As interest in Huayan thought among Western scholars has grown over the last few decades, a number of individuals have noted similarities between A. N. Whitehead's ideas of reality as a process of arising actual occasions and Huayan doctrines concerning the interdependent arising of dharmas. Comparisons of the two systems do show striking similarities, but as Steve Odin has pointed out, one area of noteworthy difference may be their views of temporal passage.1 There seems to be clear agreement among (...) Whitehead scholars that his view requires temporal asymmetry such that the present arises as a creative advance toward an open future. In contrast, Huayan is well known for advocating a symmetrical view of reality, and the Huayan view of time, it has been argued, is no exception. On this basis some have suggested that in accounting for and even requiring an open future, Whitehead's views effectively allow for a free advance of becoming that may not be possible within the context of Huayan views. But is this the case? -/- By examining sections of Fazang's works that specifically deal with tense and temporal passage, we will see that the typical view of Huayan as advocating a temporally symmetrical notion of passage is only partially accurate. Even further, it is apparent in light of that material that the Whiteheadian critique of Huayan is partly inaccurate as well. It is this latter point that may mean Huayan views allow for a type of becoming that Whitehead's cannot. To see how this is the case, it will be helpful to briefly summarize the Whiteheadian critique before focusing on key elements of Fazang's view. (shrink)

In addressing the Lucretian symmetry problem, the temporal bias approach claims that death is bad because it deprives us of something about which it is rational to care (e.g., future pleasures), whereas prenatal nonexistence is not bad because it only deprives us of something about which it is rational to remain indifferent (e.g., past pleasures). In a recent contribution to the debate on this approach, Miguel and Santos argue that a late beginning can deprive us of a future (...) pleasure. Their argument is based on the claim that for birth or death to deprive a person of any value in life, the historically closest counterfactual situation that contains the value is such that the person begins to exist earlier or dies later. This is what they call the Historical Condition. However, the Historical Condition is untenable for several reasons. First, this condition substantially weakens the explanatory capacity of the deprivation account because it implies that most ordinary sorts of pleasures are not deprived by death. In addition, the Historical Condition is vulnerable to counterexamples. In particular, what they offer as a standard case of the deprivation of future pleasure due to a late beginning (what they call Seeing The Beatles), or some of its variants, can be used to falsify this condition. Finally, the Historical Condition is theoretically indefensible because it is based on a faulty analysis of deprivation. (shrink)

The paper considers the symmetries of a bit of information corresponding to one, two or three qubits of quantum information and identifiable as the three basic symmetries of the Standard model, U(1), SU(2), and SU(3) accordingly. They refer to “empty qubits” (or the free variable of quantum information), i.e. those in which no point is chosen (recorded). The choice of a certain point violates those symmetries. It can be represented furthermore as the choice of a privileged reference frame (e.g. that (...) of the Big Bang), which can be described exhaustively by means of 16 numbers (4 for position, 4 for velocity, and 8 for acceleration) independently of time, but in space-time continuum, and still one, 17th number is necessary for the mass of rest of the observer in it. The same 17 numbers describing exhaustively a privileged reference frame thus granted to be “zero”, respectively a certain violation of all the three symmetries of the Standard model or the “record” in a qubit in general, can be represented as 17 elementary wave functions (or classes of wave functions) after the bijection of natural and transfinite natural (ordinal) numbers in Hilbert arithmetic and further identified as those corresponding to the 17 elementary of particles of the Standard model. Two generalizations of the relevant concepts of general relativity are introduced: (1) “discrete reference frame” to the class of all arbitrarily accelerated reference frame constituting a smooth manifold; (2) a still more general principle of relativity to the general principle of relativity, and meaning the conservation of quantum information as to all discrete reference frames as to the smooth manifold of all reference frames of general relativity. Then, the bijective transition from an accelerated reference frame to the 17 elementary wave functions of the Standard model can be interpreted by the still more general principle of relativity as the equivalent redescription of a privileged reference frame: smooth into a discrete one. The conservation of quantum information related to the generalization of the concept of reference frame can be interpreted as restoring the concept of the ether, an absolutely immovable medium and reference frame in Newtonian mechanics, to which the relative motion can be interpreted as an absolute one, or logically: the relations, as properties. The new ether is to consist of qubits (or quantum information). One can track the conceptual pathway of the “ether” from Newtonian mechanics via special relativity, via general relativity, via quantum mechanics to the theory of quantum information (or “quantum mechanics and information”). The identification of entanglement and gravity can be considered also as a ‘byproduct” implied by the transition from the smooth “ether of special and general relativity’ to the “flat” ether of quantum mechanics and information. The qubit ether is out of the “temporal screen” in general and is depicted on it as both matter and energy, both dark and visible. (shrink)

The Schrödinger equation for quantum mechanics, which is approachable in third-person description, takes for granted tenseless time that does not distinguish between different tenses such as past, present, and future. The time-reversal symmetry grounded upon tenseless time globally may, however, be broken once measurement in the form of exchanging indivisible quantum particles between the measured and the measuring intervenes. Measurement breaks tenseless time locally and distinguishes different tenses. Since measurement is about the material process of feeding and acting upon (...) the quantum resources already available from any material bodies to be measured internally, the agency of measurement is sought within the environment in the broadest sense. Most indicative of internal measurement of the environmental origin are chemical reactions in the reaction environment. Temporality naturalized in chemical reactions proceeding as being subjected to frequent interventions of internal measurement is approachable in second-person description because of the participation of multiple agents of measurement there. The use of second-person description is found in the appraisal of the material capacity of generating, distinguishing, and integrating different tenses. An essence of the temporality to be naturalized is within the genesis of different tenses. A most conspicuous exemplar of naturalized temporality is sought in the origins of life conceivable exclusively on the material ground. (shrink)

