Time travel is metaphysically possible. Nikk Effingham contends that arguments for the impossibility of time travel are not sound. Focusing mainly on the Grandfather Paradox, Effingham explores the ramifications of taking this view, discusses issues in probability and decision theory, and considers the potential dangers of travelling in time.
In this paper, we argue that time travel is problematic for the endurantist. For it appears to be possible, given time travel, to construct a wall out of a single time travelling brick. This commits the endurantist to one of the following: (a) the wall is composed of the time travelling brick many times over; (b) the wall does not in fact exist at all; (c) the wall is identical to the brick. We argue that each of these options is (...) unsatisfactory. (shrink)
If you are a realist about groups there are three main theories of what to identify groups with. I offer reasons for thinking that two of those theories fail to meet important desiderata. The third option is to identify groups with sets, which meets all of the desiderata if only we take care over which sets they are identified with. I then canvass some possible objections to that third theory, and explain how to avoid them.
‘Past vacillators’ believe that what was once the case may change over time. This has obvious applications to the possibility of changing the past via time travel. ‘Future vacillators’ believe that some things will happen and yet, later, will not. Further to issues in time travel, future vacillation has applications when it comes to ‘Geachian’ views about the open future. This paper argues that if you deny that the ‘earlier than’ and ‘later than’ relations are converses of one another then (...) you can develop metaphysical systems underpinning the possibility of such vacillation. (shrink)
I have previously argued in a paper with Robson that a particular time travel scenario favours perdurantism over endurantism on the grounds that endurantists must give up on the Weak Supplementation Principle. Smith has responded, arguing that the reasons we provided are insufficient to warrant this conclusion. This paper agrees with that conclusion (for slightly different reasons: that even the perdurantist has to give up on the Weak Supplementation Principle) but argues that the old argument can be supplanted with a (...) new one. (shrink)
This paper argues that, assuming properties exist and must be located in spacetime, the prevailing view that they are exactly located where their instances are is false. Instead a property is singularly located at just one region, namely the union of its instance's locations. This bears not just on issues in the metaphysics of properties, but also on the debate over whether multi-location is conceivable and/or possible.
In some stories, time travellers cannot change the past. It is widely accepted that this is metaphysically possible. In some stories, time travellers can change the past. Many philosophers have explained how that, too, is metaphysically possible. This paper considers narratives where sometimes the past can change and sometimes it cannot, arguing that this is also something that is possible. Further, I argue that we can make sense of stories where some events appear to be ‘fixed points in time’.
Sider has a favourable view of supersubstantivalism (the thesis that all material objects are identical to the regions of spacetime that they occupy). This paper argues that given supersubstantivalism, Sider's argument from vagueness for (mereological) universalism fails. I present Sider's vagueness argument (§§II-III), and explain why - given supersubstantivalism - some but not all regions must be concrete in order for the argument to work (§IV). Given this restriction on what regions can be concrete, I give a reductio of Sider's (...) argument (§V). I conclude with some brief comments on why this is not simply an ad hominem against Sider, and why this incompatibility of supersubstantivalism with the argument from vagueness is of broader interest (§VI). (shrink)
This paper argues that, in light of certain scenarios involving time travel, Sider’s definition of ‘instantaneous temporal part’ cannot be accepted in conjunction with a semantic thesis that perdurantists often assume. I examine a rejoinder from Sider, as well as Thomson’s alternative definition of ‘instantaneous temporal part’, and show how neither helps. Given this, we should give up on the perdurantist semantic thesis. I end by recommending that, once we no longer accept such semantics, we should accept a new set (...) of definitions, which are superior in certain respects to Sider’s original set. (shrink)
