Brain Transplants

In her essay, “People and their Bodies,” Judith Thomson writes an evaluation of several formulations of the psychological criterion for personal identity and attempts a strategy of criticizing each formulation of the psychological theory. This is done in order to conclude that a physical theory must be the only remaining viable sufficient candidate for explaining personal identity that is both necessary and sufficient, despite its theoretical weaknesses. This paper seeks to analyze Thomson's critique and explain why her chosen formulations of (...) psychological criterion are inadequate and easy to refine against some of her rather hasty objections. In addition, counterarguments in favor of an 'impure' psychological criterion for personal identity are presented in the hopes of clarifying the philosophical discourse. (shrink)

Many philosophers have become sceptical of the use of thought experiments in theorising about personal identity. In large part this is due to work in experimental philosophy that appears to confirm long held philosophical suspicions that thought experiments elicit inconsistent judgements about personal identity, and hence judgements that are thought to be the product of cognitive biases. If so, these judgements appear to be useless at informing our theories of personal identity. Using the methods of experimental philosophy, we investigate whether (...) people exhibit inconsistent judgements and, if they do, whether these judgements are likely to be the source of cognitive bias or, instead, sensitivity to some relevant factor. We do not find that people’s judgements are sensitive to any of the factors we investigate (relevant or irrelevant), nor that people have inconsistent judgements across cases. Rather, people’s judgements are best explained by them having a very minimal account of what it takes for a person to survive. Since this pattern of judgements is no reason to think that we are subject to cognitive bias, we see no reason, as things stand, to be sceptical of our judgements. (shrink)

Animalism is prima facie the most plausible view about what we are; it aligns better with science and common sense, and is metaphysically more parsimonious. Thought experiments involving the brain, however, tend to elicit intuitions contrary to animalism. In this paper, I examine two classical thought experiments from the literature, brain transplant and cerebrum transplant, and a new one, cerebrum regeneration. I argue that they are theoretically possible, but that a scientifically informed account of what would actually happen shows that (...) in none of the cases would the person be separated from the animal. Our intuitions in these cases, when adequately informed by neuroscience, do not conflict with animalism – rather, they suggest a correction of the animalist position: the persisting animal should be at least minimally sentient. Sentience animalism is a new formulation of the animalist account of personal identity that allows us to reconcile facts about our biological persistence conditions with the intuition that human persistence should involve some kind of psychological continuity. (shrink)

Good physical experiments conform to the basic methodological standards of experimental design: they are objective, reliable, and valid. But is this also true of thought experiments? Especially problems of personal identity have engendered hypothetical scenarios that are very distant from the actual world. These imagined situations have been conspicuously ineffective at resolving conflicting intuitions and deciding between the different accounts of personal identity. Using prominent examples from the literature, I argue that this is due to many of these thought experiments (...) not adhering to the methodological standards that guide experimental design in nearly all other disciplines. I also show how empirically unwarranted background assumptions about human physiology render some of the hypothetical scenarios that are employed in the debate about personal identity highly misleading. (shrink)

When does a human being cease to exist? For millennia, the answer to this question had remained largely unchanged: death had been diagnosed when heartbeat and breathing were permanently absent. Only comparatively recently, in the 1950s, rapid developments in intensive-care medicine called into question this widely accepted criterion. What had previously been deemed a permanent cessation of vital functions suddenly became reversible. -/- A new criterion of death was needed. It was suggested that the destruction of the brain could indicate (...) the death of the organism in the presence of external life support. Soon the so-called brain death became the new worldwide standard. In recent years, however, doubts about this neurological criterion have been growing. Is brain death really our death? -/- This is the question that this thesis seeks to answer. To this end, we shall connect the medical debate about the definition of death to the philosophical debate about personal identity. While we will find that the destruction of its brain does in fact not correspond to an organism’s death, we shall also ask whether the assumption that we are essentially organisms is correct. May brain death be the ceasing to exist of a different entity? -/- Substituting clinical case reports and considerations about human physiology for the use of thought experiments, the thesis takes a novel and philosophically unconventional approach to the problem of what we essentially are. We shall analyse various pathological conditions and their respective effects on the bodily and mental characteristics of our existence. We will conclude that brain death is indeed our death – but for reasons entirely different from those cited in the original justification of this criterion. (shrink)

