Is there a Contradiction in supposing that Ordinary Objects both Persist through Time and Change over Time?
Consider a wooden chair, in a sitting room. It is birch, with curved panelling and spindled legs. But say you leave the room for ten minutes and the chair cracks; is the chair the same when I return, or is it a new chair? The focus of this essay will be whether it is metaphysically possible for an object to persist through time whilst changing its intrinsic properties. Three – dimensionalism, or Endurantism/Adverbalism has often been referred to as the ‘common sense’ version of persistence through time. Conversely, four-dimensionalists claim that their version of persistence through time is greater connected to the physical world through the use of temporal parts as well as spatial parts (Stanford, 2015). Many contradictions arise in 3D-ism and 4-Dism when change over time is considered for an ordinary object and its identity, especially considering the intrinsic properties and configuration of the object. This essay will discuss the consideration of the identity of the object and its intrinsic properties with the overall consideration that there seems to be no contradiction between persistence over time and change over time.
A fundamental question to answer in this essay is the nature of persistence through time. What is it for an object to maintain its identity through time? Is a chair the same chair now as it will be next year? For simplicity of discussion, this essay will focus on one single object for analysis, rather than a group of objects. The interpretation of ‘ordinary objects’ will be taken as objects that are extended in space (and time), not abstract objects such as mathematics (Lewis, 1986). Furthermore, this essay will discuss the actual world, not considering other possible worlds that may experience change in a different way. It is important in this essay to distinguish identity at a particular time to identity across time. To do this one must distinguish the different types of identity claims, diachronic and synchronic. Synchronic identity claims assert that an object ‘a’ that is assumed to exist at one time is identical to an object ‘b’ that is assumed to exist at that same time, i.e. Ian Mckellen can only be Ian Mckellan now. However, Diachronic Identity claims assert that an entity ‘a’ that is assumed to exist at one time is identical to an entity ‘b’ that is assumed to exist at a different time (Lowe, 2006). David Lewis states in his paper ‘The Plurality of Worlds’ that “something persists iff, somehow or other, it exists at various times.” (Lewis, 1986, p202) Furthermore, Lewis states that persistence is a matter of identity, claiming: “[a] platitude that cannot credibly be denied: what matters is identity between myself, existing now, and myself, still existing in the future.” (Lewis, 1986, p203) Therefore, to ‘persist’ will be interpreted as existing over time, and change will be a change of intrinsic properties over time. This essay will describe intrinsic properties as shape, mass and colour, amongst others. This essay will subsequently detail the potential conflicts of an object’s persistence through time, and its rebuttals in in the form of 3D-ism and 4D-ism in various forms.
It is first necessary to understand the nature, or identity, of the object itself. There are commonly ascribed two kinds of identity; numerical and quantitative. Numerical Identity is defined as the relation that everything bears to itself and nothing else, i.e. A is numerically identical to B if they are actually the same object, not two objects A and B. Conversely, Qualitative Identity is defined as two objects being identical if they share all of their same intrinsic properties (Stanford, 2016). Intrinsic properties are defined as properties that are inherent to the identity of the object, for example its shape, colour size (Lewis, 1986). There is much debate in the philosophical world as to what is defined as an intrinsic property, however for this essay the opinion of David Lewis will be considered. What is not intrinsic to an object is its relation to other objects and its position in space. These are called relational properties like ‘is greater than’ or ‘is close to’. For example, one may have two apples that are qualitatively alike in colour, shape, size etc, yet the fact that one is three feet away from the other is not relevant to their identities (Hales, Johnson, 2003).
Numerical identity is important when defining Leibniz’s Law. This law states that: 1) two things that share all their properties with each other, are identical (the identity of indiscernibles), and 2) two things that are identical share all their properties with each other, both intrinsic and relational (the indiscernibility of identicals) (Lowe, 2002). To suppose two things indiscernible is to suppose the same thing under two names. This, in more algebraic terms, can be simplified to ‘For any x and y, if x is identical to y, then x and y have all the same properties’ (Stanford, 2015). In the natural world, this rule states that no object can be exactly alike to another object. However, this brings about a problem when one takes into account that persistence through time often amounts to intrinsic change, for example a banana changing from a seed, to a black rotten banana. One might say that your friend is the same friend that they were ten minutes ago, but what about when they were seven? These ideas seem to make sense according to our ‘common sense’ view of the world, but the definition becomes less clear when one takes into account change of the object. How can an object that persists through a change of intrinsic properties be the same identical object before and after this change? Many would affirm that this is the case. Irving Copi defines identity through time by the contrast of these statements. These statement on first glance seem to be both correct, but on further inspection many issues emerge. The first statement is ‘if a changing thing really changes, there can’t literally be one and the same thing before and after the change’. However, the second point is ‘if there isn’t literally one and the same thing before and after the change, then nothing has really undergone any change.’ (Stanford, 2015)This problem is most often named ‘The problem of temporary intrinsics’, and is resolution is essential to resolving the contradiction between an object persisting over time, and changing over time.
An initial theory to discuss is presentism. According to Presentists such as Trenton Merricks, only things that exist without argument are things that exist in the present i.e. there is no such thing as change or time, as only the present may be considered. An apple at a t1 may be round, but at t2 may be a cube. The only factors that can be true according to presentists are ones that exist in the present, who rely on ‘possible worlds’ to substantiate talk of past and future. This could be seen as an easy solution as a confirmation that there is no contradiction, since only the present exists (Merricks, 1995). However, since this discussion is taking place in the actual worlds, one cannot reply on a presentist argument for possible world. For this reason, it seems unlikely to reach a conclusion to the possible contradiction to persistence and change over time.
