Can the second law of thermodynamics explain our mental experience of the direction of time? According to an influential approach, the past hypothesis of universal low entropy also explains how the psychological arrow comes about. We argue that although this approach has many attractive features, it cannot explain the psychological arrow after all. In particular, we show that the past hypothesis is neither necessary nor sufficient to explain the psychological arrow on the basis of current physics. We propose (...) two necessary conditions on the workings of the brain that any account of the psychological arrow of time must satisfy. And we propose a new reductive physical account of the psychological arrow of time compatible with time-symmetric physics, according to which these two conditions are also sufficient. Our proposal has some radical implications, for example, that the psychological arrow of time is fundamental, whereas the temporal direction of entropy increase in the second law of thermodynamics and the past hypothesis is derived from it, rather than the other way around. 1Introduction2A Physical Account of the Psychological Arrow of Time3Necessary Conditions for the Psychological Arrow of Time4The Psychological Arrow of Time via the Second Law of Thermodynamics and the Past Hypothesis5Why the Past Hypothesis Is Insufficient for the Psychological Arrow of Time5.1Stage 1, Version 1: From the past hypothesis to the psychological arrow via typicality5.2Stage 1, Version 2: From the past hypothesis to the psychological arrow via dynamical or causal considerations5.3Stage 2: From entropy gradient in the brain to the psychological arrow of time6Why the Past Hypothesis Is Unnecessary for the Psychological Arrow of Time7A New Reductive Account of the Psychological Arrow of Time. (shrink)

In quantum statistical mechanics, equilibrium states have been shown to be the typical states for a system that is entangled with its environment, suggesting a possible identification between thermodynamic and von Neumann entropies. In this paper, we investigate how the relaxation toward equilibrium is made possible through interactions that do not lead to significant exchange of energy, and argue for the validity of the second law of thermodynamics at the microscopic scale.

Over the last 10–15 years the second law of thermodynamics has undergone unprecedented scrutiny, particularly with respect to its universal status. This brief article introduces the proceedings of a recent symposium devoted to this topic, The second law of thermodynamics: Foundations and Status, held at University of San Diego as part of the 87th Annual Meeting of the Pacific Division of the AAAS (June 19–22, 2006). The papers are introduced under three themes: ideal gases, quantum perspectives, (...) and interpretation. Roughly half the papers support traditional interpretations of the second law while the rest challenge it. (shrink)

The second law results in the growth of the entropy – in superficial interpretation this principle presumes that the sufficient energy inevitably turns into the substandard energy. Order turns into chaos over time; however, chaos also turns into order under certain circumstances. The first research objective is to establish the possible prescientific ideas about the phenomenon – some philosophical intuitions that have preceded the scientific discovery of the second law and have conformed to it in a certain sense. (...) It is essential because there are always certain bonds and continuity in the history of philosophy and science – the correct interpretation of the phenomenon becomes difficult, if not impossible, without the establishment of such bonds.Moreover, the main task is to understand what the second law is and which significance its principal corollaries have. We need to give the second law a correct interpretation that will allow making assumptions about its connection with time in the context of the initial state problem and about the possible new ways of modern physics development – in particular, the creation of the quantum theory of gravity. Two solutions to the entropy and initial state connection problem are proposed in the context of the time arrow discussion (G. Calender’s approach to solving the problem is disputed). (shrink)

The second law of thermodynamics is traditionally interpreted as a coarse-grained result of classical mechanics. Recently its relation with quantum mechanical processes such as decoherence and measurement has been revealed in literature. In this paper we will formulate the second law and the associated time irreversibility following Everett’s idea: systems entangled with an object getting to know the branch in which they live. Accounting for this self-locating knowledge, we get two forms of entropy: objective entropy measuring the (...) uncertainty of the state of the object alone, and subjective entropy measuring the information carried by the self-locating knowledge. By showing that the summation of the two forms of entropy is a conserved and perspective-free quantity, we interpret the second law as a statement of irreversibility in knowledge acquisition. This essentially derives the thermodynamic arrow of time from the subjective arrow of time, and provides a unified explanation for varieties of the second law, as well as the past hypothesis. (shrink)

