Here I respond to Anthony Brueckner and John Martin Fischer’s “The Evil of Death: A Reply to Yi.” They developed an influential strategy in defense of the deprivation account of death’s badness against the Lucretian symmetry problem. The core of their argument consists in the claim that it is rational for us to welcome future intrinsic goods while being indifferent to past intrinsic goods. Previously, I argued that their approach is compatible with the evil of late birth insofar (...) as an earlier birth would have generated more goods in the future. In reply, Brueckner and Fischer argue that my critique fails to appreciate an important aspect of their thought experiment, which aims only to show that the deprivation of past goods per se is not bad for us. Thus, purportedly, my critique poses no threat to their view. Here I argue that since the deprivation account explains the evil of death with recourse to how one’s life would have fared had one lived longer, it ought to respond to the symmetry problem with reference to how one’s life would have fared had one been born earlier. However, it is not generally true that the life one would have had with an earlier birth is not preferable to one’s actual life, because in many cases such a life would contain more future goods. (shrink)

A probability distribution is regular if it does not assign probability zero to any possible event. While some hold that probabilities should always be regular, three counter-arguments have been posed based on examples where, if regularity holds, then perfectly similar events must have different probabilities. Howson and Benci et al. have raised technical objections to these symmetry arguments, but we see here that their objections fail. Howson says that Williamson’s “isomorphic” events are not in fact isomorphic, but Howson is (...) speaking of set-theoretic representations of events in a probability model. While those sets are not isomorphic, Williamson’s physical events are, in the relevant sense. Benci et al. claim that all three arguments rest on a conflation of different models, but they do not. They are founded on the premise that similar events should have the same probability in the same model, or in one case, on the assumption that a single rotation-invariant distribution is possible. Having failed to refute the symmetry arguments on such technical grounds, one could deny their implicit premises, which is a heavy cost, or adopt varying degrees of instrumentalism or pluralism about regularity, but that would not serve the project of accurately modelling chances. (shrink)

A probability distribution is regular if no possible event is assigned probability zero. While some hold that probabilities should always be regular, three counter-arguments have been posed based on examples where, if regularity holds, then perfectly similar events must have different probabilities. Howson (2017) and Benci et al. (2016) have raised technical objections to these symmetry arguments, but we see here that their objections fail. Howson says that Williamson’s (2007) “isomorphic” events are not in fact isomorphic, but Howson is (...) speaking of set-theoretic representations of events in a probability model. While those sets are not isomorphic, Williamson’s physical events are, in the relevant sense. Benci et al. claim that all three arguments rest on a conflation of different models, but they do not. They are founded on the premise that similar events should have the same probability in the same model, or in one case, on the assumption that a single rotation-invariant distribution is possible. Having failed to refute the symmetry arguments on such technical grounds, one could deny their implicit premises, which is a heavy cost, or adopt varying degrees of instrumentalism or pluralism about regularity, but that would not serve the project of accurately modelling chances. (shrink)

Physicists often appeal to the beauty of a theory as a way to judge its credibility, and the most prevalent component of this beauty is symmetry. This paper describes the role and structure of symmetry arguments in physics. It demonstrates that the epistemic authority of an appeal to symmetry is based on empirical evidence and is independent of any aesthetic judgment. Furthermore, symmetry in nature is not evidence of design. Just the opposite, symmetry indicates a (...) lack of planning. It is about nature's disregard for details. (shrink)

This paper identifies two possible versions of the Epicurean 'Symmetry argument', both of which claim that post mortem non-existence is relevantly like prenatal non-existence and that therefore our attitude to the former should be the same as that towards the latter. One version addresses the fear of the state of being dead by making it equivalent to the state of not yet being born; the other addresses the prospective fear of dying by relating it to our present retrospective (...) attitude to the time before birth. I argue that only the first of these is present in the relevant sections of Lucretius (DRN 3.832-42, 972-5). Therefore, this argument is not aimed at a prospective fear of death, or a fear of 'mortality'. That particular fear is instead addressed by the Epicureans through the additional premise (found in the Letter to Menoeceus 125) that it is irrational to fear in prospect an event which is known to be painless when present. This still leaves unaddressed the related fear of 'premature death', which is to be removed through the acceptance of Epicurean hedonism. (shrink)