A school of thought that considers objects position in space and time is Three dimensionalism. Three dimensionalism is an umbrella term to describe both Endurantism, here represented by the views of E.J. Lowe, and Haslanger’s adverbialism. According to Lowe, objects persist by existing at more than one time, without having temporal. However, this seems to require greater explanation if the aim is to not contradict Leibniz’s Law. Both Endurantism and Adverbialism are united in the rejection of temporal parts, which will be discussed later on in this essay. The issue that endurantists often face is how to explain how ordinary objects can change their intrinsic properties whilst still maintaining the identity of the object. Endurantists consider it an obvious fallacy to deny Leibniz’s Law, and so demonstrate change over time with the use of temporal object relations. Lowe claims that the object’s intrinsic properties are a rearrangement of the fundamental particles that make up the object. This in his opinion substantiates the claim that objects can change their shape (i.e. change their intrinsic properties) because the fundamental particles rearrange themselves in such a way that a change is evident in that time relative of the time before when they were in a different state. This idea has some perceived merit as it could be seen to represent objects on an atomic level, therefore bringing Endurantism more in line with modern day physics. However, Lewis states that an object’s shape is not a relation between the object and a point in time, but the particular relation of its fundamental particles at a certain time. Intrinsic properties are defined by Lewis as ‘properties of an object which it has independently of anything else’; so, the fundamental particles cannot be intrinsic to the object as they are relative to the time in which they exist. Without intrinsic properties, there is no object; since all is relative to the time, there is no possibility of change of the single object, and the original problem of temporary intrinsics is only satisfied for as long as the relation is there. It is evident that an object lacking in intrinsic properties could not go through intrinsic change. Adverbialism uses a similar approach, yet ascribes rather than an object’s state being divided into temporal parts, one should consider the way in which the object in question has the property. For example, if one returns to the chair example; the chair has the property of being unbroken in a t1 way, and does not have the same property in a t2 way. However, this seems to fall into a similar issue; for under Lewis’s definition of identity, the intrinsic properties of the chair cannot be dependent on the time in which the chair exists. This view is echoed by Steven Hales, who claims that the ideas of endurantism do not allow for special relativity (Hales, Johnson, 2003). The temporal parts solution demonstrated in 4D-ism does not seem to indicate similar issues, but is often criticised by Butterfield, who indicates the Perdurantists inability to account for those objects that lack spatial parts but have temporal parts.
We will now return to the chair as the demonstration of Perdurantism; When the chair is present in the room, the chair is in state A (i.e., whole). Ten minutes later, the chair is in state B (cracked). The Perdurantists would qualify this statement as true, claiming that at state A, the chair had temporal part t1, whilst at state B, the chair had a temporal part t2. Temporal parts form the backbone of the perdurantist argument; that objects are extended in time as well as in space (Heller, M. 1984). Perdurantism has often been described as more relevant to the actual world, following the development of Einstein’s general relativity in the 20th Century, echoed by S. Hales (Hales, Johnson, 2003). This explanation would allow the chair to persist through time i.e. remain the same chair despite a change to its intrinsic properties (i.e. change over time). In order to fully understand perdurantism it is necessary to discuss temporal parts, for which the example of the cracked chair will be used. According to Lowe, the ‘statement ascribed the intrinsic quality of Fness [in this case, cracked] to a temporal part of A [the chair], rather than to a [the chair] as a whole’ (Lowe, 2006). If one describes the chair, cracked, at time t2, then according to the perdurantists, the chair is referred to as the temporal part of the existence of the chair that exists at time t2, and is in a certain state, cracked. Temporal parts are most often described as ‘time slices’ that themselves do not persist through time but are related to the certain intrinsic and relational properties of the object at that time. This theory would indicate that there was no contradiction between an ordinary object persisting through time and changing over time, as the chair’s change in intrinsic properties could be explained as individual temporal parts of the same object. This theory has often been hailed as the most logical solution to the famous ‘Ship of Theseus’ argument (Lowe, 2002). A similar version of perdurantism is called Stage Theory, advocated by Theodore Sider (Sider, 2001). Whilst Perdurantists would claim that what you see in the present is a section or slice of time (a temporal part), a stage theorist would content that objects are temporal parts. So an object that exists at time t is equivalent to the stage which exists at t, meaning an object has as many parts of its existence as there are temporal parts through time. Both perdurantism and stage theory seem to solve the problem of temporary intrinsics and does not contradict Leibniz’s Law. However, many have argued against perdurantism as falling into a relative issue concerning identity, and therefore persistence through time such as Merricks (Merricks, 1995). Because Perdurantists rely on the relevant temporal part to account for intrinsic change, this suggests the property instantiation is therefore relative, meaning that the intrinsic property is relative to the time. This does not seem to consider the continuation, or change of the object over time, implying a contradiction.
It seems evident from the arguments proposed, that there is no contradiction between an ordinary object persisting through time and changing over time. This is demonstrated by the arguments shown through four -dimensionalism, specifically stage theory, due to the addition of temporal parts. Firstly, the stages of time demonstrated in stage theory allow for the object to not only persist through time as the same object through the use of temporal parts theory (Magidor, 2015). Perdurantism and Stage theory seem to show issues whilst accounting for change, whilst endurantism and adverbialism do not hold identity as the reason for the existence of an ordinary object, and so fail to qualify the identity of the object at all. In his book Frege, Dummett remarks that “an observation can determine only how [an] object is at some one time” (Dummett, 1981), implying that perhaps an object exists only in the sense that one observes the object. The object changes because we in a previous state have observed the change. Perhaps another solution is to totally separate change from the passing of time as Aristotle argues, as changes happen at different rates and time is a continuous process (Stanford, 2015). Or, more controversially, argue that time does not exist as McTaggart argued in ‘The Unreality of Time’ argued, implying that an object cannot persist at all (McTaggart, 1908).
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