Eric T. Olson

In special cases of partial twinning, two heads, each supporting a more-orless normal human mental life, emerge from a single torso. It is often argued that there must be two people in such a case, even if there is only one biological organism. That would pose a problem for ‘animalism’, the view that people are organisms. The paper argues that it is very hard to say what sort of non-organisms the people in such cases would be. Reflection on partial twinning is no more comfortable for those who think we’re not organisms than for those who think we are. We may have to accept that a single person could have two separate mental lives.

[First paragraph] For a long time philosophers thought material objects were unproblematic. Or nearly so. There may have been a problem about what a material object is: a substance, a bundle of tropes, a compound of substratum and universals, a collection of sense-data, or what have you. But once that was settled there were supposed to be no further metaphysical problems about material objects. This illusion has now largely been dispelled. No one can get a Ph.D. in philosophy nowadays without encountering the puzzles of the ship of Theseus, the statue and the lump, the cat and its tail complement', amoebic fission, and others. These problems are especially pressing on the assumption that we ourselves are material objects

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.

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.

The paper concerns the metaphysical possibility of life after death. It argues that the existence of a psychological duplicate is insufficient for resurrection, even if psychological continuity suffices for personal identity. That is because our persistence requires immanent causation. There are at most three ways of having life after death: if we are immaterial souls; if we are snatched bodily from our deathbeds; or if there is immanent causation ‘at a distance’ as Zimmerman proposes--but this requires an ontology of temporal parts.

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.

In this paper I shall explore a novel alternative to these familiar views. In his recent book Sub ects of Ex erience, E. J. Lowe argues, as many others have done before, that you and I are not animals. It follows from this, he says, that we must be simple substances without parts. That may sound like Cartesian dualism. But Lowe is no Cartesian. He argues from premises that many present-day materialists accept. And he claims that our being mereologically simple is consistent with our having such paradigmatically physical properties as being six feet tall and weighing 160 pounds. You and I, he claims, are mereological atoms shaped like human beings

One big question in biology is what life is, but another is how life divides into living things. This is the problem of biological individuality. Proposed statements of the problem have been vague and incomplete. And proposed theories of biological individuality are not detailed enough to solve the problem even if they are correct. The root of these troubles is that their authors have not recognized the metaphysical claims presupposed in their statement of the problem. Making these claims explicit will enable us to see better what the problem is and what form a solution to it would need to have.

The prosaic content of these sayings is that events change from future to present and from present to past. Your next birthday is in the future, but with the passage of time it draws nearer and nearer until it is present. 24 hours later it will be in the past, and then lapse forever deeper into history. And things get older: even if they don’t wear out or lose their hair or change in any other way, their chronological age is always increasing. These changes are universal and inescapable: no event could ever fail to be first future, then present, then past, and no persisting thing can avoid growing older. We call this process time’s passage.

This chapter considers the view that we are literally brains. It argues that the view is best supported by the claim that brains are the primary subjects of mental properties, giving a “thinking‐brain problem” analogous to the thinking‐animal problem that supports animalism. The brain view is shown to have implausible consequences about our identity through time, and to presuppose that something is a part of a thinking being if and only if it is directly involved in that being's mental processes. It is then argued that the notion of direct involvement is too interest‐relative to give this principle any useful content, and that the principle is in any case unfounded.

This article concerns the claim that it is possible to create living organisms, not merely models that represent organisms, simply by programming computers. I ask what sort of things these computer-generated organisms are supposed to be. I consider four possible answers to this question: The organisms are abstract complexes of pure information; they are material objects made of bits of computer hardware; they are physical processes going on inside the computer; and they are denizens of an entire artificial world, different from our own, that the programmer creates. I argue that could not be right, that collapses into, and that would make strong alife either absurd or uninteresting. Thus, "virtual" strong alife amounts to the claim that, by programming a computer, one can literally bring bits of its hardware to life

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.

Constitutionalism says that qualitatively different objects can be made of the same matter at once. Critics claim that we should expect such objects to be qualitatively indistinguishable. E.J. Lowe thinks this complaint is based on the false assumption that differences in the way things are at a time must always be grounded in how things are at that time, and that we can answer it by pointing out that different kinds of coinciding objects are subject to different composition principles. I argue that he is mistaken on both counts