In the increasing body of metatheoretical literature on "causal mechanisms," definitions of "mechanism" proliferate, and these increasingly divergent definitions reproduce older theoretical and methodological oppositions. The reason for this proliferation is the incompatibility of the various metatheoretical expectations directed to them: (1) to serve as an alternative to the scientific theory of individual behavior (for some social theorists, most notably Jon Elster); (2) to provide solutions for causal inference problems in the quantitative social sciences, in social history, and (...) in the (3) qualitative research context; and (4) to serve as an alternative for narratives (Charles Tilly). Mechanisms can do (1) only as under-specified law-like regularities, deliver (2) as robust generative processes represented by models, and accomplish (3) as fragile generative processes (stories), but these are not all compatible. (edited). (shrink)

This book presents a historical and scientific analysis as historical epistemology of the science of weights and mechanics in the sixteenth century, particularly as developed by Tartaglia in his Quesiti et inventioni diverse, Book VII and Book VIII (1546; 1554). -/- In the early 16th century mechanics was concerned mainly with what is now called statics and was referred to as the Scientia de ponderibus, generally pursued by two very different approaches. The first was usually referred to as Aristotelian, where (...) the equilibrium of bodies was set as a balance of opposite tendencies to motion. The second, usually referred to as Archimedean, identified statics with centrobarica, the theory of centres of gravity based on symmetry considerations. In between the two traditions the Italian scholar Niccolò Fontana, better known as Tartaglia (1500?–1557), wrote the treatise Quesiti et inventioni diverse (1546). -/- This volume consists of three main parts. In the first, a historical excursus regarding Tartaglia’s lifetime, his scientific production and the Scientia de ponderibus in the Arabic-Islamic culture, and from the Middle Ages to the Renaissance, is presented. Secondly, all the propositions of Books VII and VIII, by relating them with the Problemata mechanica by the Aristotelian school and Iordani opvsculvm de ponderositate by Jordanus de Nemore are examined within the history and historical epistemology of science. The last part is relative to the original texts and critical transcriptions into Italian and Latin and an English translation. -/- This work gathers and re-evaluates the current thinking on this subject. It brings together contributions from two distinguished experts in the history and historical epistemology of science, within the fields of physics, mathematics and engineering. It also gives much-needed insight into the subject from historical and scientific points of view. The volume composition makes for absorbing reading for historians, epistemologists, philosophers and scientists. (shrink)

The notions of conservation and relativity lie at the heart of classical mechanics, and were critical to its early development. However, in Newton’s theory of mechanics, these symmetry principles were eclipsed by domain-specific laws. In view of the importance of symmetry principles in elucidating the structure of physical theories, it is natural to ask to what extent conservation and relativity determine the structure of mechanics. In this paper, we address this question by deriving classical mechanics—both nonrelativistic and relativistic—using relativity and (...) conservation as the primary guiding principles. The derivation proceeds in three distinct steps. First, conservation and relativity are used to derive the asymptotically conserved quantities of motion. Second, in order that energy and momentum be continuously conserved, the mechanical system is embedded in a larger energetic framework containing a massless component that is capable of bearing energy (as well as momentum in the relativistic case). Imposition of conservation and relativity then results, in the nonrelativistic case, in the conservation of mass and in the frame-invariance of massless energy; and, in the relativistic case, in the rules for transforming massless energy and momentum between frames. Third, a force framework for handling continuously interacting particles is established, wherein Newton’s second law is derived on the basis of relativity and a staccato model of motion-change. Finally, in light of the derivation, we elucidate the structure of mechanics by classifying the principles and assumptions that have been employed according to their explanatory role, distinguishing between symmetry principles and other types of principles (such as compositional principles) that are needed to build up the theoretical edifice. (shrink)