Three major ways in which temporal asymmetries enter into scientific induction are discussed as follows: 1. An account is given of the physical basis for the temporal asymmetry of recordability, which obtains in the following sense: except for humanly recorded predictions and one other class of advance indicators to be discussed, interacting systems can contain reliable indicators of only their past and not of their future interactions. To deal with the exceptional cases of non-spontaneous "pre-records," a clarification is (...) offered of the essential differences in the conditions requisite to the production of an indicator having retrodictive significance ("post-record"), on the one hand, and of one having predictive significance ("prerecord" or recorded prediction), on the other. Purported counter-examples to the asymmetry of spontaneous recordability are refuted. 2. It is shown how in cases of asymmetric recordability, the associated retrodiction-prediction asymmetry makes for an asymmetry of assertibility as between an explanandum (or an explanans) referring to a future event and one referring to a past one. But it is argued that this epistemological asymmetry in the assertibility per se must be clearly distinguished from a logical asymmetry between the past and the future in regard to the inferability (deductive or inductive) of the explanandum from the explanans. And it is then contended that the failure to distinguish between an epistemological and a logical asymmetry vitiates the critiques that recent writers have offered of the Popper-Hempel thesis, which affirms symmetry of inferability as between predictive and post-explanatory arguments. In reply to Scriven, it is maintained that predictions based on mere indicators (rather than causes) do not establish an asymmetry in scientific understanding as between predictive arguments and post-explanatory ones. 3. As a further philosophical ramification of the retrodiction-prediction asymmetry, a set of sufficient conditions are stated for the correctness of philosophical mechanism as opposed to teleology. (shrink)

This dissertation explores several issues related to the CPT theorem. Chapter 2 explores the meaning of spacetime symmetries in general and time reversal in particular. It is proposed that a third conception of time reversal, 'geometric time reversal', is more appropriate for certain theoretical purposes than the existing 'active' and 'passive' conceptions. It is argued that, in the case of classical electromagnetism, a particular nonstandard time reversal operation is at least as defensible as the standard view. This unorthodox time reversal (...) operation is of interest because it is the classical counterpart of a view according to which the so-called 'CPT theorem' of quantum field theory is better called 'PT theorem'; on this view, a puzzle about how an operation as apparently non-spatio-temporal as charge conjugation can be linked to spacetime symmetries in as intimate a way as a CPT theorem would seem to suggest dissolves. In chapter 3, we turn to the question of whether the CPT theorem is an essentially quantum-theoretic result. We state and prove a classical analogue of the CPT theorem for systems of tensor fields. This classical analogue, however, appears not to extend to systems of spinor fields. The intriguing answer to our question thus appears to be that the CPT theorem for spinors is essentially quantum-theoretic, but that the CPT theorem for tensor fields applies equally to the classical and quantum cases. Chapter4 explores a puzzle that arises when one puts the CPT theorem alongside a standard way of understanding spacetime symmetries, according to which spacetime symmetries are to be understood in terms of background spacetime structure. The puzzle is that a 'PT theorem' amounts to a statement that the theory may not make essential use of a preferred direction of time, and this seems odd. We propose a solution to that puzzle for the case of tensor field theories. (shrink)

In this paper, I argue that there is an inconsistency between two presentist doctrines: that of ontological symmetry and asymmetry of fixity. The former refers to the presentist belief that the past and future are equally unreal. The latter refers to the A-Theoretic intuition that the past is closed or actual, and the future is open or potential. My position in this paper is that the presentist is unable to account for the temporal asymmetry that is so fundamentally (...) a part of her theory. In Section I, I briefly outline a recent defence of presentism due to Craig, and argue that a flaw in this defence highlights the tension between the presentist's doctrines of ontological symmetry and asymmetry of fixity. In Section II, I undertake an investigation, on the presentist's behalf, in order to determine whether she is capable of reconciling these two doctrines. In the course of the investigation, I consider different asymmetries, other than that of ontology, which might be said fundamentally to constitute temporal asymmetry, and the asymmetry of fixity in particular. In Section III, I also consider whether the presentist is able to avail herself of some of the standard B-Theoretic accounts of the asymmetry of fixity, and argue that she cannot. Finally, I conclude that temporal asymmetry cannot be accounted for (or explained) other than through the postulation of an ontological asymmetry. (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)

The aim of this article is to argue that a temporal asymmetry may be established within the framework of quantum field theory, independently of any violation of CP, and thereby T, in weak interactions, and independently of the property of time reversal invariance that its dynamical equations instantiate. Particularly, I shall argue that the temporal asymmetry can be stemmed from assessing the links between the proper group of symmetries of the theory and the ontology of the theory: arguments (...) applied to establish which elements and magnitudes remain invariants under group transformations can also be used to establish a temporal asymmetry. (shrink)

In this paper, part of the ideas developed in Lewowicz (2000) will be reconsidered in the light of Pandora's Hope (1999a) - one of the latest publications of Bruno Latour. We will ponder the significance of these ideas and some of the incidental advances or retreats of the views of this author in the last 20 years. Although we still believe that, from the ontological point of view, Latour's philosophy is materialistic - then eliminativist - and not ontological relativist (contrary (...) to the opinion of his colleague philosophers), some of the symmetries developed in that text show outstanding ontological-epistemological and even methodological deficiencies which we try to show here; especially the symmetry between 'human and nonhuman actors' (Latour 1999a) and his very singular (but not without a fair amount of antecedents) concept of history of the things whose neologism is that of pragmatogony. Andrew Pickering (The mangle of practice, 1999a) proposed and developed the concept of temporary emergency. In view of this concept, he succeeds in criticising Latour's exact symmetries making use primarily of the concept of intentionality to account for the asymmetry (by no means radical, according to the latter) between 'the human and nonhuman collective'. In this paper we will try to reinforce (and inevitably to question) the notion of temporal emergency by giving it a less local aspect than the one given by this author. We will not only hold the asymmetry of certain dichotomies - presumably avoided by and avoidable according to Latour - but we will also claim the historical impossibility of such an avoidance: the concept of historialised emergency and not just temporalised, precludes this. It is concluded, firstly, that only an eliminativist materialism (within the range of materialisms) is able to avoid and even 'overcome' such pairs like nature/society and some of its derivatives like subject/object and individual/collective. Secondly, the decisive character of some dichotomies will be defended and lastly it will be attempted to account for the almost only ontological possibility of constructivism: the eliminativist materialism. (shrink)

It has been recently argued that by Leifer and Pusey, and Price, that time-symmetric quantum mechanics must entail retrocausality. Adlam responds that such theories might also entail ‘spooky action at a distance’. This paper proposes a third alternative: time-symmetric quantum mechanics might entail temporal global correlations. Unlike the traditional analysis of time symmetries in quantum mechanics, which consider linear and unitary interpretations, this paper considers the time-symmetric collapse models advanced by Bedingham and Maroney. These models are specially interesting since (...) it has been widely believed that collapse theories cannot be time-reversal invariant. (shrink)