We show that the so-called Multiple-Computations Theorem in cognitive science and philosophy of mind challenges Landauer’s Principle in physics. Since the orthodox wisdom in statistical physics is that Landauer’s Principle is implied by, or is the mechanical equivalent of, the Second Law of thermodynamics, our argument shows that the Multiple-Computations Theorem challenges the universal validity of the Second Law of thermodynamics itself. We construct two examples of computations carried out by one and the same dynamical process (...) with respect to which Landauer’s principle implies contradictory predictions concerning the entropy increase. Our two examples are based on a weak version of the Multiple-Computations Theorem, which is quite uncontroversial, and therefore they amount to a clear refutation of the universal validity of Landauer’s Principle. We consider some responses to this argument that do not attempt to single out one computation over the others, and we show that they do not work. We further consider ways out of the argument by externalist approaches supporting the computational theory of the mind who propose that the interaction of a computing system with the environment is enough to select a single computation over the others. We show on physical grounds that this approach fails too. We then reverse the direction of our challenge and formulate a dilemma for supporters of the computational theory of the mind: they must reject the causal closure of physic; or else they must accept on a priori grounds that Landauer’s Principle and the Second Law of thermodynamics are not universally valid. Finally, we present our version of a type–type mind-brain identity theory called Flat Physicalism, which is based on the paradigm case of statistical mechanics, and we show that it circumvents the challenge from Landauer’s Principle and the Multiple-Computations Theorem and does not fall prey to our dilemma. (shrink)

In this work, we have investigated the validity of the generalized second law of thermodynamics in logamediate and intermediate scenarios of the universe bounded by the Hubble, apparent, particle and event horizons using and without using first law of thermodynamics. We have observed that the GSL is valid for Hubble, apparent, particle and event horizons of the universe in the logamediate scenario of the universe using first law and without using first law. Similarly the GSL is valid (...) for all horizons in the intermediate scenario of the universe using first law. Also in the intermediate scenario of the universe, the GSL is valid for Hubble, apparent and particle horizons but it breaks down whenever we consider the universe enveloped by the event horizon. (shrink)

In this short paper we make a proposal that the second law of thermodynamics holds true for a closed physical system consisting of pure antimatter in the thermodynamical limit, but in a reversed form. We give two plausible arguments in favour to this proposal: one refers to the CPT theorem of relativistic quantum field theories while the other one is based on general thermodynamical arguments. However in our understanding the ultimate validity or invalidity of this idea can be (...) decided only by future physical experiments. As a consequence of the proposal we argue that the dynamical evolution of pure macroscopic antimatter systems can be very different from that of ordinary matter systems in the sense that sufficiently massive antimatter systems could have stronger tendency to form black holes during time evolution than their ordinary counterparts. Taking into account the various uniqueness theorems in black hole physics as well, as a result, antimatter could tracelessly disappear behind black hole event horizons faster in time than ordinary matter. The observed asymmetry of matter and antimatter could then be explained even if their presence in the Universe was symmetric in the beginning. (shrink)

Thermodynamic implications of anisotropic gas-surface interactions in a closed molecular flow cavity are examined. Anisotropy at the microscopic scale, such as might be caused by reduced-dimensionality surfaces, is shown to lead to reversibility at the macroscopic scale. The possibility of a self-sustaining nonequilibrium stationary state induced by surface anisotropy is demonstrated that simultaneously satisfies flux balance, conservation of momentum, and conservation of energy. Conversely, it is also shown that the second law of thermodynamics prohibits anisotropic gas-surface interactions in (...) “equilibrium”, even for reduced dimensionality surfaces. This is particularly startling because reduced dimensionality surfaces are known to exhibit a plethora of anisotropic properties. That gas-surface interactions would be excluded from these anisotropic properties is completely counterintuitive from a causality perspective. These results provide intriguing insights into the second law of thermodynamics and its relation to gas-surface interaction physics. (shrink)

Entangled quantum systems can be harnessed to transmit, store, and manipulate information in a more efficient and secure way than possible in the realm of classical physics. Given this resource character of entanglement, it is an important problem to characterize ways to manipulate it and meaningful approaches to its quantification. This is the objective of entanglement theory.

The aim of this article is to analyse the relation between the second law of thermodynamics and the so-called arrow of time. For this purpose, a number of different aspects in this arrow of time are distinguished, in particular those of time-reversal (non-)invariance and of (ir)reversibility. Next I review versions of the second law in the work of Carnot, Clausius, Kelvin, Planck, Gibbs, Caratheodory and Lieb and Yngvason, and investigate their connection with these aspects of the arrow (...) of time. It is shown that this connection varies a great deal along with these formulations of the second law. According to the famous formulation by Planck, the second law expresses the irreversibility of natural processes. But in many other formulations irreversibility or even time-reversal non-invariance plays no role. I therefore argue for the view that the second law has nothing to do with the arrow of time. (shrink)

