In this essay, I will be showing that material objects persist by perduring. I will be using persistence in the sense of:
A material object persists if somehow or other, it exists at different times and undergoes changes in its extrinsic properties (Van Inwagen and Zimmerman, 1998)
I will first look at some preliminaries when looking at perdurantism. I will then show that the Perdurantist theory is the best theory for explaining how objects persist through change. I will prove this by showing that Perdurance escapes the problem of temporary intrinsics, a central notion that discusses persistence despite a change in intrinsic properties. I will also put forward the argument that perdurantism is the best-fitting theory for explaining change through time through a reductio ad absurdum. I will then look at Perdurance in light of Wiggins and Van Inwagen's objections and show that neither of the objections defeats the theory and perdurance best explains the persistence of material objects.
Preliminaries
I will introduce some key issues within the preliminaries which I will be using in my argument to show that objects persist by perduring.
The Statue and the Clay
This is described as a puzzle of the material constitution; it will be used to explain and evaluate the perdurantist view of persistence. In this example, a sculptor takes a lump of clay (lump) and makes it into the statue of the biblical figure Goliath. At noon (t1) the clay is a lump and at midnight (t2) it is Goliath. (Garrett, 2006)
The Problem of Temporary Intrinsics and Leibniz's law
The problem of temporary intrinsics highlights the issues with puzzles such as that of the Statue and the Clay when it comes to persistence. Leibniz's Law (also known as the indiscernibility of identicals) states that:
Necessarily, if, for every property F, object x has F if and only if object y has F, then x is identical to y (Tallant, 2017, pp.144)
This means that for objects to be identical then they must share all the same properties. The problem of temporary intrinsics highlights that persisting things change their intrinsic properties. This in combination with Leibniz's Law means that explaining persistence becomes difficult. Lump and the Goliath do not share all the same properties, one is round and smooth, and the other is not. It is not possible for the clay to have the properties of being both round, and Goliath-shaped. Therefore, under Leibniz's Law, they cannot be identical or numerically identical. From this, we can deduce that lump new Goliath. Our intuition tells us that the lump persisted through to its existence as Goliath. Therefore, an account is needed in order to explain how the object from t1-t2 persists (Ney, 2014, pp.98)
Perdurantism
Perdurantists take the view that material objects persist in their having temporal parts at different times. In order to understand this better, perdurantists are four-dimensionality, meaning that they view material objects as four-dimensional (spread out in time just as they are spread out in space). So just as a material object has different parts at different places, it also has different parts at different times (Ney, 2014). So, to take the example of the statue and the clay, a perdurantist would not see the statue as being wholly present at all times, i.e., wholly present while it is a lump or wholly present while it is the statue, instead, the object is spread out across both time and space, so when we see the lump at noon, we are just seeing a part of the object at one time. (Garrett, 2006)
Perdurantism can be further explained through its other name ‘the worm view’. This is as perdurantism explains the persistence of objects through space-time worms. Space-time worms are spread out in all four dimensions. Each material object has its own space-time worm for which different segments have different properties (Loux, 2006, pp.245). So, for instance, the clay will have its own space-time worm and the midnight version of the clay (when it is shaped like Goliath) is merely just one part of the worm and is a completely different part of the worm from that of the clay when it is shaped in a ball. The space-time worm can help the theory in explaining how a material object has persisted through change because the worm is the whole collection of all the temporal parts and therefore shows the link of how an object has persisted.
The crux of the argument for how objects persist is that they persist by virtue of them having different temporal parts. One important thing to note is that the different temporal parts of the clay are not numerically identical to one another, instead, perdurantists use the notion of ‘partly present’ (Ney, 2014). But ultimately it is the fact that the material object has different parts or stages at different times that means it persists. (Loux and Zimmerman, 2003, pp.318) So:
The clay persists by perduring iff:
The clay has a part at t1 (at noon when it is ball-shaped), and
The clay has a part at a distinct time t2 (at midnight when it is shaped like Goliath) (Van Inwagen and Zimmerman, 1998)
Perdurantism can be contrasted to its main opponent, endurantism. Endurantism proposes that objects persist by enduring. Under the endurantist view each material object is always wholly present and is three-dimensional (not extended in time) (Garrett, 2006). The clay is, at noon (t1), identical to itself at midnight (t2). (Tallant, 2017)
Arguments in favor of Perdurantism
In this section, I will first show how perdurantism is favorable in its avoidance of the problem of temporary intrinsics. I will then go on to say how this is beneficial to the theory in explaining how objects persist.
Perdurantism escapes the problem of temporary intrinsics as it is able to account for the changes in parts of a material object without claiming that the different stages of the object are numerically identical. (Ney, 2014) To use the example of the statue and the clay, the perdurantist would not claim that the clay at t1 is identical to the clay at t2, but rather that they are each different segments of the same space-time worm for the clay. The different segments have different properties, and since each of the segments is different, there is no violation of the indiscernibility of identicals. Since t1 and t2 are two stages of the single interconnected worm, we then can also account for the persistence of the clay from t1 to t2. (Loux, 2006, pp.245)
Perdurantism is a favorable view as it allows for a change in a material object and the space-time worm provides a link for the persistence of the object. In addition to this, it makes sense for material objects to be spread across in time as well as space, the lump and the statue have very distinct properties so perdurantism is able to separate the changes but maintain that they are still a part of the same space-time worm (Loux, 2006, pp.245)
Perdurantism also is good at explaining object persistence because, as David Lewis explains (as cited in Eddon, 2010, pp. 2) through a reductio ad absurdum of endurantism perdurantism is the only logical conclusion for how objects persist through time.