Liberalism is taking a beating. Many regimes return to religious rationales for state authority. They increasingly oppose liberal institutions. This essay lays the groundwork for engaging these _religious anti-liberalisms_. In this essay, I assess the religious anti-liberalism known as Catholic integralism. This ancient doctrine challenged historic political philosophers like Thomas Hobbes and John Locke. Surprisingly, it has recently resurfaced in some Catholic intellectual circles. Integralists propose that governments exist to secure the common good: temporal and spiritual. God authorizes two powers (...) to govern humankind. The state governs in matters temporal, the church in matters spiritual. When their missions intersect, the church is sovereign owing to its nobler purpose. Contemporary Catholic political philosophy rejects integralism. But it remains overwhelmingly perfectionist: states exist to promote the authentic individual and common good. These _natural law perfectionists_ say that states should promote _natural _goods: goods, such as health and friendship, that anyone can see as such through the use of reason. States should _not_ promote _supernatural _goods: goods, such as faith and hope, that we only grasp through revelation. Catholic perfectionists treat natural and supernatural goods _asymmetrically_. Integralists reject the asymmetry. God authorizes the church to promote supernatural goods, and the church may direct the state to advance its mission. On this basis, I argue that integralists can mount a powerful philosophical argument against standard natural law perfectionism—the _symmetry argument_. It claims that natural law perfectionists cannot justify their asymmetric treatment of goodness. Integralism, in contrast, treats the good symmetrically. (shrink)

Probability kinematics is the theory of how subjective probabilities change with time, in response to certain constraints . Rules are classified by the imposed constraints for which the rules prescribe a procedure for updating one's opinion. The first is simple conditionalization , and the second Jeffrey conditionalization . It is demonstrated by a symmetry argument that these rules are the unique admissible rules for those constraints, and moreover, that any probability kinematic rule must be equivalent to a conditionalization (...) preceded by a determination of the values x i to be given to the members of such a partition. Next two rival rules which can go beyond such conditionalization are described. INFOMIN and MTP . Their properties are investigated and compared. (shrink)

abstractBy appealing to the similarity between pre-vital and post-mortem nonexistence, Lucretius famously tried to show that our anxiety about death was irrational. His so-called Symmetry Argument has been attacked in various ways, but all of these strategies are themselves problematic. In this paper, I propose a new approach to undermining the argument: when Parfit’s distinction between identity and what matters is applied, not diachronically but across possible worlds, the alleged symmetry can be broken. Although the pre-vital (...) and posthumous time spans that we could have experienced are indeed analogous with respect to our identity, they are not analogous with respect to psychological continuity, which forms the basis of prudential concern. Lucretius even anticipated the Parfitian distinction. He did not, however, notice the significance that it has for his Symmetry Argument. (shrink)

Bohmian mechanics faces an underdetermination problem: when it comes to solving the measurement problem, alternatives to the Bohmian guidance equation work just as well as the official guidance equation. One way to argue that the guidance equation is superior to its rivals is to use a symmetry argument: of the candidate guidance equations, the official guidance equation is the simplest Galilean-invariant candidate. This symmetry argument---if it worked---would solve the underdetermination problem. But the argument does not (...) work. It fails because it rests on assumptions about how Galilean transformations (especially boosts) act on the wavefunction that are (in this context) unwarranted. My discussion has larger morals about the physical significance of certain mathematical results (like, for example, Wigner's theorem) in non-orthodox interpretations of quantum mechanics. (shrink)