The search for the statistical mechanical underpinning of thermodynamic irreversibility has so far focussed on the spontaneous approach to equilibrium. But this is the search for the underpinning of what Brown and Uffink have dubbed the ‘minus first law’ of thermodynamics. In contrast, the second law tells us that certain interventions on equilibrium states render the initial state ‘irrecoverable’. In this article, I discuss the unusual nature of processes in thermodynamics, and the type of irreversibility that the (...) second law embodies. I then search for the microscopic underpinning or statistical mechanical ‘reductive basis’ of the second law of thermodynamics by taking a functionalist strategy. First, I outline the functional role of the thermodynamic entropy: for a thermally isolated system, the thermodynamic entropy is constant in quasi-static processes, but increasing in non-quasi-static processes. I then search for the statistical mechanical quantity that plays this role—rather than the role of the traditional ‘holy grail’ as described by Callender. I argue that in statistical mechanics, the Gibbs entropy plays this role. (shrink)

Cartesian mind body dualism and modern versions of this viewpoint posit a mind thermodynamically unrelated to the body but informationally interactive. The relation between information and entropy developed by Leon Brillouin demonstrates that any information about the state of a system has entropic consequences. It is therefore impossible to dissociate the mind's information from the body's entropy. Knowledge of that state of the system without an energetically significant measurement would lead to a violation of the second law of (...) class='Hi'>thermodynamics. (shrink)

We introduce a simple model for so-called spin-echo experiments. We show that the model is a mincing system. On the basis of this model we study fine-grained entropy and coarse-grained entropy descriptions of these experiments. The coarse-grained description is shown to be unable to provide an explanation of the echo signals, as a result of the way in which it ignores dynamically generated correlations. This conclusion is extended to the general debate on the foundations of statistical mechanics. We emphasize the (...) need for an appropriate mechanism to explain the gradual suppression over time of the correlations in a thermodynamic system. We argue that such a mechanism can only be provided by the interventionist approach, in which the interaction of the system with its environment is taken into account. Irreversible behavior is then seen to arise not as a result of limited measurement accuracy , but as a result of the fact that thermodynamic systems are limited systems which interact with their environment. A detailed discussion is given of recent objections to the interventionist approach in the literature. (shrink)

In a previous paper (Duncan, T.L., Semura, J.S. in Entropy 6:21, 2004) we considered the question, “What underlying property of nature is responsible for the second law?” A simple answer can be stated in terms of information: The fundamental loss of information gives rise to the second law. This line of thinking highlights the existence of two independent but coupled sets of laws: Information dynamics and energy dynamics. The distinction helps shed light on certain foundational questions in statistical (...) mechanics. For example, the confusion surrounding previous “derivations” of the second law from energy dynamics can be resolved by noting that such derivations incorporate one or more assumptions that correspond to the loss of information. In this paper we further develop and explore the perspective in which the second law is fundamentally a law of information dynamics. (shrink)

After the birth of thermodynamics’ second principle—outlined in Carnot's Réflexions sur la puissance motrice du feu —several studies provided new arguments in the field. Mainly, they concerned the thermodynamics’ first principle—including energy conceptualisation—, the analytical aspects of the heat propagation, the statistical aspects of the mechanical theory of heat. In other words, the second half of nineteenth century was marked by an intense interdisciplinary research activity between physics and chemistry: new disciplines applied to the heat developed (...) in the form of analytical, mechanical and statistical theories. Inside all these theories, entropy—the brand-new function that Clausius coined in his Mechanical theory of heat—started to play a central epistemic role. In the present paper, we analyse some steps of the historical process of conceptualisation of such function from 1850 to 1902. Particularly, we retrace the historical–foundational path that—starting from Clausius’ Second Law—lead Boltzmann and Gibbs to their distinguished formulations of statistical entropy. As usual, our research has been unrolled through the analyses of primary sources and by leaning on critical readings of the secondary literature. As for the methodological approach, text analysis of historical documents constituted our privileged modus operandi. This paper is the expression of a collaborative historical research program focused on the thermodynamic foundations of physics–chemistry relationship; early results have already been published by the same authors upon the concepts of reversibility––and––thermal equilibrium. (shrink)

Spiders’ nests, birds’ wings, airplanes, and scientific theories are all instances of adaptations. Instructionist theories implies that adaptive novelties are imposed directly on an entity by the environment while selectionist theories explains adaptive novelties to be the product of mechanisms including trial and error . This article argues that adaptive novelties are the result of selectionist mechanisms while instructionist production of adaptive novelties is impossible due to the second law of thermodynamics. Even long-term preservation of adaptive information is (...) dependent on selectionist mechanisms. These findings have important implications for both human and societal development because of the prevalence of instructionist theories. (shrink)