Universalism (the thesis that for any ys, those ys compose a further object) is an answer to the Special Composition Question. In the literature there are three arguments – what I call the arguments from elegance – that universalists often rely upon, but which are rarely examined in-depth. I argue that these motivations cannot be had by the perdurantist, for to avoid a commitment to badly behaved superluminal objects perdurantists must answer the ‘Proper Continuant Question’. Any answer to that question (...) necessarily ensures that there is a restricted answer to the Special Composition Question that is just as elegant as universalism. Thus, if you are a perdurantist, the arguments from elegance fail to motivate universalism for there will always be a restricted composition that is just as good. (shrink)
The Vagueness Argument for universalism only works if you think there is a good reason not to endorse nihilism. Sider's argument from the possibility of gunk is one of the more popular reasons. Further, Hawley has given an argument for the necessity of everything being either gunky or composed of mereological simples. I argue that Hawley's argument rests on the same premise as Sider's argument for the possibility of gunk. Further, I argue that that premise can be used to demonstrate (...) the possibility of simples. Once you stick it all together, you get an absurd consequence. I then survey the possible lessons we could draw from this, arguing that whichever one you take yields an interesting result. (shrink)
_‘Informative, accessible, and fun to read— this is an excellent reference guide for undergraduates and anyone wanting an introduction to the fundamental issues of metaphysics. I know of no other resource like it.’– __Meghan Griffith, Davidson College, USA_ _'Marvellous! This book provides the very best place to start for students wanting to take the first step into understanding metaphysics.Undergraduates would do well to buy it and consult it regularly. The quality and clarity of the material are consistently high.' – __Chris (...) Daly, University of Manchester, UK_ Ever wondered about Gunk, Brains in a Vat or Frankfurt’s Nefarious Neurosurgeon? With complete explanations of these terms and more, _Metaphysics: The Key Concepts_ is an accessible and engaging introduction to the most widely studied and challenging concepts in metaphysics. The authors clearly and lucidly define and discuss key terms and concepts, under the themes of: time particulars & universals realism & antirealism free will personal identity causation and laws. Arranged in an easy to use A-Z format, each concept is explored and illustrated with engaging and memorable examples, and accompanied by an up-to-date guide to further reading. Fully cross-referenced throughout, this remarkable reference guide is essential reading for students of philosophy and all those interested in the nature of reality. (shrink)
In this engaging and wide-ranging new book, Nikk Effingham provides an introduction to contemporary ontology - the study of what exists - and its importance for philosophy today. He covers the key topics in the field, from the ontology of holes, numbers and possible worlds, to space, time and the ontology of material objects - for instance, whether there are composite objects such as tables, chairs or even you and me. While starting from the basics, every chapter is up-to-date with (...) the most recent developments in the field, introducing both longstanding theories and cutting-edge advances. As well as discussing the latest issues in ontology, Effingham also helpfully deals in-depth with different methodological principles and introduces them alongside an example ontological theory that puts them into practice. This accessible and comprehensive introduction will be essential reading for upper-level undergraduate and post-graduate students, as well as any reader interested in the present state of the subject. (shrink)
Traynor identifies a tension between armchair reasoning telling us about the mereological structure of objects and empirical investigation telling us about the structure of spacetime. Section 1 explains, and bolsters, that tension. Section 2 discusses Traynor's resolution, and suggests some possible problems with it, whilst Section 3 discusses an alternative.