Bohmian mechanics faces an underdetermination problem: when it comes to solving the measurement problem, alternatives to the Bohmian guidance equa- tion work just as well as the official guidance equation. Dürr, Goldstein, and Zanghì have argued that of the candidate guidance equations, the official guid- ance equation is the simplest Galilean-invariant candidate. This symmetry argument—if it worked—would solve the underdetermination problem. But the argument does not work. It fails because it rests on assumptions about how Galilean transformations (...) act on the wavefunction that are unwarranted. My discussion has larger morals about the phys- ical significance of certain mathematical results in non-orthodox interpretations of quantum mechanics. (shrink)

ABSTRACT According to the Symmetry Argument against the fear of death, our attitudes towards birth and death should be identical. In this paper I defend the Deprivation Account of the badness of death, according to which death is bad because it deprives one of future goods. After rejecting previous attempts to explain and justify the asymmetry in our attitudes towards birth and death I argue that the asymmetry in our attitudes is both explained and justified by the fact (...) that contrary to birth, death is not viewed as a nomologically necessary condition for life, and therefore death is viewed as an unnecessary limitation of life. (shrink)

Several philosophers have discussed informal versions of a "symmetry argument" that seems to show that two rational maximizers will cooperate when they are in a prisoner's dilemma. I present a more precise version of that argument and I argue that it is valid only if some crucial statements are misinterpreted as material conditionals instead of being interpreted correctly as subjunctive conditionals.

Hermann Weyl succeeded in presenting a consistent overarching analysis that accounts for symmetry in material artifacts, natural phenomena, and physical theories. Weyl showed that group theory is the underlying mathematical structure for symmetry in all three domains. But in this study Weyl did not include appeals to symmetry arguments which, for example, Einstein expressed as “for reasons of symmetry”. An argument typically takes the form of a set of premises and rules of inference that lead (...) to a conclusion. Symmetry may enter an argument both in the premises and the rules of inference, and the resulting conclusion may also exhibit symmetrical properties. Taking our cue from Pierre Curie, we distinguish two categories of symmetry arguments, axiomatic and heuristic; they will be defined and then illustrated by historical cases. (shrink)

In a recent paper, Pettigrew argues that the pragmatic and epistemic arguments for Bayesian updating are based on an unwarranted assumption, which he calls deterministic updating, and which says that your updating plan should be deterministic. In that paper, Pettigrew did not consider whether the symmetry arguments due to Hughes and van Fraassen make the same assumption Scientific inquiry in philosophical perspective. University Press of America, Lanham, pp. 183–223, 1987). In this note, I show that they do.

ABSTRACT This article is a response to 'Fear of death and the symmetry argument', in this issue. In that article, the author discusses the above Lucretian symmetry argument, and proposes a view that justifies the existing asymmetry in our attitudes towards birth and death. I begin by distinguishing this symmetry argument from a different one, also loosely inspired by Lucretius, which also plays a role in the article. I then describe what I take to (...) be the author's solution to the original symmetry argument and explain why I am unpersuaded by it. (shrink)

Abstract: Most commentators have assumed that Lucretius's symmetry argument against the fear of death is flawed. There remains, however, dispute as to what the flaw is. After establishing what I understand the target of Lucretius's argument to be (a desire for a longer life as such), I argue for a novel interpretation of what the flaw is, namely, that extending one's life into the time before one was actually born would be an uncertain bet for one who (...) wanted to extend his life, whereas extending one's life beyond the time one actually dies is a sure bet. This account of what the flaw is has the particular merit of relying only on simple concepts used in everyday reasoning and thus can explain why Lucretius's argument gains no traction even in the absence of sophisticated philosophical analysis. (shrink)

The first century B.C. poet Lucretius put forth an argument for why death is not bad for the person who has died. This argument is commonly referred to as Lucretius’s “symmetry argument” because of its assumption that the period before we were born is symmetrical to the period after we die. Jeremy Simon objects to the symmetry argument, claiming that the two periods are not relevantly symmetrical: being born earlier than we actually are born (...) would not guarantee us more life, whereas extending our lifespan past the time we actually would die would guarantee us more life. Simon believes this difference between the two time periods also explains why it is reasonable for people to wish for a later death but not for an earlier birth. We raise several objections to Simon’s response. Our main objection is that insofar as people do not wish for an earlier birth, it is not because they fear losing more life, but rather is a result of being concerned about losing what is important about life, namely its unique content. (shrink)

