Persistence in Personal Identity:

Persistence in Personal Identity:

Parfit and Science Fiction Puzzles

Introduction

Most people, either consciously or implicitly, have a commonsense belief that they each constitute a unified self. David Hume reflects that some philosophers think that we cannot be certain of anything if we doubt the "perfect identity and simplicity" of our own continuing existence (131). However, based upon the numerous and diverse theories about personal identity found in the literature, one realizes that such a commonsense belief is in itself an unarticulated speculative theory. I propose a broader framework approach to this problem; one that is more comprehensive in scope than any I have found in the literature. This would include analyzing modern views about models of the self, real human puzzle cases including human oddities, paranormal phenomena and religious beliefs; science fiction thought experiments, and puzzle cases from science fiction literature.

This presentation is about the use of science fiction thought experiments to substantiate views about Personal Identity. There will be some contrasts and comparisons from other science fiction venues weaved in alongside these philosophical experiments. The moral and ethical implications from Derek Parfit’s account are far reaching and revolutionary. Because he is influential in these debates, I focus on Parfit's views. You will see how he bolsters his claims that identity can be a matter of degrees and that survival is more important than identity. Although I am critical of this methodology of basing conclusions solely on logical conclusions from these kinds of experiments, they certainly provide food for thought and have a place in a broader framework for debates about personal identity. Before presenting these experiments and other sci-fi examples, I will provide a brief outline, history, and importance of the problem.

What is the Personal Identity Problem?

Those who are doing research in Personal Identity are working on one or more of the following eight questions: (1) Who am I? This is a question about one’s individual psychological identity and how this changes over time. (2) What is necessary and sufficient for something to be counted as a person? For example, can an ovum or embryo, or someone in a vegetative state, be considered a person? (3) The Persistence question asks: What are the necessary and sufficient criteria for personal identity to obtain for a person to be the same person over time. This is different from the Evidence question: (4) What evidence determines whether the same person here now (say in the courtroom) is the one who was at a specific place yesterday? (5) The Population question asks how many people are there at a certain place at a certain time? What does that number signify? Could a human being with a split personality be considered two persons? (6) What am I, metaphysically speaking? Am I merely a biological animal, or essentially an immaterial soul, or bundles of perceptions, or the bearer of a historical narrative, or some combination of these things? (7) How could I have been different than I actually am, say if I would have had different parents? (8) What is important about the fact of my identity or my persistence? Can survival be separated from identity and can that be more important?[1] This presentation focuses on the Persistence Problem which entails also addressing the question about the nature of humans: What am I?

Brief history of the Persistence problem

Following is a very brief history for putting the modern debates in context.

René Descartes’ dictum commonly known as “I think, therefore I am” was derived from his thought experiment in which he was determined to doubt everything he believed up to that point. He could doubt that he had a body but not that he was thinking. His view of the self was that it exists as a consciousness continuing throughout one’s awareness.[2] This Cartesian view espouses that a person is essentially a non-physical substance, or soul. The current form of this view has evolved away from Descartes’ theory and is now often called the Ego Theory, or transcendental view, whereby a person continues to exist as an Ego, a subject of experience.[3] Other moderns claim that personal identity consists of some further fact, not necessarily a soul, but other than merely a body and/or a brain.

John Locke originated the important relational view and memory criterion for personal identity; that it consists in not bodily identity, but rather relations that obtain among present conscious memories and the earlier experiences or actions remembered. Locke was the first one to use thought experiments for this problem and the first to explicitly connect personal identity with ethical concerns. For example, he poses the possibility of a prince having his soul, which contains his consciousness-memories, transferred to a cobbler’s body and vice versa. Locke claims that everyone would agree that the body of the cobbler would then be the same person of the prince, accountable only for the prince’s actions. However, he thinks that no one would say that it would be the same man. He is clearly making a distinction between being a person and being a human being.