Spesso i filosofi paiono pensare di poter trarre conclusioni radicali sulla base di una semplice discussione di scenari immaginari, scenari che a volte sembrerebbero tratti da un racconto di fantascienza. Questo stile argomentativo lascia molti studenti (e anche alcuni filosofi di professione) perplessi: come può il semplice riflettere su di uno scenario immaginario permetterci di trarre conclusioni su come stanno le cose nella realtà? Questo volume cerca di giustificare l'uso di esperimenti mentali in filosofia, concentrandosi su due casi studio, entrambi (...) tratti dalla letteratura sull'identità personale: la trasformazione di un essere umano in un'entità sintetica, e la divisione di una persona in due individui distinti. (shrink)

Derek Parfit’s argument against the platitude that identity is what matters in survival does not work given his intended reading of the platitude, namely, that what matters in survival to some future time is being identical with someone who is alive at that time. I develop Parfit’s argument so that it works against the platitude on this intended reading.

In a recent series of papers, Beck and Wagner have been arguing about the general role that thought experiments can play in the debate on personal identity, showing their disagreement about the famous criticisms that Wilkes’ launched against their use. In this article I come back to Wilkes’ criticisms to show that her position is deeply problematic. If we adopt instead the mental model account of thought experiments, we can accommodate Wilkes’ criticisms and justify the use of thought experiments in (...) the debate of personal identity. This will allow us to see why Beck and Wagner were both half right and half wrong in their discussion. (shrink)

I argue that a form of animalism that does not include the belief that ‘human animal’ is a substance-sortal has a dialectical advantage over other versions of animalism. The main reason for this advantage is that Phase Animalism, the version of animalism described here, has the theoretical resources to provide convincing descriptions of the outcomes of scenarios problematic for other forms of animalism. Although Phase Animalism rejects the claim that ‘human animal’ is a substance-sortal, it is still appealing to those (...) who believe that our nature is continuous or of a similar kind to that of other physical entities. (shrink)

Theories of personal identity face a paradox, which traces back to Bernard Williams: some scenarios obviously show that mental continuity is what solely matters in survival; others, on the contrary, show with equal obviousness that it is bodily continuity. Different authors have produced diverging and partly conflicting answers in response to that problem. Based on recent research concerning the structure of philosophical thought experiment, this paper reevaluates and, for the first time, neatly classifies those answers. What is more, several existing (...) approaches of how to answer the paradox are developed further, and two new answers are introduced. (shrink)

Nils-Frederic Wagner takes issue with my argument that influential critics of “transplant” thought experiments make two cardinal mistakes. He responds that the mistakes I identify are not mistakes at all. The mistakes are rather on my part, in that I have not taken into account the conceptual genesis of personhood, that my view of thought experiments is idiosyncratic and possibly self-defeating, and in that I have ignored important empirical evidence about the relationship between brains and minds. I argue that my (...) case still stands and that transplant thought experiments can do damage to rivals of a psychological continuity theory of personal identity like Marya Schechtman’s Person Life View. (shrink)

I am very grateful to Simon Beck for his thoughtful response to my paper “Transplanting Brains?” (2016). Needless to say, he raises more issues than I can hope to answer in a brief response. While Beck seemingly feels that the deck has been stacked against him, I think that the majority of his criticisms result from misconceptions and misunderstandings that I intend to straighten out in what follows. Before proceeding, I would like to draw attention to a worry that is (...) lurking in the shadows. Perhaps Beck and I talk at cross purposes. While Beck is concerned with a metaphysical theory of personal identity that supposedly holds across all possible worlds—and as such places heavy importance on counterfactuals and intuitions—I am concerned only with the natural world with the aim of generating empirically substantiated hypotheses about how things really are when it comes to persons persisting through time. Now, here is a disclaimer: If the natural world does not exhaust reality, then my discussion is only partial. It goes without saying that most contemporary philosophers given a choice between going with science and going with intuitions, go with science. (shrink)

Brain transplant thought experiments figure prominently in the debate on personal identity. Such hypotheticals are usually taken to provide support for psychological continuity theories. This standard interpretation has recently been challenged by Marya Schechtman. Simon Beck argues that Schechtman's critique rests upon ‘two costly mistakes’—claiming that (1) when evaluating these cases, philosophers mistakenly try to figure out the intuitions that they think people inhabiting such a possible world ought to have, instead of pondering their own intuitions. Beck further asserts that (...) (2) brain transplant thought experiments cannot confirm any given theory of personal identity but rather they can only rule out theories. I argue on grounds of the social ontology of personhood that Beck has things back to front. Since our concept of personhood is shaped and informed by contingent de facto norms and structures of the natural world, and as such is heavily normatively laden, the conceptual genesis of personhood must be taken into account. This calls for constructing thought experiments as realistically as possible in order to trigger reliable intuitions. Furthermore, drawing on recent evidence from cognitive science, an empirically informed look at brain transplant thought experiments considering ‘Embodied Cognition’ reveals that Beck's arguments not only fall short for supporting psychological continuity theories, but also suggests an advantage of Schechtman's ‘Person Life View’. (shrink)

