338 / AMERICAN PHILOSOPHICAL QUARTERLY that the individual at the later time is the same person as the one at the earlier time. Now, the most obvious difficulty with understand ing personal identity in terms of memory is that it seems possible for one to remain the same person while having no memories of one's life at some earlier time (as Reid's famous Brave Officer example shows). So an important question for a memory theorist is whether there are suitable indirect memory connections that might constitute a person's persistence conditions. Is there a type of psychological continuity in Parfit's sense, i.e., overlapping chains of direct psychological connections, that might plausibly be thought necessary for remaining the same person?3 Another well-known concern for memory versions of PC A is that one can have a mem ory of doing something that someone else did. This possibility raises the issue of whether we can characterize the act of remembering in a way that rules out pseudomemories without making the analysis circular?i.e., without requiring that the person who recollects doing the deed is the same person as the one who actually did it.4 For the sake of the present discussion, it is left open whether either of these major dif ficulties is a serious obstacle to the success of memory versions of PCA. Even if there is no grave threat here to memory accounts, there remains a different worry that has not been widely discussed in the literature. The problem presented below deserves serious attention, since it applies not only to versions of PCA that appeal to memory links, but also to versions that rely on psychological connections of other types. It will be shown that regardless of the type of psychological continuity invoked, PCA conflicts with the doctrine of the Necessity of Identity (NI)?the idea that genuine identity is never contingent. The conflict with NI is described in sections III and IV. But before getting to that, let us first see what a version of PCA would have to entail to be compatible with NI. II "Augusta is the capital of Maine" is con tingently true; the capital of Maine might have been some city other than Augusta. This does not mean, however, that Augusta is only contingently identical with itself, for we can hold that "is" occurs in the sentence "Augusta is the capital of Maine" as an "is" of predica tion and not an "is" of identity. In that case, we would interpret the sentence as claiming only that Augusta exemplifies the property of being the capital of Maine, thereby allowing that it plays this role contingently, while also insisting that the city is necessarily identical with itself. So from the contingency of "Au gusta is the capital of Maine" we cannot infer that the identity relation sometimes holds contingently. Indeed, there is good reason to think that identity cannot hold contingently; that is, (NI) for any objects x and y, if x = y, then nec essarily x = y. For suppose that x = y. Given that x is neces sarily identical with x and the Indiscernibility of Identicals, it seems to follow that x is necessarily identical with y.5 The formulation of PCA offered at the start of this essay does not contain any modal terminology. Yet as a conceptual analysis of personal identity, PCA is certainly meant to report on more than just what happens to be the case while one remains the same person. It also aims to specify what must be the case to be the same person. Obviously, then, in formulating PCA, a necessity operator is required. The theory requires at least that the following is true: (1) necessarily, for any persons, x and y, and times, t and t*, x at t = y at t* only if x at t bears R to y at t*,6 where R is whatever psychological relation is supposed to yield the identity of persons. However, PCA will have to entail more than (1) if it is to honor NI. (1) entails that there is This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions CONTINUITY AND IDENTITY / 339 no possible world where x is the same person as y without bearing R to y, but it does allow that x bears R to y in one possible world and not in some other possible world, and therefore that x is the same person as y in one possible world and not the same person as y in another. To be compatible with NI, PCA will need to specify transworld persistence conditions, requiring that (2) necessarily, for any persons, x and y, and times, t and t*, x at t = y at t* only if necessarily x at t bears R to y at t*.7 As with (1), (2) entails that there is no pos sible world where x is the same person as y without bearing R to y. But thanks to the embedded necessity operator, (2) also entails that if person x bears R to y in one possible world, then x bears R to y in every other pos sible world at which x and y exist. So (2) does not allow that identity holds contingently.8 We will consider various candidates for re lation R in sections III and IV to see if any of them yields a true instance of (2). It is argued that they do not. But before turning to that dis cussion, a brief note about the endurantism/ perdurantism debate is in order. According to endurantism, an individual is wholly pres ent at each point in the individual's career, which entails that one's persistence through time consists in one's being wholly present throughout that period. If this view is correct, then it is perfectly appropriate to talk about an individual at one time being numerically identical with an individual at some other time. However, if the perdurantist is right, then what exists at any one moment in the life of a persisting object is not the object as a whole, but