Eric T. Olson

This chapter examines David Lewis's view that we are temporal parts of animals. It examines three arguments for the view that persisting things have temporal parts–four‐dimensionalism. One is that it solves the problem of temporary intrinsics. The second is that it solves metaphysical problems about the persistence of material objects without the mystery of constitutionalism–though these solutions require a counterpart‐theoretic account of modality. The third is that it solves problems of personal identity–involving fission, for instance–in an attractive way. It is then argued that according to four‐dimensionalism, the bearers of such properties as thinking and acting are momentary stages, forcing us to choose between saying that we don't strictly think and saying that we don't persist.

This chapter is about the view that we are simple immaterial substances–immaterialism–and related views. It is claimed to be best supported by the difficulty of saying what material things we could be. For instance, the paradox of increase threatens to show that nothing can have different parts at different times, and materialists can solve it only at considerable cost. Immaterialism is then shown to face grave problems concerning the relation of souls to material things. Compound dualism, Swinburne's view that each of us is composed of an immaterial soul and a material body, is shown to face difficulties in addition to those of immaterialism. The Thomistic view that we are hylomorphic compounds is shown to combine the problems of compound dualism with those of the bundle view. The views of Chisholm and Lowe that we are simple material things are then critically discussed.

Personal identity deals with the many philosophical questions about ourselves that arise by virtue of our being people. The most frequently discussed is what it takes for a person to persist through time. Many philosophers say that we persist by virtue of psychological continuity. Others say that our persistence is determined by brute physical facts, and psychology is irrelevant. In choosing among these answers we must consider not only what they imply about who is who in particular cases, both real and imaginary, but also their implications about our metaphysical nature in general

This chapter examines the view that we do not exist because there are no human thinkers: nihilism. Nihilism is defended against the charge that it is an absurd denial of the obvious, or that it is self‐refuting. Attempts by Kant and others, such as Russell, Unger, and Wittgenstein, to defeat nihilism by showing that thought requires a thinker are examined and found wanting. Attention then turns to attempts to paraphrase statements apparently about people into terms compatible with nihilism. Although this is difficult because nihilists will want to deny the existence of any composite objects, no conclusive objections to the project are found. It is then argued that nihilism, like solipsism, is depressing, and that someone who accepted it consistently would appear to deprive herself of any reasons for action.

This chapter examines animalism, the view that we are biological organisms. It is based on the claim that human organisms think just as we do. This implies that if I am not an organism, I am one of at least two thinkers of my thoughts, making it hard to see how I could know that I am the nonanimal thinker: the thinking-animal problem. Some proposed solutions are critically examined, notably Shoemaker's claim that human organisms cannot think and Noonan's account of how we might know that we are not the animals thinking our thoughts. Familiar objections to animalism are then reviewed, such as its implication that personal identity does not consist in psychological continuity. It is argued that these objections are weak and that more serious worries lie elsewhere.

This chapter considers Hume's proposal that we are made up entirely of particular mental states and events: the bundle view. An argument for the bundle view is based on the claim that the traditional idea of substance is dismissed. The bundle view is then shown to follow naturally from widely held claims about diachronic and synchronic personal identity. Reid's objection that bundles of thoughts cannot be thinkers is elaborated and endorsed. It is then argued that the bundle view cannot easily avoid the thinking‐animal problem. There follows a critical discussion of two related views: that we are bundles of universals and that we are something like computer programs. Both are found to be hopeless.

This chapter is about the view that we are material things constituted by organisms; this view is advocated by Baker, Shoemaker, and others. Each of us is made of the same matter as an organism, but our persistence conditions or essential properties preclude our being organisms ourselves. This goes together with the general view that qualitatively different objects can be made of the same matter at once: constitutionalism. Constitutionalism is supported by arguments involving the persistence of artifacts. It is argued, however, that the view faces the thinking‐animal problem, that it rules out any principled account of when one thing constitutes another, that it cannot explain why our boundaries lie where they do, and that it conflicts with a popular claim about synchronic identity.

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.