In spite of being a well articulated proposal, the theory of quantum histories, in its different versions, suffers from certain difficulties that have been pointed out in the literature. Nevertheless, two facets of the proposal have not been sufficiently stressed. On the one hand, it is a non-collapse formalism that should be technically appropriate to supply descriptions based on quantum properties at different times. On the other hand, it intends to provide an interpretation of quantum mechanics that solves the traditional (...) puzzles of the theory. In this article we spell out the main criticisms to TQH and classify them into two groups: theoretical and interpretive. Whereas the latter might be ignored if the TQH were considered as a quantum formalism with its minimum interpretation, the former seems to point toward technical difficulties that must be faced in a theoretically adequate proposal. Precisely with the purpose of solving these difficulties, we introduce a different perspective, called Formalism of Generalized Contexts or Formalism of Contextual Histories, which supplies a precise condition for consistently talking of quantum properties at different times without the theoretical shortcomings of the TQH. (shrink)

This book presents a historical and scientific analysis as historical epistemology of the science of weights and mechanics in the sixteenth century, particularly as developed by Tartaglia in his Quesiti et inventioni diverse, Book VII and Book VIII (1546; 1554). In the early 16th century mechanics was concerned mainly with what is now called statics and was referred to as the Scientia de ponderibus, generally pursued by two very different approaches. The first was usually referred to as Aristotelian, where the (...) equilibrium of bodies was set as a balance of opposite tendencies to motion. The second, usually referred to as Archimedean, identified statics with centrobarica, the theory of centres of gravity based on symmetry considerations. In between the two traditions the Italian scholar Niccolò Fontana, better known as Tartaglia (1500?-1557), wrote the treatise Quesiti et inventioni diverse (1546). This volume consists of three main parts. In the first, a historical excursus regarding Tartaglia's lifetime, his scientific production and the Scientia de ponderibus in the Arabic-Islamic culture, and from the Middle Ages to the Renaissance, is presented. Secondly, all the propositions of Books VII and VIII, by relating them with the Problemata mechanica by the Aristotelian school and Iordani opvsculvm de ponderositate by Jordanus de Nemore are examined within the history and historical epistemology of science. The last part is relative to the original texts and critical transcriptions into Italian and Latin and an English translation. This work gathers and re-evaluates the current thinking on this subject. It brings together contributions from two distinguished experts in the history and historical epistemology of science, within the fields of physics, mathematics and engineering. It also gives much-needed insight into the subject from historical and scientific points of view. The volume composition makes for absorbing reading for historians, epistemologists, philosophers and scientists. (shrink)

While much interdisciplinarity brings together proximate fields, broad interdisciplinarity sees integration between disciplines that are perceived to be non-neighboring. This paper argues that the heterogeneity among disciplines in broad interdisciplinarity calls for stricter epistemic norms of testimony for experts that act as translators between the disciplines than those suggested for intra-scientific testimony. The paper is structured around two case studies: the affective turn in social theorizing and the use of quantum mechanics in critical theory as exemplified by Vicky Kirby’s use (...) of work by Karen Barad. These are argued to be instances of broad interdisciplinary borrowing where few translators have joint expertise in both disciplines. For most, therefore, the engagement with for instance the integration between quantum mechanics and critical theory is possible only by the aid of translators. For those without sufficient interactional expertise, however, the epistemic credentials of the translations they inevitably rely upon are inscrutable. Furthermore, any comparison between translations is challenged since translations are argued to be few due to the cognitive divergence between disciplines in broad interdisciplinarity. Consequently, the epistemic integrity of broad interdisciplinarity can only be secured through additional norms of testimony for translators. The paper proposes that (a) all translator’s testimony in broad interdisciplinarity must aim to be neutral with respect to disputed issues within the relevant disciplines and (b) any deviation from (a) must be clearly highlighted. (shrink)