The visual arts offer refreshing and novel resources through which to understand the representation, power, ideology and critique of law. This vibrantly interdisciplinary book brings the burgeoning field to a new maturity through extended close readings of major works by artists from Pieter Bruegel and Gustav Klimt to Gordon Bennett and Rafael Cauduro. At each point, the author puts these works of art into a complex dance with legal and social history, and with recent developments in legal and art theory. (...) Manderson uses the idea of time and temporality as a focal point through which to explore how the work of art engages with and constitutes law and human lives. In the symmetries and asymmetries caused by the vibrating harmonic resonances of these triple forces - time, law, art - lies a way of not only understanding the world, but also transforming it. (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)

This dissertation is about the sense in which the laws of quantum theory distinguish between the past and the future. I begin with an account of what it means for quantum theory to make such a distinction, by providing a novel derivation of the meaning of "time reversal." I then show that if Galilei invariant quantum theory does distinguish a preferred direction in time, then this has consequences for the ontology of the theory. In particular, it requires matter to admit (...) "internal" degrees of freedom, in that the position observable generates a maximal abelian algebra. I proceed to show that this is not a purely quantum phenomenon, but can be expressed in classical mechanics as well. I then illustrate three routes for generating quantum systems that distinguish a preferred temporal direction in this way. (shrink)

This authored monograph introduces a genuinely theoretical approach to biology. Starting point is the investigation of empirical biological scaling including their variability, which is found in the literature, e.g. allometric relationships, fractals, etc. The book then analyzes two different aspects of biological time: first, a supplementary temporal dimension to accommodate proper biological rhythms; secondly, the concepts of protension and retention as a means of local organization of time in living organisms. Moreover, the book investigates the role of symmetry (...) in biology, in view of its ubiquitous importance in physics. In relation with the notion of extended critical transitions, the book proposes that organisms and their evolution can be characterized by continued symmetry changes, which accounts for the irreducibility of their historicity and variability. The authors also introduce the concept of anti-entropy as a measure for the potential of variability, being equally understood as alterations in symmetry. By this, the book provides a mathematical account of Gould's analysis of phenotypic complexity with respect to biological evolution. The target audience primarily comprises researchers interested in new theoretical approaches to biology, from physical, biological or philosophical backgrounds, but the book may also be beneficial for graduate students who want to enter this field. (shrink)

In contrast to temporal asymmetry stressed in process philosophy, symmetry prevails in Mahayana Buddhism and East Asian philosophy formed under its influence. The paper clarifies the meaning of symmetry from the perspectives of Kitaro Nishida and Dogen, it explores similar or overlapping ideas in Whitehead’s philosophy oforganism, and it suggests that the differences among them are much smaller than commonly believed.

How the cilium appeared is still such a poorly defined question that current hypotheses range from a symbiotic spirochaete to a cellular eye. In this paper, the whole question is subdivided into a list of problems which are morphological, physiological and temporal. These problems are examined one by one, in order to analyse the most popular exogenous hypothesis of Margulis as well as other recent exogenous and endogenous hypotheses. To overcome fundamental topological and temporal difficulties, a new endogenous (...) hypothesis is expounded, according to which the cilium derives from a cellular peduncle reinforced with microtubules. This hypothesis implies a geometrical rationale for the ninefold symmetry. In the last paragraph the consequences of the various hypotheses are compared. (shrink)

The homogeneity of time (i.e. the fact that there are no privileged moments) underlies a fundamental symmetry relating to the energy conservation law. On the other hand the obvious asymmetry between past and future, expressed by the metaphor of the arrow of time or flow of time accounts for the irreversibility of what happens. One takes this for granted but the conceptual tension it creates against the background of time''s presumed homogeneity calls for an explanation of temporal becoming. (...) Here, it is approached with the help of a claim to the effect that the instant (moment) itself has a structure isomorphic to that of time as a whole. Then the asymmetry of past and future in regard to temporal becoming is associated with the internal structure of the very moment, and not with external relations between different moments of time. In this paper ideas of ancient atomism and contemporary dialectics are brought together. It is for the sake of a contrast to what is known as logical atomism that I choose to call this view dialectical atomism. The latter admits dialectical contradictions and, so far as the logical status of contradictions is concerned, bears reference to paraconsistent logics. In the paper there is an outline of a method of converting any consistent axiomatic formal system into a paraconsistent theory. (shrink)

Temporal becoming is usually considered the essence of the concept of time. But in our century most physicists and philosophers have defended the view that becoming is dependent on the existence of conscious beings and that there is no ontological difference between past and future. I evaluate these related claims both in light of their conceptual implications and by bringing to bear our best spacetime theories. ;Since a mind-independent becoming should be grounded in an ontological, non-epistemic asymmetry between past (...) and future, I discuss the philosophical motivations for various "non-full views" of the future in contrast to the view that the future is as real as the past. I present the disagreement between these views both in terms of what is and in terms of possession of a definite truth value, thereby distinguishing an ontological and a semantic formulation. A formal definition of the "tree model" of reality allows a clear distinction of the often conflated notions of 'determinate', 'determined' and 'stable', and helps to formulate the differences between the "non-full" views and the "full view" of reality. ;To settle the issue concerning these views, I bring into the discussion the special theory of relativity . I show that oft-discussed arguments against the openness of the future presuppose a clarification of the properties of the relation 'being determinate for', in particular symmetry and transitivity. Within STR, objective becoming can be defended at the cost of relativizing what is determinate to spacetime points, of making the relation of determinedness time-asymmetric, and of denying determinateness to spacelike-related events. ;I conclude by urging that mind-independent temporal becoming can find a more hospitable environment in some isotropic cosmological models of general relativity, a claim that has been unreasonably neglected. If the universe does not present causal anomalies , the proper time of a co-moving 'fundamental particle' can be made common to every other world line. The existence of such a cosmic time would make current scientific talk of 'cosmic evolution' and 'the future of the universe' non-metaphorical. (shrink)

There are basically four options to which state the limiting instant in a change from one state to its opposite belongs – only the first, only the second, both or none. This situation is usually referred to as the limit decision problem since all of these options seem troublesome: The first two alleged solutions are asymmetric and thus need something to ground this asymmetry in ; while the last two options leave the realm of classical logic. I argue that including (...) the debate about dispositions enables new options for solutions to the temporal limit decision problem. Metaphysical considerations function as a symmetry-breaker and thus remove the need for a non-classical solution. Dispositions bring about the changes in the world, so they constitute the metaphysical background for the instant of change. In particular, I argue that according to the triadic process account of dispositions, the limiting instant belongs to the second interval and only the second interval. (shrink)