only a temporal part. On this view, if t and t* are distinct times, then x-at-t and y-at-t* are distinct temporal parts of the object. They are temporal parts of the same temporally extended object, but the parts themselves are distinct. So the perdurantist advocate of PCA does not seek to explain what makes a person at one time identical with an individual at some other time, but instead aims to explain what makes those different temporal parts parts of the same (identical) person, which means that the per durantist would not accept (2), and need not accept (2) to honor NI.9 It might be thought, then, that only endurantist versions of PCA conflict with NI. However, in section V it is argued that the conflict with NI described in sections III and IV is also a problem for the perdurantist advo cate of PCA. But for ease of exposition, let us postpone further discussion of perdurantism until then. The conflict with NI presented in III and IV is couched in endurantist terms; there I shall speak of a person at one time being identical with a person at some other time. Ill Suppose that body x of some person at some time, t, is spatio-temporally continuous with body y at a later time, t*. Suppose also that the memories housed in body y are con nected, as strongly as you like, to the thoughts and actions of body x. While a memory connection actually does obtain in this case, it seems that this memory connection could have failed to obtain. Even if a body at one time actually houses psychological states that relate it memory-wise to a body at some other time, it is certainly not necessary that they are related in this way. Whatever memories a body happens to store are not essential to that body; it might have had very different memories, or none at all, while remaining the same body. So it seems that whatever memories connect body x with body y, it is possible for x and y to be the same body without these memory connections. The same seems to apply to the person, and not just the constituent body.10 While it is far from clear how exactly our life experiences could have been different while being the same person (and not just the same body), it does seem that some significant differences This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions 340 / AMERICAN PHILOSOPHICAL QUARTERLY might have occurred. For instance, you could have met someone who inspired you to pursue a career in architecture rather than philoso phy. Then you (the person) would have had a very different set of experiences than what you actually had. Your encounters would have differed?different classes, teachers, friends, and projects. As a result, your thoughts, beliefs, and desires, along with the behavior caused by these, would also have differed, and all of these differences would have produced memories very different from those you actu ally acquired.11 It seems that where relation R is understood in terms of memory, R does not connect yourself in the counterfactual case just described to the way you actually are now. So it seems that the memory relation contingently connects your actual present self with how you actually were in the past. So where R is the memory relation, the following appears to be false: (3) for any persons, x and y, and times, t and t*, x at t bears R to y at t* only if necessarily x at t bears R to y at t*. Given PCA, if (3) is false, then (2) is also false?i.e., it is then false that person x at t is identical with y and t* only if necessarily x at t bears R to y at t*. But if (2) is false, then given PCA, NI is false as well. So if (3) is false, as it seems to be, then the proponent of PCA forfeits NI. One might bite the bullet at this point and insist that things could not have gone any differently for a person so that the person is not related memory-wise, in any other possible world where she exists, to the way she actually was or is. However, this view places severe limitations on the ways our lives could have gone, limitations that seem unreasonable. On this view, you or I could not have met anyone who inspired us to pursue a career in architecture, astronomy, music, or real estate?or at least, we could not have pursued such alternative paths with memories (discontinuous with those we have actually acquired) that these alternatives would nor mally produce. This result is hard to believe, even for advocates of PCA. PCA theorists would have to admit that the experiences we have at one time in our lives can greatly differ from those we have at other times. So it seems they have no good reason to deny that at any one time we could have had experiences dif ferent from those we actually do have at that time.12 Differences in experience normally lead to differences in memory. So it seems that even if memory links relate one stage of a person's life with other actual stages of that person's life, there is no good reason to think these memory relations will always hold between the actual stages of a person's life and the various ways that person's life could have been. In other words, even if it is true that memory relations connect the vari ous stages of a person's life within possible worlds, it seems implausible to think that they always do so across possible worlds. To honor NI, an advocate of PCA needs to endorse (2), which tells us that relation R binds a person at one time in one possible world to the per son at any time in any other possible world. However, where R consists in memory links, it is doubtful that (2) is true. It seems that the very same person who actually had one set of life experiences might have had different