A short paper proving what the title says.

In a recent paper titled ' Simples ', Ned Markosian asks and answers the Simple Question, which is, 'under what circumstances is it true of some object that it has no proper parts?' Markosian 's answer to the simple question is MaxCon, which states that an object is a simple if and only if it is a maximally continuous object. I present several arguments against MaxCon.

Can we understand being valuable for in terms of being valuable? Three different kinds of puzzle cases suggest that the answer is negative. In what follows, I articulate a positive answer to this question, carefully present the three puzzle cases, and then explain how a friend of the positive answer can successfully respond to them. This response requires us to distinguish different kinds of value bearers, rather than different kinds of value, and to hold that among the value bearers are (...) totality states of affairs. The final section of the article discusses the possibility of organic unification without organic unities. (shrink)

I argue that composition as identity is incompatible with the possibility of emergent properties (as characterized in the paper) and so should be rejected.

David Lewis, following in the tradition of Broad, Quine and Goodman, says that change in an object X consists in X's being temporally extended and having qualitatively different temporal parts. Analogously, change in a spatially extended object such as a road consists in its having different spatial parts . The alternative to this view is that ordinary objects undergo temporal change in virtue of having different intrinsic non-relational properties at different times. They endure, remaining the same object throughout change, whereas (...) Lewis's temporally extended 4D objects perdure.It is impossible to come down on one side or the other of the endurance/perdurance debate without a clear and unambiguous understanding of what ‘endurance’ is. ‘Perdurance’ is clear enough. Every 4D object of non-zero temporal thickness perdures simply by having temporal extension, i.e. by having different temporal parts, or stages, at different times. But Lewis muddies the waters by giving a confused and ultimately untenable definition of endurance.His first step is to cover both perduring and enduring by offering the neutral word persist. ‘Let us say that something persists iff, somehow or other, it exists at various times’ . Something then perdures if it persists by having different temporal parts at different times, no one part being wholly present at more than one time. In contrast, a thing endures if it persists by being wholly present at more than one …. (shrink)

Richard Heck, Jr has recently argued against Russellianism about proper names not in the usual way—by appeal to “intuitions” about the truth conditions of “that”-clause belief ascriptions—but by appeal to our need to specify beliefs in a way that reflects their individuation. Since beliefs are individuated by their psychological roles and not their Russellian contents, he argues, Russellianism is precluded in principle from accounting for our ability to specify beliefs in ordinary language. I argue that Heck thus makes things easier (...) for the Russellian. For by framing the issue as one concerning the specificatory powers of ordinary language in general, rather than just of “that”-clause ascriptions, Heck weakens the implications of any claim about the semantics of that one type of belief-specifying locution. I augment this diagnosis with a positive account of the specificatory usefulness, and attested commonness, of (partly or wholly) quotational belief ascriptions, e.g. “Lois believes that ‘Superman’ is at the meeting.” This proposal is not of the usual sort concerning such locutions since it does not involve the (dubious) claim that they are in some way equivalent to “that”-clause ascriptions. (shrink)

According to three-dimensionalism, objects persist in time by being wholly present at each time they exist; on the contrary, four-dimensionalism asserts that objects persist by having different temporal parts at different times or that they are instantaneous temporal parts of four-dimensional aggregates. Le Poidevin has argued that four-dimensionalism better accommodates two common assumptions concerning persistence and continuity; namely, that time itself is continuous and that objects persist in time in a continuous way. To this purpose, he has offered two independent (...) arguments, each of which moves from a different understanding of continuity. In this paper, both of Le Poidevin’s arguments will be discussed and rejected. (shrink)

There seem to be topics on which people can disagree without fault. For example, you and I might disagree on whether Picasso was a better artist than Matisse, without either of us being at fault. Is this a genuine possibility or just apparent? In this paper I pursue two aims: I want to provide a systematic map of available responses to this question. Simultaneously, I want to assess these responses. I start by introducing and defining the notion of a faultless (...) disagreement. Then I present a simple argument to the conclusion that faultless disagreement is not possible. Those who accept the argument have to explain away apparent cases of faultless disagreement. Those who want to maintain the possibility of faultless disagreement must deny one of the argument's premisses. The position I want to promote belongs to the latter category and is a form of genuine relativism. (shrink)

That there could be ontologically complex concrete particulars is self-evidently true. A reductio may however be formulated which contradicts this truth. In this paper I argue that all of the reasonable ways in which we might refute this reductio will require the existence of at least some tropes.