It is argued that if the non-unitary measurement transition, as codified by Von Neumann, is a real physical process, then the ‘probability assumption’ needed to derive the Second Law of Thermodynamics naturally enters at that point. The existence of a real, indeterministic physical process underlying the measurement transition would therefore provide an ontological basis for Boltzmann’s Stosszahlansatz and thereby explain the unidirectional increase of entropy against a backdrop of otherwise time-reversible laws. It is noted that the Transactional Interpretation (...) of quantum mechanics provides such a physical account of the non-unitary measurement transition, and TI is brought to bear in finding a physically complete, non-ad hoc grounding for the Second Law. (shrink)

We present a Gedankenexperiment that leads to a violation of detailed balance if quantum mechanical transition probabilities are treated in the usual way by applying Fermi’s “golden rule”. This Gedankenexperiment introduces a collection of two-level systems that absorb and emit radiation randomly through non-reciprocal coupling to a waveguide, as realized in specific chiral quantum optical systems. The non-reciprocal coupling is modeled by a hermitean Hamiltonian and is compatible with the time-reversal invariance of unitary quantum dynamics. Surprisingly, the combination of non-reciprocity (...) with probabilistic radiation processes entails negative entropy production. Although the considered system appears to fulfill all conditions for Markovian stochastic dynamics, such a dynamics violates the Clausius inequality, a formulation of the second law of thermodynamics. Several implications concerning the interpretation of the quantum mechanical formalism are discussed. (shrink)

The arrow of time is a familiar phenomenon we all know from our experience: we remember the past but not the future and control the future but not the past. However, it takes an effort to keep records of the past, and to affect the future. For example, it would take an immense effort to unmix coffee and milk, although we easily mix them. Such time directed phenomena are sub- sumed under the Second Law of Thermodynamics. This law (...) characterizes our experience of the arrow of time in terms of an increase of a theoretical magnitude called entropy. Statistical mechan- ics tries to explain the Second Law as an effect of the behavior of the microscopic particles that make up the universe. Since our senses are too coarse to see this microstructure, statistical mechanics describes our experience in terms of probability, or in terms of the partial information we have about the particles. In this paper we explain the workings of statistical mechanics; how it accounts for probability as an objective feature of the world based on the underlying dynamics; how it accounts for our memories of the past; how the statistical mechanical probability under- writes the Second Law; and how, at the same time, it leads to a violation of the Second Law by the so-called Maxwell’s Demon. (shrink)

In a previous work (M. Campisi. Stud. Hist. Phil. M. P. 36 (2005) 275-290) we have addressed the mechanical foundations of equilibrium thermodynamics on the basis of the Generalized Helmholtz Theorem. It was found that the volume entropy provides a good mechanical analogue of thermodynamic entropy because it satisfies the heat theorem and it is an adiabatic invariant. This property explains the ``equal'' sign in Clausius principle ($S_f \geq S_i$) in a purely mechanical way and suggests that the volume (...) entropy might explain the ``larger than'' sign (i.e. the Law of Entropy Increase) if non adiabatic transformations were considered. Based on the principles of microscopic (quantum or classical) mechanics here we prove that, provided the initial equilibrium satisfy the natural condition of decreasing ordering of probabilities, the expectation value of the volume entropy cannot decrease for arbitrary transformations performed by some external sources of work on a insulated system. This can be regarded as a rigorous quantum mechanical proof of the Second Law. We discuss how this result relates to the Minimal Work Principle and improves over previous attempts. The natural evolution of entropy is towards larger values because the natural state of matter is at positive temperature. Actually the Law of Entropy Decrease holds in artificially prepared negative temperature systems. (shrink)

It was first suggested by Albert that the existence of real, physical non-unitarity at the quantum level would yield a complete explanation for the increase of entropy over time in macroscopic systems. An alternative understanding of the source of non-unitarity is presented herein, in terms of the Transactional Interpretation. The present model provides a specific physical justification for Boltzmann’s Stosszahlansatz, thereby changing its status from an ad hoc postulate to a theoretically grounded result, without requiring any change to the basic (...) quantum theory. In addition, it is argued that TI provides an elegant way of reconciling, via collapse, the time-reversible Liouville evolution with the time-irreversible evolution inherent in master equations. The present model is contrasted with the GRW ‘spontaneous collapse’ theory previously suggested for this purpose by Albert. (shrink)

The arrow of time is a familiar phenomenon we all know from our experience: we remember the past but not the future and control the future but not the past. However, it takes an effort to keep records of the past, and to affect the future. For example, it would take an immense effort to unmix coffee and milk, although we easily mix them. Such time directed phenomena are subsumed under the Second Law of Thermodynamics. This law characterizes (...) our experience of the arrow of time in terms of an increase of a theoretical magnitude called entropy. Statistical mechanics tries to explain the Second Law as an effect of the behavior of the microscopic particles that make up the universe. Since our senses are too coarse to see this microstructure, statistical mechanics describes our experience in terms of probability, or in terms of the partial information we have about the particles. In this paper we explain the workings of statistical mechanics; how it accounts for probability as an objective feature of the world based on the underlying dynamics; how it accounts for our memories of the past; how the statistical mechanical probability underwrites the Second Law; and how, at the same time, it leads to a violation of the Second Law by the so‐called Maxwell’s Demon. (shrink)