The results of Endurantism in contrast to perdurantism are absurd and show that clearly, perdurantism is the best theory.
Endurantism explains that objects are wholly present at all times and this means it struggles with the problem of temporary intrinsics. In the case of the statue and the clay, the lump and the statue cannot be numerically identical as their properties are different. And because of Leibniz's law, the endurantist will be forced to come up with a solution to explain the persistence through change such as stating that the statue and the clay are a case in which two objects are wholly located at the same place and at the same time. They can come up with other ‘solutions’, but, in short, there is not a solution that the endurantist can come up with that adequately explains how the lump has persisted through to it becoming the statute which avoids the problem of temporary intrinsics. This, therefore, means that Endurantism leaves us with an inadequate conclusion. This is also especially damning as persistence, by definition, entails change (Ney, 2014). This is a reductio ad absurdum as the conclusion we are left with by being an endurantist is absurd, and because of this, we should therefore, embrace perdurantism as it is the best theory for explaining persistence through change.
Arguments against Perdurantism
I will now evaluate the two main objections to Perdurantism that I have identified. I will first look at one of Wiggins' objections and then evaluate it, before proceeding to one of Van Inwagen's.
As Ney explains: David Wiggins's argument is that four-dimensional is confusing. In his paper, he explains that four-dimensional are not an answer to how objects persist over time (Ney, 2014). His main difficulty is in understanding the notion of a temporal part of a material object. To expand, in material objects such as phones we recognise that they have physical boundaries and when asking about their location at one time we ask where it is wholly located. From this Wiggins argues that if you are able to examine an object and identify its boundaries at one time then the object cannot be extended in time, for then it would have more parts and a boundary that you cannot see. (Ney, 2014)
Prima facie this may appear to be true, however, it is my contention that the premises do not show that material objects cannot have temporal parts. Wiggins's view is based on the intuition that it only makes sense for an object to be wholly present at each time. I believe that this can be disputed, it indeed may be that you can reach the physical boundaries of an object at one time, but that does not bind time to the object in the way that Wiggins envisages (Ney, 2014). To use an example, even though at 9 pm when I see my friend Jones' phone and inspect that it has a screen of approximately 6 inches, I don't think that identifying its boundaries and tying the identification to the time of 9 pm means that it cannot have temporal parts, at 10 pm it can have the same boundaries, and 11 pm and so on. Therefore, it can still be the case that it is an object extended in time as well as space.
To then say that if it was extended in time it would entail it having more parts and a boundary that you cannot see, again is not valid. Firstly, an object having a boundary that you cannot see does not mean that it doesn't exist, having a time boundary that you cannot see makes logical sense, and there are lots of things within philosophy that cannot be seen but yet are still believed in. Therefore, I argue that Wiggins is making too big of a leap to his conclusion.
Wiggins' attack on four-dimensionalism is not valid. He rests on the assumption that a material object being four-dimensional does not make sense. I disagree. To use an example: we can identify a human's physical boundaries at one time however, I would argue that we tend to think of humans as spread out across time and that it is not fair to say that all a human is there at one time, how can all of Smith be there at 10 pm when he has lived 30 years? (Ney,2014) (Loux and Zimmerman, 2003) Although this example does not apply to a material object, I believe that the same concept applies to material objects and it shows that Wiggins' view that it does not make sense for an object to have temporal parts isn't fair. I then, therefore, believe that whilst Wiggins believes that four-dimensional is mistaken in that it denies that an object is wholly present, he is making an unfair argument, and not making an argument that points to the conclusion that a material object cannot have temporal parts. If Wiggins is to make a valid argument explaining how material objects cannot have temporal parts, he needs to add more premises to his argument for it to be sound.
Philosophers like Van Inwagen and Haslanger put forward another argument against perdurantism attacking its answer to the problem of persistence. They argue that perdurantism is not a theory that sufficiently answers how objects persist. Instead, perdurantism merely overlooks the whole issue of persistence over time, for, in such views, an object is not really persisting over time if there is not one numerically same thing that is present at one time and then present at a later time. (Ney,2014)
The argument that perdurantism does not sufficiently explain the issue of persistence is contingent upon one's view of what it is for an object to persist. When we initially think of persistence, we can tend to think of an object retaining its numerical identity, but in cases such as the statue and the clay our intuitions are challenged because they (the statue and lump) cannot be identical. Perdurance has many virtues at the cost of the theory perhaps not aligning with our pre-philosophical conception of ‘persisting’ however, we get an account for how an object can change through time and remain part of the same object.
Van Inwagen and Haslanger's criticisms are taken from the viewpoint that persistence requires strict numerical identity, however, I believe that like Ted Sider (as cited in Loux and Zimmerman, 2003, pp. 327) the goal is to provide ‘underliers’ or ‘quasi-truthmakers’ for our original assumptions rather than ‘interpretations’ of the persistence of an object. Using this notion, we are left with Perdurantism, if you are only after an explanation for a theory of persistence that means objects keep their numerical identity, then perdurantism will not be the theory you choose, but in virtue of its benefits for allowing for change and fitting quite well with our understanding of time, I think it is best to overlook the fact that when you see an object at one time you are only seeing part of it, for the fact that perdurantism has many virtues that fit with our logical views like how object do change over time.
Conclusion
In this essay, I have shown that objects persist by perduring as it is the theory that has the most virtues. Perdurantism escapes the problem of temporary intrinsics, it allows for a change in an object and although two material objects such as the statue and the clay are only parts of the same thing, it does not encounter issues such as the indiscernibility of identicals. So, overall, even though it faces objections such as those proposed by Van Inwagen, Haslanger, and Wiggins, perdurantism is the best explanation for how objects persist, and therefore, objects persist by perduring.