The standard analysis of quantification says that determiner quantifiers (such as every) take an NP predicate and create a generalized quantifier. The goal of this paper is to subject these beliefs to crosslinguistic scrutiny. I begin by showing that in St'á'imcets (Lillooet Salish), quantifiers always require sisters of argumental type, and the creation of a generalized quantifier from an NP predicate always proceeds in two steps rather than one. I then explicitly adopt the strong null hypothesis that the denotations of (...) quantifiers should be crosslinguistically uniform. Since the Salish data cannot be captured by the usual analysis of English, I pursue the idea that English is reducible to the Salish pattern. Reanalysis of many English constructions is required. I argue that the reanalysis has advantages over the standard analysis for partitives, as well as for non-partitive all- and most-phrases, which I analyze as containing bare plurals of argumental type. Even where the new analysis faces some challenges (for example, with every), the attempt still leads to fruitful results. It forces us to view familiar constructions in a new light, and to redefine, I believe correctly, which quantificational constructions are ‘basic’ and which stand in need of further explanation. (shrink)

Metaontology – the study of the nature of ontological issues – has flourished in recent years. The focus of this summary will be on some views and arguments that are central to today’s debate. One theme will be that of how seriously to take ontology: whether there is reason to take a skeptical or deflationary attitude toward ontological claims, as theorists like Rudolf Carnap, Hilary Putnam, and Eli Hirsch in different ways have urged. The other theme will be that of (...) the viability of the Fregean and Quinean approaches to ontology that have been and still are central to analytic philosophy. (shrink)

According to the doctrine of Super-Humeanism, the world’s mosaic consists only of permanent matter points and changing spatial relations, while all the other entities and features figuring in scientific theories are nomological parameters, whose role is merely to build the best law system. In this paper, I develop an argument against Super-Humeanism by pointing out that it is vulnerable to and does not have the resources to solve the well-known problem of immanent comparisons. Firstly, I show that it cannot endorse (...) a fundamentalist solution à la Lewis, since its two pillars—a minimalist ontology and a best system account of lawhood—would generate, together, a tedious problem of internal coherence. Secondly, I consider anti-fundamentalist strategies, proposed within Humeanism, and find them inapplicable to the Super-Humean doctrine. The concern is that, since it is impossible to choose the best law system within Super-Humeanism, this doctrine may be charged with incoherence. (shrink)

This paper addresses a famous objection against David Lewis’s Best System Analysis (BSA) of laws of nature. The objection—anticipated and discussed by Lewis (1994)—focuses on the standards of simplicity and strength being (in part) a matter of psychology. Lewis’s answer to the objection relies on his metaphysics of natural properties and its ability to single out the robustly best system, a system that is expected to come out far ahead of its rivals under any standard of simplicity and strength. The (...) main task of this paper is to argue that Lewis’s reply to the objection in terms of nature being kind to us does not succeed, if nature’s kindness is understood in terms of the naturalness of the properties composing the Humean mosaic. For epistemic access to natural properties is downstream to any previous identification of the best system. A possible Lewisian rejoinder in terms of a cross-world Humean mosaic of natural properties is considered and rebutted. The paper concludes by suggesting that Lewis could instead avail himself of a better answer to the objection, if the standards of simplicity and strength were reinterpreted along perspectivalist lines. (shrink)

Intrinsicality is a central notion in metaphysics that can do important work in many areas of philosophy. It is not widely appreciated, however, that there are in fact a number of different notions of intrinsicality, and that these different notions differ in what work they can do. This paper discusses what these notions are, describes how they are related to each other, and argues that each of them can be analysed in terms of a single notion of intrinsic aboutness that (...) relates states of affairs to the things they are intrinsically about. (shrink)

This paper argues for including stuff in one's ontology. The distinction between things and stuff is first clarified, and then three different ontologies of the physical universe are spelled out: a pure thing ontology, a pure stuff ontology, and a mixed ontology of both things and stuff. Eleven different reasons for including stuff in one's ontology are given. Then five objections to positing stuff are considered and rejected.

Miller (2005) and Miller (2008) argue that the branching picture of time is incompatible with the possibility of backwards time travel. In this paper I show that Miller’s conclusion is based on a hidden assumption which, while generally plausible, is unwarranted if time travel is possible. Branching time is, after all, compatible with time travel as Miller characterises it.