The first edition of Newton’s Principia opens with a “Praefatio ad Lectorem.” The first lines of this Preface have received scant attention from historians, even though they contain the very first words addressed to the reader of one of the greatest classics of science. Instead, it is the second half of the Preface that historians have often referred to in connection with their treatments of Newton’s scientific methodology. Roughly in the middle of the Preface, Newton defines the purpose of philosophy (...) as a twofold task: to investigate the forces of the phenomena of nature and, once having established the forces, to demonstrate the remaining phenomena. Newton then introduces a distinction between the first two books, which deal with general propositions, and the third, where the propositions are applied to particular instances of celestial phenomena. From these phenomena, Newton claims, the force of gravity, thanks to which bodies tend toward the Sun, is derived. By assuming this force in mathematical propositions, other motions are deduced: the motions of the planets, the comets, the moon, and the sea. Newton then declares his hope that phenomena relative to small particles will also be explained, as per the celestial ones, thanks to the understanding of attractive forces hitherto unknown to philosophers. The Preface ends with a well-deserved laudatio of Edmond Halley and an apologetic passage concerning certain imperfections in the presentation of advanced subjects, such as the motions of the moon. It is these lines to which historians have given most attention in their various studies. (shrink)

Mechanisms, in the prominent biological sense of the term, are historical entities. That is, whether or not something is a mechanism for something depends on its history. Put differently, while your spontaneously-generated molecule-for-molecule double has a heart, and its heart pumps blood around its body, its heart does not have a mechanism for pumping, since it does not have the right history. My argument for this claim is that mechanisms have proper functions; proper functions are historical (...) entities; so, mechanisms are historical entities, too. This thesis runs against the mainstream new mechanist way of thinking about mechanisms, where mechanisms are generally thought of in an ahistorical way. After arguing for this thesis, I draw out some consequences for philosophy of science and metaphysics. (shrink)

Computing formulae and solving equations are essential elements of scientific analysis. While today digital tools are almost always applied, analog computing is a rich part of the larger history of science and technology. Graphical methods are an integral element of computing history and still find some use today. This paper presents the history of nomograms, a historically-relevant tool for solving mathematical problems in various branches of science and engineering; in particular, we consider their role in mechanical engineering, (...) especially for education, and discuss their mathematical properties. Each nomogram is a graphical description of a specific mathematical equation, designed such that the solution can be found through a simple geometric construction that can be performed with a straightedge. By design, using nomograms requires little skills and can be done even in adverse environments; a solution of sufficient accuracy for most purposes can then be found in a very short time. Another important advantage of nomograms is that they offer clear insight on the relationships between the variables, an insight which can be lost by looking at a complex equation. First introduced in the late $$19^{\textrm{th}}$$ century, nomograms were used by engineers and scientists due to their speed with respect to manual calculations, before being superseded by computers. While now mostly obsolete in practice, nomograms can still prove useful in workshops and teaching classes: we thus also discuss their educational applications and present a few original examples. (shrink)

In this paper, I will examine John Smeaton’s contribution to the vis viva controversy in Britain, focusing on how the hybridization of science, technology, and industry helped to establish vis viva, or mechanic power, as a measure of motive force. Smeaton, embodying the ‘hybrid expert’ who combined theoretical knowledge and practical knowhow, demonstrated that the notion of vis viva possessed a greater explanatory power than momentum, because it could be used to explain the difference in efficiency between overshot and undershot (...) waterwheels. Smeaton’s conclusions were correct since waterwheel efficiency was already measured in terms that were proportional to vis viva, not momentum, as a result of the industrial applications of waterwheel technology, which favored measuring efficiency by the product of mass and vertical displacement. Toward the end of the eighteenth century, the loss of motive force in the inelastic collision driving the undershot wheel began to be seen as equivalent to the expenditure of labor in the manufacture of commodities, further underlining how strictly scientific conclusions about motive force could have their origin in industrial practices. (shrink)

The following article by Grete Hermann arguably occupies an important place in the history of the philosophical interpretation of of quantum mechanics. The purpose of Hermann's writing on natural philosophy is to examine the revision of the law of causality which quantum mechanics seems to require at a fundamental level of theoretical description in physics. It is Hermann's declared intention to show that quantum mechanics does not disprove the concept of causality, "yet has clarified [it] and has removed from (...) it other principles which are not necessarily connected to it." She attempts to show that this most "obvious" counter-example to the aprioricity of causality, quantum theory, is in fact not a counter-example at all. (shrink)

