We discuss Boltzmann’s probabilistic explanation of the second law of thermodynamics providing a comprehensive presentation of what is called today the typicality account. Countering its misconception as an alternative explanation, we examine the relation between Boltzmann’s H-theorem and the general typicality argument demonstrating the conceptual continuity between the two. We then discuss the philosophical dimensions of the concept of typicality and its relevance for scientific reasoning in general, in particular for understanding the reduction of macroscopic laws to microscopic laws. Finally, (...) we reply to various common criticisms of the typicality account. (shrink)

Recent discussions of theorigins of the thermodynamical temporal asymmetry (thearrow of time) by Huw Price and others arecritically assessed. This serves as amotivation for consideration of relationshipbetween thermodynamical and cosmologicalcauses. Although the project of clarificationof the thermodynamical explanandum is certainlywelcome, Price excludes another interestingoption, at least as viable as the sort ofAcausal-Particular approach he favors, andarguably more in the spirit of Boltzmannhimself. Thus, the competition of explanatoryprojects includes three horses, not two. Inaddition, it is the Acausal-Particular approachthat could benefit enormously (...) from dissociationfrom fanciful ideas of low-entropy futureboundary conditions entertained by Price. Novelrevolutionary developments in observationalcosmology, as well as in the nascentastrophysical discipline of physicaleschatology, have obliterated such hypotheses.Also, the Acausal-Anthropic approach wepropose, offers another clear instance ofdisteleological nature of the anthropicprinciple. (shrink)

Relying on the universality of quantum mechanics and on recent results known as the “threshold theorems,” quantum information scientists deem the question of the feasibility of large‐scale, fault‐tolerant, and computationally superior quantum computers as purely technological. Reconstructing this question in statistical mechanical terms, this article suggests otherwise by questioning the physical significance of the threshold theorems. The skepticism it advances is neither too strong (hence is consistent with the universality of quantum mechanics) nor too weak (hence is independent of technological (...) contingencies). *Received June 2009; revised August 2009. †To contact the author, please write to: Department of History and Philosophy of Science, College of Arts and Sciences, Indiana University, Bloomington, IN 47405; e‐mail: [email protected]. (shrink)

Thermodynamics is the science that describes much of the time asymmetric behavior found in the world. This entry's first task, consequently, is to show how thermodynamics treats temporally ‘directed’ behavior. It then concentrates on the following two questions. (1) What is the origin of the thermodynamic asymmetry in time? In a world possibly governed by time symmetric laws, how should we understand the time asymmetric laws of thermodynamics? (2) Does the thermodynamic time asymmetry explain the other temporal asymmetries? Does it (...) account, for instance, for the fact that we know more about the past than the future? The discussion thus divides between thermodynamics being an explanandum or explanans. In the former case the answer will be found in philosophy of physics; in the latter case it will be found in metaphysics, epistemology, and other fields, though in each case there will be blurring between the disciplines. (shrink)

As the past-future asymmetry – that fact that we have records of the past but not the future – is still a puzzle the aim of this paper is twofold: a) to explain the asymmetry and its status in philosophy and physics and to critically review the proposed solutions to this puzzle; b) to advance a dynamic solution to the puzzle in terms of the ‘universality’ of the entropy relation in statistical mechanics.

The aim of this paper is to show that a new understanding of fundamentality, can be applied successfully in classical cosmology and is able to improve a fundamental understanding of cosmological time asymmetries. In the introduction, I refer to various views from different literature. I begin by arguing against various arguments, provided in favour of the view that the directedness of time is not a fundamental property of nature, ]) in section 1.1. Next, in section 1.2, I refer to some (...) suggestions for defining the arrow of time in cosmology via the behaviour of entropy. In addition, I argue that the various types of such approaches cannot explain the occurrence of a fundamental arrow of time in cosmology; I believe that this argument is mostly acknowledged in the literature. Moreover, in section 1.3, I broaden my scope in order to formulate approaches in the context of theories of a multiverse and hyperbolic curved spacetimes as well. After that overview of different approaches, I provide a definition of my understanding of fundamentality. To verify the effectiveness of this new understanding, I present an example to show that it can be applied in classical cosmology in sections 3.1–3.5. Finally, in section 4 I conclude by regarding the effects of adding the new understanding of fundamentality to classical cosmology. (shrink)