If we are physical things with parts, then accounts of what we are and accounts of when composition occurs have important implications for one another. Defenders of restricted composition tend to endorse a sparse ontology in taking an eliminativist stance toward composite objects that are not organisms, while claiming that we are organisms. However, these arguments do not entail that we are organisms, for they rely on the premise that we are organisms. Thus, sparsist reasoning need not be paired with (...) animalism, but could instead be paired with other accounts according to which we are composites. The embodied mind account—a version of the brain view—is one such account. Replacing the premise that we are organisms with the premise that we are embodied minds, in arguments that otherwise parallel those supporting animalist sparsism, yields an account according to which composite objects include thinkers, but perhaps nothing else. Since animalism has implausible implications about scenarios which are handled better by the embodied mind account, this approach is preferable to animalist sparsism. Furthermore, the role of mental features in sparsism makes embodied mind sparsism the more reasonable conclusion. Meanwhile, adopting sparsism allows the embodied mind account to dodge objections that may not be as easily avoided by it or other versions of the brain view if not paired with sparsism. These include objections about brains that are not persons, inorganic part replacement, and another form of part replacement that might seem to allow one to get a new brain. (shrink)

‘Transplant’ thought-experiments, in which the cerebrum is moved from one body to another, have featured in a number of recent discussions in the personal identity literature. Once taken as offering confirmation of some form of psychological continuity theory of identity, arguments from Marya Schechtman and Kathleen Wilkes have contended that this is not the case. Any such apparent support is due to a lack of detail in their description or a reliance on predictions that we are in no position to (...) make. I argue that the case against them rests on two serious misunderstandings of the operation of thought-experiments, and that even if they do not ultimately support a psychological continuity theory, they do major damage to that theory’s opponents. (shrink)

Können wir als Personen irreversible Gedächtnisverluste überleben? Wie steht es mit Teletransportationen? Wie mit jahrelangem Einfrieren? Fragen wie diese sind weit davon entfernt, bloße Denksportaufgaben für Science-Fiction-Fans zu sein. Vielmehr verraten uns Antworten darauf, welche unserer Eigenschaften uns wirklich wichtig sind und was unser Wesen ausmacht. -/- Unglücklicherweise beantworten Vertreter unterschiedlicher Theorien personaler Identität diese Fragen auf völlig verschiedene Weise. Manche schöpfen die Plausibilität ihrer Positionen aus phantasievollen Gedankenexperimenten; anderen sind dieselben Gedankenexperimente für eine ernsthafte Einbeziehung in die philosophische Theoriebildung (...) schlicht zu wirklichkeitsfern. Es überrascht daher kaum, dass jene Anhänger unterschiedlicher Theorien einander oft wenig zu sagen haben. Im ersten Teil des Buches wird untersucht, unter welchen Umständen Gedankenexperimente aussagekräftige philosophische Werkzeuge sind. Auf der Basis dieser Analyse werden die diversen zeitgenössischen Theorien personaler Identität dann im zweiten Teil einer Neubewertung unterzogen – nicht ohne dass dabei mit vielen selbstverständlich erscheinenden Überzeugungen aufgeräumt wird. (shrink)

It is worthwhile comparing Hylomorphic and Animalistic accounts of personal identity since they both identify the human animal and the human person.The topics of comparison will be three: The first is accounting for our intuitions in cerebrum transplant and irreversible coma cases. Hylomorphism, unlike animalism, appears to capture “commonsense” beliefs here, preserves the maxim that identity matters, and does not run afoul of the Only x and y rule. The next topic of comparison reveals how the rival explanations of transplants (...) and comas are both at odds with some compelling biological assumptions. The third issue deals with our practical concerns, most notably, the possibility of an afterlife. It turns out that the hylomorphic treatment of Purgatory raises the spectra of the “too many thinkers” problem and some considerable unfairness. Contrary to expectations, an animalist insistence on uninterrupted bodily continuity between this life and the next does not involve deceptive body snatching. (shrink)

We defend the view that we are not identical to organisms against the objection that it implies that there are two subjects of every conscious state one experiences: oneself and one’s organism. We then criticize animalism —the view that each of us is identical to a human organism—by showing that it has unacceptable implications for a range of actual and hypothetical cases of conjoined twinning : dicephalus, craniopagus parasiticus, and cephalopagus.

