Persistence

We call the phenomenon of objects existing through time, persistence. Theories of persistence aim to spell out the conditions under which objects persist. A useful way to think about this task is to see that in order for an object to persist from one time to another, it needs to be that in some good sense the object that is located at the earlier time, is the same object as the object located at the later time. Competing theories of persistence can be thought of as offering different ways of understanding the sense in which an object located at one time is the same object as an object located at some other time. These different accounts are, in part, motivated by the need to reconcile four apparent truisms: (a) an object persists iff it exists at different times, and at each of those times what exists is numerically identical with what exists at every other one of those times; (b) persisting objects change their intrinsic properties over time; (c) x = y only if x and y share all of the same properties; and (d) no object instantiates incompatible properties. The tension between these four plausible claims is known as the problem of temporary intrinsics, and different attempts to solve the problem lead to different theories of persistence. Historically, there have been two main theories of persistence. The articulation of these theories can be traced to David Lewis, who distinguishes endurance from perdurance. The theory that says that objects persist by enduring is known as endurantism, and the theory that says that objects persist by perduring is known as perdurantism. Put somewhat roughly for now, endurantism is the view that objects persist by being wholly present at more than one time. Perdurantism is the view that objects persist by being partially present at more than one time. Section 1 considers these two theories of persistence in more detail, and then introduces two more recent views: exdurantism (also known as stage theory) and transdurantism. Section 2 considers how these four theories respond to the problem of temporary intrinsics.