The first century B.C. poet Lucretius put forth an argument for why death is not bad for the person who has died. This argument is commonly referred to as Lucretius’s “symmetry argument” because of its assumption that the period before we were born is symmetrical to the period after we die. Jeremy Simon objects to the symmetry argument, claiming that the two periods are not relevantly symmetrical: being born earlier than we actually are born (...) would not guarantee us more life, whereas extending our lifespan past the time we actually would die would guarantee us more life. Simon believes this difference between the two time periods also explains why it is reasonable for people to wish for a later death but not for an earlier birth. We raise several objections to Simon’s response. Our main objection is that insofar as people do not wish for an earlier birth, it is not because they fear losing more life, but rather is a result of being concerned about losing what is important about life, namely its unique content. (shrink)

The leaders of the Scientific Revolution were not Baconian in temperament, in trying to build up theories from data. Their project was that same as in Aristotle's Posterior Analytics: they hoped to find necessary principles that would show why the observations must be as they are. Their use of mathematics to do so expanded the Aristotelian project beyond the qualitative methods used by Aristotle and the scholastics. In many cases they succeeded.

In the recent philosophical literature, several counterexamples to the interpretative principle that symmetry-related models are physically equivalent have been suggested The Oxford handbook of philosophy of physics, Oxford University Press, Oxford, 2013, Noûs 52:946–981, 2018; Fletcher in Found Phys 50:228–249, 2020). Arguments based on these counterexamples can be understood as arguments from scientific practice of roughly the following form: because in scientific practice such-and-such symmetry-related models are treated as representing distinct physical situations, these models indeed represent distinct physical (...) situations. In this paper, a strategy for analysing arguments of this type is presented and applied to the examples that can be found in the literature. I argue that if we are exclusively interested in models understood as representing entire possible worlds, arguments from scientific practice should involve some additional assumptions to guarantee they are relevant for models understood in this way. However, none of the examples presented in the literature satisfy all these additional assumptions, which leads to the conclusion that arguments from scientific practice based on these examples do not undermine the interpretative principle that different symmetry-related models represent the same possible world. (shrink)

A new argument is given for the thesis that only symmetry-invariant physical quantities are real. Non-invariant quantities are dynamically epiphenomenal in that they have no effect on the evolution of invariant quantities, and it is a significant theoretical vice to posit epiphenomenal quantities.

Metaphysicians speak of laws of nature in terms of necessity and universality; scientists, in terms of symmetry and invariance. In this book van Fraassen argues that no metaphysical account of laws can succeed. He analyzes and rejects the arguments that there are laws of nature, or that we must believe there are, and argues that we should disregard the idea of law as an adequate clue to science. After exploring what this means for general epistemology, the author develops the (...) empiricist view of science as a construction of models to represent the phenomena. (shrink)

Bertrand Russell famously argued that causation is not part of the fundamental physical description of the world, describing the notion of cause as “a relic of a bygone age”. This paper assesses one of Russell’s arguments for this conclusion: the ‘Directionality Argument’, which holds that the time symmetry of fundamental physics is inconsistent with the time asymmetry of causation. We claim that the coherence and success of the Directionality Argument crucially depends on the proper interpretation of the (...) ‘ time symmetry’ of fundamental physics as it appears in the argument, and offer two alternative interpretations. We argue that: if ‘ time symmetry’ is understood as the time -reversal invariance of physical theories, then the crucial premise of the Directionality Argument should be rejected; and if ‘ time symmetry’ is understood as the temporally bidirectional nomic dependence relations of physical laws, then the crucial premise of the Directionality Argument is far more plausible. We defend the second reading as continuous with Russell’s writings, and consider the consequences of the bidirectionality of nomic dependence relations in physics for the metaphysics of causation. (shrink)

