What justifies our holding a person morally responsible for some past action? Why am I justified in having a special prudential concern for some future persons and not others? Why do many of us think that maximizing the good within a single life is perfectly acceptable, but maximizing the good across lives is wrong? In these and other normative questions, it looks like any answer we come up with will have to make an essential reference to personal identity. So, for (...) instance, it seems we are justified in holding X responsible for some past action only if X is identical to the person who performed that action. Further, it seems I am justified in my special concern for some future person only if he will be me. Finally, many of us think that while maximization within a life affects only one person, a metaphysical unity, maximization across lives affects many different, metaphysically distinct, persons, and so the latter is wrong insofar as it ignores this fundamental separateness of persons. (shrink)

In this paper, I argue that standard psychological continuity theory does not account for an important feature of what is important in survival – having the property of personhood. I offer a theory that can account for this, and I explain how it avoids the implausible consequences of standard psychological continuity theory, as well as having certain other advantages over that theory.

On person-affecting views in population ethics, the moral import of a person’s welfare depends on that person’s temporal or modal status. These views typically imply that – all else equal – we’re never required to create extra people, or to act in ways that increase the probability of extra people coming into existence. -/- In this paper, I use Parfit-style fission cases to construct a dilemma for person-affecting views: either they forfeit their seeming-advantages and face fission analogues of the problems (...) faced by their rival impersonal views, or else they turn out to be not so person-affecting after all. In light of this dilemma, the attractions of person-affecting views largely evaporate. What remains are the problems unique to them. (shrink)

This thesis consists of a series of papers in population ethics: a subfield of normative ethics concerned with the distinctive issues that arise in cases where our actions can affect the identities or number of people of who ever exist. Each paper can be read independently of the others. In Chapter 1, I present a dilemma for Archimedean views in population axiology: roughly, those views on which adding enough good lives to a population can make that population better than any (...) other. In Chapter 2, I extend Gustaf Arrhenius’s famous impossibility theorems in population axiology into the domain of choices under risk. My risky impossibility theorems dispense with the assumption that welfare levels are finitely fine-grained, and so tell against lexical views in population axiology. In Chapter 3, I present objections to critical-level and critical-range views in population axiology. I then sketch out what I call the ‘Imprecise Exchange Rates View’ and argue that it is an attractive alternative. In Chapter 4, I address critical-level and critical-range views again. This time, I note that they are vulnerable to objections from biographical identity: identity between lives. I suggest that these objections give us reason to reject critical-level and critical-range views and embrace the Total View. In Chapter 5, I argue that objections of the same form – objections from personal identity – tell against person-affecting views in population ethics. In Chapter 6, I draw out some counterintuitive implications of two recent complaints-based theories of the procreation asymmetry. (shrink)

In his work on personal identity, Derek Parfit makes two revolutionary claims: firstly, that personal identity is not what matters in survival; and secondly, that what does matter is relation R. In this article I demonstrate his position here to be inconsistent, with the former claim being defensible only in case the latter is false. Parfit intends his famous fission argument to establish the unimportance of identity – a conclusion disputed by, among others, Mark Johnston. My approach is to critically (...) assess their debate, focusing on Johnston's reductio of Parfit's position. I contend that although Parfit's own response fails, there are other ways to save the fission argument. The unimportance of identity then comes at a cost, however, because the reductio can only be avoided by accepting either that nothing matters in survival, or else that facts about particles and forces do. Either way, relation R cannot be what matters. (shrink)

In this paper, I argue that standard psychological continuity theory does not account for an important feature of what is important in survival—having the property of personhood. I offer a theory that can account for this, and I explain how it avoids the implausible consequences of standard psychological continuity theory, as well as having certain other advantages over that theory.

One of the most popular and enduring approaches to indeterminacy phenomena (e.g., vagueness) over the past several decades has been some form or another of supervaluationism. I argue that supervaluationism is inadequate as a model of indeterminacy: There is an entire class of examples of indeterminacy, characterized by a common “branching” structure, that cannot be modeled in the way supervaluationism proposes. I demonstrate my conclusion explicitly with respect to two specific examples—indeterminate personal identity and indeterminate reference—showing how supervaluationism can model (...) neither. Importantly, my arguments apply to both traditional “semantic” and more recent “metaphysical” versions of supervaluationism. (shrink)

Derek Parfit has offered numerous arguments in an attempt to establish that identity is not what matters. Jens Johannson has recently argued that Parfit's various arguments for the claim that identity is not what matters fail to establish what Parfit takes such arguments to establish. Johannson contends that this is due in part to the invalidity of one of Parfit's key arguments, and the fact that Parfit ignores a position that is compatible with the conclusions of his successful arguments and (...) the claim that identity is in fact what matters, namely, that I survive fission as either one of the fission products or the other, but it is indeterminate which one I survive as. I aim to establish here that both of Johannson's assertions are problematic. As a corollary of this task, I hope to shed some light on the relationship between indeterminacy and fission-based arguments for the claim that identity is not what matters. (shrink)

Your replica is created on Mars and you, on Earth, are destroyed. Parfit claims that your replica may still have what prudentially matters for you – provided that you are psychologically connected and continuous with your replica. If someone accidentally destroys the tapes containing your psychological profile used in the production of your replica and this same action fortuitously produces a functionally equivalent tape, Ehring claims that Parfit should maintain that the resulting new individual may still have what matters. Nihilism (...) about what matters follows, or so Ehring claims. I argue that Ehring is wrong and that the difference between the two ways of creating a replica is not trivial – there is no trivial survival. (shrink)

Johansson, in “Parfit on Fission,” rejects Parfit’s thesis that fission demonstrates that identity does not matter in survival based on the following assumption (call the person who fissions, “Mr. Fissiony” and the fission products, “Lefty” and “Righty”): It is determinately true that Mr. Fissiony is identical to Lefty or that he is identical to Righty, but it is indeterminate whether Mr. Fissiony is identical to Lefty and it is indeterminate whether Mr. Fissiony is identical to Righty. Johansson argues that there (...) are identity-based answers to the following questions that apply in fission case: (Future Time) Concerning any future time, what matters in my relation to it? (Future Person) Concerning any future individual, what matters in my relation to him? The identity-based answers are these: (Future Time Answer) That I am identical with someone at that time. (Future Person Answer) That it is not false that I and that future individual are identical and that this relation of it not being false that we are identical is not close to not obtaining. I argue that the combination of these answers is inconsistent with the implication that if person C1 at t1 stands in the mattering relation to person C2 at t2, then C1 gets what matters with respect to t2 and that the degree to which the relation specified in Future Person Answer holds between Mr. Fissiony and Lefty in the fission case does not match up to the degree to which Mr. Fissiony gets what matters with respect to Lefty. (shrink)

Parfit has argued for the revolutionary thesis that personal identity does not matter in ordinary survival, only the R-relation does. “Reconciliationists,” such as Lewis, have tried to stop this revolution, arguing that both personal identity and the R-relation matter. The disagreement has been between those who hold that only the R-relation matters and those who hold that, in addition, personal identity matters. But there is a third option. I argue that Parfit is right that personal identity does not matter but (...) he is wrong that the R-relation matters, and the reconciliationists are wrong to think both matter since neither does. (shrink)