It is argued that the conventional descriptions of chemical bonds as covalent, ionic, metallic, and Van der Waals are compromising the usefulness of quantum mechanics in the synthesis and design of new molecules and materials. Parallels are drawn between the state of chemistry now and when the idea that phlogiston was an element impeded the development of chemistry. Overcoming the current obstacles will require new methods to describe molecular structure and bonding, just as new concepts were needed before the phlogiston (...) theory could be set aside. (shrink)

In the consistent histories formalism one specifies a family of histories as an exhaustive set of pairwise exclusive descriptions of the dynamics of a quantum system. We define branching families of histories, which strike a middle ground between the two available mathematically precise definitions of families of histories, viz., product families and Isham’s history projector operator formalism. The former are too narrow for applications, and the latter’s generality comes at a certain cost, barring an intuitive reading of the “histories”. (...) Branching families retain the intuitiveness of product families, they allow for the interpretation of a history’s weight as a probability, and they allow one to distinguish two kinds of coarse-graining, leading to reconsidering the motivation for the consistency condition. (shrink)

While Aristotle is mostly famous as the father of natural teleology, De Groot sets out to offer us a picture of the “other,” hitherto neglected Aristotle, whose natural science is thoroughly influenced by mechanistic procedures and ideas. Her monograph is impressive: it provides a wealth of detailed and philosophically rich discussions of sometimes overlooked Aristotelian texts, diagrams, and tables that help visualize the often technical materials she discusses, and bold and original claims that will perhaps not convince everyone, but that (...) will need to be taken into account in future studies of Aristotle’s natural philosophy. By drawing attention to the operation of mechanical notions... (shrink)

Biology and history are often viewed as closely related disciplines, with biology informed by history, especially in its task of charting our evolutionary past. Maximizing the opportunities for cross-fertilization in these two fields requires an accurate reckoning of their commonalities and differences-precisely what this volume sets out to achieve. Specially commissioned essays by a team of recognized international researchers cover the full panoply of topics in these fields and include notable contributions on the correlativity of evolutionary and historical (...) explanations, applying to history the latest causal-mechanical approach in the philosophy of biology, and the question of generalized laws that might pertain across the two subjects. The collection opens with a vital interrogation of general issues on explanation that apart from potentially fruitful areas of interaction (could the etiology of the causal-mechanical perspective in biology account for the historical trajectory of the Roman Empire?) this volume also seeks to chart relative certainties distinguishing explanations in biology and history. It also assesses techniques such as the use of probabilities in biological reconstruction, deployed to overcome the inevitable gaps in physical evidence on early evolution. Methodologies such as causal graphs and semantic explanation receive in-depth analysis. Contributions from a host of prominent and widely read philosophers ensure that this new volume has the stature of a major addition to the literature. (shrink)

The sub-title of this essay might very well be: “A Study in the Biology and Mechanics of Historical Research and Interpretation”. A study in biology because historians can be divided into two classes: invertebrates and vertebrates. The invertebrate historians are those who have inarticulate major premises; the vertebrate historians are those having articulate major premises. A study in mechanics because analysis of historical thought reveals that the principle of least action holds literal sway so far as many historians' critical awareness (...) of their assumptions is concerned. (shrink)