I argue that time travel to the past is impossible, given a certain metaphysical theory, namely, The Dynamic Theory of Time. I first spell out my particular way of capturing the difference between The Dynamic Theory of Time and its rival, The Static Theory of Time. Next I offer four different arguments for the conclusion that The Dynamic Theory is inconsistent with the possibility of time travel to the past. Then I argue that, even if I am wrong about this, (...) it will still be true that The Dynamic Theory entails that you should not want to travel back to the past. Finally, I conclude by considering a puzzle that arises for those who believe that time travel to the past is metaphysically impossible: What exactly are we thinking about when we seem to be thinking about traveling back in time? For it certainly does not feel like we are thinking about something that is metaphysically impossible. (shrink)

In the first part of the paper, I present a framework for the description and evaluation of teleosemantic theories of intentionality, and use it to argue that several different objections to these theories (the various indeterminacy and adequacy problems) are, in a certain precise sense, manifestations of the same underlying issue. I then use the framework to show that Millikan's biosemantics, her own recent declarations to the contrary notwithtanding, presents indeterminacy. In the second part, I develop a novel teleosemantic proposal (...) which makes progress in the treatment of this family of problems. I describe a procedure to derive a (unique) homeostatic property cluster [HPC] from facts having to do with the properties that a certain indicator relied on, in the events leading to its fixation in a certain population. This HPC is the one that should figure in the content attribution to the indicator in question. (shrink)

I raised the following question in a recent paper: What are the necessary and jointly sufficient conditions for an object's being a simple? And I proposed and defended this answer (which I called 'MaxCon'): Necessarily, x is a simple iff x is a maximally continuous object. In a more recent paper, Kris McDaniel raises several objections to MaxCon, including, in particular, two objections based on a principle about the supervenience of constitution that he calls 'SoC'. The purpose of the present (...) paper is to address the main objections raised by McDaniel, and to show that none of them poses a serious threat to MaxCon. (shrink)

Deflationary positions have been defended in many areas of philosophy. Most prominent are semantic deflationism about truth and reference, and meta-ontological deflationism, according to which existence has no deep nature and the standard neo-Quinean approach to ontology is misguided. Although both kinds of views have generated much discussion, surprisingly little attention has been paid to the question of how they relate to each other. Are they independent, is it advisable to hold them all at once, or do they even entail (...) each other? One exception is Amie Thomasson, who has argued that semantic deflationism actually entails meta-ontological deflationism. This is unexpected, since semantic deflationism is usually regarded as much less controversial than meta-ontological deflationism. In our paper, we will argue that Thomasson’s argument fails though, and that the connection between the views is in fact weaker than she makes them out to be. (shrink)

Quantum Ontology: A guide to the Metaphysics of Quantum Mechanics by P. Lewis, is a book with a philosophical orientation devoted to delve into the metaphysics of quantum mechanics. This book provides a comprehensive and detailed study to the various interpretations of quantum mechanics and their metaphysical consequences in relation to indeterminism, locality, free will, probability, holism and many other topics. Due to its rich philosophical perspective the author has dispensed with the mathematical formalism aiming to a rigorous conceptual approach.

It is often held that identity properties like the property of being identical to Paris are intrinsic. It is also often held that, while some logically uninstantiable properties are intrinsic, some logically uninstantiable properties are non-intrinsic. The combination of these views, however, raises a problem, since virtually every existing account of intrinsicality fails to analyse a notion of intrinsicality on which both these views are true. In this paper, I argue that, given the orthodox theory of counterlogicals, there is no (...) notion of intrinsicality on which both these views are true. If this argument is sucessful, then, at least given orthodoxy about counterlogicals, we face no challenge in analysing a notion of intrinsicality on which both these views are true, since there is no such notion. In addition, if we are also convinced that there is a notion of intrinsicality on which one of these views is true and a notion of intrinsicality on which the other of these views is true, we should hold that there is more than one notion of intrinsicality. (shrink)

A number of philosophers have recently claimed that intrinsicality can be analysed in terms of the metaphysical notion of grounding. Since grounding is a hyperintensional notion, accounts of intrinsicality in terms of grounding, unlike most other accounts, promise to be able to discriminate between necessarily coextensive properties that differ in whether they are intrinsic. They therefore promise to be compatible with popular metaphysical theories that posit necessary entities and necessary connections between wholly distinct entities, on which it is plausible that (...) there are such properties. This paper argues that this promise is illusory. It is not possible to give an analysis of intrinsicality in terms of grounding that is consistent with these theories. Given an adequate analysis should be compatible with these theories, it follows that it is not possible to analyse intrinsicality in terms of grounding. (shrink)

