There are two competing views of time, the endurance view and the perdurance view. According to endurantism, objects are wholly present at every moment in which they exist, while according to perderantism, objects extend across time and only temporal slices of those objects exist at each moment. So temporal objects are either viewed as 4D objects that perder across their temporal dimension or else as 3D objects that endure through different times. Accordingly, all times according to perderantism have the same ontological status across the 4^th dimension, while times according to endurantism are distinguished as past times, present times, and future times. Although the debate between the two views of time is involved, I propose that objects endure rather than perder since there are no compelling arguments to think objects do not endure, while there are compelling arguments to think they do endure. In particular, the arguments against endurantism based on relativity equations, change in properties, a vicious temporal regress, or change in parts are unpersuasive, while the arguments for endurantism based on consciousness, time’s arrow, and temporal becoming are persuasive.

First, I think it is a mistake to think that perdurantism is implied by scientific equations that view time as a dimension on par with spatial dimensions. Those who are science-minded sometimes suggest that we must view time as a four-dimensional extension of spatial objects since relativity equations (which enjoy much empirical support) make no ontological distinction between time and space. However, according to Loux, even those who argue for perdurantism recognize the difficulty of understanding the nature of time merely based on equations that describe things in relation to time. Furthermore, time’s intrinsic character is hardly determined to be on par with the intrinsic nature of space simply because we can describe the physics of the universe as if time is analogous to space. For, relativity equations can still be a valid description of the universe even while time is not analogous to space. Thus, scientific equations involving time do not imply that things perdure.

Even still, how can things change in properties when things that endure through time are numerically identical at every moment? According to endurantism, objects existing at one time are numerically identically to what they were at a previous time. But since objects can change through time, it seems we can have a scenario where qualitatively dissimilar objects are numerically identical (which is a violation of the Indiscernability of Identicales). For example, if I get cancer, then I will have changed from not having cancer to having cancer, and yet on the endurantist view, I must also admit I am the same before and after getting cancer, which violates our most basic intuition about identity. So change might seem to be a problem for endurantists.

However, the problem of change involving transtemporal individuals can be resolved similar to the way Lewis’s problem with transworld individuals is resolved by Plantinga. For just as transworld individuals are proposed to have world-indexed properties, transtemporal individuals can have time-indexed properties. In this way, change in time does not result in numerically identical objects possessing different properties since the objects possess all their time-relative properties at every time. For example, when I get cancer, I would have the property of having cancer in the present even while I have the property of not having cancer in the past. If it is persisted that time-relative properties are counterintuitive to the way we normally describe change, then we can just point out that the time-relative properties do not preclude describing change without time-relative properties as long as we adopt a tensed language to describe the world. So I could say that though I have cancer now, I did not have cancer before. Thus, presently there is no violation of the Indiscernability of Identicales despite my real change over time, and the argument against endurantism based on the change in properties fails.

In addition, I think the argument that tensed properties results in a vicious regress does not undermine endurantism. One might think that we can only understand the meaning of a time-indexed property, such as having cancer in the future, as having cancer at some time past the present time. But since endurantists do not admit non-time-indexed properties, such as having cancer, the property of having cancer must be understood as having cancer presently, in the past, and in the future. But now we see that we have an additional property of having cancer in the future to understand in order to complete our understanding of the original property of having cancer in the future, and thus a vicious infinite regress emerges. And I am inclined to think that this regress sheds serious doubts on the existence of tensed properties or a tensed temporal order. However, what is unclear to me is why endurantism is required to adopt presentism and view tensed language as corresponding to a tensed world. For the tensed language may only need to be invoked as the intuitive shorthand for time-indexed properties, thus subverting the claim that the time-indexed solution to change is counterintuitive to our descriptions of change. So the failure of presentism does not imply the failure of endurantism.

Probably the most serious argument against endurantism is to show that endurantism cannot account for change in parts, though I find this type of argument unsatisfying. According to the Hellerian version, the argument can be understood by considering a pear that is nibbled. If a nibble is taken out of the pear at time A, the pear still exists at a time subsequent to A, say time B, and so the pear at A and B are numerically identical according to endurantism. Also, the object identified as the pear minus the piece that was nibbled is also numerically identical at A and B. But since this object has the same properties at B as the pear does at B, it must be identical with the pear at B, and by transitivity also with the pear at A, which would imply that the pear minus the piece nibbled is identical to the non-nibbled pear. So endurantism seems to lead to a problem when numerically identical things change in their parts.

Although I admit that Geache’s complaint that the argument implies a universal notion of identity when we have none seems somewhat ad hoc and misguided (since I think we do have such a notion), I think Chisholm provides a relatively convincing rebuttal to the argument. He proposes that things can change over time, but they cannot lose any of their parts without losing their identity. In this way, the pear after it is nibbled is not strictly identical to the pear before it was nibbled. This seems plausible since our common talk about identity is normally about a loose identity, such that different, yet very similar things are said to be identical. So though we might talk about the pear at B as being the same as the pear at A, we don’t need to regard them as strictly identical. If the perdurantist contends that we do mean strict identity in the case of persons who change, then it must be shown that persons defined as independent of the changing body parts is incoherent, and I doubt they have succeeded in doing so (of course a thorough investigation of the nature of persons is beyond the scope of this essay). Therefore, objects that change in parts do not need to be understood as identical objects, and so I am not persuaded that endurantism fails to account for change in parts.

Not only are the arguments against endurantism unconvincing, it is difficult to see how perdurantism can account for my consciousness, time’s arrow, and temporal becoming. If I am really a 4D object, why is that I am so conscious of existing at a single moment? More formally, perdurantism implies that a person X is defined as a being that possesses many temporal moments of consciousness, where each conscious moment is fully aware only of a single temporal slice of X. Thus, it seems that our strong sense of self-consciousness would hardly apply to reality if our consciousness turns out to only capture a tiny fraction of our being at any moment. Furthermore, in light of causal theory as well as our memory of the past but not the future, it seems as though there is a metaphysical difference between past times and future times, namely that future times result or come from past times. But on the perdurantist view, all times are identical, so it is a wonder how perdurantism can account for the time’s arrow. Finally, it is with utmost philosophical sincerity that I feel as if the future is becoming the present, but that the past is not becoming the present, and so once again it seems that perdurantism fails to account for the apparent difference between the future and the past.

In conclusion, the arguments against endurantism are unconvincing, and yet the arguments for endurantism provide serious doubts about perdurantism. Perdurantists do not adequately show that endurantism cannot properly account for change, while perdurantism does not seem to be able to account for the evidential difference between the future and the past. And so it seems that tomorrow is another day in which I will be involved, but now I, all of I, must wait until then. However, I make my conclusion tentatively and with deep respect for the philosophical complexities related to understanding time.