In this paper a symmetry argument against quantity absolutism is amended. Rather than arguing against the fundamentality of intrinsic quantities on the basis of transformations of basic quantities, a class of symmetries defined by the Π-theorem is used. This theorem is a fundamental result of dimensional analysis and shows that all unit-invariant equations which adequately represent physical systems can be put into the form of a function of dimensionless quantities. Quantity transformations that leave those dimensionless quantities invariant are (...) empirical and dynamical symmetries. The proposed symmetries of the original argument fail to be both dynamical and empirical symmetries and are open to counterexamples. The amendment of the original argument requires consideration of the relationships between quantity dimensions. The discussion raises a pertinent issue: what is the modal status of the constants of nature which figure in the laws? Two positions, constant necessitism and constant contingentism, are introduced and their relationships to absolutism and comparativism undergo preliminary investigation. It is argued that the absolutist can only reject the amended symmetry argument by accepting constant necessitism. I argue that the truth of an epistemically open empirical hypothesis would make the acceptance of constant necessitism costly: together they entail that the facts are nomically necessary. (shrink)

Science and mathematics continually change in their tools, methods, and concepts. Many of these changes are not just modifications but progress---steps to be admired. But what constitutes progress? This dissertation addresses one central source of intellectual advancement in both disciplines: reformulating a problem-solving plan into a new, logically compatible one. For short, I call these cases of compatible problem-solving plans "reformulations." Two aspects of reformulations are puzzling. First, reformulating is often unnecessary. Given that we could already solve a problem using (...) an older formulation, what do we gain by reformulating? Second, some reformulations are genuinely trivial or insignificant. Merely replacing one symbol with another does not lead to intellectual progress. What distinguishes significant reformulations from trivial ones? According to what I call "conceptualism" (or "conceptual empiricism"), reformulations are intellectually significant when they provide a different plan for solving problems. Significant reformulations provide inferentially different routes to the same solution. In contrast, trivial reformulations provide exactly the same problem-solving plans, and hence they do not change our understanding. This answers the second question about what distinguishes trivial from significant reformulations. However, the first question remains: what makes a new way of solving an old problem valuable? Here, a bevy of practical considerations come to mind: one formulation might be faster, less complicated, or use more familiar concepts. According to "instrumentalism," these practical benefits are all there is to reformulating. Some reformulations are simply more instrumentally valuable for meeting the aims of science than others. At another extreme, "fundamentalism" contends that a reformulation is valuable when it provides a more fundamental description of reality. According to this view, some reformulations directly contribute to the metaphysical aim of carving reality at its joints. Conceptualism develops a middle ground between instrumentalism and fundamentalism, preserving their benefits without their costs. I argue that the epistemic value of significant reformulations does not reduce to either practical or metaphysical value. Reformulations are valuable because they are a constitutive part of problem-solving. Both science and mathematics aim at solving all possible problems within their respective domains. Meeting this aim requires being able to plan for any possible problem-solving context, and this requires reformulating. By reformulating, we clarify what we need to know to solve problems. Still, one might wonder whether the value of reformulations requires underlying differences in explanatory power. According to "explanationism," a reformulation is valuable only when it provides a better explanation. Explanationism stands as a rival middle ground position to my own. However, it faces numerous counterexamples. In many cases, two reformulations provide the same explanation while nonetheless providing different ways of understanding a phenomenon. Hence, reformulating can be valuable even when neither formulation is more explanatory. Methodologically, I draw on a variety of case studies to support my account of reformulation. These range from classical mechanics to quantum chemistry, along with examples from mathematics. Symmetry arguments provide a paradigmatic example: the mathematics of symmetry groups radically recasts quantum mechanics and quantum chemistry. Nevertheless, elementary approaches exist that eschew this additional mathematical apparatus, solving problems in a more tedious but less mathematically-demanding manner. Further examples include reformulations of quantum field theory, Arabic vs. Roman numerals, and Fermat's little theorem in number theory. In each case, my account identifies how reformulations change and improve our understanding of science and mathematics. (shrink)