If one demystifies entropy the second law of thermodynamics comes out as an emergent property entirely based on the simple dynamic mechanical laws that govern the motion and energies of system parts on a micro-scale. The emergence of the second law is illustrated in this paper through the development of a new, very simple and highly efficient technique to compare time-averaged energies in isolated conservative linear large scale dynamical systems. Entropy is replaced by a notion that is (...) much more transparent and more or less dual called ectropy. Ectropy has been introduced before but we further modify the notion of ectropy such that the unit in which it is expressed becomes the unit of energy. The second law of thermodynamics in terms of ectropy states that ectropy decreases with time on a large enough time-scale and has an absolute minimum equal to zero. Zero ectropy corresponds to energy equipartition. Basically we show that by enlarging the dimension of an isolated conservative linear dynamical system and the dimension of the system parts over which we consider time-averaged energy partition, the tendency towards equipartition increases while equipartition is achieved in the limit. This illustrates that the second law is an emergent property of these systems. Finally from our large scale linear dynamic model we clarify Loschmidt’s paradox concerning the irreversible behavior of ectropy obtained from the reversible dynamic laws that govern motion and energy at the micro-scale. (shrink)

Well known quantum and time paradoxes, and the difficulty to derive the second law of thermodynamics, are proposed to be the result of our historically grown paradigm for energy: it is just there, the capacity to do work, not directly related to change. When the asymmetric nature of energy is considered, as well as the involvement of energy turnover in any change, so that energy can be understood as fundamentally "dynamic", and time-oriented (new paradigm), these paradoxes and problems (...) dissolve. The most basic consequence concerns the particle-wave dualism. For a reversible inter-conversion of a particle into a wave, subject to a dynamic energy, a self-image of information has to be generated: quantum theory has to be complemented by a theory of information. Then, quantum processes can be derived from classical ones and the second law of thermodynamics with the tendency of increasing entropy follows in a straightforward way. (shrink)

The epistemic arrow of time is the fact that our knowledge of the past seems to be both of a different kind and more detailed than our knowledge of the future. Just like with the other arrows of time, it has often been speculated that the epistemic arrow arises due to the second law of thermodynamics. In this paper, we investigate the epistemic arrow of time using a fully formal framework. We begin by defining a memory system as (...) any physical system whose present state can provide information about the state of the external world at some time other than the present. We then identify two types of memory systems in our universe, along with an important special case of the first type, which we distinguish as a third type of memory system. We show that two of these types of memory systems are time-symmetric, able to provide knowledge about both the past and the future. However, the third type of memory systems exploits the second law of thermodynamics, at least in all of its instances in our universe that we are aware of. The result is that in our universe, this type of memory system only ever provides information about the past. We also argue that human memory is of this third type, completing the argument. We end by scrutinizing the basis of the second law itself. This uncovers a previously unappreciated formal problem for common arguments that try to derive the second law from the “Past Hypothesis”, i.e., from the claim that the very early universe was in a state of extremely low entropy. Our analysis is indebted to prior work by one of us but expands and improves upon this work in several respects. (shrink)

We show that the velocity distribution in rarefied (i.e., Knudsen) gases is spontaneously weighted in favor of small speeds away from the Maxwellian distribution corresponding to the temperature of the container walls—despite thermodynamic equilibrium with the walls. The consequent paradox concerning the second law of thermodynamics is discussed.

Well known quantum and time paradoxes, and the difficulty to derive the second law of thermodynamics, are proposed to be the result of our historically grown paradigm for energy: it is just there, the capacity to do work, not directly related to change. When the asymmetric nature of energy is considered, as well as the involvement of energy turnover in any change, so that energy can be understood as fundamentally "dynamic", and time-oriented, these paradoxes and problems dissolve. The (...) most basic consequence concerns the particle-wave dualism. For a reversible inter-conversion of a particle into a wave, subject to a dynamic energy, a self-image of information has to be generated: quantum theory has to be complemented by a theory of information. Then, quantum processes can be derived from classical ones and the second law of thermodynamics with the tendency of increasing entropy follows in a straightforward way. (shrink)