A number of philosophers have recently claimed that intrinsicality can be analysed in terms of the metaphysical notion of grounding. Since grounding is a hyperintensional notion, accounts of intrinsicality in terms of grounding, unlike most other accounts, promise to be able to discriminate between necessarily coextensive properties that differ in whether they are intrinsic. They therefore promise to be compatible with popular metaphysical theories that posit necessary entities and necessary connections between wholly distinct entities, on which it is plausible that (...) there are such properties. This paper argues that this promise is illusory. It is not possible to give an analysis of intrinsicality in terms of grounding that is consistent with these theories. Given an adequate analysis should be compatible with these theories, it follows that it is not possible to analyse intrinsicality in terms of grounding. (shrink)

This paper first offers a standard modal extension of dialetheic logics that respect the normal semantics for negation and conjunction, in an attempt to adequately model absolutism, the thesis that there are true contradictions at metaphysically possible worlds. It is shown, however, that the modal extension has unsavoury consequences for both absolutism and dialetheism. While the logic commits the absolutist to dialetheism, it commits the dialetheist to the impossibility of the actual world. A new modal logic AV is then proposed (...) which avoids these unsavoury consequences by invalidating the interdefinability rules for the modal operators with the use of two valuation relations. However, while using AV carries no significant cost for the absolutist, the same isn't true for the dialetheist. Although using AV allows her to avoid the consequence that the actual world is an impossible world, it does so only on the condition that the dialetheist admits that she cannot give a dialetheic solution to all self-refe.. (shrink)

An intrinsic property is roughly a property things have in virtue of how they are, as opposed to how they are related to things outside of them. This paper argues that it is not possible to give a definition of 'intrinsic' that involves only logical, modal and mereological notions, and does not depend on any special assumptions about either properties or possible worlds.

Over the last thirty years there have been a number of attempts to analyse the distinction between intrinsic and extrinsic properties in terms of the facts about naturalness. This article discusses the three most influential of these attempts, each of which involve David Lewis. These are Lewis's 1983 analysis, his 1986 analysis, and his joint 1998 analysis with Rae Langton.

Causal inference plays a central role in behavioral science. Historically, behavioral science methodologies have typically sought to infer a single causal relation. Each of the major approaches to causal inference in the behavioral sciences follows this pattern. Nonetheless, such approaches sometimes differ in the causal relation that they infer. Incremental causal inference offers an alternative to this conceptualization of causal inference that divides the inference into a series of incremental steps. Different steps infer different causal relations. Incremental causal inference is (...) consistent with both causal pluralism and anti-pluralism. However, anti-pluralism places greater constraints the possible topology of sequential inferences. Arguments against causal inference include questioning consistency with causation as an explanatory principle, charging undue complexity, and questioning the need for it. Arguments in favor of incremental inference include better explanation of diverse causal inferences in behavioral science, tailored causal inference, and more detailed and explicit description of causal inference. Incremental causal inference offers a viable and potentially fruitful alternative to approaches limited to a single causal relation. (shrink)

The leading account of intrinsicality over the last thirty years has arguably been David Lewis's account in terms of perfect naturalness. Lewis's account, however, has three serious problems: i) it cannot allow necessarily coextensive properties to differ in whether they are intrinsic; ii) it falsely classifies non-qualitative properties like being Obama as non-intrinsic; and iii) it is incompatible with a number of metaphysical theories that posit irreducibly non-categorical properties. I argue that, as a result of these problems, Lewis's account should (...) be rejected and replaced with an alternative account, which also analyses intrinsicality in terms of perfect naturalness, but which avoids these problems. (shrink)

In this article I advocate a worldly account of normative reasons according to which there is an ontological gap between these and the premises of practical thought, i.e. motivating considerations. While motivating considerations are individuated fine-grainedly, normative reasons should be classified as coarse-grained entities, e.g. as states of affairs, in order to explain certain necessary truths about them and to make sense of how we count and weigh them. As I briefly sketch, acting for normative reasons is nonetheless possible if (...) the connection between normative reasons and motivating considerations is a competence-based correspondence. (shrink)

What distinguishes a whole from an arbitrary sum of elements? I suggest a temporal and causal oriented approach. I defend two connected claims. The former is that existence is, by every means, coextensive with being the cause of a causal process. The latter is that a whole is the cause of a causal process with a joint effect. Thus, a whole is something that takes place in time. The approach endorses an unambiguous version of Restricted Composition that suits most commonsensical (...) intuitions about wholes. (shrink)