experiences and thereby might have acquired memories that are not continuous with those she actually acquired. Of course, a memory account of personal identity does not have a chance of success if it relies on direct links between actual memories. To accommodate the various ways in which a person forgets (while remaining the same person), expressing the requisite memory relations takes some ingenuity. Ob viously, these memory connections cannot be restricted to what one actually recollects, for there are many occasions when one is not actually recollecting any of the stages of one's former life. We need to allow that (i) the memory connections include potential This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions CONTINUITY AND IDENTITY / 341 memories, what one would remember under suitable conditions. Also, we might follow Quinton (1962, p. 398) and require only that (ii) a person at any one time of her life is related to various other moments of her life by a series of memory links rather than one direct connection.13 This amounts to saying, as Shoemaker (1984, p. 81) puts it, "that two stages belong to the same person if and only if they are the end-points of a series of stages such that each member of the series is memory-connected with the preceding member."14 We might wish to allow for even weaker memory links, as does Grice (1941, p. 343), who proposes that (iii) each point in a person's career is memory-linked to either a preceding or a subsequent moment. This proposal, Perry (1975, pp. 19-20) notes, handles the case of the Senile General who can remember boyhood events but not his officer days. However, despite these emendations, the threat of violating NI remains. Consider each of the actual moments of someone's life, stretching from t to t+n, and suppose that this series enjoys just the sort of continuity of memories described by (i)-(iii). Keeping in mind the variety of different ways our lives could have gone (different classes, teachers, friends, and projects, producing different thoughts, beliefs, desires, and behavior, in addition to all of the differences in memories that would result), it seems quite clear that there are many counterfactual moments of one's life at some time, say t+n/2, that are not related to the actual moments of one's life in the manner described by (i)-(iii). It seems that things could have gone differently in my life so that in some other possible world at which I exist I am now reflecting on, for example, the previous experiences in my life as a bartender, a job that I reluctantly sought after failing to get an academic position after my arduous study of art history (none of which actually occurred). Take each mo ment of my actual history up to the present and replace the last in this series with the counterf actual reflective stage just described. Now we have a series the last of which lacks even potential memories of the previous mo ments. So it seems that even a sophisticated memory version of PCA fails to make (3) true; i.e., the memory relation that is supposed to be essential to personal identity still fails to hold with necessity. It is not clear how a memory account could be revised any further than (i)-(iii) to avoid this result. So the threat of violating NI remains.15 IV We could have had psychological features different from those we actually do or did have. That is why (3) and therefore (2) seem false where R is understood in terms of memory. That is also why (3) and therefore (2) appear to be false with other candidates for relation R. Clearly, the body might have had wildly different personality traits while being the same body. This seems to be true of the person, too. We certainly wish to allow that a person's life experiences could have gone a bit and perhaps quite a bit differently, differently enough that one's personality in some counterfactual scenario is not continu ous in a suitable way with one's actual per sonality at the time or with the personality one actually has had in the past or will have in the future. Marty's life experiences could have been other than what they actually are, and these different experiences might have lead to personality traits different from those he actually did acquire. With more success ful relationships, less critical bosses, and a few nurturing friends, Marty could have been more optimistic, self-confident, pas sionate about life, and in general had a life much happier than the one he has actually had. To honor NI, the proponent of PCA needs to accept (2)?the claim that relation R binds a person at one time in one possible world This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions 342 / AMERICAN PHILOSOPHICAL QUARTERLY with the person at any time in any other possible world. But compare Marty in the counterfactual case described above with how things actually turned out for him. Where R is continuity of personality traits, R does not obtain in this case. Even if Marty today actu ally is continuous personality-wise to the way he is at other times in his actual career, he is not psychologically continuous in this way to stages of the counterfactual self described above. It seems, then, that while continuity of personality actually holds between the current and prior stages of Marty's life, it holds contingently. So it seems that when R is understood as continuity of personality, (3) is false?i.e., it is false that for any persons, x and y, and times, t and t*, x at t bears R to y at t* only if necessarily x at t bears R to y at t*. But if (3) is false, then so is (2). So, again, the proponent of PCA seems to forfeit