A similar example of Locke’s prince and pauper exchange is found in the 1988 movie big in which a young boy makes a wish at a fairground machine to be big. To his amazement, he wakes up the following morning to find out that his body now looks like a thirty year old man, played by Tom Hanks. However, he is still a kid and continues to act like a twelve year old boy. [4] This movie illustrates the importance of the body in how others perceive one’s self as a human, and how they expect one to act, even though the person inside that body has the memories and psychological makeup of who he was before the drastic change in the body.

Locke thought that what we call our self is that person who is a continuing same intelligent agent and that the self is a forensic term that applies to one’s actions and their merit. With his view the justice of reward and punishment as well as one’s desire to be concerned primarily with one’s own life is founded upon the personal identity of one’s consciousness.[5] This thinking is the foundation for one of the dominant theories in ethics, that of self-interest. Locke has been called the father of the personal identity problem, because for a long time most thinkers who wrote on this subject were responding to him.

Joseph Butler took exception to having personal identity become separated from both biological and substance-soul identity. He called Locke’s notion a “wonderful mistake” because Locke failed to recognize the circularity of his thoughts. Consciousness-memory presupposes identity and therefore cannot constitute it. A memory of an experience is not what makes it mine; I am able to remember it because it is already mine. Butler’s view is that these are experiences of a substance that constitutes me now.[6]

One might say that David Hume is the father of logical construction theories for personal identity. In contrast with the Cartesian view of a substantial self, Hume offers the Bundle view which accounts for our concept of self in terms of bundles of experiences that are connected by the logical relationships of contiguity and resemblances of our perceptions .[7] On Hume's view, one mistakes what is merely a bundle of perceptions for a self as a perceiver. We merely construct a concept of an ego, or a self, in our minds based on the connections we make from these various perceptions.

Immanuel Kant agreed with Descartes in that inner experience is extended in time, and outer experience is extended in space as well as in time. On the other hand Kant agreed with Hume in that one could not derive an overall principle of unity, or any definite concept of a necessarily inferred unitary self, from the content of one's experiences. Instead, Kant called such an overall unity "the transcendental unity of apperception." The self, according to Kant, can only be known as an abstraction, a "something=X." Because both Descartes and Hume were right in that the self is both absolutely necessary and at the same time vacuous and ungraspable, Kant muses that this paradox "mocks and torments" men.[8]

Even though Kant's theory of a transcendental self still has influence, it accounts for personal identity by appealing to such substances which focuses such an inquiry outside the bounds of both experience and science. Contemporary theorists usually work within the context of relational views. They use complex types of memory and psychological relationships in their neo-Humean theories. Reductionist accounts of identity are still Lockean in that personal identity consists in overlapping chains of continuity and psychological connectedness that hold strongly from a day to day basis. Parfit’s theory is Reductionist; you will see later more fully what that means. The contemporary debates gained momentum with Parfit’s early 1970s articles.

Why is this problem important?

The topic is still very much alive and heavily debated in our contemporary world. There are investigations about personal identity within the areas of psychology, metaphysics, epistemology, and ethics. This discussion focuses about how important personal identity theory is in relationship to moral theory. One could argue that one's belief about personal identity is implicit in whatever moral theory that one adopts.

Many object to the disunifying implications from reductionist accounts like Parfit’s. Some assert that identity accounts must be constrained by ethical considerations. In other words, if an identity theory disrupts what one perceives to be the right moral theory, then that identity account needs to be tossed out. This begs the question about which is the right moral theory upon which to base personal identity theory. We still have good reason to maintain that ethics depends on the metaphysics.[9] In any case, most people working on this problem seem to be in agreement regarding the important relationship between personal identity and ethics. Currently, a fundamental assumption in social science, law and theology is the notion of the enduring identity of individual persons to which legal and moral responsibility can be attached. One can only ponder the implications of the possibility that philosophy would discover that the enduring self is an erroneous notion. What kind of impact would such a finding have on our legal and moral institutions?[10]