The formal time symmetry of the quantum measurement process is extensively discussed. Then, the origin of the alleged association between a fixed temporal direction and quantum measurements is investigated. It is shown that some features of such an association might arise from epistemological rather than purely physical assumptions. In particular, it is brought out that a sequence of statements bearing on quantum measurements may display intrinsic asymmetric properties, irrespective of the location of corresponding measurements in time t of (...) the Schrodinger equation. The situation of an observer performing two measurements in two opposite directions of t is eventually investigated. Essential differences are found between two descriptions of this situation: the internal one (taking only into account what is recorded in the observer's memory) and the external one (whereby the observer is considered as a quantum system ruled by the Schrodinger equation). Finally, a method allowing several observers to establish a correspondence between their memory sizes is analyzed. The most important facts that usually lead to the associating of a preferential temporal direction with quantum measurements may be inferred from this correspondence. (shrink)

We introduce the Relational Blockworld (RBW) as a paradigm for deflating the mysteries associated with quantum non-separability/non-locality and the measurement problem. We begin by describing how the relativity of simultaneity implies the blockworld, which has an explanatory potential subsuming both dynamical and relational explanations. It is then shown how the canonical commutation relations fundamental to non-relativistic quantum mechanics follow from the relativity of simultaneity. Therefore, quantum mechanics has at its disposal the full explanatory power of the blockworld. Quantum mechanics exploits (...) this expanded explanatory capability since event distributions among detectors per the density matrix follow from spacetime relations (symmetry group) alone. Thus, the event distributions of non-relativistic quantum mechanics follow from a blockworld wherein spacetime relations are fundamental. Per RBW "quantum mysteries" are deflated and the implications for consciousness and the perception of temporal flow and absolute becoming are explored. We conclude that given RBW, consciousness is no less fundamental than any "physical" feature of the world such as brain states. Further, active consciousness is needed to explain the illusion that it is a dynamical world and consciousness in its most fundamental state is relational and non-local. (shrink)

Philosophers who work on time often ignore the implications their doctrines have for the common sense intuition that the past is fixed and the future not. Similarly, those who work on fatalism, and whose arguments often imply an assertion or denial of the common sense intuition, rarely take into account the implicit dependence their arguments have upon specific theories of time. I take the intuition, and its relation to the nature of time, seriously. In Part I of my thesis, I (...) investigate the relations between the dynamic and static theories of time, on the one hand, and the intuition, on the other. I argue that the so called 'pure' forms of these theories, inasmuch as they both posit an ontological temporal symmetry, cannot do justice to the intuition. The 'pure' B-Theory, with its denial of objective temporal becoming, cannot allow for a robust sense in which the future is non-fixed. The 'pure' A-Theory, according to which only the present exists, acknowledges the robustness of the asymmetry, but cannot provide a ground for it. I conclude Part I of my thesis with the claim that only a conception of time according to which the past exists and the future does not, can account for the intuition. In Part II, I discuss those fatalistic arguments which rely upon the determinateness of future truth as their key premise, and argue that these fail either because they rely on an illegitimate modal concept, or because they rely on a key undefended assumption. Finally, in the Epilogue, I provide a more detailed sketch of the account of time posited at the end of Part I, and suggest that it can also provide a more thoroughgoing rejection of the logical fatalistic argument. (shrink)

I. Prigogine has proposed, and the writings of N. S. Krylov to some extent suggest, a novel and unorthodox solution to foundational problems in statistical mechanics. In particular, the view claims to offer new insight into two interconnected problems: understanding the role of probability in physics, and that of reconciling the irreversibility of physical processes with the temporal symmetry of dynamical theories. The approach in question advocates a conception of the state of a system which incorporates features of (...) the quantum mechanical state concept in a context, classical statistical mechanics, where quantum considerations are generally considered to be irrelevant. I examine the plausibility of this new approach by offering an analysis of the various notions of state employed in modern physics. ;In the first chapter, I analyze the conceptual connections between dynamical laws and the nature of a system's state. I argue that laws and states are correlative. In constructing dynamical theories one does not start with a fixed or pre-determined state concept. Neither is one given the laws of the theory from which the conception of state is derived. Rather, we get the law/state structure as a "package." In light of this general analysis, I next examine the notion of state employed in the quantum theory. Here I consider a variety of conceptions of quantum states and assess their ability to answer the "paradoxes" of quantum theory. I pay particular attention to the role of probability and related restrictions on the realization of certain states. The new approach to statistical mechanics proposes to exploit similar restrictions on states in order to resolve the irreversibility problem. But is this unorthodox approach viable? In the final four chapters, I offer a detailed critique of this approach, examining the plausibility of the radical reworking of the state concept. I argue that while some important progress can be made, certain old puzzles remain, and new and difficult ones arise--ones which raise serious doubts about the ultimate success of this particular approach. I conclude, however, by arguing that such radical proposals are not unmotivated; and that novel and unorthodox proposals concerning the foundations of statistical mechanics must be taken seriously. (shrink)

This contribution addresses major distinctions between the notions of determinism, causation, and prediction, as they are typically used in the sciences. Formally, this can be elegantly achieved by two ingredients: (i) the distinction of ontic and epistemic states of a system, and (ii) temporal symmetry breakings based on the mathematical concept of the affine time group. Key aspects of the theory of deterministically chaotic systems together with historical quotations from Laplace, Maxwell, and Poincare provide significant illustrations. An important (...) point of various discussions in consciousness studies (notably about 'mental causation' and 'free agency'), the alleged 'causal closure of the physical', will be analysed on the basis of the affine time group and the breakdown of its symmetries. (shrink)

The arrow of time is one of the big unclaimed prizes of modern physics. The problem is to reconcile the temporal asymmetry of thermodynamics with the apparent temporal symmetry of fundamental physical theories. Some major players have wrestled with the issue over the past century or so, but is still up for grabs--and very much in the air of late, having been discussed in recent books by Stephen Hawking..