Talk of metaphysical modality as “absolute” is ambiguous, as it appears to convey multiple ideas. Metaphysical possibility is supposedly completely unrestricted or unqualified; metaphysical necessity is unconditional and exceptionless. Moreover, metaphysical modality is thought to be absolute in the sense that it’s real or genuine and the most objective modality: metaphysical possibility and necessity capture ways things could and must have really been. As we disentangle these ideas, certain talk of metaphysical modality qua “absolute” turns out to be misguided. Metaphysical (...) possibility isn't completely unrestricted or most inclusive compared to the other modalities; metaphysical necessity, like all kinds of necessities, is relative to or conditional upon a specific framework of reference. Still, metaphysical modality captures how things could and must have really been most generally because it deals with reality and the nature of things or their essence. That’s the chief interest of metaphysics. Arguments against the alleged absoluteness of metaphysical modality may not thereby undermine its philosophical significance. (shrink)

The fourteen papers in this collection offer a variety of original contributions to the epistemology of modality. In seeking to explain how we might account for our knowledge of possibility and necessity, they raise some novel questions, develop some unfamiliar theoretical perspectives, and make some intriguing proposals. Collectively, they advance our understanding of the field. In Part I of this Introduction, I give some general background about the contemporary literature in the area, by sketching a timeline of the main tendencies (...) of the past twenty-five years or so, up to the present debates. Next, I focus on four features that largely characterize the latest literature, and the papers in the present collection in particular: (i) an endorsement of the importance of essentialism; (ii) a shift to a “metaphysics-first” approach to modal epistemology; (iii) a focus on metaphysical modality as opposed to other kinds of modality; and (iv) a preference for non-uniform modal epistemology. In Part II, I present the individual papers in the volume. These are organized around the following four chapters, based on their topic: (A) Skepticism & Deflationism; (B) Essentialism; (C) Non-Essentialist Accounts; (D) Applications. -/- LIST OF CONTRIBUTORS: Francesco Berto; Stephen Biggs & Jessica Wilson; Justin Clark-Doane; Philip Goff; Bob Hale; Frank Jackson; Mark Jago; Boris Kment; Antonella Mallozzi; Graham Priest; Gabriel Rabin; Amie Thomasson; Anand Vaidya & Michael Wallner; Jennifer Wang. -/- The volume is dedicated to the memory of Bob Hale. -/- . (shrink)

In this article, I discuss Hawthorne'€™s contextualist solution to Benacerraf'€™s dilemma. He wants to find a satisfactory epistemology to go with realist ontology, namely with causally inaccessible mathematical and modal entities. I claim that he is unsuccessful. The contextualist theories of knowledge attributions were primarily developed as a response to the skeptical argument based on the deductive closure principle. Hawthorne uses the same strategy in his attempt to solve the epistemologist puzzle facing the proponents of mathematical and modal realism, but (...) this problem is of a different nature than the skeptical one. The contextualist theory of knowledge attributions cannot help us with the question about the nature of mathematical and modal reality and how they can be known. I further argue that Hawthorne'€™s account does not say anything about a priori status of mathematical and modal knowledge. Later, Hawthorne adds to his account an implausible claim that in some contexts a gettierized belief counts as knowledge. (shrink)

Modal arguments like the Knowledge Argument, the Conceivability Argument and the Inverted Spectrum Argument could be used to argue for experiential primitivism; the view that experiential truths aren’t entailed from nonexperiential truths. A way to resist these arguments is to follow Stoljar (Ignorance and imagination. Oxford University Press, Oxford, 2006) and plead ignorance of a type of experience-relevant nonexperiential truth. If we are ignorant of such a truth, we can’t imagine or conceive of the various sorts of scenarios that are (...) required to make these arguments sound. While I am sympathetic to this response, in this article I will argue that we have good reason to believe that this particular ignorance hypothesis is false. (shrink)

We tend to think that our concepts are stable in the sense that, whilst their extensions may vary across distinct epistemic scenarios, the reference-fixing conditions by which we discover these extensions remain fixed. This paper challenges this orthodoxy. In particular, it aims to motivate the position that some concepts are unstable in that their reference-fixing conditions themselves vary across distinct epistemic scenarios. Furthermore, it aims to draw out the implications such instability has for epistemic possibility and apriority. I shall argue (...) that when unstable concepts are concerned epistemic space will be widened, which in turn will restrict our a priori knowledge; and in ways that might be salient to solving certain familiar philosophical problems. (shrink)