Parfit declares his agenda to refute the Self-interest Theory by targeting and dismantling two commonly held beliefs. The first belief is about the nature of personal identity that holds that in all cases the question about identity must be determinate. With this view, one must be able to definitively know whether one would exist or not given any scenario of future events that may befall one. For example, if I were to wake up tomorrow with total amnesia, will I, the person yesterday, still exist? The second commonly held belief is that if the question about identity is indeterminate, then we are unable to answer related important questions such as those about survival, memory, and responsibility.[11] Parfit asserts that he will convince us to change our view about the nature of personal identity and that this should persuade us "to change our beliefs about rationality, and about morality."[12] He stresses the strong relationship between these themes in quoting Rawls, who said that “the correct regulative principle for anything depends upon the nature of that thing.”[13]

Parfit thinks his view liberates one from morose feelings resulting from thinking about one's eventual demise. One will see how adopting his account of personal identity enables one to be more impartial and to move away from Self-Interest and toward impersonal rational altruism. For example, he is a proponent for these wide-sweeping social changes: a distribution of wealth; paternalistic government intervention to prevent great imprudence by individuals; a legal distinction between persons and humans, thus enabling the killing of humans via abortion and euthanasia; and less punishment the further away from a crime a convict is with respect to his psychological connections in regard to the crime.[14]

Necessary and Sufficient Criteria: Using Thought Experiments

Proposed solutions to the Persistence Question fall into one of three categories, or types of criteria necessary for personal identity to obtain. With the Psychological Approach, you are the future being that inherits its mental features such as memories, beliefs, desires, etc., from you, and you are that past being whose mental features you inherited. There is dispute about whether these mental features must be underpinned by the physical continuity of the body or brain. The second approach claims that whether or not you survive has nothing to do with psychological facts; rather, your body must survive. (This should not be confused with the Evidence Question that deals with finding out who is who.) The third view, called the Simple View, denies that something, either body or mental continuity, is necessary for identity to persist through time: something other than itself. This is often combined, but not necessarily, with the view that we are immaterial (with souls) and have no parts.[15]

Thought experiments are used in an attempt to tease apart physical structures from psychological structures in order to determine what constitutes necessary criteria for personal identity. With such cases, one can posit that either the physical structures are preserved while the psychological ones are disrupted or vice versa, and then determine whether or not personal identity is preserved or not as a result of the experiment.[16]

Parfit thinks that our current false beliefs about ourselves and what persons are can be best brought to light through the use of science fiction imaginary cases. He acknowledges that others have questioned whether he exceeds the effective limits of this method. He proclaims justification in that we can discover the nature of personal identity because "these cases arouse in most of us strong beliefs."[17] One can argue, however, that religious sermons and stories also produce among listeners strong reactions and beliefs about our human nature; beliefs that usually subscribe to some form of the transcendental, or ego, view of personal identity.

Parfit admits that most of his cases are either "merely technically" impossible or that they contravene the laws of nature and are therefore "deeply" impossible. This does not matter, he claims, if the question of what one is trying to show is structured properly. "But," Parfit cautions, ". . . depending on our question, impossibility may make some thought-experiment irrelevant."[18] We will proceed to look at some of these experiments to see if he and others heed this advice and to see what strong beliefs are aroused in us.

Sci-Fi Thought Experiments and Parfit’s Personal Identity Account

He sets the stage for changing the debate by changing one of the central questions. Instead of focusing on the question 'Under what condition is your personal identity preserved?' he asks 'Under what conditions is what matters primarily to you in survival preserved?' The importance of personal identity was called into question through the use of thought experiments involving hypothetical fission cases in which one person splits into two new qualitatively identical persons who are also qualitatively identical to the original person.