This thesis develops a detailed account of the emergence of for all practical purposes continuous, quasi-classical world histories from the discontinuous, stochastic micro dynamics of Minimal Bohmian Mechanics (MBM). MBM is a non-relativistic quantum theory. It results from excising the guiding equation from standard Bohmian Mechanics (BM) and reinterpreting the quantum equilibrium hypothesis as a stochastic guidance law for the random actualization of configurations of Bohmian particles. On MBM, there are no continuous trajectories linking up individual configurations. Instead, individual configurations (...) are actualized independently of each other, carving out the decoherence-induced branching structure of the universal wave function. Yet, by contrast to the Everett interpretation, branches of the universal wave function are not actualized in parallel, i.e. all at the same time. Rather, world branches, on MBM, are actualized sequentially. -/- For an introduction to MBM, the transition from BM to MBM is described, and their empirical equivalence is established. I present the conditions under which MBM can be classified as a primitive ontology (PO) theory, regarded as crucial for the acceptance of a theory as Bohmian by many proponents of BM. While rendering MBM compatible with the PO approach, it must not fall prey to the problem of communication, arising from the two-space reading of BM. -/- The issue of temporal solipsism, identified by Bell as a serious problem for his “Everett (?) theory” – the historic predecessor of MBM – is discussed. I argue that Barbour’s time capsule approach does not provide a satisfactory solution. In particular, his adopting a more than minimal psychophysical parallelism between brain processes and experience of macroscopic change is argued to be reasonable in light of our current best neuroscience, yet problematic for theories relying solely on time capsules, understood as highly structured, individual, internally static configurations. As a solution, I introduce worlds, and world histories, as key concepts in providing a link between MBM’s micro dynamics and macroscopic phenomena. Worlds, other than time capsules, are coarse-grained regions in phase- or configuration space, defined as sets of possible micro states satisfying a relation of sufficient similarity from a macroscopic perspective, with respect to a given micro state. Hence, worlds may overlap. -/- I argue that worlds thus construed are a reasonable option for replacing the disjoint macro regions of phase space, resulting from the usual way of partitioning phase space in the standard framework of Boltzmannian statistical mechanics. This move solves the issue of discontinuous change of macro variables upon the micro state crossing the boundary between different macro regions. -/- I adapt this move for MBM’s discontinuous micro dynamics in configuration space. Issues revolving around the microscopic-macroscopic distinction, particle identity, impenetrability and haecceity in light of the desideratum of particle number conservation, etc., are discussed. I provide a detailed explanation of how overlapping worlds in MBM form world histories, thereby linking up macroscopically distinct worlds. Thus, the problem of temporal solipsism is resolved in a way that is compatible with a more than minimal psychophysical parallelism. (shrink)

A major approach to cancer research in the late twentieth century was to search for genes that, when altered, initiated the development of a cell into a cancerous state or failed to stop this development. But as researchers acquired the capacity to sequence tumors and incorporated the resulting data into databases, it became apparent that for many tumors no genes were frequently altered and that the genes altered in different tumors in the same tissue type were often distinct. To address (...) this heterogeneity problem, many researchers looked to a higher level of organization—to mechanisms in which gene products participated. They proposed to reduce heterogeneity by recognizing that multiple gene alterations affect the same mechanism and that it is the altered mechanism that is responsible for the cell developing one or more hallmarks of cancer. I examine how mechanisms figure in this research and focus on two heuristics researchers use to integrate proteins into mechanisms, one focusing on pathways and one focusing on clusters in networks. (shrink)

This paper discusses the prospect of the "new social history" guided by the recent work of Charles Tilly on the methodology of social and historical explanation. Tilly advocates explanation by mechanisms as the alternative to the covering law explanation. Tilly's proposals are considered to be the attempt to reshape the practices of social and historical explanation following the example set by the explanatory practices of molecular biology, neurobiology, and other recent "success stories" in the life sciences. Recent work (...) in the philosophy of science on these practices by Peter Machamer, Lindley Darden, Carl Craver and others is used as the foil to disclose the difficulties of Tilly's project. Most important among them is the dilemma of specification: if diagrams (standard forms of the representation of mechanisms) are intended as representations of robust causal processes, they cannot be specific enough to provide complete mechanism schemata, and are bound to remain mechanism sketches. If mechanism sketches are elaborated in detail by tracing particular causal processes, they provide representations of fragile causal processes, which cannot be considered as mechanisms comparable to those in advanced life and other special sciences. Tilly's work on the explanation of mechanisms can be considered as symptomatic for the recent trend to visualize the forms of historical representation. As far as diagrams seem to be able to communicate stories in a direct way (without narrative discourse), this trend is a challenge for the theory of historical representation. The new theories of scientific explanation focusing on the explanatory practices of the life sciences can provide examples and be the source of inspiration for the work on the theory of historical and social explanation, going beyond the confines of the received framework of the covering law model of explanation. (shrink)