My aim in this paper is to destabilise the brain-is-self thesis, something that is now regarded in some quarters as philosophical commonsense. My contention is that it is the epithelial body that enters into the formation of our sense of self and that largely bears the burden of personal identity as well as playing the key role in grounding our psychological ascriptions. Lacking any sensorimotor or social presence of its own, the brain by itself cannot "underlie" selfhood, but only as (...) part of the whole living human being. If the minded individual is embodied, this must mean more than being embrained. (shrink)

In this article I revisit earlier stages of the discussion of personal identity, before Neo-Lockean psychological continuity views became prevalent. In particular, I am interested in Bernard Williams’ initial proposal of bodily identity as a necessary, although not sufficient, criterion of personal identity. It was at this point that psychological continuity views came to the fore arguing that bodily identity was not necessary because brain transplants were logically possible, even if physically impossible. Further proposals by Shoemaker of causal relations between (...) mental states in our memory and Parfit’s discussion of branching causal chains created additional complications. My contention in this paper is that psychological continuity views deflected our attention from what should have remained in the spotlight all the time: the intersubjective character (or not) of criteria proposed to decide personal identity in our language game, and ultimately our form of life concerning ourselves as persons. B. Williams’ emphasis on the body was not just common sense. It was also recognition of the importance of giving priority to criteria that could be kept under intersubjective control. (shrink)

Shoemaker maintains that when a functionalist theory of mind is combined with his belief about individuating properties and the well-known cerebrumtransplant thought experiment, the resulting position will be a version of the psychological approach to personal identity that can avoid The Problem of Too Many Thinkers. I maintain that the costs of his solution—that the human animal is incapable of thought—are too high. Shoemaker also has not provided an argumentagainst there existing a merely conscious being that is not essentially self-conscious (...) but is spatially coincident with a person who is essentially self-conscious. Both the person and the merely sentient being will be transplanted when the cerebrum is. And another thought experiment will make it impossible for Shoemaker to identify the person and the merely conscious being. (shrink)

Most contributors to the debate about brain death, including Dr. James Bernat, share certain assumptions. They believe that the concept of death is univocal, that death is a biological phenomenon, that it is necessarily irreversible, that it is paradigmatically something that happens to organisms, that we are human organisms, and therefore that our deaths will be deaths of organisms. These claims are supposed to have moral significance. It is, for example, only when a person dies that it is permissible to (...) extract her organs for transplantation.It is also commonly held that our univocal notion of death is the permanent cessation of integrated functioning in an organism and that the criterion for determining when this has occurred in animals with brains is the death of the brain as a whole – that is, brain death. The reason most commonly given for this is that the brain is the irreplaceable master control of the organism's integration. (shrink)

Eric Olson argues in The Human Animal that thought-experiments involving body-swapping do not in the end offer any support to psychological continuity theories, nor do they pose any threat to his Biological View. I argue that he is mistaken in at least the second claim.

Recent work in personal identity has emphasized the importance of various conventions, or ‘person-directed practices’ in the determination of personal identity. An interesting question arises as to whether we should think that there are any entities that have, in some interesting sense, conventional identity conditions. We think that the best way to understand such work about practices and conventions is the strongest and most radical. If these considerations are correct, persons are, on our view, conventional constructs: they are in part (...) constituted by certain conventions. A person exists only if the relevant conventions exist. A person will be a conscious being of a certain kind combined with a set of conventions. Some of those conventions are encoded in the being itself, so requiring the conventions to exist is requiring the conscious being to be organized in a particular way. In most cases the conventions in question are settled. There is no dispute about what the conventions are, and thus no dispute about which events a person can survive. These are cases where we take the conventions so much for granted, that it is easy to forget that they are there, and that they are necessary constituents of persons. Sometimes though, conventions are not settled. Sometimes there is a dispute about what the conventions should be, and thus a dispute about what events a person can survive. These are the traditional puzzle cases of personal identity. That it appears that conventions play a part in determining persons’ persistence conditions only in these puzzle cases is explained by the fact that only in these cases are the conventions unsettled. Settled or not though, conventions are necessary constituents of persons. (shrink)