Sydney Shoemaker claims that if I were given two options for having my healthy half-brain transplanted into another body that is healthy, I should choose the less risky procedure whereby my cancer ridden half-brain and body would be destroyed after the operation. With this option, it would mean for certain that my identity will not carry forward onto the recipient person because two persons cannot have the same identity at one time. The more risky process entails first destroying my diseased half-brain and then transplanting the other half: then the recipient person would have no "competitor" at any time for the status of being me, and therefore, she could count as me. However, I should choose the less risky procedure because in a case like this survival is more important than identity.[19]

Shoemaker then describes the fission case (also called the My Division case). This case involves a car wreck of identical triplets where my body is destroyed but my brain is intact, and my siblings’ brains were destroyed but their bodies were not. My healthy brain is halved and then transplanted successfully into my siblings’ bodies. Even if I realize that neither recipient person will be me because there can not be duplication in identity, nevertheless, I should not consider this procedure as impending death. Instead, assuming that the psychological continuity criteria of personal identity is a correct view, I should have an attitude toward my two successor persons essentially like I would normally have about my own future delights, successes and failures under normal circumstances.[20]

Parfit maintains that “[. . .] to be a person, a being must be self-conscious, aware of its identity and its continued existence over time.” His reductionist view begins with the notion that “personal identity just consists in physical and psychological continuity.” Parfit expands Locke’s memory-consciousness concept such that psychological continuity occurs when we have an “overlapping chain of experience-memories,” and he adds other psychological components such as intentions and desires. We may have thousands of direct psychological connections between who we are today (X) and who we were yesterday (Y). But there may only be a few connections between who we are today and who we were twenty years ago. These overlapping chains of psychological components throughout one’s life are what counts for a continuous person. This expanded Lockean view gives us Parfit’s Psychological Criterion, or deep psychological connectedness (hereafter called Relation R).[21]

There are three versions of this criterion based on what is the right kind of cause of continuity: the Narrow version stipulates that it must be the normal cause; it can be any reliable cause with the Wide version; and any cause under the Widest version. Using Parfit’s simple Teletransportation example, let us say that I enter a teletransporter whereby my body and brain are exactly replicated on Mars out of new material and my original body and brain are destroyed. Under the Narrow version the replica on Mars would not be me because the continuance was not due to a normal cause. A normal cause would be if I were transported to Mars and landed there in some spaceship. It would be me, however, under the two Wide formulae. Why should it matter whether this brain and body gets to Mars? The natural fear, Parfit construes, is that, according to most peoples’ belief, only that condition within a Narrow cause will ensure that I get to Mars.[22] However, those of us who enjoyed hearing Captain Kirk in Star Trek constantly imploring “Beam me up Scottie” thought that the Kirk who was in immediate danger on some planet was the same Kirk who almost instantly reappeared in the transporter room. And he did not get there by any narrow cause.

In another experiment, Parfit imagines that the teletransporter malfunctions such that my body and brain are not destroyed on earth, yet there is an identical duplicate made of me that is now on Mars. This is an example of a branching form of an experiment whereby the result is two qualitatively and psychologically identical persons. Personal identity does not obtain in cases where there are duplicates because two people cannot be the same person even though they share the same psychology. How weird would that be for you to talk to your duplicate on Mars? Something similar happens to Captain Kirk in the Star Trek episode The Enemy Within. The transporter malfunctions and it splits Kirk into two selves who have interactions with each other, even fighting with each other. In this case the Relation R did not carry forward to Kirk’s doppelganger from the original Kirk in an identical fashion.[23]

Parfit admits that it is a logical truth that we can only remember our own experiences. In order to get around this logical truth and Butler’s circularity objection, he develops a wider relational theory of personal identity using concepts called q, or quasi-relationships such as quasi-memory. On this account, our ordinary memories of past events become a sub-class of quasi-memories. Even though we do not quasi-remember others’ experiences, we might be able to do so if science could find a way to create a copy of another’s memory-trace within one’s brain. Parfit thinks he has met Butler’s challenge. He now reduces his criteria for personal identity in claiming that “personal identity just consists in the holding of Relation R.”[24]