In mid-Victorian Britain, reconciling elite mathematical expertise with practical mechanical experience presented both engineering and social challenges. Nowhere was this more apparent than in the construction of the Westminster Clock at Britain’s Houses of Parliament. Realizing this scheme engendered the collaboration between Cambridge mathematicians George Biddell Airy and Edmund Beckett Denison, and the clockmaker Edward John Dent. Transforming theoretical mathematical drawings into physical apparatus challenged existing relations between conveyors of privileged scientific knowledge and those with practical experience of what was, (...) and what was not, mechanically possible. My article demonstrates how, within this project, physical models and devices provided material solutions to ambiguities over authority and social disorder in Victorian Britain. (shrink)

With In Search of Mechanisms, Carl F. Craver and Lindley Darden offer both a descriptive and an instructional account of how biologists discover mechanisms. Drawing on examples from across the life sciences and through the centuries, Craver and Darden compile an impressive toolbox of strategies that biologists have used and will use again to reveal the mechanisms that produce, underlie, or maintain the phenomena characteristic of living things. They discuss the questions that figure in the search for (...) mechanisms, characterizing the experimental, observational, and conceptual considerations used to answer them, all the while providing examples from the history of biology to highlight the kinds of evidence and reasoning strategies employed to assess mechanisms. At a deeper level, Craver and Darden pose a systematic view of what biology is, of how biology makes progress, of how biological discoveries are and might be made, and of why knowledge of biological mechanisms is important for the future of the human species. (shrink)

In Descartes’s reformulation of natural philosophy, two aspects of what came to be known as the mechanical philosophy were intimately joined: mechanism as an ontology of nature, according to which all natural things had only ‘mechanical’ properties; and mechanism as a method of explanation. One could, and many philosophers did, adopt mechanism as a method of explanation without adopting a mechanistic ontology. I examine two successors of Descartes who did just that, and one who did not. Giovanni Alfonso Borelli in (...) his De motu animalium and Charles Perrault in his Mécanique de animaux propose and argue for a variety of mechanical accounts of the operations of animals, in particular of their muscles. They reject, however, the Cartesian reduction of animal souls to mechanical forces; the principle of animal motion for them remains a non-mechanical soul. Pierre Sylvain Régis in his Cours entier de philosophie follows Descartes in taking the ‘physical cause’ of motion in animals to be the fermentation of blood in the heart, and thus denies animal souls any role in his physiology. That he can do so while taking over, sometimes word for word, Perrault’s accounts of animal motion shows that mechanistic explanation and mechanistic ontology could easily part company. (shrink)

This book gathers the latest advances in the field of history of science and technology, as presented by leading international researchers at the 8th International Symposium on History of Machines and Mechanisms (HMM), held in Ankara, Turkey on April 18-20, 2024. The Symposium, which was promoted by the permanent commission for the History of Machine and Mechanism Science (MMS) of IFToMM, provided an international forum to present and discuss historical developments in the field of MMS. The (...) contents cover all aspects of the development of MMS from antiquity until the present era and its historiography: modern reviews of past works, engineers in history and their works, the development of theories, history of the design of machines and mechanisms, historical developments of mechanical design and automation, historical developments of teaching, the history of schools of engineering, the education of engineers. The contributions, which were selected by means of a rigorous international peer-review process, highlight numerous exciting ideas that will spur novel research directions and foster multidisciplinary collaborations. (shrink)