NI. The result is the same when R is continuity of intentions or narrative unity. The typical person could have had different intentions in the past from those he or she actually did have. Circumstances could have differed so that in college you decided to take a differ ent major or perhaps skip college altogether and turn to a life of crime. So the intentions a person actually does have at the present time need not be continuous with those that the person could have had at that time or other times in her life. Regarding narrative unity, since a person could have differed in terms of past experiences, the result could have been different memories, intentions, and personal ity traits, and therefore the person might have made sense of herself with a narrative that is discontinuous with any narrative the person actually did construct.16 One might insist that things could not have gone differently for us so that we are not continuous in terms of personality or narra tive unity in other possible worlds where we exist with the way we actually are. But this view places severe limitations on the ways our lives could have gone, limitations that seem unreasonable. The idea that you or I could not have had different experiences, which produced different intentions or dif ferent narratives to make sense of our lives, is hard to believe. Even proponents of PCA would have to admit that the experiences we have at one time in our lives can greatly dif fer from those we have at other times. But if this is granted, then it seems there is no good reason to deny that at any one time we could have had experiences very different from those we actually did have at that time.17 And with these differences in experience, there are likely to be great differences in intentions and self-narratives. So it seems that viewing the R-relation in terms of either continuity of intentions or narrative unity also makes (3) dubious, and this, again, undermines (2). Might there be some sufficiently sophisti cated appeal to continuity of personality, or continuity of intentions, or narrative unity, that makes (3) true? I think there is reason to be suspicious. Recall the suggestions, men tioned in section III, about how a simplistic memory version of PCA might be emended to account for the various ways in which a person forgets, and let us imagine analogues of these for the R-relations discussed in this section. Let us require that (i*) these R-relations need not actually be conscious and need not actually manifest themselves in behavior, but only that they would affect behavior and consciously so under suitable conditions. Also suppose that we include indirect connections of personality, inten tions, or narrative unity so that (ii*) person x is identical with y if x and y are R-related by a series of psychological links. We might also wish to weaken (ii*) to allow that (hi*) each stage in a person's career is R-related, in terms of personality, intentions, or narrative unity, to either a preceding or a subsequent stage. Given the variety of different ways our lives could have gone, it seems that there are many counterfactual stages of one's life that This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions CONTINUITY AND IDENTITY / 343 are not related to the actual stages of one's life in the manner described by either (i*), (ii*), or (iii*). I might have chosen to spend more time in my childhood with Jack instead of Jill, which would have led to meeting dif ferent students in high school, sparking an interest in becoming a firefighter, causing me to pursue training in this field instead of a degree in philosophy, and as a result meeting and eventually marrying so-and-so, with the tumultuous relationship that ensued, result ing in failing my firefighter training, leading to unemployment, poverty, and eventually a life of crime ... all of which is quite differ ent from the way my life has actually gone. It seems that the personality, intentions, and narrative unity I would have acquired in this counterfactual scenario are such that I am not, in that case, R-related in ways (i*)-(iii*) with the actual stages of my life. Suppose we combine a few, or more, dif ferent respects of psychological continuity? continuity of memory, intentions, personality traits, and narrative unity. On this view, x and y are the same person only if x and y are con tinuous in each of these ways (assuming no branching has occurred). But, clearly, if each of these psychological relations holds only contingently, then so does any conjunction of them; for any relation rv if r{ contingently binds x and y, then for any relation, r2, the conjunctive relation r1 & r2 contingently binds x and y. As shown above, it seems that for each of these ways to understand relation R, R connects a person with other actual stages of his or her life only contingently. Suppose that instead of conjoining the vari ous R relations, we disjoin them. While we are at it, let us add some more psychological traits to the mix. On this view, for x and y to be the same person, it is enough that x and y are connected in any of the various ways that might be considered definitive of personal identity?in terms of memory, or personality, or intentions, or narrative unity, or prefer ences, or habits, or character, etc.18 But recall the counterfactual firefighter scenario above and the counterfactual "self-reflective" case described near the end of section III. In both cases, it is reasonable to suppose that there are counterfactual moments of the person's life that are not continuous either in terms of memory, or personality, or