Spock of Star Trek fame employed another way to have these quasi-relationships: he used the Vulcan mind fusion whereby his consciousness would merge with another’s consciousness such that the thoughts and emotions were shared by Spock and the person or creature he melded with.[25] Parfit recounts the My Division case: The resultant two people would have to acknowledge that right after such an operation they have only q-memories, q-intentions, etc., of the third person whose half brain they now each possess.[26] We can imagine a case like this, Parfit claims, because it is factually true that one brain hemisphere is enough for survival in cases of some stroke and other brain injury cases where one loses the function of one hemisphere.[27]

It was pointed out that Parfit’s analysis still remains circular if one's q-memory is of one's own past experience if and only if there are numerous other q-memories of one's own earlier experiences. To meet this objection, Parfit needs to explain the unity of consciousness, i.e., what unifies simultaneous experiences into one and the same person.[28] Parfit responds that one can describe the relations between many experiences and those relations to a person’s brain without considering that these experiences are had, or owned, by a person.[29] With this view, in the brain at any instant in time there is merely a single state of awareness of simultaneous experiences.[30] For Reductionists, nothing more is involved in unity of consciousness.

The empirical evidence Parfit uses to make this point is actual cases where surgeons have performed commissurotomies[31] by cutting the fibers connecting the two upper hemispheres of the brain in order to reduce the severity of fits of epileptic patients. A side effect of the operation, according to various tests, is the creation of “two separate spheres of consciousness.” If it were not possible to divide a person’s consciousness into two separate streams, Parfit supposes that this impossibility would support the notion of an indivisible Cartesian Ego. Using the My Division thought experiment, Parfit declares the brain as an unfit bearer of personal identity and that personal identity is not what matters.[32] Parfit acknowledges that he has to make many assumptions to make My Division work, such as both hemispheres have full range of capabilities, and he admits that this case will probably never be possible.[33] Others have pointed out facts about brain physiology that make Parfit’s claims about the importance of commissurotomy patients unjustified.

Nevertheless, what Parfit wants to accomplish with the My Division thought experiment is that the answer to the question ‘which person, if either, will be me?’ is indeterminate to a Reductionist. It is irrational, to a Reductionist, to regard the prospect of division in the triplet's case as death. Likewise, one should be glad that in My Division, one’s Relation R continues on in two separate persons, somewhat like having doubled one’s life span. One can say that neither of the resultant people will be identical to the original and that the original person is about to die. But, one can state that one survives in terms of Relation R as two different people. Whereas identity is an all-or-nothing relation, relations that matter in survival are relations of degree. Parfit proclaims: "If we ignore this, we shall be led into quite ill-grounded attitudes and beliefs."[34]

Now, let us see how Parfit attempts to demonstrate that questions about identity can be empty questions with no determinate answer. He introduces the Physical Spectrum case to counter one of the physical criterion views that holds that as long as my physical brain continues to exist and to be the brain of a living person then I shall be that person even if there would be no psychological connections between who I am now and who I would be later. For example: Do you think that Ronald Reagan was the same person right before he died with an advanced stage of Alzheimers disease as the person who was the U.S. President in the 1980s? The answer to this depends upon one’s concept of person versus human, and one’s views about personal identity.

In the Physical Spectrum case there are 100 possible operations to be performed. In a case at the near end, scientists replace 1% of one’s brain and 1% of one’s body with material made of new organic matter which contains copies of one's own cells. Near the far end, 99%, and at the farthest end, one’s complete body and brain are replaced only after they are first destroyed and a replica is made at a later time. At the farthest end of this spectrum, one sees that there is no physical continuity. He realizes that most of the far end cases will remain impossible, but that is irrelevant since one is testing only what one believes about such cases. If one continues to believe that one’s identity must be determinate, then one must therefore believe that somewhere along the spectrum there is a sharp borderline where one ceases to exist. . . . This arbitrary decision cannot justify any claim about what matters. Reductionism entails that, in some cases, questions about personal identity are indeterminate and that they are empty questions.[35]