Symmetry, intended as invariance with respect to a transformation (more precisely, with respect to a transformation group), has acquired more and more importance in modern physics. This Chapter explores in 8 Sections the meaning, application and interpretation of symmetry in classical physics. This is done both in general, and with attention to specific topics. The general topics include illustration of the distinctions between symmetries of objects and of laws, and between symmetry principles and symmetry arguments (such (...) as Curie's principle), and reviewing the meaning and various types of symmetry that may be found in classical physics, along with different interpretative strategies that may be adopted. Specific topics discussed include the historical path by which group theory entered classical physics, transformation theory in classical mechanics, the relativity principle in Einstein's Special Theory of Relativity, general covariance in his General Theory of Relativity, and Noether's theorems. In bringing these diverse materials together in a single Chapter, we display the pervasive and powerful influence of symmetry in classical physics, and offer a possible framework for the further philosophical investigation of this topic. (shrink)

James Henry Collin recently developed a new symmetry breaker favouring the ontological argument’s possibility premiss over that of the reverse ontological argument. The symmetry breaker amounts to an undercutting defeater for the reverse possibility premiss based on Kripkean cases of a posteriori necessity. I argue, however, that symmetry re-arises in two forms. First, I challenge the purported asymmetry in epistemic entitlements to the original and reverse possibility premisses. Second, relevantly similar Kripkean cases equally undercut the (...) original possibility premiss. (shrink)

This volume brings together a collection of essays on the history and philosophy of probability and statistics by one of the eminent scholars in these subjects. Written over the last fifteen years, they fall into three broad categories. The first deals with the use of symmetry arguments in inductive probability, in particular, their use in deriving rules of succession. The second group deals with four outstanding individuals who made lasting contributions to probability and statistics in very different ways: Frank (...) Ramsey, R. A. Fisher, Alan Turing, and Abraham de Moivre. The last group of essays deals with the problem of 'predicting the unpredictable' - making predictions when the range of possible outcomes is unknown in advance. The essays weave together the history and philosophy of these subjects and document the fascination that they have exercised for more than three centuries. (shrink)

The dominance of string theory in the research landscape of quantum gravity physics (despite any direct experimental evidence) can, I think, be justified in a variety of ways. Here I focus on an argument from mathematical fertility, broadly similar to Hilary Putnam’s ‘no miracles argument’ that, I argue, many string theorists in fact espouse in some form or other. String theory has generated many surprising, useful, and well-confirmed mathematical ‘predictions’—here I focus on mirror symmetry and the mirror (...) theorem. These predictions were made on the basis of general physical principles entering into string theory. The success of the mathematical predictions are then seen as evidence for the framework that generated them. I shall attempt to defend this argument, but there are nonetheless some serious objections to be faced. These objections can only be evaded at a considerably high (philosophical) price. (shrink)

Symmetry considerations dominate modern fundamental physics, both in quantum theory and in relativity. Philosophers are now beginning to devote increasing attention to such issues as the significance of gauge symmetry, quantum particle identity in the light of permutation symmetry, how to make sense of parity violation, the role of symmetry breaking, the empirical status of symmetry principles, and so forth. These issues relate directly to traditional problems in the philosophy of science, including the status of (...) the laws of nature, the relationships between mathematics, physical theory, and the world, and the extent to which mathematics suggests new physics.This entry begins with a brief description of the historical roots and emergence of the concept of symmetry that is at work in modern science. It then turns to the application of this concept to physics, distinguishing between two different uses of symmetry: symmetry principles versus symmetry arguments. It mentions the different varieties of physical symmetries, outlining the ways in which they were introduced into physics. Then, stepping back from the details of the various symmetries, it makes some remarks of a general nature concerning the status and significance of symmetries in physics. (shrink)