intentions, or nar rative unity, or preferences, or habits, or char acter to the actual stages of the person's life. It seems, then, that no collection (conjunctive or disjunctive) of the psychological relations that might be thought definitive of personal identity makes (3) true.19 At least, the burden is on the advocate of PCA to prove otherwise. And if (3) cannot be supported, then given PCA, (2) is indefensible as well, in which case the proponent of PCA seems to forfeit NI. One might wonder whether the conflict between PCA and NI noted here applies only to endurantist versions of PCA. In the next section, it will be argued that it does not. V If the perdurantist is right, then what exists at any one moment in the life of a persisting object is not the object as a whole, but only a temporal part. If t and t* are distinct times, then x-at-t and y-at-t* are distinct temporal parts of the object. They are temporal parts of the same temporally extended, 4-D object, but the parts themselves are distinct. So per durantist advocates of PCA do not seek to explain what makes a person at one time the same (identical) person as a person at some other time; instead, they aim to explain what makes those distinct temporal parts parts of the same person. Thus, perdurantist support ers of PCA would not accept (2) and need not accept (2) to endorse NI. To honor NI they need not accept the following either: (2p) any person-stages, x-at-t and y-at-t*, are temporal parts of the same person only if neces sarily x-at-t bears R to y-at-t*. Allowing that R holds contingently between x-at-t and y-at-t* amounts to allowing that This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions 344 / AMERICAN PHILOSOPHICAL QUARTERLY x-at-t and y-at-t* are parts of the same person contingently, and not that they are identical contingently. It might appear, then, that the perdurantist advocate of PCA avoids the conflict with NI described in sections III and IV. The conflict, however, is not completely avoided. While perdurantist advocates of PCA need not accept either (2) or (2p) to honor NI, by endorsing NI they are com mitted to the following restricted version of (2p): (2p=) x-at-t and y-at-t* are temporal parts of the same person and x-at-t = y-at-t* only if necessarily x-at-t bears R to y-at-t*.20 Why does accepting NI commit them to (2p=)? Well, the symbols "x," "y," "t," and "t*" in the formulations above obviously are meant to be variables; and as is customary, tokens of two distinct variable-types can be used to refer to the very same thing; e.g., while "t" and "t*" are often used to designate different times, they can, of course, also be used to refer to the same time. Now suppose that perdurantism is true and that "x-at-t" and "y-at-t*" are used to designate the same temporal part of a person. It is trivially true that numerically identical parts are parts of the same thing. So when x-at-t is identical with y-at-t*, x-at-t and y-at-t* are temporal parts of the same person. According to a per durantist version of PCA, x-at-t and y-at-t* are temporal parts of the same person only if they are R-related. So given PCA, the fact that x-at-t is identical with y-at-t* entails that they are R-related (and in that case, they are R-related in the strongest possible sense: by being indistinguishable, since every tempo ral part is indistinguishable from itself). Of course, if NI is true, then if x-at-t and y-at-t* are identical, they are necessarily identical. Given PCA, it follows that if x-at-t and y-at-t* are identical, then they are necessarily R related. For if x-at-t could fail to be R-related to y-at-t*, then they could fail to be stages of the same person. But numerically identical person-stages could not fail to be stages of same person. So if x-at-t and y-at-t* could fail to be stages of the same person, then they could fail to be identical, contrary to NI. So their being necessarily identical entails that they are necessarily R-related, given PCA. To rehearse the line of argument: suppose that (i) a and b are temporal parts of a person and also suppose that (ii) a is identical with b, i.e., a and b are the same temporal part. This temporal part might be the whole of the continuant person, where "a" and "Z?" both designate the improper temporal part of the continuant person?perhaps the instanta neous stage of an instantaneous person, or the day-long stage of a day-long person, or the ninety-year-long stage of a person lasting ninety years. In each case, not only would a and b be the same temporal part of a person; they would also be the same person. However, this supposition is not crucial to the present line of argument. We need only suppose that a is identical with b, whether this is a proper temporal part or the improper temporal part of a continuant person. Now, it is trivially true that (iii) necessarily, numerically identical person parts (temporal or spatial) are parts of the same person; \J[a = b ?