Sheehan and coworkers have claimed [D. P. Sheehan et al., Found. Phys. 30, 1227 ; 32, 441 ; D. P. Sheehan, in Quantum Limits to the Second Law, AIP Conference Proceedings 643, p. 391] that a dilute gas trapped between an external shell and a gravitator can support a steady state in which energy flux by particles in one direction is balanced by energy flux by radiation in the opposite direction, and in which work can be extracted from an (...) isothermal heat reservoir, thereby violating the second law of thermodynamics. In this paper, we identify a fundamental error in their simulation and analysis of their model system that vitiates their conclusions. We analyze a simpler, exactly soluble, three-dimensional model of a very dilute gas in a gravitational field between two thermal reservoirs, and show that their conclusions are not supported for the simple model. We show that their method of simulation, when applied to either the simple model or their more complex model under simpler conditions where the answers are known, leads to unphysical results. We also show that, when appropriate sampling is done, their model gives results in accord with the second law and detailed balance. (shrink)

It is commonly thought that there is some tension between the second law of thermodynam- ics and the time reversal invariance of the microdynamics. Recently, however, Jos Uffink has argued that the origin of time reversal non-invariance in thermodynamics is not in the second law. Uffink argues that the relationship between the second law and time reversal invariance depends on the formulation of the second law. He claims that a recent version of the second (...) law due to Lieb and Yngvason allows irreversible processes, yet is time reversal invariant. In this paper, I attempt to spell out the traditional argument for incompatibility between the second law and time reversal invariant dynamics, making the assumptions on which it depends explicit. I argue that this argument does not vary with different versions of the second law and can be formulated for Lieb and Yngvason's version as for other versions. Uffink's argument regarding time reversal invariance in Lieb and Yngvason is based on a certain symmetry of some of their axioms. However, these axioms do not constitute the full expression of the second law in their system. (shrink)

After deconstructing the thermodynamic concepts of work and waste, I take up Howard Odum’s idea of energy quality, which tallies the overall amount of energy needed to be dissipated in order to accomplish some work of interest. This was developed from economic considerations that give obvious meaning to the work accomplished. But the energy quality idea can be used to import meaning more generally into Nature. It could be viewed as projecting meaning back from any marked work into preceding energy (...) gradient dissipations that immediately paved the way for it. But any work done by an abiotic dissipative structure, since it would be without positive economic significance, would also be difficult to mark as a starting point for the energy quality calculation. Furthermore, any destructive work as by hurricanes or floods, with negative economic significance, would not seem to merit the quality calculation either. But there has been abiotic work of keen interest to us—that which mediated the origin of life. Some kind of abiotic dissipative structures had to have been the framework that fostered this process, regardless of how it might come to be understood in detail. Since all dissipative structures have the same thermodynamic and informational organization in common, any of them might provide the material context for the origin of something. So we can pick any starting point we wish, and calculate backward what sequence of energy usages would have been necessary to set it up. Given such an open ended project, we could not find an obvious place in any sequence to stop and start the forward the calculation, and so we would need to take it right back to an ultimate beginning, like the insolation of some area, or the outpouring of Earth’s thermal energy. Any energy dissipation might be the beginning of something of importance, and so Nature is as replete with potential meanings as it is with energy gradients. (shrink)

After deconstructing the thermodynamic concepts of work and waste, I take up Howard Odum’s idea of energy quality, which tallies the overall amount of energy needed to be dissipated in order to accomplish some work of interest. This was developed from economic considerations that give obvious meaning to the work accomplished. But the energy quality idea can be used to import meaning more generally into Nature. It could be viewed as projecting meaning back from any marked work into preceding energy (...) gradient dissipations that immediately paved the way for it. But any work done by an abiotic dissipative structure, since it would be without positive economic significance, would also be difficult to mark as a starting point for the energy quality calculation. Furthermore, any destructive work as by hurricanes or floods, with negative economic significance, would not seem to merit the quality calculation either. But there has been abiotic work of keen interest to us—that which mediated the origin of life. Some kind of abiotic dissipative structures had to have been the framework that fostered this process, regardless of how it might come to be understood in detail. Since all dissipative structures have the same thermodynamic and informational organization in common, any of them might provide the material context for the origin of something. So we can pick any starting point we wish, and calculate backward what sequence of energy usages would have been necessary to set it up. Given such an open ended project, we could not find an obvious place in any sequence to stop and start the forward the calculation, and so we would need to take it right back to an ultimate beginning, like the insolation of some area, or the outpouring of Earth’s thermal energy. Any energy dissipation might be the beginning of something of importance, and so Nature is as replete with potential meanings as it is with energy gradients. (shrink)