In addressing the Lucretian symmetry problem, the content-based approach attends to the difference between the contents of the actual life and those of relevant possible lives of a person. According to this approach, the contents of a life with an earlier beginning would substantially differ from, and thus be discontinuous with, the contents of the actual life, whereas the contents of a life with the same beginning but a later death would be continuous with the contents of the actual (...) life. In this paper, I examine two versions of the content-based approach: the identity account and the preference account. The identity account holds that, in the sense of identity which is relevant to the evil of nonexistence, the subject of the actual life, though identical to the person in the life with a later death, is distinct from the subject of the life with an earlier beginning. The preference account maintains that, given one’s attachments to actual particulars, a life with an earlier beginning is not rationally preferable to one’s actual life, whereas a life with a later death is. I argue that each version of the content-based approach is implausible, while discussing some of the complications that face each of them. (shrink)

I examine the link between extensionality principles of classical mereology and the anti‐symmetry of parthood. Varzi's most recent defence of extensionality depends crucially on assuming anti‐symmetry. I examine the notions of proper parthood, weak supplementation and non‐well‐foundedness. By rejecting anti‐symmetry, the anti‐extensionalist has a unified, independently grounded response to Varzi's arguments. I give a formal construction of a non‐extensional mereology in which anti‐symmetry fails. If the notion of ‘mereological equivalence’ is made explicit, this non‐anti‐symmetric mereology recaptures (...) all of the structure of classical mereology. (shrink)

Collin (2022) attempts to break the symmetry between the modal ontological argument for the existence of God and the reverse modal ontological argument against the existence of God by drawing on some Kripkean lessons about a posteriori necessity. He argues that there is an undercutting defeater for taking God’s non-existence to be possible. In this paper, I reply that taking the Kripkean considerations about a posteriori necessity into account does not help break the symmetry. For we (...) can argue in a similar way that there is an undercutting defeater for taking God’s existence to be possible. (shrink)

This paper continues the recent tradition of investigating iterated AGM revision by reasoning directly about the dynamics for total pre-order (“implausibility ordering”) representations of AGM revision functions. We reorient discussion, however, by proving that symmetry considerations, almost by themselves, suffice to determine a particular, AGM-friendly implausibility ordering dynamics due to Spohn 1988, which we call “J-revision”. After exploring the connections between implausibility ordering dynamics and the social choice theory of Arrow 1963, we provide symmetry arguments in the social (...) choice-theoretic framework for an interesting generalization of J-revision due to Nayak 1994. We conclude by arguing that the symmetry principles that uniquely favor J-revision and its generalizations are importantly expressive of the purely qualitative framework for representing beliefs that distinguishes the AGM program. Our results therefore comprehensively vindicate Spohn's 1988 conjecture that essentially J-revision is the best that can be done by way of a purely qualitative model of belief revision. (shrink)

This paper has three main objectives: (a) Discuss the formal analogy between some important symmetry-invariance arguments used in physics, probability and statistics. Specifically, we will focus on Noether’s theorem in physics, the maximum entropy principle in probability theory, and de Finetti-type theorems in Bayesian statistics; (b) Discuss the epistemological and ontological implications of these theorems, as they are interpreted in physics and statistics. Specifically, we will focus on the positivist (in physics) or subjective (in statistics) interpretations vs. objective interpretations (...) that are suggested by symmetry and invariance arguments; (c) Introduce the cognitive constructivism epistemological framework as a solution that overcomes the realism-subjectivism dilemma and its pitfalls. The work of the physicist and philosopher Max Born will be particularly important in our discussion. (shrink)