> PSPab]. Also, given PCA, if a and b are temporal parts of the same person, then they are R-related. This is meant to be a necessary truth, since PCA purports to give necessary (and also sufficient) conditions for being stages of the same person (or necessary and sufficient conditions for being the same person on an endurantist reading). So a perdurantist ver sion of PCA entails that (iv) necessarily, if a and b are temporal parts of the same person, then a and b are R-related; [PSP^-^R^]. This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions CONTINUITY AND IDENTITY / 345 From (iii) and (iv) it follows that (v) necessarily, if a is identical with b, then a and b are R-related; = b ?? Rafr]. Given NI, it follows from (ii) that (vi) a is necessarily identical with b;Oa = b, which together with (v) entails that (vii) necessarily, a is R-related to b\ [JRab. This shows that a perdurantist advocate of PCA who accepts NI cannot consistently deny (2p=)?i.e., cannot deny that if a and b are temporal parts of the same person, and the same temporal part, then a and b are neces sarily R-related. However, the discussion in sections III and IV shows that a person at one time, due to different life experiences, could have had very different psychological properties at that time, and these possible differences seem great enough to show that (2p=) is false. The possible psychological differences seem to be such that a person at a time is not R-related to all the ways the person could have been at that time, which means that even if a and b actually are R-related, they are not necessarily R-related.21 However, if (2p=) were false, then on a perdurantist ver sion of PCA, NI would be false as well. So a perdurantist version of PCA does not avoid the conflict with NI described in sections III and IV. VI Let us summarize the results of this discus sion. According to an endurantist construal of PCA, there is a psychological relation, R, in virtue of which a person x at time t is numeri cally identical with y at time t*. Assuming, also, that NI is true, R will be a relation that necessarily holds between x and y?a relation that x bears to y in all possible worlds where x and y exist. So in order to consistently accept NI, the endurantist proponent of PCA needs to hold that (2) necessarily, for any persons, x and y, and times, t and t*, x at t = y at t* only if necessarily x at t bears R to y at t*. Typical candidates for relation R were considered here. For each of these, it seems to be false that (3) for any persons, x and y, and times, t and t*, x at t bears R to y at t* only if necessarily x at t bears R to y at t*. There is reason to think that not only bodies, but also the persons they constitute, could have had very different experiences. Since differences in experience may lead to dif ferences in memory, intentions, personality traits, preferences, habits, and character, it seems that relation R does not link how we actually are to all the ways we could have been. Perhaps there is some other brand of psychological continuity, one not considered here, that makes (3) true, thereby allowing that (2) is true as well. Whether there actually is remains to be seen, but given our discussion of the typical candidates, there certainly is reason to be suspicious. A perdurantist advocate of PCA will not accept (2), and need not do so to honor NI, as noted in section V. However, there it was argued that this does not eliminate the threat of forfeiting NI. On a perdurantist reading of PCA, allowing that R holds contingently be tween x-at-t and y-at-t* amounts to allowing that x-at-t and y-at-t* are parts of the same person contingently. This does not entail that x-at-t and y-at-t* are identical contingently? unless they are the same temporal part. In that case, if relation R holds contingently, then given PCA so does the identity relation. But it seems that R does hold contingently even when x-at-t = y-at-t*, for it seems that a person at one time could have had very dif ferent psychological states at that time, ones that are discontinuous with those the person actually has at that time. So it seems that the risk of forfeiting NI remains. This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions 346 / AMERICAN PHILOSOPHICAL QUARTERLY The problem presented here deserves seri ous consideration, since it applies not only to versions of PCA that appeal to memory links, but also to versions (endurantist or perdurantist) that rely on mental connec tions of other types. It has been argued that regardless of the type of mental continuity that might be thought definitive of being the same person, PCA conflicts with NI. Whether the specific problems of the various individual versions of PCA can be solved, the general worry presented here remains. Of course, it is perfectly open to proponents of PCA to reject the well-established NI, which would require some strong independent justification. Otherwise, they will need to convince us that the psychological ways we could have been are far more limited than we are inclined to believe.22 San Diego State University NOTES 1. To be sufficient for being the same person, relation R must be understood as nonbranching psycho logical continuity. This is to handle cases of fission. 2. Olson also claims that the broad question is what psychological continuity theorists mean to ad dress, for they "claim that one ceases to exist if one's mind is destroyed, not merely that one ceases to be a person." The theory "purports to tell us what it takes for one of us to survive . . . simpliciter, not merely what it takes for one of us to survive as a person" (1997, p. 26). 3. SeeParfit(1984,p. 206). 4. Perry (1975, Ch. 9: "Personal Identity, Memory, and the Problem of Circularity") tries to avoid this circularity worry by appealing to the notion of memories caused in the right way (i.e., there being a suitable causal mechanism connecting the memory to the original experience of the event). Also, see Shoemaker (1984, p. 83). 5. See Marcus (1961) and Kripke (1971). 6. The reason for emphasis on "only if" and not "if and only if" in (1)?and (2), (3), (2p), and (2p=) to follow?is that this essay concerns what is necessary, given PCA and NI, for being the same person. 