This paper considers the possibility that nonrelativistic quantum mechanics tells us that Nature cares about time reversal. In a classical world we have a fundamentally reversible world that appears irreversible at higher levels, e.g., the thermodynamic level. But in a quantum world we see, if I am correct, a fundamentally irreversible world that appears reversible at higher levels, e.g., the level of classical mechanics. I consider two related symmetries, time reversal invariance and what I call ‘Wigner reversal invariance.’ Violation of (...) the first is interesting, for not only would it fly in the face of the usual story about temporal symmetry, but it also appears to imply (as I’ll explain) that time is ‘handed’, or as some have misleadingly said in the literature, ‘anisotropic’. Violation of the second is, as I hope to show, even more interesting. The paper also contains a discussion of two mostly neglected topics: what it means to say time is handed and what warrants such an attribution to time. (shrink)

One obstacle faced by proposals of retrocausal influences in quantum mechanics is the perceived high conceptual cost of making such a proposal. I assemble here a metaphysical picture consistent with the possibility of retrocausality and not precluded by the known physical structure of our reality. This picture employs two relatively well-established positions—the block universe model of time and the interventionist account of causation—and requires the dismantling of our ordinary asymmetric causal intuition and our ordinary intuition about epistemic access to the (...) past. The picture is then built upon an existing model of agent deliberation that permits us to strike a harmony between our causal intuitions and the fixity of the block universe view. I conclude that given the right mix of these reasonable metaphysical and epistemological ingredients there is no conceptual cost to such a retrocausal picture of quantum mechanics. (shrink)

A theory is usually said to be time reversible if whenever a sequence of states S 1 , S 2 , S 3 is possible according to that theory, then the reverse sequence of time reversed states S 3 T , S 2 T , S 1 T is also possible according to that theory; i.e., one normally not only inverts the sequence of states, but also operates on the states with a time reversal operator T . David Albert and (...) Paul Horwich have suggested that one should not allow such time reversal operations T on states. I will argue that time reversal operations on fundamental states should be allowed. I will furthermore argue that the form that time reversal operations take is determined by the type of fundamental geometric quantities that occur in nature and that we have good reason to believe that the fundamental geometric quantities that occur in nature correspond to irreducible representations of the Lorentz transformations. Finally, I will argue that we have good reason to believe that space-time has a temporal orientation. (shrink)

Rohrlich claims that “the problem of the arrow of time in classical dynamics has been solved”. The solution he proposes is based on the equations governing the motion of extended particles. Rohrlich claims that these equations, which must take self-interaction into account, are not invariant under time reversal. I dispute this claim, on several grounds.

The analysis of the temporal structure of canonical general relativity and the connected interpretational questions with regard to the role of time within the theory both rest upon the need to respect the fundamentally dual role of the Hamiltonian constraints found within the formalism. Any consistent philosophical approach towards the theory must pay dues to the role of these constraints in both generating dynamics, in the context of phase space, and generating unphysical symmetry transformations, in the context of (...) a hypersurface embedded within a solution. A first denial of time in the terms of a position of reductive temporal relationalism can be shown to be troubled by failure on the first count, and a second denial in the terms of Machian temporal relationalism can be found to be hampered by failure on the second. A third denial of time, consistent with both of the Hamiltonian constraints roles, is constituted by the implementation of a scheme for constructing observables in terms of correlations and leads to a radical Parmenidean timelessness. The motivation for and implications of each of these three denials are investigated. (shrink)

This thesis introduces and defends a ‘C theory’ of time. The metaphysics of time literature is primarily concerned with the distinction between the A and B theories of time, with the disagreement concerning whether the passage of time is an objective feature of reality. I argue that the distinction between the B and C theories—in terms of whether time has a ‘privileged’ direction—is of more obvious relevance to the philosophy of physics than is the distinction between the A and B (...) theories. The thesis has three main contentions. (1) In order to maintain a substantial metaphysical dispute between the different theories of time, they must be defined in terms of structural properties, and the naturalistic metaphysics of time direction involves the assessment of these structures in light of contemporary physics. (2) The A theory of time requires a model with two temporal dimensions, and although such a model provides a resolution to a number of problems faced by standard A theories, it is not motivated by physical theory. (3) The dispute between the B and C theories of time is of direct relevance to the philosophy of physics: the B theorist’s assumption of the existence of a privileged temporal direction is of explanatory relevance to physics; and a comparison between unidirectional and adirectional explanations in physics can in principle shed light on whether time is B- or C-theoretic. (shrink)

Already in 1835 Lobachevski entertained the possibility of multiple geometries of the same type playing a role. This idea of rival geometries has reappeared from time to time but had yet to become a key idea in space-time philosophy prior to Brown's _Physical Relativity_. Such ideas are emphasized towards the end of Brown's book, which I suggest as the interpretive key. A crucial difference between Brown's constructivist approach to space-time theory and orthodox "space-time realism" pertains to modal scope. Constructivism takes (...) a broad modal scope in applying to all local classical field theories---modal cosmopolitanism, one might say, including theories with multiple geometries. By contrast the orthodox view is modally provincial in assuming that there exists a _unique_ geometry, as the familiar theories have. These theories serve as the "canon" for the orthodox view. Their historical roles also suggest a Whiggish story of inevitable progress. Physics literature after c. 1920 is relevant to orthodoxy primarily as commentary on the canon, which closed in the 1910s. The orthodox view explains the spatio-temporal behavior of matter in terms of the manifestation of the real geometry of space-time, an explanation works fairly well within the canon. The orthodox view, Whiggish history, and the canon have a symbiotic relationship. If one happens to philosophize about a theory outside the canon, space-time realism sheds little light on the spatio-temporal behavior of matter. Worse, it gives the _wrong_ answer when applied to an example arguably _within_ the canon, a sector of Special Relativity, namely, _massive_ scalar gravity with universal coupling. Which is the true geometry---the flat metric from the Poincare' symmetry group, the conformally flat metric exhibited by material rods and clocks, or both---or is the question faulty? How does space-time realism explain the fact that all matter fields see the same curved geometry, when so many ways to mix and match exist? Constructivist attention to dynamical details is vindicated; geometrical shortcuts can disappoint. The more exhaustive exploration of relativistic field theories in particle physics, especially massive theories, is a largely untapped resource for space-time philosophy. (shrink)