One of the central debates in contemporary metaphysics has been the debate between endurantism and perdurantism about persistence. In this paper I argue that much of this debate has been misconstrued: most of the arguments in the debate crucially rely on theses which are strictly orthogonal to the endurantism/perdurantism debate. To show this, I note that the arguments in the endurantism/perdurantism debate typically take the following form: one presents a challenge that endurantists allegedly have some trouble addressing, and to which (...) perdurantism apparently has a straightforward response. I argue, however, that in each case, there are versions of endurantism that can offer precisely the same response to the challenge, and thus the ability to provide this particular solution does not directly tell in favour of one the two views. In §1, I elaborate two views which will be particularly prominent in the discussion: liberal endurantism and restrictive perdurantism. In §2–6 I discuss in turn the central pro-perdurantism arguments: the argument from anthropocentricism, the argument from vagueness, the argument from recombination, the argument from temporary intrinsics, and the argument from coincidence. In §7–8, I discuss the main pro-endurantism arguments: the arguments from motion, and the argument from permanent coincidence. Finally, in §9, I discuss what conclusion can be drawn from this discussion. (shrink)

David Lewis claims that his theory of modality successfully reduces modal items to nonmodal items. This essay will clarify this claim and argue that it is true. This is largely an exercise within ‘Ludovician Polycosmology’: I hope to show that a certain intuitive resistance to the reduction and a set of related objections misunderstand the nature of the Ludovician project. But these results are of broad interest since they show that would-be reductionists have more formidable argumentative resources than is often (...) thought. Lewis’s reduction depends on a set of methodological commitments each of which is fairly plausible or at least currently popular, and none of which is particular to modality. The choice of which of these commitments to reject I leave to the discerning antireductionist. The essay proceeds as follows: §1 discusses reduction generally and one or two relevant puzzles; §2 discusses Lewis’s reduction in particular; the longest section, §3 replies to four objections. (shrink)

It seems plausible to say that what changes an entity can or cannot survive depends on its persistence conditions, and that these depend, in turn, on its sortal kind. It might seem to follow that an entity cannot belong to two sortal kinds with potentially conflicting persistence conditions. Notoriously, though, this conclusion is denied by ‘contingent identity’ theorists, who hold, for example, that a permanently coincident statue and piece of clay are identical, although the persistence conditions associated with the kinds (...) statue and piece of clay are potentially conflicting. A clash with Leibniz’s Law is avoided by treating modal predicates as what Harold Noonan has called ‘Abelardian predicates’, as in the version of ‘inconstant’ counterpart theory developed by David Lewis. In addition to other difficulties, however, there is a question whether this ‘Abelardian’ theory does justice to the intuitions expressed in such statements as that the piece of clay could, while the statue could not, have survived a radical reshaping of its matter. I present an argument, which I call ‘the vacuous satisfaction argument’, for the conclusion that the theory does indeed fail to capture the significance of such de re modal statements. (shrink)

The contemporary Humean programme that seeks to combine property realism with the denial of necessary connections between distinct existences is flawed. Objects and properties by their very natures are entangled in such connections. It follows that modal notions cannot be reductively analysed by appeal to the concept property, not even if the reducing theory posits an abundant supply of entities to fall under that concept.

In several writings, John Martin Fischer has argued that those who deny a principle about abilities that he calls ‘the Fixity of the Past’ are committed to absurd conclusions concerning practical reasoning. I argue that Fischer’s ‘practical rationality’ argument does not succeed. First, Fischer’s argument may be vulnerable to the charge that it relies on an equivocation concerning the notion of an ‘accessible’ possible world. Secondly, even if Fischer’s argument can be absolved of that charge, I maintain that it can (...) be defeated by appeal to an independently plausible principle about practical reasoning that I call ‘the Knowledge Principle’. In addition, I point out that Fischer’s own presentation of his argument is flawed by the fact that the principle that he labels ‘the Fixity of the Past’ does not, in fact, succeed in representing the intuitive idea that it is intended to capture. Instead, the debate should be recast in terms of a different principle, which I call ‘the Principle of Past-Limited Abilities’. The principal contribution of my paper is thus twofold: to clarify the terms of the debate about the fixity of the past, and to undermine Fischer’s ‘practical rationality’ argument for the fixity of the past. (shrink)