The Problem of Personal Identity and Contemporary Approaches to Cognition

This dissertation examines the problem of diachronic personal identity, specifically the question of what necessary and sufficient conditions determine whether a person x₁ at time t₁ is numerically identical to a person xₙ at some other time tₙ, whether in the past or the future. Although this problem has a long history in Western philosophy, my focus here will be on contemporary approaches to it. I begin by analyzing Locke’s criterion as interpreted in modern discussions, where personal identity is often explained exclusively in terms of psychological factors. I will argue that no psychological criterion—whether considered independently or in conjunction with the later introduced bodily and brain criteria—provides necessary and sufficient conditions for personal identity. I then turn to Parfit’s view and the animalist criterion, which has become one of the more influential contemporary attempts to resolve the problem of personal identity. In light of the difficulties and shortcomings of the criteria discussed in the first five chapters, in the sixth chapter, I will propose a combined criterion that integrates elements of animalism and Parfit’s view, while further justifying them by drawing on contemporary insights from the philosophy of cognition. According to this combined criterion, we are identical to certain embodied cognitive systems, some of which—along with certain cognitive processes—may be extended. At the same time, persons are best understood as phasal (sortal) properties of these cognitive systems, meaning that they are properties instantiated by such systems over specific periods of time. The primary objective of this dissertation is to show that the combined criterion successfully accounts for problematic cases—such as the possibility of artificial persons and branching scenarios—while also avoiding most of the theoretical and practical objections commonly raised against previous criteria.