Eric T. Olson

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.

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.

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

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

E. J. Lowe and others argue that there can be 'uncountable' things admitting of no numerical description. This implies that there can be something without there being at least one such thing, and that things can be identical without being one or nonidentical without being two. The clearest putative example of uncountable things is portions of homogeneous stuff or 'gunk'. The paper argues that there is a number of portions of gunk if there is any gunk at all, and that the possibility of uncountable things is inadequately supported.