Humberstone has shown that if some set of agents is collectively omniscient (every true proposition is known by at least one agent) then one of them alone must be omniscient. The result is paradoxical as it seems possible for a set of agents to partition resources whereby at the level of the whole community they enjoy eventual omniscience. The Humberstone paradox only requires the assumption that knowledge distributes over conjunction and as such can be viewed as a reductio against the (...) universal validity of that principle. A new route to this paradox is presented which does not require the distribution principle, building on earlier work of Jago and Williamson on Fitch’s paradox. The result relies on an axiom strictly weaker than one necessary for the Jago-Fitch variant. It is shown that the same reasoning behind the variant form of Humberstone’s paradox can recover Bigelow’s results in action theory in a way that is immune to an objection brought against it by Guigon and Humberstone. (shrink)

Kai Wehmeier’s Wittgensteinian Predicate Logic is a formulation of first-order logic under the exclusive interpretation of the quantifiers. W-logic has a distinguished relation constant for co-reference but no sign for objectual identity. Wehmeier denies that objectual identity exists on the grounds that it cannot be a genuine binary relation. Fortunately W-logic is equi-expressive with standard first-order logic with identity and it appears that objectual identity is dispensable across the broader logical enterprise. This paper challenges the latter claim as objectual identity (...) seems to be needed in the exclusive interpretation of quantified modal logic, specifically, for implementing certain kinds of de re quantification. (shrink)

This paper is about the neglected question of what sort of things we are metaphysically speaking. It is different from the mind-body problem and from familiar questions of personal identity. After explaining what the question means and how it differs from others, the paper tries to show how difficult it is to give a satisfying answer.

From the time of Locke, discussions of personal identity have often ignored the question of our basic metaphysical nature: whether we human people are biological organisms, spatial or temporal parts of organisms, bundles of perceptions, or what have you. The result of this neglect has been centuries of wild proposals and clashing intuitions. What Are We? is the first general study of this important question. It beings by explaining what the question means and how it differs from others, such as (...) questions of personal identity and the mind-body problem. It then examines in some depth the main possible accounts of our metaphysical nature, detailing both their theoretical virtues and the often grave difficulties they face. The book does not endorse any particular account of what we are, but argues that the matter turns on more general issues in the ontology of material things. If composition is universal--if any material things whatever make up something bigger--then we are temporal parts of organisms. If things never compose anything bigger, so that there are only mereological simples, then we too are simples--perhaps the immaterial substances of Descartes--or else we do not exist at all (a view Olson takes very seriously). The intermediate view that some things compose bigger things and others do not leads almost inevitably to the conclusion that we are organisms. So we can discover what we are by working out when composition occurs. (shrink)

There is much to admire in this book. It is written in a pleasingly straightforward style, and offers insight on a wide range of important issues.

Personal identity deals with questions about ourselves qua people (or persons). Many of these questions are familiar ones that occur to everyone at some time: What am I? When did I begin? What will happen to me when I die? Discussions of personal identity go right back to the origins of Western philosophy, and most major figures have had something to say about it. (There is also a rich literature on personal identity in Eastern philosophy, which I am not competent (...) to discuss. Collins 1982 is a good source.). (shrink)

The view that we are human animals, " animalism ", is deeply unpopular. This paper explains what that claim says and why it is so contentious. It then argues that those who deny it face an awkward choice. They must either deny that there are any human animals, deny that human animals can think, or deny that we are the thinking things located where we are.

It is often said that the same particles can simultaneously make up two or more material objects that differ in kind and in their mental, biological, and other qualitative properties. Others wonder how objects made of the same parts in the same arrangement and surroundings could differ in these ways. I clarify this worry and show that attempts to dismiss or solve it miss its point. At most one can argue that it is a problem we can live with.

The Standard View of personal identity says that someone who exists now can exist at another time only if there is continuity of her mental contents or capacities. But no person is psychologically continuous with a fetus, for a fetus, at least early in its career, has no mental features at all. So the Standard View entails that no person was ever a fetus--contrary to the popular assumption that an unthinking fetus is a potential person. It is also mysterious what (...) does ordinarily happen to a human fetus, if it does not come to be a person. Although an extremely complex variant of the Standard View may allow one to persist without psychological continuity before one becomes a person but not afterwards, a far simpler solution is to accept a radically non-psychological account of our identity. (shrink)

Trust me: my chair isn't big enough for two. You may doubt that every rational, conscious being is a person; perhaps there are beings that mistakenly believe themselves to be people. If so, read ‘rational, conscious being’ or the like for 'person'.

