This is an extension of my earlier work, How in the World Are There Many Worlds and it's a lot more interesting! This paper explores personal identity and persistence through time in the many-worlds framework, governed by the Many Worlds Interpretation (MWI) of quantum mechanics (QM). First, I will motivate our consideration of the MWI in this context. Second, I will introduce endurantism, which is one answer to the puzzle concerning persistence through time. Third, I will explain the foundational physics (...) underlying the MWI that lends itself to branching worlds. In turn, I will explain what exactly a world amounts to in this picture. Then, I will present three views on personal identity and persistence through time: the bye-bye Betty view, the every-branch view, and the privileged branch view. I will argue that the privileged branch view is the most attractive of the bunch for determining the best candidate among close continuers. Finally, I will discuss knowledge, attitudes, and moral responsibility within the privileged branch view. (shrink)

This note criticizes Andrew Brennan's attempt to defend best?candidate theories of the identity of artefacts over time against certain now familiar objections. Adoption of a mereological conception of individuals does not, in itself, provide the means for a satisfactory response to objections of Wiggins and Noonan (some of which are anyway ill?focused). The way forward consists in recognizing that the consequences of best?candidate theories which have been thought objectionable (in particular, commitment to the extrinsicness of identity) do not violate the (...) necessity of identity and imply ? what anyway ought to seem unexceptionable ? that a predicate such as ?constituting the ship which is the Ship of Theseus? does not denote a genuine property of the hunk of matter of which the predicate is true. Once these consequences have been clearly mapped out, the best?candidate theorist's commitment to the extrinsicness of identity does not appear absurd. (shrink)

In this paper, I consider the validity and proper formulation of the only-x-and-y principle, which states, roughly, that whether a later individual, y, is numerically identical to an earlier individual, x, can depend only on facts about x and y and the relationships between them. In the course of my investigation, I distinguish between two classes of physical entities - those that exist in a 'real' sense, and those that exist in a mere Cambridge sense. This distinction is grounded in (...) Peter Geach's distinction between 'real' and mere Cambridge change. I argue in favor of a modified version of the only-x-and-y principle - the qualified only-x-and-y principle - which applies to entities that exist in a 'real' sense, but not to mere Cambridge entities. It is also argued that the plausibility of the qualified only-x-and-y principle has more to do with facts about the nature of causality than with intuitions we have about existence or numerical identity. I finish by considering some traditional objections to the only-x-and-y principle, and conclude that they do not succeed in refuting the qualified only-x-and-y principle. (shrink)