Questions: Three-Dimensionalism and Endurance

Question 1

How does three-dimensionalism explain the fact that a person can be sitting at noon and standing at midnight without contradiction?

Model answer: Three-dimensionalism relativizes the instantiation of properties to times. The person is not simply 'sitting' and 'standing' — they are sitting-at-noon and standing-at-midnight. These are compatible because the properties are indexed to different times. The person is wholly present at both times (endurance), but their properties are understood as time-relative rather than as bare intrinsic properties that could generate a contradiction.

This is the core move three-dimensionalism must make to handle change. The cost is that shape, posture, and other apparently intrinsic properties become relational or time-indexed, which some philosophers find objectionable. Lewis called this the 'problem of temporary intrinsics' — if properties like shape were truly intrinsic (determined entirely by the thing as it is in itself), then having incompatible shapes at different times would be a contradiction. Three-dimensionalists deny that shape is a bare intrinsic by relativizing it to times.

Question 2

On three-dimensionalism, the person who existed five years ago is a different entity from the person who exists now.

• T. True
• F. False

Answer: False

This is precisely what three-dimensionalism denies. It holds that the same entity — wholly and entirely — is present at each time of its existence. The person who existed five years ago and the person who exists now are numerically identical: one object persisting through time, not two distinct temporal stages. This is the 'endurance' part of the view: objects endure through time by being wholly present at each moment, rather than persisting by having distinct temporal parts at each moment (which is the four-dimensionalist perdurantist picture).