In 2000, a simple, foundational thermodynamic paradox was proposed: a sealed blackbody cavity contains a diatomic gas and a radiometer whose apposing vane surfaces dissociate and recombine the gas to different degrees (A $_{2} \rightleftharpoons $ 2A). As a result of differing desorption rates for A and A $_{2}$ , there arise between the vane faces permanent pressure and temperature differences, either of which can be harnessed to perform work, in apparent conflict with the second law of thermodynamics. (...) Here we report on the first experimental realization of this paradox, involving the dissociation of low-pressure hydrogen gas on high-temperature refractory metals (tungsten and rhenium) under blackbody cavity conditions. The results, corroborated by other laboratory studies and supported by theory, confirm the paradoxical temperature difference and point to physics beyond the traditional understanding of the second law. (shrink)

A unique solution is proposed to the problem of how thermodynamic processes between thermodynamic systems at relative rest “appear” to a moving observer. Assuming only transformations for entropy, pressure, and volume and the invariance of the “fundamental thermodynamic equation,” one can derive transformations for (thermodynamic) energy and temperature. The invariance of the first and second laws entails transformations for work and heat. All thermodynamic relations become Lorentz-invariant. The transformations thus derived are in principle equivalent to those of Einstein and (...) Planck, except that our expressions for energy and work do not include the mass motion energy. This results in a simpler formulation and endows our transformations (especially that of temperature) with a straightforward physical interpretation. (shrink)

This paper investigates what the source of time asymmetry is in thermodynamics, and comments on the question whether a time-symmetric formulation of the Second Law is possible.

One finds, in Maxwell's writings on thermodynamics and statistical physics, a conception of the nature of these subjects that differs in interesting ways from the way that they are usually conceived. In particular, though—in agreement with the currently accepted view—Maxwell maintains that the second law of thermodynamics, as originally conceived, cannot be strictly true, the replacement he proposes is different from the version accepted by most physicists today. The modification of the second law accepted by most (...) physicists is a probabilistic one: although statistical fluctuations will result in occasional spontaneous differences in temperature or pressure, there is no way to predictably and reliably harness these to produce large violations of the original version of the second law. Maxwell advocates a version of the second law that is strictly weaker; the validity of even this probabilistic version is of limited scope, limited to situations in which we are dealing with large numbers of molecules en masse and have no ability to manipulate individual molecules. Connected with this is his concept of the thermodynamic concepts of heat, work, and entropy; on the Maxwellian view, these are concepts that must be relativized to the means we have available for gathering information about and manipulating physical systems. The Maxwellian view is one that deserves serious consideration in discussions of the foundation of statistical mechanics. It has relevance for the project of recovering thermodynamics from statistical mechanics because, in such a project, it matters which version of the second law we are trying to recover. (shrink)

This paper investigates Jaynes’ “unbelievably short proof” of the 2nd law of thermodynamics. It assesses published criticisms of the proof and concludes that these criticisms miss the mark by demanding results that either import expectations of a proof not consistent with an information-theoretic approach, or would require assumptions not employed in the proof itself, as it looks only to establish a weaker conclusion. Finally, a weakness in the proof is identified and illustrated. This weakness stems from the fact the (...) Jaynes’ assumption of unitary evolution is too strong given his perspective, rather than too weak to provide the desired results. (shrink)

In the history of thermodynamics, two dates stand out as especially important: 1824, when Sadi Carnot's brilliant memoirRéflexions sur la puissance motrice du feuappeared in print; and 1850, when Rudolf Clausius published his similarly titled paper ‘Ueber die bewegende Kraft der Wärme’. In this paper Clausius narrowly beat the Scottish physicist William Thomson to the solution of a puzzle which had been highlighted in the latter's recent publications: how could Carnot's theory, with all its intellectual attractions, be reconciled with (...) the newly discovered principle of the inter-convertibility of heat and work? Clausius's solution (as is well known) was to replace Carnot's axiom of heat conservation, with the axiom now known as the second law of thermodynamics. (shrink)

We present here a cosmological myth, alternative to "the Universe Story" and "the Epic of Evolution", highlighting the roles of entropy and dissipative structures in the universe inaugurated by the Big Bang. Our myth offers answers these questions: Where are we? What are we? Why are we here? What are we to do? It also offers answers to a set of "why" questions: Why is there anything at all? and Why are there so many kinds of systems? - the answers (...) coming from cosmology and physics ; Why do systems not last once they exist? - the answer coming from a materialist interpretation of information theory; and, Why are systems just the way they are and not otherwise? - the answer coming from evolutionary biology. We take into account the four kinds of causation designated by Aristotle as efficient, final, and material formal, with the Second Law of thermodynamics in the role of final cause. Conceptual problems concerning reductionism, "teleology", and the choice/chance distinction are dealt with in the framework of specification hierarchy, and the moral implications of our story explored in the conclusion. (shrink)