7. Both (1) and (2) answer what Olson calls the narrow question of personal identity; both concern what makes a person at t identical with a person at t*. This is not meant to presuppose that the narrow rather than the broad question is the more important one to ask. For if we can show that (2) is false, for some relation R, then we will also have shown that the answer to the broad question is false as well; if (2) is false, then it is also false that for any person x at t and any individual y at t*, x at t = y at t* only if necessarily x at t bears R to y at t*. 8. Those who reject the idea of transworld identity in favor of counterpart theory make sense of the difference between having features necessarily or only contingently in terms of which properties are exemplified, not by oneself, but by one's counterparts at other possible worlds. (2) will then be interpreted as claiming that person x = person y if and only if in every possible world at which x has a person-counterpart and so does y, the person-counterpart of x at that world is R-related to the person counterpart of y at that world. (The emphasis on person-counterparts is to allow that a person exists, i.e., a counterpart of a person exists, at some possible world without being a person at that world.) 9. For the perdurantist, the formulation of PCA given at the start of this essay should be changed to read: there is a relation, R, of psychological continuity such that person-stage x-at-t is a temporal part of the same person as y-at-t* if and only if x-at-t bears R to y-at-t* (or as an answer to what Olson calls This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions CONTINUITY AND IDENTITY / 347 the broad question: person-stage x-at-t is a temporal part of the same individual as y-at-t* if and only if x at t bears R to y-at-t*). 10. It is tempting to think that each person is identical with a body?a body endowed with person making properties. However, many believe otherwise. Some believe that a person is an immaterial substance. Others think that while each person is constituted entirely by a body, there is a difference between constitution and identity. The person and the constituent body seem to have different persis tence conditions: the person can continue to exist without the former body, e.g., in the brain-transplant case, and the body can continue to exist without the former person. It is arguable that the difference in persistence conditions shows that the person is not identical with the constituent body, just as a differ ence in persistence conditions might be thought to show that a statue is not identical with the constituent lump of marble or clay. 11. See Campbell's (2000) intricate discussion of the various difficulties that arise for a psychological account of personal identity when it comes to the intuition that we could have led different mental lives. As Campbell expresses the intuition, "I could have been sold into slavery at an early age, and have grown up in a very different culture. Or I might have had a mystical experience at fifteen, and become a monk.... I could have won a lottery and become a decadent multi-millionaire. And so on" (p. 37). Unlike Campbell's essay, the discussion here focuses on how exactly this intuition conflicts with NI in particular. 12. Suppose an advocate of PCA accepts mereological essentialism, according to which, concrete particulars have all of their parts essentially. In that case, the idea that a person could not have been very different mentally might seem perfectly welcome. However, even if we were to accept the highly counterintuitive doctrine of mereological essentialism, this should not lead us to deny that we could have been very different mentally. It seems possible (certainly logically, but also metaphysically and even physically) for a person to undergo great mental changes without losing or gaining any parts; the difference in mentality might be due to, e.g., differences in the way the parts are interrelated or differences in the external objects toward which one's intentional states are directed. Further, it seems at least metaphysically possible for a person to be an indivisible substance?e.g., an immaterial soul, or perhaps a microscopic part of one's brain, as Chisholm (1989, p. 126) suggests. If persons were indivisible, then their mental changes would occur without a loss of parts, since they would have no parts to lose. 13. Quinton talks of continuity of memory and continuity of character. Psychological relations other than memory are discussed in the next section. 14. Talk of "person-stages" does not automatically commit one to perdurantism. As Shoemaker notes, "Person-stages can be thought of as 'temporal slices,' not of persons, but of the histories or careers of persons" (1984, p. 75). 15. A nonbranching constraint does not help here, since in the case described above, we need not suppose that any fission has occurred. Note also that to avoid the circularity problem mentioned in section II (the issue of characterizing the act of remembering in a way which does not presuppose that the person who recollects doing the deed is the same person as the one who actually did it), it is not uncommon to impose a causal constraint (see note 4). This causal constraint does not help with the threat to NI; it actually imposes an additional worry, since the causal requirement will be satisfied only within worlds, i.e., a counterfactual stage is not causally connected in any way with stages of one's actual history. 