The unprecedented circumstances of the COVID-19 pandemic have intensified the demands placed upon parliamentarians to scrutinize and evaluate evidence-based government proposals, making visible the parliamentary mechanisms that enable them to do so. This paper examines the steps that led two such mechanisms to become embedded in the institution of Parliament during from 1964 to 2001: the House of Commons Select Committee on Science and Technology (a scrutiny and information-gathering body) and the Parliamentary Office of Science and Technology (a (...) legislative science and technology advice body). Drawing on official papers, Hansard records and unpublished archival material, this account complements existing studies of the relationships between government ministers and experts. It highlights how individual members of the all-party Parliamentary and Scientific Committee have influenced institutional change. In so doing it exposes some of the challenges confronting Parliament in the scrutiny of science policy from the mid-twentieth century to today. In particular, it reveals MPs’ concerns about their ability to scrutinize science policy in the absence of a select committee on science and technology in the Commons during the 1980s. This shows that parliamentary scrutiny of science was compromised during the very period when the Conservative government under Margaret Thatcher set about making major changes to the organization and funding of government-sponsored research in the UK. (shrink)

In a recent paper [3] Arroyo and Arenhart presented a detailed critical analysis regarding some essential aspects of representational realism and the logos approach to Quantum Mechanics (QM) addressed in terms of i) “a diagnosis of what is wrong with currently available solutions”; ii) “a proposal of a new methodology for addressing the problem”; and finally, iii) “a positive proposal to answer the question, which is arrived at by following the methodology suggested.” In this work we provide a detailed reply (...) to some deep misunderstandings that arise in this presentation and which, in turn, allow Arroyo and Arenhart to conclude that “contrarily to what de Ronde has suggested, his proposal is not a way to avoid commitment to uncritical images of reality, but rather, one further position in the already huge cart of options of quantum mechanics.” After providing a more accurate account of our diagnosis, we continue to address our methodology which —like that of Einstein, Heisenberg, Pauli and Schrödinger— goes back to the Greek-Modern account of physics. We then present our proposal grounded on the invariant-objective search for theoretical unity and discuss why intensive powers of action cannot be considered in dispositional or teleological terms with respect to actuality. Finally, we list some of the main results already accomplished by the logos approach and discuss the essential role of ‘intuition’ and ‘understanding’ within the realist setting. (shrink)

This paper investigates dynamical relaxation to quantum equilibrium in the stochastic de Broglie–Bohm–Bell formulation of quantum mechanics. The time-dependent probability distributions are computed as in a Markov process with slowly varying transition matrices. Numerical simulations, supported by exact results for the large-time behavior of sequences of (slowly varying) transition matrices, confirm previous findings that indicate that de Broglie–Bohm–Bell dynamics allows an arbitrary initial probability distribution to relax to quantum equilibrium; i.e., there is no need to make the ad-hoc assumption that (...) the initial distribution of particle locations has to be identical to the initial probability distribution prescribed by the system’s initial wave function. The results presented in this paper moreover suggest that the intrinsically stochastic nature of Bell’s formulation, which is arguable most naturally formulated on an underlying discrete space-time, is sufficient to ensure dynamical relaxation to quantum equilibrium for a large class of quantum systems without the need to introduce coarse-graining or any other modification in the formulation. (shrink)

Developing models of biological mechanisms, such as those involved in respiration in cells, often requires collaborative effort drawing upon techniques developed and information generated in different disciplines. Biochemists in the early decades of the 20th century uncovered all but the most elusive chemical operations involved in cellular respiration, but were unable to align the reaction pathways with particular structures in the cell. During the period 1940-1965 cell biology was emerging as a new discipline and made distinctive contributions to understanding (...) the role of the mitochondrion and its component parts in cellular respiration. In particular, by developing techniques for localizing enzymes or enzyme systems in specific cellular components, cell biologists provided crucial information about the organized structures in which the biochemical reactions occurred. Although the idea that biochemical operations are intimately related to and depend on cell structures was at odds with the then-dominant emphasis on systems of soluble enzymes in biochemistry, a reconceptualization of energetic processes in the 1960s and 1970s made it clear why cell structure was critical to the biochemical account. This paper examines how numerous excursions between biochemistry and cell biology contributed a new understanding of the mechanism of cellular respiration. (shrink)