Eric T. Olson

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..

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

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?

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.

One of the main problems of personal identity is supposed to be how we relate to our bodies. A few philosophers endorse what is called a 'bodily criterion of personal identity': they say that we are our bodies, or at any rate that our identity over time consists in the identity of our bodies. Many more deny this--typically on the grounds that we can imagine ourselves coming apart from our bodies. But both sides agree that the bodily criterion is an important view which anyone thinking about personal identity must consider.

This book consists of fifteen new essays and an introduction by Zimmerman. Most of the authors are Christian philosophers in the ‘analytic’ tradition, and the book is of particular interest to readers of that sort; but there is nothing here that will interest only Christians. As the title suggests, all the essays have at least something to do with persons as such, and most deal with metaphysical issues. Beyond that they are pretty disparate. Seven papers are on substance dualism or idealism, which get a more sympathetic hearing than current fashion would dictate. Lynn Rudder Baker, Hud Hudson, and Peter van Inwagen discuss materialist accounts of human people that they have developed elsewhere. There are papers on specifically Christian doctrines--immortality, divine incarnation, the trinity, and original sin--and one on the value of human people by Philip Quinn. For better or worse, there is almost no discussion of the existence of God. Even so, no one can accuse the authors of avoiding the big questions and retreating to narrow, technical issues. There is as much at stake in these essays as there is in any work of Plato or Kant.