Proceedings of the Kent State University May 4th Philosophy Graduate Student Conference The Real Distinction Between Perdurance and Endurance Jeremy Buxbaum University of Colorado at Boulder Abstract Theories of persistence fall into two general categories. Perdurance theories hold that an object persists in virtue of having temporal parts, and that no one temporal part of an object is present at more than one time. Endurance theories hold that an object persists in virtue of being wholly present at more than one time. The debate then, seems to center on whether or not persisting objects are wholly present at more than one time. But what is it for an object to be wholly present? Persistence theorists on both sides of the debate have claimed to not understand what exactly this feature of objects is. Ned Markosian says of ‘wholly present’, “This expression is crucial to [three- dimensionalism], but many find it somewhat mysterious.” Indeed there is something peculiar about the notion, but almost all of the literature on persistence makes use of the notion of an object being wholly present. In what follows, I want to look at three proposed definitions of ‘wholly present’, offered by Trenton Merricks, Ted Sider, and Ned Markosian, respectively. I will argue that all three are unsatisfactory because they fail in distinguishing perdurance from endurance, commit us to controversial doctrines, or fail in being informative. I will then propose a fourth definition of ‘wholly present’, one which I think adequately distinguishes between perdurance and endurance, and which is informative. This proposal will ultimately rely on a distinction between ‘existing’ and ‘existing at a time’. Theories of persistence fall into two general categories. whether or not persisting objects are wholly present at more Perdurance theories hold that an object persists in virtue of than one time. having temporal parts, and that no one temporal part of an But what is it for an object to be wholly present? object is present at more than one time. Endurance theories Persistence theorists on both sides of the debate have claimed to hold that an object persists in virtue of being wholly present at not understand what exactly this feature of objects is. E.J. Lowe more than one time.1 The debate then, seems to center on expresses concern about this notion: “I can find no useful application for the notion of such a thing being ‘wholly present’ 1 Notice that within these general groups the persistence theorist is left with at a time, any more than I can for that of its being ‘partially non- the task of explaining how it is that an object has temporal parts or how it is present’ (in the sense, of course, of having earlier or later that an object is wholly present at more than one time. This results in the standard internecine debates. But, one can stake out a position in the more general debate without necessarily entering into the in-house debates about which particular perdurance or endurance theory is correct. 1 Jeremy Buxbaum parts).”2 In discussing the notion of ‘wholly present’ Ted Sider the doctrine of presentism.” 6 Indeed a number of theorists on says, “ This is an unfortunate way to formulate three- both sides of the debate have offered definitions. But none of dimensionalism. What is it for an object x to be ‘wholly present’ these attempts seem satisfactory because they fail in at time t?”3 He goes on to say, “ A three-dimensionalist might distinguishing perdurance from endurance, commit us to give up on the attempt to give a mereological account of an controversial doctrines, or fail in being informative. object’s being wholly present and understand the notion in In what follows, I want to look at three proposed some other way. One wonders whether ‘wholly present’ would definitions of ‘wholly present’, offered by Trenton Merricks, then be an apt term.”4 Ned Markosian says of ‘wholly present’, Ted Sider, and Ned Markosian, respectively. I will argue that “ This expression is crucial to [three-dimensionalism], but many all three are unsatisfactory. I will then propose a fourth find it somewhat mysterious.”5 Indeed there is something definition of ‘wholly present’, one which I think adequately peculiar about the notion. None the less, almost all of the distinguishes between perdurance and endurance, and which is literature on persistence makes use of the notion of an object informative. This proposal will ultimately rely on a distinction being wholly present, either by denying that objects are ever between ‘existing’ and ‘existing at a time’. wholly present (perdurance) or affirming that they are (endurance). I. Three Failed Attempts At Defining ‘Wholly Present’ This leaves us in an uncomfortable situation. Either we must give a perspicuous definition of ‘wholly