The Structure of Personal Persistence

Reductionism about people is the view that people exist but they are not a fundamental part of the world. The view is perhaps best explained through David Hume’s analogy with reductionism about nations. Most of us are reductionists about nations: We believe that nations exist but also that their existing consists in more basic facts, such as the existence of citizens who organize themselves in certain ways on certain territories. So we could, in principle, provide a complete description of the world (and these more basic facts) without asserting that nations exist. In this manner, reductionism about people says that the world could, in principle, be completely described without asserting that people exist.

On this reductionist view, personal persistence has to consist fundamentally in an impersonal continuity relation holding over time. Some standard candidates for this reductionist continuity are different kinds of psychological, physical, and phenomenal continuity. These continuity relations consist in overlaping chains of some basic form of connectedness, for example, psychological, physical, or phenomenal connectedness. The logical form of the relationship between the underlying basic connectedness and personal persistence is controversial, however. What happens when the contiuities branch? And what counts as branching? Below, you can explore interactively some of the most discussed proposals along with a new one.


You need a browser with support for the canvas tag in HTML5, such as Firefox 1.5+, Chrome, Safari 2.0+, or Opera 9.0+.


Add person-stages by clicking on the intersections of the grid. Connect two person-stages by clicking on one of them and then the other. The person-stages are represented by dots and a connection between two person-stages is represented by a black curve between them. Remove a person-stage by clicking on it twice. Remove a connection by clicking on one of the connected person-stages and then on the other. You can also try some standard cases by pressing the buttons above the grid.

See which person-stages are part of the same continuant person according to different theories by pressing the buttons below the grid. That two person-stages are part of the same person is represented by a red curve between them. If a person-stage is part of the same continuant person as itself, then it is red; othewise, it is black.

The bracketed numbers for the theories correspond to the numbering in Johan E. Gustafsson ‘Non-Branching Personal Persistence’, Philosophical Studies, forthcoming. See this paper for definitions and sources of the theories.