Universalism (the thesis that distinct objects always compose a further object) has come under much scrutiny in recent years. What has been largely ignored is its role in the metaphysics of classes. Not only does universalism provide ways to deal with classes in a metaphysically pleasing fashion, its success on these grounds has been offered as a motivation for believing it. This paper argues that such treatments of classes can be achieved without universalism, examining theories from Goodman and Quine, Armstrong (...) and Lewis. In the case of each theory, universalism is drafted in to ensure that there are enough material objects to play a particular role. I argue that, for each theory, there's a better theory that ditches universalism and instead uses an alternative principle of composition demanding that the unrestricted composition of entities other than material objects (respectively: regions, states of affairs and singletons) play that role instead. I conclude that (1) non-universalists can consider accepting such theories of classes and (2) we should ignore any alleged motivation for universalism on the basis of dealing with classes. (shrink)
The Multiverse Response to the problem of evil has it that God made our universe because God makes every universe meeting a certain standard. The main problem for that response is that there’s no explanation for why God didn’t just keeping making duplicates of perfect universes. This paper introduces the ‘Multiactualities Response’, which says that God actualises every possible world that meets a certain standard of value. It avoids the corresponding problem about duplication because different propositions must always be true (...) at distinct worlds. The Multiactualities Response nevertheless has its own problem, namely that it requires the possibility of multiple actual worlds. This paper argues that if we consider spacetimes with wormholes, we have good cause to think there can be multiple metaphysically privileged present moments; given a suitable analogy between time and modality, it follows that there can be multiple metaphysically privileged (i.e. actual) worlds. This paper includes an in–depth examination of the metaphysics of both the temporal and modal cases. (shrink)
One reading of the Doctrine of Original Sin has it that we are guilty of a sin committed by Adam, thousands of years ago. Fission theorists account for this by saying that Adam fissioned after he sinned and that each of us is one of his ‘fission successors’. This paper recaps the current discussion in the literature about this theory, arguing that the proposed version does not work for reasons already raised by Rea and Hudson. I then introduce a new (...) version of fission theory that avoids the Rea-Hudson objection. (shrink)
If a lump of clay is shaped into a statue, is there one thing or are there two? That is: are the lump and the statue two distinct things? This dialogue introduces some reasons to think they are two different things and then discusses the issues involved.
This paper argues that, if we believe both in works of music and sets, that the former are the latter. My argument is that such an ontology offers more explanatory power than the alternatives when it comes to explaining why works of music fall under the predicates that they do.
Mereological nominalism is the thesis that properties are identical to mereological fusions of their instances. Cumpa and Declos have raised two problems for the view. This paper is a reply to both problems.
It is a common view that if composition as identity is true, then so is mereological universalism (the thesis that all objects have a mereological fusion). Various arguments have been advanced in favour of this: (i) there has been a recent argument by Merricks, (ii) some claim that Universalism is entailed by the ontological innocence of the identity relation, (or that ontological innocence undermines objections to universalism) and (iii) it is entailed by the law of selfidentity. After a preliminary introduction (...) to the competing theories of persistence (necessary for a discussion of Merricks’ argument) I examine each in turn and demonstrate how they fail. I conclude that the prejudice that if composition as identity is true then Universalism is true, is unwarranted. Thus one motivation for believing Universalism is lost and those who believe composition as identity should now be receptive to some form of restricted composition. (shrink)
This paper investigates ‘exterminous hypertime’, a model of time travel in which time travellers can change the past in virtue of there being two dimensions of time. This paper has three parts. Part one discusses the laws which might govern the connection between different ‘hypertimes’, showing that there are no problems with overdetermination. Part two examines a set of laws that mean changes to history take a period of hypertime to propagate through to the present. Those laws are of interest (...) because: at such worlds, a particular problem for non-Ludovician time travel is avoided; and they allow us to make sense of certain fictional narratives. Part three discusses how to understand expectations and rational decision making in a world with two dimensions of time. I end with an appendix discussing how the different theories in the metaphysics of time marry up with exterminous hypertime. (shrink)
‘Instantiation-directed slot theorists’ believe that properties/relations have slots which are filled by their instances/relata e.g., where Abigail is taller than Bronia, there are two slots in the relation Taller Than such that Abigail fills the first slot and Bronia fills the second. This crude statement of the theory runs into ‘The Problem of Filling’, whereby a natural understanding of the relation between slots, filling, and instantiation leads to absurd results. This paper examines a variety of solutions to that problem, one (...) of which is an extension of slot theory that adds an additional category of entities, ‘slotites’. (shrink)
When a study shows statistically significant correlation between an exposure and an outcome, the credence of a real connection between the two increases. Should that credence remain the same when it is discovered that further independent studies between the exposure and other independent outcomes were conducted? Matthew Kotzen argues that it should remain the same, even if the results of those further studies are discovered. However, we argue that it can differ dependent upon the results of the studies.