The Standard View of personal identity says that someone who exists now can exist at another time only if there is continuity of her mental contents or capacities. But no person is psychologically continuous with a fetus, for a fetus, at least early in its career. has no mental features at all. So the Standard View entails that no person was ever a fetus---contrary to the popular assumption that an unthinking fetus is a potential person. It is also mysterious what (...) does ordinarily happen to a human fetus, if it does not come to be a person. Although an extremely complex variant of the Standard View may allow one to persist without psychological continuity before one becomes a person but not afterwards, a far simpler solution is to accept a radically non-psychological account of our identity. (shrink)

In discussions of the ethics of human gene therapy, it has become standard to draw a distinction between the use of human gene transfer techniques to treat health problems and their use to enhance or improve normal human traits. Some dispute the normative force of this distinction by arguing that it is undercut by the legitimate medical use of human gene transfer techniques to prevent disease - such as genetic engineering to bolster immune function, improve the efficiency of DNA repair, (...) or add cellular receptors to capture and process cholesterol. If disease prevention is a proper goal of medicine, these critics argue, and the use of gene transfer techniques to enhance human health maintenance capacities will help achieve that goal, then the “treatment/enhancement‘ distinction cannot define the limits of legitimate gene therapy. In this paper, I argue that a line can be drawn between prevention and enhancement for gene therapy (and thus between properly medical and nonmedical uses of gene therapy), but only if one is willing to accept two rather old-fashioned claims: 1) Some health problems are best understood as if they were entities in their own right, reifiable as processes or parts in a biological system, with at least as much ontological objectivity and theoretical significance as the functions that they inhibit. 2) Legitimate preventive genetic health care should be limited to efforts to defend people from attack by these more robust pathological entities, rather than changing their bodies to evade social injustices. (shrink)

The apparent fact that each of us coincides with a thinking animal looks like a strong argument for our being animals (animalism). Some critics, however, claim that this sort of reasoning actually undermines animalism. According to them, the apparent fact that each human animal coincides with a thinking body that is not an animal is an equally strong argument for our not being animals. I argue that the critics' case fails for reasons that do not affect the case for animalism.

The extended-mind thesis says that mental states can extend beyond one’s skin. Clark and Chalmers infer from this that the subjects of such states also extend beyond their skin: the extended-self thesis. The paper asks what exactly the extended-self thesis says, whether it really does follow from the extended-mind thesis, and what it would mean if it were true. It concludes that the extended-self thesis is unattractive, and does not follow from the extended mind unless thinking beings are literally bundles (...) of mental states. (shrink)

Many philosophers say that time involves a kind of passage that distinguishes it from space. A traditional objection is that this passage would have to occur at some rate, yet we cannot say what the rate would be. The paper argues that the real problem with time’s passage is different: time would have to pass at one second per second, yet this is not a rate of change. This appears to refute decisively not only the view that time passes, but (...) any tensed theory of time. (shrink)

According to a view attractive to both metaphysicians and ethicists, every period in a person’s life is the life of a being just like that person except that it exists only during that period. These “subpeople” appear to have moral status, and their interests seem to clash with ours: though it may be in some person’s interests to sacrifice for tomorrow, it is not in the interests of a subperson coinciding with him only today, who will never benefit from it. (...) Or perhaps there is no clash, and a subperson’s interests derive from those of the person it coincides with. But this makes it likely that our own interests derive from those of other beings coinciding with us. (shrink)

It is often said that the same particles can simultaneously make up two or more material objects that differ in kind and in their mental, biological and other qualitative properties. Others wonder how objects made of the same parts in the same arrangement and surroundings could differ in these ways. I clarify this worry and show that attempts to dismiss or solve it miss its point. At most one can argue that it is a problem we can live with.

In this essay I explore the idea that the solution to some important problems of personal identity lies in the philosophy of language: more precisely in the nature of first-person reference. I will argue that the “linguistic solution” is at best partly successful.

What is a temporal part? Most accounts explain it in terms of timeless parthood: a thing's having a part without temporal qualification. Some find this hard to understand, and thus find the view that persisting things have temporal parts--fourdimensionalism--unintelligible. T. Sider offers to help by defining temporal parthood in terms of a thing's having a part at a time. I argue that no such account can capture the notion of a temporal part that figures in orthodox four-dimensionalism: temporal parts must (...) be timeless parts. This enables us to state four-dimensionalism more clearly. (shrink)

Conjoined twinning is said to show that the number of human people—the number of us—can differ from the number of human organisms, and hence that we are not organisms. The paper shows that these arguments either assume the point at issue, rely on dubious and undefended assumptions, or add nothing to more familiar arguments for the same conclusion.