Some physicists would point out a flaw in the notion that if you were able to make an atom-for-atom copy of something, then the replicated object will be an exact duplicate of the original at all levels. Quantum mechanics discloses that this thesis is false "even for a single pair of electrons.” This has to do with supervenience theory, something beyond the scope of this presentation.[36] Others claim that psychological properties supervene upon physiological properties and that explaining survival involves understanding the properties, the facts, over and above those about psychological continuity and connectedness.[37]

These objections are illustrated in the Sci-Fi comedy Multiplicity starring Michael Keaton as Doug Kinney and Andie MacDowell as his wife Laurel who has no clue as to why her life is falling apart during this adventure. For the philosophers in the audience, this movie also demonstrates Plato’s Theory of Forms. Overworked and always overscheduled as a contractor, Doug never has enough time for his wife and family or for himself. A geneticist offers Doug a solution to this problem: cloning. The geneticist ‘xeroxes’ Doug and Doug has to keep this a secret from his wife. However, Doug #2 who takes care of the contracting business is much more macho than Doug #1. Doug #2 needs someone to take care of his apartment and Doug #1’s wife, so he gets himself cloned. Doug #3 represents the feminine side of Doug #1. Doug #3 feels he too needs help, so this copy of a copy gets cloned. Well, Doug #4 is a disaster, a total imbecile. This goes to prove that a copy is not quite ‘as good’ as the original, and that copies of copies are further degraded.

Now let us look at additional cases Parfit provides in order to prove identity is indeterminate and a matter of degrees.[38] These experiments involve human reproduction. Another purpose these cases fulfill is an attempt to create metaphysical links among persons such that we would be led to believe that impersonal altruism is a higher moral code than Self-Interest.

There is the Fusion Case: What would it mean if two people were to fuse into one, such that the resulting person would q-remember the lives of the two former individuals? Those who regard survival as a matter of all-or-nothing would regard this as death for the two beginning persons. Parfit recognizes the challenges presented by such a prospect as this. How would the characteristics and desires of the former individuals get blended? Nevertheless, he maintains that “only the very self-satisfied would think of this as death.” This case brings up other questions. What would society be like if this were possible? Would there be marriages or family structures? What would they be like? Even if this fusion process were a plausible possibility to consider, would anyone feel confident about the outcome of such a fusion?

In the Natural Division case, one is to imagine beings that would divide into two separate persons, much like an amoeba divides. One can envision an inversion of a family tree structure diagram, with one, Eve, at the root and branching off into several generations of future, seemingly exactly similar, persons. For Parfit, survival and relationships with one's ‘past selves’ and ‘future selves’ should be treated as relations of degrees.

We can contrast this method of reproduction with that of the Tribbles in the Star Trek episode “The Trouble with Tribbles.” When charmed by the purring ball of fluff, Uhura takes a Tribble back to the Enterprise. McCoy learns that Tribbles are asexual and born pregnant and that the more they eat the more they multiply. And that, my friends, is a recipe for disaster.

Now, put Parfit’s two new processes together and imagine the Fusion and Division case; another type of human whereby one reproduces by fusing every autumn and then divides every spring. This would make a human a kind of everlasting being in which psychological relations would hold only over limited periods of time. It is entirely a matter of choice whether, when talking about any of these persons along the fusion-division chain, one would say “I”, “one of my future selves,” or “a descendant self.”

