Argument from Temporary Intrinsics

Overview and Motivation

The Argument from Temporary Intrinsics is a central argument in analytic metaphysics concerning how objects persist through time and how they can undergo change. It targets endurantism, the view that ordinary objects (such as people, chairs, or planets) are wholly present at each moment of their existence, and contrasts it with perdurantism or four-dimensionalism, according to which objects persist by having different temporal parts at different times.

The argument focuses on temporary intrinsic properties—properties that an object appears to have intrinsically (i.e., not in virtue of its relations to other things) but only for a period of time. Example candidates include being bent, being red, or having a particular shape at a given moment. The problem arises when an object seems to have incompatible intrinsic properties at different times—for instance, a straight rod that later becomes bent, or a person who is first sitting and then standing.

Proponents of the argument claim that endurantists cannot explain how a single, wholly present object can genuinely have such time-varying intrinsic properties without illicitly turning those properties into relational ones (e.g., “being bent-at-t1”) and thereby undermining their status as intrinsic. The argument is most closely associated with David Lewis, who uses it to support perdurantism and four-dimensionalism.

Formal Structure of the Argument

The core idea can be framed using a simple case: a ball that is initially round and later becomes squashed.

1. Change in temporary intrinsic properties
   The ball is round at time t1 and not-round (squashed) at time t2. These properties are naturally described as intrinsic: whether the ball is round does not seem to depend on other objects, only on the ball’s own shape.

2. Endurantism and sameness
   According to endurantism, the very same ball is wholly present at both t1 and t2. Thus, there is one object that is first round and later not-round.

3. The problem of incompatibility
   The ball cannot be both round and not-round at the same time, but it appears it is both round and not-round simpliciter (without qualification) if these properties are truly intrinsic and possessed by exactly the same object.

4. Time-indexing strategy
   To avoid a contradiction, the endurantist naturally says: the ball is round-at-t1 and not-round-at-t2. This suggests that the properties in question are not plain roundness and not-roundness, but rather more complex, time-indexed properties like being-round-at-t1 and being-not-round-at-t2.

5. From time-indexed to relational
   However, time-indexed properties seem relational: being-round-at-t1 is having a relation to a time, t1. If all changing properties are treated in this way, then they are not intrinsic in the strict metaphysical sense; they are partly determined by relations to times.

6. Loss of genuine temporary intrinsics
   If endurantism must reinterpret all apparently changing intrinsic properties as time-indexed relational properties, then the world no longer contains genuine temporary intrinsic properties. It contains only objects bearing relational properties to times, contrary to our ordinary and scientific understanding.

7. Perdurantism’s purported advantage
   By contrast, perdurantism postulates that the ball has different temporal parts at t1 and t2. The temporal part at t1 is intrinsically round; the distinct temporal part at t2 is intrinsically not-round. Each temporal part has its intrinsic properties non-relationally, and the tension between change and intrinsicness is avoided.

From this, proponents infer that the best explanation of the possibility of temporary intrinsic properties and ordinary change is that objects persist by having temporal parts (perdurantism), rather than by being wholly present at each moment (endurantism).

Responses and Debates

The Argument from Temporary Intrinsics has generated extensive discussion and has not been universally accepted as decisive. Responses cluster around three main strategies: revising the notion of intrinsicness, reformulating endurantism, and challenging the need for temporal parts.

1. Redefining or weakening intrinsicness

Some philosophers argue that the notion of an intrinsic property should be loosened or reconceived so that time-indexed properties can still count as intrinsic in a qualified sense. On such views, a property may be intrinsic-at-a-time even if, at a more abstract level, it can be represented as involving a relation to a time.

Others claim that intrinsicness is not a fundamental metaphysical category and that it is acceptable if talk of “intrinsic” properties is partly pragmatic or context-relative. If so, the argument’s pressure on endurantism weakens, because the contrast between “intrinsic” and “relational” may not carry deep metaphysical significance.

2. Sophisticated endurantism

Another family of responses comes from “sophisticated” endurantists, who accept that objects persist by being wholly present at each time but resist the idea that all changing properties must be reduced to relational, time-indexed ones.

Several strategies appear here:

• Adverbialism about property possession: Instead of saying the object has a time-indexed property (being-red-at-t), we might say it is red, at t, in a temporally adverbial manner. On this view, the mode of instantiation is time-relative, but the property of redness itself is not relational. This aims to preserve the intrinsicness of the property while still allowing for change.

• Tensed properties or tensed predication: Some endurantists appeal to the idea that properties can be had tenselessly or tensely, and that the metaphysics of tense can bear some of the explanatory load. The ball is simply formerly round and now not-round, without needing to treat these as relational in a problematic way.

• Relations to times as harmless: Another move is to accept that possession of properties is in some sense time-relative but argue that relations to times are metaphysically benign. On this approach, the fact that an object’s having a property involves a time does not threaten the property’s being intrinsic “enough” for explanatory purposes.

Sophisticated endurantists contend that such refinements allow them to keep both temporary intrinsics and wholly present objects, and thus to resist the move to perdurantism.

3. Questioning the force of the argument

Critics also challenge specific premises of the argument:

• Some argue that it is not clear that perdurantism preserves intrinsicness any better than endurantism; after all, the temporal parts of an object might themselves be understood only in relation to a larger spacetime structure, raising similar relational concerns.

• Others question whether our intuitions about intrinsicness are reliable enough to constrain theories of persistence so strongly. They maintain that the explanatory benefits of endurantism (e.g., aligning with ordinary talk about “the same” enduring object) may justify revising or complicating the notion of intrinsic properties.

• There is also debate on whether the apparent theoretical cost of losing strict temporary intrinsics is significant. Some philosophers contend that what matters for science and ordinary life is the pattern of change over time, not the exact metaphysical classification of properties as intrinsic or relational.

In light of these responses, the Argument from Temporary Intrinsics is generally regarded as a powerful but controversial consideration in favor of perdurantism and four-dimensionalism. It plays a central role in contemporary discussions of persistence, change, and the nature of properties, but most commentators agree that it does not conclusively settle the debate between endurantists and perdurantists.