A decade after the completion of the Human Genome Project, the widespread appeal of personalized genomic medicine's vision and potential virtues for health care remains compelling. Advocates argue that our current medical regime “is in crisis as it is expensive, reactive, inefficient, and focused largely on one size fits all treatments for events of late stage disease.” What is revolutionary about this kind of medicine, its advocates maintain, is that it promises to resolve that crisis by simultaneously increasing the ability (...) to be “personalized,” “predictive,” “preventive,” and “participatory.” Some call personalized genomic medicine “P4 Medicine,” inscribing these cardinal virtues into the movement's name. All of these putative virtues have interesting implications for the future of health care. In this essay, we are especially interested in the claims that personalized medicine will lead to a more “participatory” or “patient‐centered” approach to health care, in which patients are “empowered” to take more personal control over their care. The rhetoric of patient empowerment is nothing new in health care, but personalized medicine is an interesting case study because it portrays empowerment as one of its key virtues and as a mechanism for fixing the health care “crisis.”. (shrink)

ABSTRACTMany philosophers say that the nature of personal identity has to do with narratives: the stories we tell about ourselves. While different narrativists address different questions of personal identity, some propose narrativist accounts of personal identity over time. The paper argues that such accounts have troubling consequences about the beginning and end of our lives, lead to inconsistencies, and involve backwards causation. The problems can be solved, but only by modifying the accounts in ways that deprive them of their appeal.

In 2015, a flourish of “alarums and excursions” by the scientific community propelled CRISPR/Cas9 and other new gene-editing techniques into public attention. At issue were two kinds of potential gene-editing experiments in humans: those making inheritable germ-line modifications and those designed to enhance human traits beyond what is necessary for health and healing. The scientific consensus seemed to be that while research to develop safe and effective human gene editing should continue, society's moral uncertainties about these two kinds of experiments (...) needed to be better resolved before clinical trials of either type should be attempted. In the United States, the National Academies of Science, Engineering and Medicine convened the Committee on Human Gene Editing: Scientific, Medical and Ethical Considerations to pursue that resolution. The committee's 2017 consensus report has been widely interpreted as “opening the door” to inheritable human genetic modification and holding a line against enhancement interventions. But on a close reading it does neither. There are two reasons for this eccentric conclusion, both of which depend upon the strength of the committee's commitment to engaging diverse public voices in the gene-editing policy-making process. (shrink)

The Epicurean view is that there is nothing bad about death, and we are wrong to loathe it. This paper distinguishes several different such views, and shows that while some of them really would undermine our loathing of death, others would not. It then argues that any version that did so could be at best vacuously true: If there is nothing bad about death, that can only be because there is nothing bad about anything.

It seems evident that things sometimes get bigger by acquiring new parts. But there is an ancient argument purporting to show that this is impossible: the paradox of increase or growing argument.i Here is a sketch of the paradox. Suppose we have an object, A, and we want to make it bigger by adding a part, B. That is, we want to bring it about that A first lacks and then has B as a part. Imagine, then, that we conjoin (...) B to A in some appropriate way. Never mind what A and B are, or what this conjoining amounts to: let A be anything that can gain a part if anything can gain a part, and let B be the sort of thing that can become a part of A, and suppose we do whatever it would take to make B come to be a part of A if this is possible at all. Have we thereby made B a part of A? It seems not. We seem only to have brought it about that B is attached to A, like this. (shrink)

Because there is no agreed use of the term 'self', or characteristic features or even paradigm cases of selves, there is no idea of "the self" to figure in philosophical problems. The term leads to troubles otherwise avoidable; and because legitimate discussions under the heading of 'self' are really about other things, it is gratuitous. I propose that we stop speaking of selves.

In The Human Animal I argued that we are animals, and that those animals do not persist by virtue of any sort of psychological continuity. Rather, personal identity in this sense consists in having the same biological life. And I said that a human life requires a functioning brainstem. Rina Tzinman takes this and other remarks to imply that personal identity consists in the continued functioning of the brainstem, which looks clearly false. I say it doesn’t follow. But Alan Shewmon (...) appears to have refuted my claim about the brainstem. (shrink)

Animalism is the view that you and I are animals. That is, we are animals in the straightforward sense of having the property of being an animal, or in that each of us is identical to an animal-not merely in the derivative sense of having animal bodies, or of being "constituted by" animals. And by 'animal' I mean an organism of the animal kingdom." Sensible though it may appear, animalism is highly contentious. The most common objection is that it conflicts (...) with widespread and deep beliefs about our identity over time. These beliefs are brought out in reactions to fictional cases. Suppose, for instance, that your brain is transplanted into my head. The being who ends up with that organ, everyone assumes, will remember your life and not mine. More generally, he will have your beliefs, preferences, plans, and other mental properties, for the most part at least. Who would he be-you, me, or someone else? (shrink)

It is widely held that every person is a person essentially, where being a person is having special mental properties such as intelligence and self-consciousness. It follows that nothing can acquire or lose these properties. The paper argues that this rules out all familiar psychological-continuity views of personal identity over time. It also faces grave difficulties in accounting for the mental powers of human beings who are not intelligent and self-conscious, such as foetuses and those with dementia.