He admits that one's belief that identity is what matters is hard to vanquish, especially in light of discussions about problem cases that actually occur; cases like ones involving amnesia or brain damage. Nevertheless, he considers that the My Division case produces a breach in this belief and, therefore, the remaining certainty should be easy to topple.[39]

Conclusion: Using Science Fiction for the Personal Identity Problem

There are three main criticisms others have put forth about using science fiction thought experiments to determine necessary and sufficient criteria for personal identity. (1) Some series of cases can be interpreted to bolster the physical criteria while the same series is used to argue for psychological criteria;[40] (2) The philosophers who use this method seem to know little, or care little, about biology and physiology; and (3) Judgments should not be made based on stories describing how the world might become other than how it is currently configured. With this kind of experiment the relative background about how society would be structured in a certain scenario is too ambiguous to know whether any given conclusion is clearly established.[41] One can argue that using real human cases such as fetuses, amnesia, Alzheimer’s disease, insanity, fugues, hypnosis, multiple personality, and others are more interesting and productive in this debate; and that the everyday proverb that truth is stranger than fiction seems correct in this venue.

By looking only through the lens of science fiction thought experiments, one may begin to adopt Hume's skeptical despair over coming to any adequate account of the self and personal identity. Nevertheless, Parfit and other philosophers, and the many science fiction characters and plots in literature, have provided creative and provocative ideas to this conversation. These experiments and fictional stories do have a place within a broader framework of concepts by which one attempts to understand the nature of human beings and whether there are real metaphysical underpinnings to personal identity.

I will conclude this discussion by briefly giving a few other examples from popular Sci-Fi to demonstrate the value this genre adds to debates about various personal identity questions.

In the Star Trek, Next Generation episode “The Measure of a Man,” a commander wants to disassemble Data in order to find out how to make more androids for Starfleet’s use. Data protests and thus a dramatic courtroom drama unfolds whereby Captain Picard defends Data’s rights as a sentient, intelligent being who is also a machine. The most dramatic moment in this trial occurs when Riker, who was assigned to be the prosecutor, simply switches Data off to demonstrate Data’s inability to achieve self-determination. Consider Doctor, the emergency medical hologram in the form of a man in The Voyager Star Trek series. This hologram experienced ongoing evolution of its being due to his adaptive programming. His evolving nature enabled him to learn how to turn himself off, showing a great deal of independence. Then there is HAL in 2001: A Space Oddyssey. Who can deny that HAL had great intelligence and that he displayed feelings when Dave began to unplug HAL’s circuitry one by one? If humans are able to create such androids as Data, holograms like Doctor, and computers like HAL, what should be their place and their use in our society? Would they to be considered persons?

What about the practice of cryonics where people bank on the hope that one’s deceased body can be frozen and stored until some future time when medical science would be able to cure whatever caused the death. The prospect of this can create the phenomenon of time travel. Imagine coming back to life, say, three hundred years from now. Just think of the psychological displacement that might be involved in trying to figure out the ‘who am I’ question after landing in a far away time zone. Various Star Trek episodes involving time travel and the movie trilogy Back To The Future show what troubles brew when one messes with one’s place in the history of time.

Lastly, consider Seven of Nine and the Borg in the Star Trek Voyager series. I doubt whether the Borg is what Derek Parfit has in mind in order to move us toward more collective living. For philosophers, the Borg represents a classic example of the One and the Many problem of individuation. The Borg Queen, who is the central locus of the Borg Collective, has a unique personality and sense of individuality that other Borg drones are not allowed. However, for her, the concepts “I” and “we” are interchangeable as she declares that she is the “one who is many.” It is not clear how she gets replicated and replaced when she dies in various episodes.[42] The Borg is a civilization that Starfleet does want to destroy for the very reason that its voracious appetite to assimilate individuals from all other civilizations is destroying individuality and diversity per se. A doctor was able to extract eighty-two percent of Seven of Nine’s Borg hardware implants. In the episode “The Gift” she demanded to be returned to the Borg Collective. However, Captain Janeway was determined to make her fully human again. Seven of Nine’s life history of first being human, then transformed into a Borg drone, then back into almost fully human is a great Sci-Fi puzzle case for exploring what are the necessary and sufficient criteria for personal identity to obtain.

ENDNOTES (to be cross referenced with Works Cited for full reference)