The standard argument for the Lorentz invariance of the thermodynamic entropy in equilibrium is based on the assumption that it is possible to perform an adiabatic transformation whose only outcome is to accelerate a macroscopic body, keeping its rest mass unchanged. The validity of this assumption constitutes the very foundation of relativistic thermodynamics and needs to be tested in greater detail. We show that, indeed, such a transformation is always possible, at least in principle. The only two assumptions invoked (...) in the proof are that there is at least one inertial reference frame in which the second law of thermodynamics is valid and that the microscopic theory describing the internal dynamics of the body is a field theory, with Lorentz invariant Lagrangian density. The proof makes no reference to the connection between entropy and probabilities and is valid both within classical and quantum physics. To avoid any risk of circular reasoning, we do not postulate that the laws of thermodynamics are the same in every reference frame, but we obtain this fact as a direct consequence of the Lorentz invariance of the entropy. (shrink)

We present here a cosmological myth, alternative to "the Universe Story" and "the Epic of Evolution", highlighting the roles of entropy and dissipative structures in the universe inaugurated by the Big Bang. Our myth offers answers these questions: Where are we? What are we? Why are we here? What are we to do? It also offers answers to a set of "why" questions: Why is there anything at all? and Why are there so many kinds of systems? - the answers (...) coming from cosmology and physics ; Why do systems not last once they exist? - the answer coming from a materialist interpretation of information theory; and, Why are systems just the way they are and not otherwise? - the answer coming from evolutionary biology. We take into account the four kinds of causation designated by Aristotle as efficient, final, and material formal, with the Second Law of thermodynamics in the role of final cause. Conceptual problems concerning reductionism, "teleology", and the choice/chance distinction are dealt with in the framework of specification hierarchy, and the moral implications of our story explored in the conclusion. (shrink)

Despite over one-hundred years of effort, the origin of temporal asymmetry in the physical world still eludes us. While much has been learned about the role played by fundamental instabilities in microdynamics, by the imperfect isolation of systems and by cosmological facts in the origin of the behavior described by kinetic theory and thermodynamics, important puzzles still remain which continue to make the origins of asymmetric thermal behavior out of dynamically time symmetric underlying laws mysterious to us.

Jacob Bekenstein's identification of black hole event horizon area with entropy proved to be a landmark in theoretical physics. In this paper we trace the subsequent development of the resulting generalized second law of thermodynamics (GSL), especially its extension to incorporate cosmological event horizons. In spite of the fact that cosmological horizons do not generally have well-defined thermal properties, we find that the GSL is satisfied for a wide range of models. We explore in particular the case of (...) an asymptotically de Sitter universe filled with a gas of small black holes as a means of casting light on the relative entropic ‘worth’ of black hole versus cosmological horizon area. We present some numerical solutions of the generalized total entropy as a function of time for certain cosmological models, in all cases confirming the validity of the GSL. (shrink)

Language & Logic -- Glossary -- Aristotle's syllogisms -- Russell's paradox & Frege's logicism -- profile: Aristotle -- Russell's theory of description -- Frege's puzzle -- Gödel's theorem -- Epimenides' liar paradox -- Eubulides' heap -- Science & Epistemology -- Glossary -- I think therefore I am -- Gettier's counter example -- profile: Karl Popper -- The brain in a vat -- Hume's problem of induction -- Goodman's gruesome riddle -- Popper's conjectures & refutations -- Kuhn's scientific revolutions -- Mind (...) & Metaphysics -- Glossary -- Descartes mind-body problem -- Brentano's intentionality -- Fodor's language of thought -- Parfit's persons -- profile: René Descartes -- Chalmer's zombies -- Zeno's paradoxes -- Kant's left hand -- Theseus' ship -- Laplace's demon, determinism, & free will -- Ryle's ghost in the machine -- Ethics & Political Philosophy -- Glossary -- Aristotle's ethics -- States of nature and the social contract -- Kant's categorical imperative -- profile: Immanuel Kant -- Mill's utilitarianism -- Marx's historical materialism -- The trolley problem -- Religion -- Glossary -- Aquinas' five ways -- Anselm's ontological argument -- profile: Thomas Aquinas -- Epicurus' riddle -- Paley's watchmaker -- Pascal's wager -- Hume against miracles -- Grand Moments -- Glossary -- Socrates' method -- Plato's cave -- Aristotle's four causes -- Lucretius' atomism -- profile: Ludwig Wittgenstein -- Berkeley's idealism -- Kant's synthetic a priori -- Hegel's dialectic -- James' pragmatism -- Moore's common sense -- Wittgenstein's picture theory of language -- Continental Philosophy -- Glossary -- Nietzsche's Superman -- profile: Friedrich Nietzsche -- Derrida's deconstruction -- Heidegger's nothing -- Sartre's bad faith. (shrink)