16. Yet narrative accounts of personal "identity" are often not meant to explain the strict numerical identity of persons over time. For example, Schechtman's (1996) narrative account is not meant to address the "reidentification question" of strict identity over time, but the "characterization question," concerned with "which characteristics are truly attributable to a person" (p. 76)?characteristics that are truly hers in the sense of being those most central to making her the person she is. And Flanagan's This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions 348 / AMERICAN PHILOSOPHICAL QUARTERLY (1996) narrative account is meant to describe "the sort of connectedness that constitutes a normatively acceptable self or life" (p. 67). 17. See the points about mereological essentialism in note 12. 18. Shoemaker proposes that "memory continuity is now seen as just a special case of psychological continuity, and it is in psychological continuity that personal identity is now held to consist" (1984, p. 90). 19. The phrase, "that might be thought definitive of personal identity," is included because it is argu able that there are certain very general relations that are essential to being the same person. Consider the relational property, being alike in terms of having rationality, or the even more general, being alike in terms of having psychological states. If persons are essentially rational or essentially bearers of consciousness (both of which are controversial), then (3) is true. However, neither of these overly broad relations is definitive of personal identity, since both are obviously insufficient for being the same person. So what is doubtful is that any R or collection of Rs that is necessary for being the same person is also sufficient for being the same person. Lynne Baker contends that x is the same person as y just in case x and y share the same first-person perspective, where a first-person perspective is "a perspective from which one thinks of oneself as an individual facing a world, as a subject distinct from everything else" (2000, p. 60). One might argue that having the same first-person perspective is necessary for being the same person, in which case, (3) would be true where R is having the same first-person perspective. However, it is doubtful that this would be necessary unless the notion of a first-perspective is defined in a way that entails being the same person. Indeed, Baker admits that she "cannot give noncircular conditions under which a first-person perspective considered at one time is the same first-person perspective as a first-person perspective considered at another time" (2000, p. 132). So, strictly speaking, what is doubtful is that any R that is both necessary and sufficient for being the same person can provide a noncircular account of personal identity. 20. I delete the outer necessity operator in (2p) and (2p=) for the sake of simplicity. 21. If perdurantism is true, then persons have temporal parts as well as spatial parts, and if we conjoin perdurantism with mereological essentialism, the result is that a person's temporal parts are ones she has essentially. However, even if it is true that persons have their temporal parts essentially, it does not follow that the temporal parts themselves could not have differed mentally. Even if it were true that a 4-D person could not have existed without the temporal parts she actually has, it might still be that the temporal parts themselves could have had different mental features. 22. Campbell (2000, p. 48) proposes that the advocate of a psychological account of personal identity should agree with Parfit that identity is not what matters in survival while holding the minimalist view that for any actual person, x, and any y in another possible world, y has what matters to x's survival if y is psychologically similar to x (with the qualification that after x's death what matters is not psy chological similarity to x, but that there is a person R-related to y). However, even if we accept this minimalist view about what matters in survival, we need not?and it seems we should not?accept it as a view about personal identity. REFERENCES Baker, Lynne. 2000. Persons and Bodies (Cambridge: Cambridge University Press). Campbell, Scott. 2000. "Could Your Life Have Been Different?" American Philosophical Quarterly, vol. 37, pp. 37-50. Chisholm, Roderick. 1989. On Metaphysics (Minneapolis: University of Minnesota Press). This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions CONTINUITY AND IDENTITY / 349 Flanagan, Owen. 1996. Self Expressions (Oxford: Oxford University Press). Grice, H. P. 1941. "Personal Identity," Mind, vol. 50, pp. 330-350, reprinted in Perry (1975), pp. 73-95. Kripke, Saul. 1971. "Identity and Necessity," in Identity and Individuation, ed. M. K. Munitz (New York: New York University Press), pp. 135-164. Marcus, Ruth. 1961. "Modalities and Intensional Languages," Synthese, vol. 13, pp. 303-322. Olson, Eric. 1997. The Human Animal (Oxford: Oxford University Press). Parfit, Derek. 1984. Reasons and Persons (Oxford: Clarendon Press). Perry, John. 1975. Personal Identity (Berkeley and Los Angeles: University of California Press). Quinton, Anthony. 1962. "The Soul," The Journal of Philosophy, vol. 59, pp. 393-409, reprinted in Perry (1975), pp. 53-72. Schechtman, Marya. 1996. The Constitution of Selves (Ithaca, N.Y: Cornell University Press). Shoemaker, Sydney. 1984. "Personal Identity: A Materialist's Account," in Personal Identity, ed. S. Shoemaker and R. Swinburne (Oxford: Basil Blackwell), pp. 67-132. This content downloaded from 130.191.17.38 on Mon, 28 Jul 2014 17:44:21 PM All use subject to JSTOR Terms and Conditions