The conservation of energy and momentum have been viewed as undermining Cartesian mental causation since the 1690s. Modern discussions of the topic tend to use mid-nineteenth century physics, neglecting both locality and Noether’s theorem and its converse. The relevance of General Relativity has rarely been considered. But a few authors have proposed that the non-localizability of gravitational energy and consequent lack of physically meaningful local conservation laws answers the conservation objection to mental causation: conservation already fails in GR, so there (...) is nothing for minds to violate. This paper is motivated by two ideas. First, one might take seriously the fact that GR formally has an infinity of rigid symmetries of the action and hence, by Noether’s first theorem, an infinity of conserved energies-momenta. Second, Sean Carroll has asked how one should modify the Dirac–Maxwell–Einstein equations to describe mental causation. This paper uses the generalized Bianchi identities to show that General Relativity tends to exclude, not facilitate, such Cartesian mental causation. In the simplest case, Cartesian mental influence must be spatio-temporally constant, and hence 0. The difficulty may diminish for more complicated models. Its persuasiveness is also affected by larger world-view considerations. The new general relativistic objection provides some support for realism about gravitational energy-momentum in GR. Such realism also might help to answer an objection to theories of causation involving conserved quantities, because energies-momenta would be conserved even in GR. (shrink)

In the Critique of the Power of Judgment, Immanuel Kant proposes a puzzling account of the experience of the beautiful: that aesthetic judgments are both subjective and speak with a universal voice. 1 These properties – the subjective and the universal – seem mutually exclusive but Kant maintains that they are compatible if we explain aesthetic judgment in terms of the mind’s a priori structure, as explicated in his earlier Critique of Pure Reason. Kant advances two major claims towards arguing (...) for the compatibility of the subjectivity and universality of the experience of beauty: that aesthetic judgments are ‘disinterested’, and that the universality of an aesthetic judgment derives from the transcendental idealist’s account of ordinary spatio-temporal experience – that is, our ordinary cognitive framework can explain the experience of beauty. If correct, these two claims support the thesis that, while the experience of beauty is wholly subjective, it nevertheless speaks with a universal voice . I will move to interpret Kant’s theory of the beautiful with reference to his earlier two Critiques in order to better understand the marriage of subjectivity and universality. In turn, this re- veals a deeper symmetry between the disinterestedness of the experience of beauty and the freedom of moral action, allowing Kant to maintain, as he indeed does, that “beauty is the symbol of morality.”. (shrink)

Following the experimental discovery of the Higgs boson, physicists explained the discovery to the public by appealing to analogies with condensed matter physics. The historical root of these analogies is the analogies to models of superconductivity that inspired the introduction of spontaneous symmetry breaking into particle physics in the early 1960s. We offer a historical and philosophical analysis of the analogies between the Higgs model of the electroweak interaction and the Ginsburg-Landau and Bardeen-Cooper-Schrieffer models of superconductivity, respectively. The conclusion (...) of our analysis is that both sets of analogies are purely formal in virtue of the fact that they are accompanied by substantial physical disanalogies. In particular, the formal analogies do not map the temporal, causal, or modal structures of SSB in superconductivity to temporal, causal, or modal structures in the Higgs model. These substantial physical disanalogies mean that analogies to models of superconductivity cannot supply the basis for the physical interpretation of EW SSB; however, an appreciation of the contrast between the physical interpretations of SSB in superconductivity and the Higgs model does help to clarify some foundational issues. Unlike SSB in superconductivity, SSB in the Higgs sector of the Standard Model is neither a temporal nor a causal process. We discuss the implications for the `eating' metaphor for mass gain in the Higgs model. Furthermore, the distinction between the phenomenological GL model and the dynamical BCS model does not carry over to EW models, which clarifies the desiderata for so-called `dynamical' models of EW SSB. Finally, the development of the Higgs model is an illuminating case study for philosophers of science because it illustrates how purely formal analogies can play a fruitful heuristic role in physics. (shrink)

The questions of what represents space-time in GR, the status of gravitational energy, the substantivalist-relationalist issue, and the exceptional status of gravity are interrelated. If space-time has energy-momentum, then space-time is substantival. Two extant ways to avoid the substantivalist conclusion deny that the energy-bearing metric is part of space-time or deny that gravitational energy exists. Feynman linked doubts about gravitational energy to GR-exceptionalism, as do Curiel and Duerr; particle physics egalitarianism encourages realism about gravitational energy. In that spirit, this essay (...) proposes a third possible view about space-time, one involving a particle physics-inspired non-perturbative split that characterizes space-time with a constant background _matrix_, a sort of vacuum value, thus avoiding the inference from gravitational _energy to substantivalism. On this proposal, space-time is, where eta=diag is a spatio-temporally constant numerical signature matrix, a matrix already used in GR with spinors. The gravitational potential, to which any gravitational energy can be ascribed, is g_{\mu\nu}- eta, an _affine_ geometric object with a tensorial Lie derivative and a vanishing covariant derivative. This non-perturbative split permits strong fields, arbitrary coordinates, and arbitrary topology, and hence is pure GR by almost any standard. This razor-thin background, unlike more familiar backgrounds, involves no extra gauge freedom and so lacks their obscurities and carpet lump-moving. After a discussion of Curiel's GR exceptionalist denial of the localizability of gravitational energy and his rejection of energy conservation, the two traditional objections to pseudotensors, coordinate dependence and nonuniqueness, are explored. Both objections are inconclusive and getting weaker. A literal interpretation involving infinitely many energies corresponding by Noether's first theorem to the infinite symmetries of the _action_ largely answers Schroedinger's false-negative coordinate dependence problem. Bauer's false-positive objection has multiple answers. Non-uniqueness might be handled by Nester et al.'s finding physical meaning in multiplicity in relation to boundary conditions, by an optimal candidate, or by Bergmann's identifying the non-uniqueness and coordinate dependence ambiguities as one. (shrink)

Quantum electrodynamics is a time-symmetric theory that is part of the electroweak interaction, which is invariant under a generalized form of this symmetry, the PCT transformation. The thesis is defended that the arrow of time in electrodynamics is a consequence of the assumption of an initial state of high order, together with the quantum version of the equiprobability postulate.