In this quite modestly ambitious essay, I'll generally just assume that, for the most part, our "scientifically informed" commonsense view of the world is true. Just as it is with such unthinking things as planets, plates and, I suppose, plants, too, so it also is with all earthly thinking beings, from people to pigs and pigeons; each occupies a region of space, however large or small, in which all are spatially related to each other. Or, at least, so it is (...) with the bodies of these beings. And, even as each of these ordinary entities extends through some space, so, also, each endures through some time. In line with that, each ordinary entity is at least very largely, and is perhaps entirely, an enduring physical entity (which allows that many might have certain properties that aren't purely physical properties.) Further, each ordinary enduring entity is a physically complex entity: Not only is each composed of parts, but many of these parts, whether or not absolutely all of them, are themselves enduring physical entities, and many of them also are such physically complex continuing entities. When an ordinary entity undergoes a significant change, then, at least generally, this change will involve changes concerning that entity's constituting physical parts, whether it be a rearrangement of (some of) these parts, or a loss of parts, or a gain of parts, or whatever. Often, the entity will still exist even after the change occurs. As we may well suppose, this happens when, from two strokes of an ax, an ordinary log loses just a chip of wood. As we may then say, such a change conforms with the log's "persistence conditions." Somewhat less often, such an ordinary entity undergoes a change that means an end to it: When a bomb's explosion makes our log become just so many widely scattered motes of dust, the log will no longer exist. Such a momentous change doesn't conform with the log's persistence conditions. (shrink)

Imagine that you and a duplicate of yourself are lying unconscious, next to each other, about to undergo a complete step-by-step exchange of bits of your bodies. It certainly seems that at no stage in this exchange of bits will you have thereby switched places with your duplicate. Yet it also seems that the end-result, with all the bits exchanged, will be essentially that of the two of you having switched places. Where will you awaken? I claim that one and (...) the same person possesses both bodies, occupies both places and will experience both awakenings, just as a person whose brain has been bisected must at once experience both of the unconnected fields of awareness, even though each of these will falsely appear to him as the entirety of his experience. I also claim that the more usual apparent boundaries of persons are as illusory as those in brain bisection; personal identity remains unchanged through any variation or multiplication of body or mind. In all conscious life there is only one person - I - whose existence depends merely on the presence of a quality that is inherent in all experience - its quality of being mine, the simple immediacy of it for whatever is having experience. One powerful argument for this is statistical: on the ordinary view of personhood it is an incredible coincidence for you (though not for others) that out of 200,000,000 sperm cells the very one required on each occasion for your future existence was first to the egg in each of the begettings of yourself and all your ancestors. The only view that does not make your existence incredible, and that is not therefore (from your perspective) an incredible view, is that any conscious being would necessarily have been you anyway. It is a consequence that self-interest should extend to all conscious organisms. (shrink)

This collection of twelve essays on the problem of persons is divided into two general themes. Essays on "identity and physical continuity" are presented by: Lewis, Rey, Perry, Parfit, Shoemaker, and Wiggins, while Dennett, Williams, de Sousa, Frankfurt, Penelhum, and Taylor write on "social and moral conditions of personhood." A. O. Rorty’s introduction is especially lucid, arguing that the concept of a person must, finally, be treated as a moral one. With advances in technology, e.g., the plausibility of brain transplants (...) and robots that can think, conditions of responsibility change hand in hand with changes in the meaning of persons. The philosopher’s job is not to introduce new, ingenious "final" solutions but to understand the roles of conflicting as well as interrelated definitions of persons. (shrink)

Much mischief concerning the concept of a human body is generated by the failure of philosophers to distinguish various important senses of the term 'body.' I discuss three of those senses and illustrate the issues they can generate by discussing the concept of a Lockean exchange of bodies as well as the brain-body switch.

Most philosophers in the analytical philosophy answer the question what personal identity is in psychological terms. Arguments for substantiating this view are mainly based on thought experiments of brain transfer cases and the like in which persons change brains. However, in these thought experiments the remaining part of the body plays only a passive part. In this paper I argue that the psychological approach of personal identity cannot be maintained, if the whole body is actively involved in the analysis, and (...) that the body is an intrinsic part of what I am as a person. (shrink)