structure for 'Objects'    |     alphabetical list of themes    |     unexpand these ideas

9. Objects / E. Objects over Time / 5. Temporal Parts

[things have parts in time, as they do in space]

21 ideas
Temporal parts is a crazy doctrine, because it entails constantly creating stuff ex nihilo [Thomson, by Koslicki]
     Full Idea: Thomson famously objects that the doctrine of temporal parts is 'a crazy metaphysic - obviously false', since it entails that material objects are constantly being generated ex nihilo (or, at least, the stuff of which they are composed is).
     From: report of Judith (Jarvis) Thomson (Parthood and Identity across Time [1983], p.210) by Kathrin Koslicki - The Structure of Objects 2.2
     A reaction: The related objections are to ask what the temporal 'width' of a part is, and whether the joins are visible.
How can point-duration slices of people have beliefs or desires? [Thomson]
     Full Idea: Can one really think that point-duration temporal slices of bodies believe things or want things?
     From: Judith (Jarvis) Thomson (People and Their Bodies [1997], p.211), quoted by Katherine Hawley - How Things Persist 2.9 n21
     A reaction: There is a problem with a slice doing anything long-term. The bottom line is that things are said to 'endure', but that is precisely what time-slices are unable to do. Hawley rejects this idea.
You can't have the concept of a 'stage' if you lack the concept of an object [Ayers]
     Full Idea: It would be impossible for anyone to have the concept of a stage who did not already possess the concept of a physical object.
     From: M.R. Ayers (Individuals without Sortals [1974], 'Concl')
Temporal 'parts' cannot be separated or rearranged [Ayers]
     Full Idea: Temporally extended 'parts' are still mysteriously inseparable and not subject to rearrangement: a thing cannot be cut temporally in half.
     From: M.R. Ayers (Individuals without Sortals [1974], 'Prob')
     A reaction: A nice warning to anyone accepting a glib analogy between spatial parts and temporal parts.
Stage theorists accept four-dimensionalism, but call each stage a whole object [Noonan]
     Full Idea: Stage theorists, accepting the ontology of perdurance, modify the semantics to secure the result that fatness is a property of a cat. Every temporal part of a cat (such as Tabby-on-Monday) is a cat. …(but they pay a price over the counting of cats).
     From: Harold Noonan (Identity [2009], §5)
     A reaction: [Noonan cites Hawley and Sider for this view. The final parenthesis compresses Noonan] I would take the difficulty over counting cats to be fatal to the view. It produces too many cats, or too few, or denies counting altogether.
Three-dimensionalist can accept temporal parts, as things enduring only for an instant [Fine,K]
     Full Idea: Even if one is a three-dimensionalist, one might affirm the existence of temporal parts, on the grounds that everything merely endures for an instant.
     From: Kit Fine (In Defence of Three-Dimensionalism [2006], p.2)
     A reaction: This seems an important point, as belief in temporal parts is normally equated with four-dimensionalism (see Idea 12296). The idea is that a thing might be 'entirely present' at each instant, only to be replaced by a simulacrum.
Even a three-dimensionalist might identify temporal parts, in their thinking [Fine,K]
     Full Idea: Even the three-dimensionalist might be willing to admit that material things have temporal parts. For given any persisting object, he might suppose that 'in thought' we could mark out its temporal segments or parts.
     From: Kit Fine (Guide to Ground [2012], 1.02)
     A reaction: A big problem with temporal parts is how thin they are. Hawley says they are as fine-grained as time itself, but what if time has no grain? How thin can you 'think' a temporal part to be? Fine says imagined parts are grounded in things, not vice versa.
Temporal parts are instantaneous [Sider]
     Full Idea: Unless otherwise noted, I will think of temporal parts as being instantaneous.
     From: Theodore Sider (Four Dimensionalism [2001], 3.2)
     A reaction: This comes up against all the Augustinian worries about the intrinsic nature of time. How many temporal parts does a typical object possess? Is a third temporal part always to be found between any two of them? How do they 'connect'?
Temporal parts exist, but are not prior building blocks for objects [Sider]
     Full Idea: My four-dimensionalism implies the existence of temporal parts, but not that those parts are more fundamental, nor that the object is 'constructed' from its parts, nor that identity over time is reducible to parts.
     From: Theodore Sider (Four Dimensionalism [2001], 3.2)
     A reaction: That's a rather negative account of temporal parts, which makes you ask what their positive role could be. Do they contribute anything to our understanding of a temporally extended object?
How can an instantaneous stage believe anything, if beliefs take time? [Sider]
     Full Idea: How can an instantaneous stage believe anything? Beliefs take time.
     From: Theodore Sider (Four Dimensionalism [2001], 5.8)
     A reaction: Sider's four-dimensionalist answer is that the belief is embodied in the earlier counterparts, making belief a 'highly relational property'. I am not impressed by this answer to the very nice problem which he has raised. It's a problem for 3D, too.
Four-dimensionalism says temporal parts are caused (through laws of motion) by previous temporal parts [Sider]
     Full Idea: The sensible four-dimensionalist will claim that current temporal parts are caused to exist by previous temporal parts. The laws that govern this process are none other than the familiar laws of motion.
     From: Theodore Sider (Four Dimensionalism [2001], 6.3)
     A reaction: I keep struggling with the instantaneous natural of temporal parts, and now I find that they have to do the job of being causal relata. When do they do their job? They've gone home before they've finished clocking in. Continuance requires motion?
