Online research in philosophy

Abstract: Those who endorse the Psychological Continuity Approach (PCA) to analyzing personal identity need to impose a non-branching constraint to get the intuitively correct result that in the case of fission, one person becomes two. With the help of Brueckner's (2005) discussion, it is shown here that the sort of non-branching clause that allows proponents of PCA to provide sufficient conditions for being the same person actually runs contrary to the very spirit of their theory. The problem is first presented in connection with perdurantist versions of PCA. The difficulty is then shown to apply to endurantist versions as well.

Parfit’s well known book, Reasons and Persons, argues, among other things, that ‘what matters’ in regard to ‘survival’ is not personal identity but something he calls ‘relation R.’ On this basis, plus other considerations, he rejects the ‘Self-interest’ theory as to what should be our aim in life. Here I show, or try to show, that his over-all argument is seriously defective. In particular, he fails to prove that personal identity is not what matters for survival.

David Lewis's cohabitation theory suffered damaging criticism from Derek Parfit. Though many have defended versions of Lewis's theory Parfit's criticism has not been answered. This paper shows how to defend the cohabitation theory against Parfit's criticism.

In this paper I shall argue that if the Parfitian psychological criterion or theory of personal identity is true, then a good case can be made out to show that the psychological theorist should accept the view I call “psychological sequentialism”. This is the view that a causal connection is not necessary for what matters in survival, as long as certain other conditions are met. I argue this by way of Parfit’s own principle that what matters in survival cannot depend upon a trivial fact.

Contra Derek Parfit’s psychological continuity theory, I argue for an externalist conception of what matters in the survival of persons over time. Specifically, I claim that what matters in the survival of persons is the preservation of what I call their “life trajectories.” I justify this conclusion by considering the implications of what I call cases of “complete virtual immersion”-- the immersing of a psychological subject in a completely virtual world, a world in which experiences are de-correlated with events in the objective world. Consideration of these kinds of cases demonstrates that psychological continuity over time is insufficient for preserving what matters in the survival of persons. This is because certain ways of being virtually immersed, while maintaining psychological continuity, compromise a person’s agency. Because being an agent is plausibly an essential feature of being a person, these ways of being immersed compromise features of what matters in a person’s survival. Of course, the idea that externalist constraints are important in a complete account of what constitutes persons and what matters in their survival is not new, but I propose a very specific theory about how to understand these constraints. What’s more, I explain in detail why incorporating externalist constraints in an account of what matters in survival proves to rule out fission as a case of preserving what matters equally as well as the single case, and unlike the traditional way of rejecting these cases, I do so without thereby committing to an identity theory of what matters.

In his Reasons and Persons, Derek Parfit argues from the possibility of cases of fission and/or fusion of persons that one must reject identity as what matters for personal survival. Instead Parfit concludes that what matters is “psychological connectedness and/or continuity with the right kind of cause,” or what he calls an R-relation. In this paper, I argue that, if one accepts Parfit’s conclusion, one must accept that R-relations are what matter for moral responsibility as well. Unfortunately, it seems that accepting that the R-relation is what matters for both survival and moral responsibility leads to a contradiction. My goal, however, is not merely to point out a problem in Parfit’s account. Instead, I believe that once we understand the basic intuitions which lead to this contradiction, it is clear that there is no fully satisfactory way to account for what matters with respect to survival and moral responsibility.

As regards the question of what matters in survival two views have been identified: on the one hand, we have the view that what matters is identity (the so-called 'commonsense view') and, on the other hand, we have the view that what matters is the holding of certain psychological connections between various mental states over time (the relation R). Several attempts have tried to reconcile these two views involving the so-called 'multiple occupancy view' or 'cohabitation thesis'. Even if the latter comes in several formulations, common elements are, positing the appropriateness of a description of the fission case according to which the post-fission persons existed prior to fission and also, that what determines that two persons who exist at a certain time are distinct can be facts about what is the case at other times. The paper discusses three of the most influential formulations of the multiple occupancy view, which intend to reconcile identity with what matters, and argues that for various reasons these at least do not work in this regard.