Beginning with Anderson, spontaneous symmetry breaking in infinite quantum systems is often put forward as an example of emergence in physics, since in theory no finite system should display it. Even the correspondence between theory and reality is at stake here, since numerous real materials show ssb in their ground states, although they are finite. Thus against what is sometimes called ‘Earman's Principle’, a genuine physical effect seems theoretically recovered only in some idealisation, disappearing as soon as the idealisation (...) is removed.We review the well-known arguments that no finite system can exhibit ssb, using the formalism of algebraic quantum theory in order to control the thermodynamic limit and unify the description of finite- and infinite-volume systems. Using the striking mathematical analogy between the thermodynamic limit and the classical limit, we show that a similar situation obtains in quantum mechanics versus classical mechanics.This discrepancy between formalism and reality is quite similar to the measurement problem, and hence we address it in the same way, adapting an argument of the Landsman and Reuvers that was originally intended to explain the collapse of the wave-function within conventional quantum mechanics. Namely, exponential sensitivity to perturbations of the dynamics as the system size increases causes symmetry breaking already in finite but very large quantum systems. This provides continuity between finite- and infinite-volume descriptions of quantum systems featuring ssb and hence restores Earman's Principle. (shrink)

Two symmetry arguments are discussed, each purporting to show that there is no more room for a preferred division of spacetime into instants of time in general relativistic cosmology than in Minkowski spacetime. The first argument is due to Gödel, and concerns the symmetries of his famous rotating cosmologies. The second turns upon the symmetries of a certain space of relativistic possibilities. Both arguments are found wanting.

In this paper, I consider the role of exact symmetries in theories of physics, working throughout with the example of gravitation set in Newtonian spacetime. First, I spend some time setting up a means of thinking about symmetries in this context; second, I consider arguments from the seeming undetectability of absolute velocities to an anti-realism about velocities; and finally, I claim that the structure of the theory licences us to interpret models which differ only with regards to the absolute velocities (...) of objects as depicting the same physical state of affairs. In defending this last claim, I consider how ideas and resources from the philosophy of language may usefully be brought to bear on this topic. (shrink)

This paper is a logical study of valid uses of symmetry in deductive reasoning, of what underlying principles make some appeals to symmetry legitimate but others illegitimate. The issue is first motivated informally. A framework is then given covering a fairly broad range of symmetry arguments, and the formulation of symmetry provided is shown to be a valid principle of reasoning, as is a slightly stronger principle of reasoning, one that is shown to be in some (...) sense as strong as possible. The relationship between symmetry and isomorphism is discussed, and finally the framework is extended to a more general model-theoretic setting. (shrink)

In this article I aim to offer a first critical assessment of the most prominent arguments in favour of restricting the voting rights of senior citizens. The first argument discussed, most thoroughly articulated by van Parijs, maintains that intergenerational justice would be improved under schemes which restrict the voting rights of senior citizens, thereby diminishing their overall electoral weight. The second argument, reconstructed from Lau's defence of child enfranchisement, maintains that the cognitive decline associated with the process of (...) aging should lead us to treat children and senior citizens identically in respect to electoral rights; thus, if we agree that children should not have the right to vote, consistency dictates that senior citizens should be disenfranchised as well. I respond to these arguments with several objections, arguing that the former relies on a number of faulty empirical premises and has deeply unattractive implications for enfranchisement once consistently applied, and that the latter fails to make empirically salient distinctions between children and senior citizens when it comes to the political domain. (shrink)

A prima facie plausible and widely held view in epistemology is that the epistemic standards governing the acquisition of testimonial knowledge are stronger than the epistemic standards governing the acquisition of perceptual knowledge. Conservatives about testimony hold that we need prior justification to take speakers to be reliable but recognise that the corresponding claim about perception is practically a non-starter. The problem for conservatives is how to establish theoretically significant differences between testimony and perception that would support asymmetrical epistemic standards. (...) In this paper I defend theoretical symmetry of testimony and perception on the grounds that there are no good reasons for taking these two belief forming methods to have significant theoretical differences. I identify the four central arguments in defence of asymmetry and show that in each case either they fail to establish the difference that they purport to establish or they establish a difference that is not theoretically significant. (shrink)

A survey of the main themes and arguments concerning symmetry and invariance in physics and philosophy of physics.