The stages of Stage Theory seem too thin to populate the world, or to be referred to [Hawley]
     Full Idea: A third worry for Stage Theory is that the momentary stages themselves are just too thin to populate the world, and too thin to be the objects of reference.
     From: Katherine Hawley (How Things Persist [2001], 2.3)
     A reaction: Her three objections to her own theory add up to sufficient to refute it, in my view, though a large chunk of her book is spent trying to refute the objections.
Stage Theory seems to miss out the link between stages of the same object [Hawley]
     Full Idea: The first worry for Stage Theory is that many present stages are bananas, and many stages tomorrow are bananas, but this seems to omit the important fact that some of those stages are intimately linked, that certain stages are the same banana.
     From: Katherine Hawley (How Things Persist [2001], 2.3)
     A reaction: Hawley has a theory to do with external relations, which I didn't find very persuasive. Just to say stages have a 'relation' seems too abstract. Stages of disparate things can also have 'relations', but presumably the wrong sort.
Stage Theory says every stage is a distinct object, which gives too many objects [Hawley]
     Full Idea: The second worry for Stage Theory is that there are far too many bananas in the world on this account.
     From: Katherine Hawley (How Things Persist [2001], 2.3)
     A reaction: The point is that each (instantaneous) stage is considered to be a whole banana (as opposed to one sum of all the stages of the banana, in the Perdurance view). A pretty serious problem, which she tries to deal with.
Stages must be as fine-grained in length as change itself, so any change is a new stage [Hawley]
     Full Idea: To account for change, stages and temporal parts must be as fine-grained as change: a material thing must have as many stages or parts as it is in incompatible states during its lifetime.
     From: Katherine Hawley (How Things Persist [2001], 2.4)
     A reaction: There seems to be a dilemma for stages here, of being so fat that they are divisible and change, or so thin that they barely exist. Lose-lose, I'd say.
An isolated stage can't be a banana (which involves suitable relations to other stages) [Hawley]
     Full Idea: A single isolated stage could not be a banana, because in order to be a banana a stage must be suitably related to other stages with appropriate properties.
     From: Katherine Hawley (How Things Persist [2001], 3.4.1)
     A reaction: This seems at odds with the claim that each stage is the whole thing (rather than the long temporal 'worm' of perdurance theory). Isolated stages are instantaneous, so can't be anything, really. Her 'relations' seem hand-wavy to me. Connections?
Stages of one thing are related by extrinsic counterfactual and causal relations [Hawley]
     Full Idea: I claim that there are relations between the distinct stages of a persisting object which are not determined by the intrinsic properties of those stages. …The later stages depend, counterfactually and causally, upon the earlier stages.
     From: Katherine Hawley (How Things Persist [2001], 3.5)
     A reaction: This is the heart of her theory. How can there be a causal link between two stages which is not the result of intrinsic properties of the stages? This begins to sound like Malebranche's Occasionalism.
We must explain change amongst 'momentary entities', or else the world is inexplicable [Haslanger]
     Full Idea: If the world of time-slices is to be explicable, then it must be possible to provide explanations of change understood as a continual generation and destruction of these 'momentary entities'.
     From: Sally Haslanger (Persistence, Change and Explanation [1989], 7)
     A reaction: While fans of time-slices can offer some sort of explanation, in the process of explaining a 'worm', there don't seem to be the sort of causal chains that we traditionally rely on. Maybe there are no explanations of anything?
If the things which exist prior to now are totally distinct, they need not have existed [Haslanger]
     Full Idea: How is the case in which A exists prior to B, but is distinct from B, different (especially from B's point of view) from the case in which nothing exists prior to B?
     From: Sally Haslanger (Persistence, Change and Explanation [1989], 7)
     A reaction: I sympathise with her view, but this isn't persuasive. For A substitute 'Sally's mother' and for B substitute 'Sally'. A 4D-ist could bite the bullet and say that, indeed, previous parts of my 'worm' need not have existed.
You believe you existed last year, but your segment doesn't, so they have different beliefs [Merricks]
     Full Idea: Your belief that you existed in the year 2000 is true; the belief of a segment of you that it then existed is false; so, by the indiscernibility of identicals, there must be two beliefs here.
     From: Trenton Merricks (Truth and Ontology [2007], 6.IV n20)
     A reaction: Merricks may be begging the question here. But in the segment view there is nothing which can truly believe it existed a year ago, so therefore nothing here has continued existence, so the segments cannot be part of a single thing.
Perdurantism imposes no order on temporal parts, so sequences of events are contingent [Mumford/Anjum]
     Full Idea: Perdurantism tends to go with the view that it is essentially contingent what follows what, because it is no part of the essence of temporal parts that they be arranged in any particular order.
     From: S.Mumford/R.Lill Anjum (Getting Causes from Powers [2011], 5.5 1)
     A reaction: Nice. There is nothing illogical, then, in elderly me intervening between childish me and middle-aged me. Essentialists like me must clearly oppose this view. Elderly me must be preceded and caused by middle-aged me.