present’, or we Trenton Merricks finds the standard, negative definition must deny that the debate between perdurance theories and of ‘wholly present’ unsatisfactory. The standard account of endurance theories turns on this notion. To complicate matters, being ‘wholly present’ can be taken to amount to ‘not having there is some pressure, particularly from Trenton Merricks, to temporal parts’. Merricks says, “ Enduring, it would seem, just give more than a negative definition, such as ‘not consisting of is lasting over time, but not by way of temporal parts. I think an temporal parts’. That is to say, there is some contention over account of endurance can be provided that says more than that what would count as a perspicuous definition of ‘wholly enduring objects are not perduring objects.” 7 Certainly there is present’. Furthermore, Merricks insists that ‘wholly present’ a sense in which Merricks is right to suggest that this negative cannot be defined without recourse to presentism. He says, “ I account of ‘wholly present’, and hence of endurance, is think that there is no way at all to make sense of an object’s uninformative. Knowing that enduring objects are not ‘being wholly present at every time at which it exists’ without perduring objects does not necessarily tell one what the nature of an enduring object is, and subsequently, does not really tell 2 Lowe, E.J., “ Lewis On Perdurance Versus Endurance” , Analysis 47 (1987), p. one what it is for an object to be wholly present. Specifically, 152. 3 Sider, Theodore, “ Four-Dimensionalism” , The Philosophical Review 106 (1997), p. 209. 6 Merricks, Trenton, “ Persistence, Parts and Presentism” , Nous 33:3, (1999). p. 4 Sider, p. 213. 229. 5 Markosian, Ned, “ The 3D/4D Controversy and Non-Present Objects” , 7 Merricks, Trenton, “ Endurance and Indiscernibility” , Journal of Philosophy, Philosophical Papers 23:3, (1994). April, (1994). 2 Proceedings of the Kent State University May 4th Philosophy Graduate Student Conference not having temporal parts may be a necessary feature of namely, presentism. With regard to the first assumption, he enduring objects, but it hardly seems sufficient. For it is says: possible that there be objects which don’t have any parts at all, but which certainly do not strike us as enduring objects. We can It does not follow from the fact that, necessarily, O exists iff O’s parts exist, imagine there being momentary micro-particles which by that O has all of its parts necessarily. That is, it does not follow from ‘in every world, O exists iff O’s parts’ that ‘in every world, O exist iff O’s parts definition do not persist, and hence cannot be enduring objects, in every world exist’. Likewise, it does not follow from ‘at every time, O whether or not they have parts. We might very well desire a exist iff O’s parts exist’ that ‘at every time, O exists iff its parts at every time more informative definition, and as metaphysicians, it would exist.8 not be odd to insist upon it. In light of these considerations, Merricks offers what he Here I think Merricks nicely exploits a point about modal scope. takes to be an informative definition of ‘wholly present’. For With this point understood I think it becomes clear that his Merricks, an object O is wholly present iff all of O’s parts exist. definition of ‘wholly present’ does not commit us to According to him, this notion serves to distinguish perduring mereological essentialism. and enduring objects, for if O is a perduring object that exists But in order to avoid this commitment, and at the same now and existed at some time in the past, then O has a past time have ‘wholly present’ as the distinguishing feature temporal part which does not exist now. On the other hand, between perduring and enduring objects, Merricks finds himself since enduring objects don’t have temporal parts, it is not the committed to presentism. Presentism holds that the only objects case that if O is an enduring object then O has some temporal that exist are presently existing objects. This commitment can part which does not exist now. If O is an enduring object and O be brought out by considering the following quotation: “ A exists now, then all of O’s parts exist now. perduring object is not wholly present at each time at which it Merricks’ only concern with this definition has to do with exists. Assume O is a four-dimensional object that existed in the the possible commitment to mereological essentialism. past, and exists now. O has a past temporal part P that does not Mereological essentialism is the doctrine that whatever is a part exist now.” This is true only if presentism is true, for if there are of O at any time at which O exists is a part of O at every time at objects which exist which do not presently exist, then it would which O exists.