Available methods such as technology assessment and risk analysis have failed to predict the effects of technological choices. We need to give up the futile predictive ambitions of previous approaches and instead base decisions on systematic studies of alternative future developments. It will then be necessary to cope with mere possibility arguments, i.e., arguments in which a conclusion is drawn from a mere possibility that a course of action may have certain consequences. A five-step procedure is proposed for the assessment (...) of such arguments. It includes a search for mere possibility arguments pointing in different directions, a scientific evaluation that may lead to the specification or refutation of some of these arguments, two symmetry tests, evaluation of the seriousness of the arguments in terms of novelty, spatio-temporal unlimitedness and interference with complex systems, and hypothetical retrospection that aims at finding a course of action that will be defensible in retrospect. (shrink)

Many philosophical and scientific discussions of topics of mind-matter research make implicit assumptions, in various guises, about the distinction between mind and matter. Currently predominant positions are based on either reduction or emergence, providing either monistic or dualistic scenarios. A more-involved framework of thinking, which can be traced back to Spinoza and Leibniz, combines the two scenarios, dualistic (with mind and matter separated) and monistic (with mind and matter unseparated), in one single picture. Based on such a picture, the transition (...) from a domain with mind and matter unseparated to separate mental and material domains can be viewed as a result of a general kind of symmetry breaking, which can be described formally in terms of inequivalent representations. The possibility of whether this symmetry breaking might be connected to the emergence of temporal directions from temporally non-directed or even non-temporal levels of reality will be discussed. Correlations between mental and material aspects of reality could then be imagined as remnants of such primordial levels. Different conceivable types of inequivalent representations would lead to correlations with different characteristics. (shrink)

The two main arguments concern(1) the presence of an “enlightened complementarity” between philosophic (including scientific) and religious (not including mystic) thought, and(2) the necessity to postulate a “threefold relationship” whenever one is to gain knowledge of any kind. They are both inspired by physics (from Bohr's “strict complementarity”, resp. from Newton's fundamental postulate).God's perfection resides at least in Symmetry in a generalized (not restrictively spatial) sense. Yet, as the argument goes, Space does not “exist” as a thing. Consequently, the (...) Great Geometer (God) cannot dwell within a World He creates, and it is wrong to speak about His (God's) ‘existence’; for, existence is bound to the temporal, and Time is, together with the World, part of God's creation. Thus the only possible creation consists in God separating World and Time from Himself: This is the paradigm of Symmetry-breaking.Polytheistic mythologies all assume such and such imperfection of their deities; hence perfection is meaningful for monotheism only. A relationship of a threefold (‘trinitary’) nature must then obtain between God, World, and Time; this is analogous to Newton's postulate relating force, momentum and time. Just as the latter and its specific generalizations must be “found true” by verification, the said threefold relationship must also be found true: within philosophic thoughtmore geometrico (in a generalized sense), within religious thoughtmore “hymnometrico”. Yet the complementarity (called “enlightened”) arising between the two kinds of thought is of a higher nature than Bohr's “strict” complementarity. While it can be understood from the role assumed by language itself, it can however only be disposed of within mystic contemplation. (shrink)

argues that the success of the backward causation hypothesis in quantum mechanics would provide strong support for a version of Reichenbach's account of the direction of causal processes, which takes the direction of causation to rest on the fork asymmetry. He also criticises my perspectival account of the direction of causation, which takes causal asymmetry to be a projection of our own temporal asymmetry as agents. In this reply I take issue with Dowe's argument at three main points: his (...) claim that the backward causation hypothesis in QM is incompatible with my perspectival approach to the direction of causation; his defence of the fork asymmetry approach against a general criticism of mine based on the time-symmetry of microphysics; and his application of his preferred account of the direction of causal processes to the relevant cases in QM. (shrink)

We discuss a new theory of the universe in which the vacuum energy is of classical origin and dominates the energy content of the universe. As usual, the Einstein equations determine the metric of the universe. However, the scale factor is controlled by total energy conservation in contrast to the practice in the Robertson–Walker formulation. This theory naturally leads to an explanation for the Big Bang and is not plagued by the horizon and cosmological constant problem. It naturally accommodates the (...) notion of dark energy and proposes a possible explanation for dark matter. It leads to a dual description of the universe, which is reminiscent of the dual theory proposed by Milne in 1937. On the one hand one can describe the universe in terms of the original Einstein coordinates in which the universe is expanding, on the other hand one can describe it in terms of co-moving coordinates which feature in measurements. In the latter representation the universe looks stationary and the age of the universe appears constant. The paper describes the evolution of this universe. It starts out in a classical state with perfect symmetry and zero entropy. Due to the vacuum metric the effective energy density is infinite at the beginning, but diminishes rapidly. Once it reaches the Planck energy density of elementary particles, the formation of particles can commence. Because of the quantum nature of creation and annihilation processes spatial and temporal inhomogeneities appear in the matter distributions, resulting in residual proton (neutron) and electron densities. Hence, quantum uncertainty plays an essential role in the creation of a diversified complex universe with increasing entropy. It thus seems that quantum fluctuations play a role in cosmology similar to that of random mutations in biology. Other analogies to biological principles, such as recapitulation, are also discussed. (shrink)

Current views of the control of complex, purposeful movements acknowledge that organizational processes must reconcile multiple concerns. The central priority is of course accomplishing the actor's goal. But in specifying the manner in which this occurs, the action plan must accommodate such factors as the interaction of mechanical forces associated with the motion of a multilinked system (classical mechanics) and, in many cases, intrinsic bias toward preferred movement patterns, characterized by so‐called “coordination dynamics.” The most familiar example of the latter (...) is the symmetry constraint, where spatial trajectories and/or temporal landmarks (e.g., reversal points) of concurrentlymoving body segments (limbs, digits, etc.) exhibit mutual attraction. The natural coordination tendencies that emerge through these constraints can facilitate or hinder motor control, depending on the degree of congruency with the desired movement pattern. Motor control theorists have long recognized the role of classical mechanics in theories of movement organization, but an appreciation of the importance of intrinsic interlimb bias has been gained only recently.Although detailed descriptions of temporal coordination dynamics have been provided, systematic attempts to identify additional salient dimensions of interlimb constraint have been lacking. We develop and implement here a novel method for examining this problem by exploiting two robust principles of psychomotor behavior, the symmetry constraint and the Two‐Thirds Power Law. Empirical evidence is provided that the relative spatial patterns of concurrently moving limbs are naturally constrained in much the same manner as previously identified temporal constraints and, further, that apparent velocity interference is an indirect, secondary consequence of primary spatial assimilation. The theoretical implications of spatial interference are elaborated with respect to movement organization and motor learning. The need to carefully consider the appropriate dimensions with which to characterize coordination dynamics is also discussed. (shrink)