Sydney Shoemaker argues that the functionalist theory of mind entails a psychological-continuity view of personal identity, as well as providing a defense of that view against a crucial objection. I show that his view has surprising consequences, e.g. that no organism could have mental properties and that a thing's mental properties fail to supervene even weakly on its microstructure and surroundings. I then argue that the view founders on "fission" cases and rules out our being material things. Functionalism tells us (...) little if anything about personal identity. (shrink)

Cartesian or substance dualism is the view that concrete substances come in two basic kinds. There are material things, such as biological organisms. These may be either simple or composed of parts. And there are immaterial things--minds or souls--which are always simple. No material thing depends for its existence on any soul, or vice versa. And only souls can think.

Philosophers often talk as if what it takes for a person to persist through time were up to us, as individuals or as a linguistic community, to decide. In most ordinary situations it might be fully determinate whether someone has survived or perished: barring some unforeseen catastrophe, it is clear enough that you will still exist ten minutes from now, for example. But there is no shortage of actual and imaginary situations where it is not so clear whether one survives. (...) Here reasonable people may disagree. There are "fission" cases where each of one's cerebral hemispheres is transplanted into a different head; Star-Trek-style "teletransportation" stories; actual cases of brain damage so severe that one can never again regain consciousness, even though one's circulation, breathing, digestion, and other "animal" functions continue; and stories where one's brain cells are gradually removed and replaced by cells from someone else, to name only a few favorites. (shrink)

This paper—written for nonspecialist readers—asks whether life after death is in any sense possible given the apparent fact that after we die our remains decay to the point where only randomly scattered atoms remain. The paper argues that this is possible only if our remains are not in fact dispersed in this way, and discusses how that might be the case. -/- 1. Life After Death -- 2. Total Destruction -- 3. The Soul -- 4. Body-Snatching -- 5. Radical Resurrection (...) -- 6. Irreversibility -- 7. Atomic Reassembly -- 8. The Transporter -- 9. Replicas and Originals -- 10. Survival and Causal Connections. (shrink)

Recently, in this journal, Jeremy Gwiazda has offered a critique of our separationist view of hell. His objection relies on two key assumptions, and we show in our reply that both assumptions can be denied.

Many philosophers say that the same atoms may compose at once a statue and a lump of matter that could outlive the statue. I reject this because no difference between the statue and the lump could explain why they have different persistence conditions. But if we say that the lump is the statue, it is difficult to see how there could be any human beings. I argue that this and analogous problems about material objects admit only of solutions that at (...) least appear to be radically at odds with our ordinary thinking. (shrink)

Slowing the aging process would be one of the most dramatic and momentous ways of enhancing human beings. It is also one that mainstream science is on the brink of pursuing. The state of the science, together with its possible impact, make it an important example for how to think about research into all enhancement technologies.

Many philosophers say that two or more people or thinking beings could share a single human being in a split‐personality case, if only the personalities were sufficiently independent and individually well integrated. I argue that this view is incompatible with our being material things, and conclude that there could never be two or more people in a split‐personality case. This refutes the view, almost universally held, that facts about mental unity and disunity determine how many people there are. I suggest (...) that the number of human people is simply the number of appropriately endowed human animals. (shrink)

Derek Parfit claims that we are not human beings. Rather, each of us is the part of a human being that thinks in the strictest sense. This is said to solve a number of difficult metaphysical problems. I argue that the view has metaphysical problems of its own, and is inconsistent with any psychological-continuity account of personal identity over time, including Parfit's own.

Accounts of personal identity over time are supposed to fall into two broad categories: 'complex views' saying that our persistence consists in something else, and 'simple views' saying that it doesn' t. But it is impossible to characterize this distinction in any satisfactory way. The debate has been systematically misdescribed. After arguing for this claim, the paper says something about how the debate might be better characterized.

Substance dualism says that all thinking beings are immaterial. This sits awkwardly with the fact that thinking requires an intact brain. Many dualists say that bodily activity is causally necessary for thinking. But if a material thing can cause thinking, why can’t it think? No argument for dualism, however convincing, answers this question, leaving dualists with more to explain than their opponents.

: Some argue that human groups have a stake in the outcome of population-genomics research and that the decision to participate in such research should therefore be subject to group permission. It is not possible, however, to obtain prior group permission, because the actual human groups under study, human demes, are unidentifiable before research begins. Moreover, they lack moral standing. If identifiable social groups with moral standing are used as proxies for demes, group approval could be sought, but at the (...) expense of unfairly exposing these surrogates to risks from which prior group approval is powerless to protect them. Unless population genomics can proceed without targeting socially defined groups, or can find other ways of protecting them, it may fall to individuals to protect the interests of the groups they care about, and to scientists to warn their subjects of the need to do so. (shrink)