ABSTRACT
This chapter considers some well-known accounts of synchronic identity from both the dual-ist and materialist traditions. It discusses approaches to diachronic personal identity, the best known of which is John Locke's which emphasizes memories linking one person-stage to another prior to it. It discusses challenges to the Lockean view and considers whether it can be refined to accommodate them. The chapter also discusses challenges to Locke involving the possibility of "uploading" one's memories onto a server, as well as those concerning person-fission. It explores a few of the more prominent accounts of personhood (both synchronic and diachronic) in the Western philosophical tradition. A question is synchronic if it concerns how things are at a certain time. By contrast, we ask a diachronic question when we are concerned with how things are over a stretch of time. Thomas Reid was right in suggesting that psychological continuity is, at best, evidence of personal identity over time but is not what constitutes it.