Since Tversky argued that similarity judgments violate the three metric axioms, asymmetrical similarity judgments have been particularly challenging for standard, geometric models of similarity, such as multidimensional scaling. According to Tversky, asymmetrical similarity judgments are driven by differences in salience or extent of knowledge. However, the notion of salience has been difficult to operationalize, especially for perceptual stimuli for which there are no apparent differences in extent of knowledge. To investigate similarity judgments between perceptual stimuli, across three experiments, we collected (...) data where individuals would rate the similarity of a pair of temporally separated color patches. We identified several violations of symmetry in the empirical results, which the conventional multidimensional scaling model cannot readily capture. Pothos et al. proposed a quantum geometric model of similarity to account for Tversky's findings. In the present work, we extended this model to a more general framework that can be fit to similarity judgments. We fitted several variants of quantum and multidimensional scaling models to the behavioral data and concluded in favor of the quantum approach. Without further modifications of the model, the best-fit quantum model additionally predicted violations of the triangle inequality that we observed in the same data. Overall, by offering a different form of geometric representation, the quantum geometric framework of similarity provides a viable alternative to multidimensional scaling for modeling similarity judgments, while still allowing a convenient, spatial illustration of similarity. (shrink)

Relativistic quantum field theories (RQFTs) are invariant under the action of the Poincaré group, the symmetry group of Minkowski spacetime. Non-relativistic quantum field theories (NQFTs) are invariant under the action of the symmetry group of a classical spacetime; i.e., a spacetime that minimally admits absolute spatial and temporal metrics. This essay is concerned with cashing out two implications of this basic difference. First, under a Received View, RQFTs do not admit particle interpretations. I will argue that the (...) concept of particle that informs this view is motivated by nonrelativistic intuitions associated with the structure of classical spacetimes, and hence should be abandoned. Second, the relations between RQFTs and NQFTs also suggest that routes to quantum gravity are more varied than is typically acknowledged. The second half of this essay is concerned with mapping out some of this conceptual space. (shrink)

On the base of the classical logic the connectives of necessity and possibility have the equivalent positions in this sense that each of them is definable by the other one. The consequence of this fact is the possibility to define of the both modalities using the connective of identity. Thus, the connective of propositional identity defining the congruence of the propositional language has become the base of the reconstruction of necessity operator in some modal systems. Already in 1957 Greniewski [9] (...) obtained system S5 on the base of the propositional calculus with identity. Next, Cresswell [3], [4] reconstructed S4 and S5 in a similar way. Systematic investigations of this problem were undertaken by Suszko within the broader frame of SCI programme [16], [17], [18]. The connections between modal connectives and the connective of identity settle some philosophical sense of both modalities. Something is necessary, if it is identical with a logical truth. If something is different from the negation of some logical truth, it is possible. It is however, the “ontological” characteristics typical for modalities defined on the base of the classical logic. The settling of similar connections between intuitionistic identity and intuitionistic modalities uncover the philosophical sense of the “epistemic” necessity and possibility. Unfortunately, the symmetry between the classical and intuitionistic case is not entire. The acceptance of both equalities: = ¬ ¬ and = ¬ ¬, in the intuitionistic logic yields the classical versions of both modalities . Thus, there is a problem with defining the connective of intuitionistic possibility by the connective of identity. In Sections 2 and 3 two “partial” solutions of the mentioned problem are presented. They are “partial” because the connective of possibility has undesirable properties. The second solution yields the strengthening of the necessity connective, too. The main aim of this paper is obtained in Section 5, where a definition of the intuitionistic possibility is given. This definition uses the new connective of nonidentity, presented in Section 4. The new approach bases on the idea that some connectives like implication, negation, identity, necessity are “Heyting's” ones. The case of possibility is different. Together with coimplication, weak negation, and nonidentity, possibility belongs to the so-called “Brouwerian” connectives. The connectives of the first kind have such property that in Kripke's style semantics their interpretations in each point of this semantics are related to the interpretations in next points. In the case of the “Brouwerian” connectives the interpretations in each point depend on the interpretations in previous points. In this sense, “Heyting's” connectives are interpreted from the point of view of the future, while the interpretations of the “Brouwerian” connectives are from the point of view of the past. The relations between nonidentity and possibility connectives allow to say that in temporal semantics something is possible in the moment a, if before a there was such moment b in which it was different from the contradiction. Thus, “something is possible” does not mean that it held once in the past. A broader philosophical remarks about the nature of intuitionistic possibility are contained in two Comments in the last Section. (shrink)

Many philosophers of physics take the failure of the laws of physics to be invariant under the time reversal transformation to give us good reason to think that spacetime is temporally anisotropic, yet the details of this inference are rarely made explicit. I discuss two reasonable ways of filling in the details of this inference, the first of which utilizes a symmetry principle proposed by John Earman and the second of which utilizes Harvey Brown’s account of spacetime. I contend (...) that neither of the resulting arguments is sound. (shrink)

Symplectic reduction is a formal process through which degeneracy within the mathematical representations of physical systems displaying gauge symmetry can be controlled via the construction of a reduced phase space. Typically such reduced spaces provide us with a formalism for representing both instantaneous states and evolution uniquely and for this reason can be justifiably afforded the status of fun- damental dynamical arena - the otiose structure having been eliminated from the original phase space. Essential to the application of symplectic (...) reduction is the precept that the first class constraints are the relevant gauge generators. This prescription becomes highly problematic for reparameterization invariant theories within which the Hamiltonian itself is a constraint; not least because it would seem to render prima facie distinct stages of a history physically identical and observable functions changeless. Here we will consider this problem of time within non-relativistic me- chanical theory with a view to both more fully understanding the temporal struc- ture of these timeless theories and better appreciating the corresponding issues in relativistic mechanics. For the case of nonrelativistic reparameterization invariant theory application of symplectic reduction will be demonstrated to be both unnec- essary; since the degeneracy involved is benign; and inappropriate; since it leads to a trivial theory. With this anti-reductive position established we will then examine two rival methodologies for consistently representing change and observable func- tions within the original phase space before evaluating the relevant philosophical implications. We will conclude with a preview of the case against symplectic re- duction being applied to canonical general relativity. (shrink)