That grass is green, that pigs don’t fly, and that you are now awake are all hard facts. But there is often said to be something soft about matters of identity over time. Is today’s village church the very church that was first built here, despite centuries of repairs and alterations? How many parts of my bicycle do I need to replace before I get a numerically different bike? If a club disbands and years later some of the original members start a similar club with the same name, have we got two clubs, or one club with a discontinuous history? It is tempting to say that there are no hard answers to these questions laid up in heaven. There is no determinate fact of the matter. Those who disagree about such things are arguing about words, not facts. We are free to say what we like.

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.

Beginning with Locke, most philosophers writing on personal identity have claimed that some sort of psychological continuity is necessary for a person to persist from one time to another. I argue that this "psychological approach" to personal identity faces ontological difficulties that many of its proponents have not appreciated. In its place I advocate a "biological approach" to personal identity: you and I are human organisms, and our persistence, like that of other organisms, consists in narrowly biological facts alone. ;Since its biological functions are distinct from its psychology, a human organism can survive without psychological continuity. Thus the psychological approach apparently entails that you and I are not human organisms. But what are we, if not organisms? And how are we related to "our" human organisms? I consider a number of possible answers: perhaps we are not material objects at all; perhaps each of us is a material object coincident with though numerically distinct from a human organism; perhaps identity is not "absolute" but "relative," and a human organism may be different persons at different times; perhaps you and I do not really exist; perhaps we are temporally extended, "four-dimensional" objects and typically share most of our temporal parts with a human organism. The last option is the most popular, and rightly so. However, I argue that it faces technical problems and that it is wildly at odds with our ordinary beliefs about ourselves. ;After considering a wide range of arguments for the psychological approach, I conclude that most are grounded in confusion and have no force whatever. The best arguments appeal to our intuitive convictions about whether we would survive in various science-fiction stories in which the psychological and biological approaches diverge . Without dismissing these intuitions, I argue that they do not unequivocally support the psychological approach

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.)

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

Suppose a certain man, Dion, has his foot amputated, and lives to tell the tale. That tale involves a well-known metaphysical puzzle, for most of us assume that there was, before the operation, an object made up of all of Dion’s parts except those that overlapped with his foot-- ”all of Dion except for his foot”, we might say, or Dion’s “foot-complement”. Call that object Theon. (Anyone who doubts that there is such a thing as Dion’s undetached foot-complement may imagine that ‘Theon’ is a name for Dion’s undetached head. Surely there is such a thing as Dion’s head? And surely Dion could, in principle, survive if his head were detached from the rest of him and kept alive?) It seems obvious that Theon, like Dion, continues to exist after the operation, for you cannot destroy an object merely by changing its surroundings--merely by removing something that was never a part of it. The puzzle, then (which might be called the problem of undetached parts), is how Dion and Theon are related after the operation. The most common answer to this question is that Dion and Theon come to occupy just the same region of space and to be made of just the same matter after the operation. The next-mostpopular answer is that Dion and Theon are made up of temporal parts, and while those of their temporal parts that “occur” before the operation only partly overlap, Dion and Theon have the very same post-operative temporal parts. Much as two roads can merge and have spatial parts in common, Dion and Theon merge and have temporal parts in common. Less popular accounts of the relation between Dion and Theon involve relativizing identity to concepts or times, and denying that there is such a thing as Theon. Michael Burke has recently proposed an intriguing new solution (or resurrected an ancient one) to the problem of undetached parts. [1] He argues that, despite appearances, Theon-- Dion’s foot-complement--ceases to exist when Dion’s foot is removed..

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?

Most philosophers writing about personal identity in recent years claim that what it takes for us to persist through time is a matter of psychology. In this groundbreaking new book, Eric Olson argues that such approaches face daunting problems, and he defends in their place a radically non-psychological account of personal identity. He defines human beings as biological organisms, and claims that no psychological relation is either sufficient or necessary for an organism to persist. Olson rejects several famous thought-experiments dealing with personal identity. He argues, instead, that one could survive the destruction of all of one's psychological contents and capabilities as long as the human organism remains alive--as long as its vital functions, such as breathing, circulation, and metabolism, continue