Recent models in quantum cosmology make use of the concept of imaginary time. These models all conjecture a join between regions of imaginary time and regions of real time. We examine the model of James Hartle and Stephen Hawking to argue that the various no-boundary attempts to interpret the transition from imaginary to real time in a logically consistent and physically significant way all fail. We believe this conclusion also applies to quantum tunneling models, such as that proposed by Alexander (...) Vilenkin. We conclude, therefore, that the notion of emerging from imaginary time is incoherent. A consequence of this conclusion seems to be that the whole class of cosmological models appealing to imaginary time is thereby refuted. (shrink)
The following is an essay review of Paul Needham's translation of Pierre Duhem's Lemixte et la combinaison chimique and a numberof other essays. In this review we describe theintent and general features of Le mixte and try to place it in the larger context of Duhem'sprogram for energetics. The long essay (Essay3) opposing Marcellin Berthelot'sthermochemistry is singled out for detailedcommentary, since it gives Duhem's reasons forendorsing Josiah Willard Gibbs's chemicalstatics. We argue that a chemical mechanics ofa Gibbsian sort, defended in (...) Le mixte and otheressays in this volume, was the inspiration for,and basis of, Duhem's energetics. Needham'swelcome translations help an English-languageaudience to better understand the basiccontours of Duhem's important, if ultimatelymisguided, project. We conclude with somecomments on the difficulties in translatingDuhem and on the quality of the translationsNeedham has provided. (shrink)
This essay focuses on the place of the second law of thermodynamics in Wilhelm Ostwald's physical chemistry. After a brief introduction to his energetic theory, which was supposed to be a generalization of thermodynamics, I contrast Ostwald's understanding of the second law, which ignored entropy and irreversibility, with Max Planck's, which emphasized both. I then consider how Ostwald sought to develop physical chemistry without any concern for irreversibility and little concern for entropy, and I argue that he was mistaken.
The essay "Physique de croyant" is an important statement of Pierre Duhem's position on the relation between his science and his religion. Duhem trod a difficult path, some might say an impossible one, in Republican France because he was both a physicist and a devout Catholic. In this essay, using "Physique de croyant" as a touchstone, I explore the way in which he tried to reconcile his conflicting allegiances. There are several strands in Duhem's strategy that need to be teased (...) out. First, Duhem sought to defend his science against the charge that it was materialist and atheist. He did this with his claim, usually called the autonomy thesis, that physics and metaphysics are fundamentally different enterprises—that physics, properly conducted, has no metaphysical implications and requires no metaphysical support. This did not deny metaphysics its rightful territory. Second, Duhem used his segregationist position to defend the Roman Catholic Church against the assaults of the positivist scientism then in favor with the Republicans. Third, he also sought to protect his science against fellow Catholics who wanted to use it for polemical purposes. I develop and evaluate these lines of defense. (shrink)
This is the third of a series of essays on the development and reception of Wilhelm Ostwald’s energetics. The first essay described the chemical origins of Ostwald’s interest in the energy concept and his motivations for seeking a comprehensive science of energy. The second essay and the present one discuss his various attempts, beginning in 1891 and extending over almost 3 years, to develop a consistent and coherent energetic theory. A final essay will consider reactions to this work and Ostwald’s (...) replies, and will also seek to evaluate his program of research. Ostwald’s project—to reconstruct physics and chemistry “as a pure energetics”—is worth attending to for several reasons: first, because Ostwald did ground-breaking work in chemistry (he was awarded a Nobel Prize in 1909 for his studies in catalysis and rates of reaction); second, because an important school of physical chemistry formed around him at Leipzig, a school that promoted his ideas; and, finally, because he was a prominent and vigorous participant in debates at the end of the nineteenth century concerning the proper course of physical theory. (shrink)
Quentin Smith has been arguing for more than a decade that the universe is uncaused. For nearly as long he has also argued that it appeared spontaneously from literally nothing. I have replied to these arguments in many places, including a recent essay in Philosophy. Now, apparently, Smith has changed his mind: in his most recent contribution to Philosophy, he argues not that the universe is uncaused, but that it is self-caused. His motives for so doing remain much the same, (...) however: he would like to undermine the efforts of theists to show that the universe requires an external cause, by arguing that the universe can cause itself (580). I do not think that the arguments he gives for this new position are any more plausible than his older ones for an uncaused universe, so I don't think that he has advanced the cause of atheism. This essay defends that evaluation. (shrink)
Quentin Smith has argued that it is logically impossible for there to be a divine cause of the universe. His argument is based on a Humean analysis of causation (confined to event causation, specifically excluding any consideration of agency) and a principle drawn from that analysis that he takes to be a logical requirement for every possibly valid theory of causation. He also thinks that all divine volitions are efficacious of logical necessity. We argue that all of these claims are (...) faulty, and that theists can resist Smith’s arguments without merely begging the question in favor of a divine cause. (shrink)
Fr. Ernan McMullin wrote at least five essays in which anthropic reasoning in cosmology was a prominent topic of discussion and evaluation. Unlike thewritings of many passionate advocates and hostile critics of the so-called “anthropic principle” , they are all nuanced essays—very much in keeping with Fr. Ernan’s usual approach to difficult and controversial subjects. Supporters of that approach will praise what he has to say as properly cautious and circumspect; others will likely find him often indecisive. In this essay, (...) I will indicate why, while I largely agree with the first group of readers, I am nevertheless sympathetic to the concerns of the latter group. (shrink)
This essay has three interrelated goals: first, to sketch the basic contours of Georg Helm's energetic theory; second, to describe his attempt in his Grundzüge der mathematischen Chemie. Energetik der chemischen Erscheinungen (1894) to apply that theory to the (then) burgeoning new field of physical chemistry. This is of some interest historically, since Helm's work is the most sophisticated attempt to develop the whole of physical chemistry mathematically from an energetic point of view. Nevertheless, it is seriously flawed technically. Moreover, (...) that development is inconsistent with Helm's considered way of thinking about energy and energetic change. So a third goal of the essay is to explain his mature conception of the goal of energetics. I begin with a brief introduction to Helm and energetics, and end with some general conclusions about the success of Helm's mathematische Chemie. (shrink)
Recently, different versions of a cosmological “anthropic principle” have been used to try to explain various features of the universe. This essay, which focuses on some early uses of AP, argues that even modest appeals to it cannot be regarded as genuinely explanatory.