This paper examines two recent approaches to the nature and functioning of economic models: models as isolating representations and models as credible constructions. The isolationist view conceives of economic models as surrogate systems that isolate some of the causal mechanisms or tendencies of their respective target systems, while the constructionist approach treats them rather like pure constructions or fictional entities that nevertheless license different kinds of inferences. I will argue that whereas the isolationist view is still tied to (...) the representationalist understanding of models that takes the model-target dyad as the basic unit of analysis, the constructionist perspective can better accommodate the way we actually acquire knowledge through them. Using the example of Tobin’s ultra-Keynesian model I will show how many of the epistemic characteristics of modelling tend to go unrecognised if too much focus is placed on the model-target dyad. (shrink)

Modelling cannot be characterized as isolating, nor models as isolations. This article presents three arguments to that effect, against Uskali Mäki's account of models. First, while isolation proceeds through a process of manipulation and control, modelling typically does not proceed through such a process. Rather, modellers postulate assumptions, without seeking to justify them by reference to a process of isolation. Second, while isolation identifies an isolation base—a concrete environment it seeks to control and manipulate—modelling typically does not identify such (...) a base. Rather, modellers construct their models without reference to concrete environments, and only later seek to connect their models to concrete situations of the real world. Third, Mäki argues that isolation employs idealization to control for disturbing factors, but does not affect the factors or mechanisms that are supposed to be isolated. However, models typically make idealizing assumptions about the factors and mechanisms that are the focus of investigation. Thus, even the product of modelling often cannot be characterized as isolation. (shrink)

We formalize the notion of isolated objects, and we build a consistent theory to describe their evolution and interaction. We further introduce a notion of indistinguishability of distinct spacetime paths of a unit, for which the evolution of the state variables of the unit is the same, and a generalization of the equivalence principle based on indistinguishability. Under a time reversal condition on the whole set of indistinguishable paths of a unit, we show that the quantization of motion of spinless (...) elementary particles in a general potential field can be derived in this framework, in the limiting case of weak fields and low velocities. Extrapolating this approach to include weak relativistic effects, we explore possible experimental consequences. We conclude by suggesting a primitive ontology for the theory of isolated objects. (shrink)

We consider the problem of whether there are deterministic theories describing the evolution of an individual physical system in terms of the definite trajectories of its constituent particles and which stay in the same relation to quantum mechanics as Bohmian mechanics but which differ from the latter for what concerns the trajectories followed by the particles. Obviously, one has to impose on the hypothetical alternative theory precise physical requirements. We analyze various such constraints and we show step by step how (...) to meet them. This way of attacking the problem turns out to be useful also from a pedagogical point of view since it allows one to recall and focus on some relevant features of Bohm's theory. One of the central requirements we impose on the models we are going to analyze has to do with their transformation properties under the transformation of the extended Galilei group. In a context like the one we are interested in, one can put forward various requests that we refer to as physical and genuine covariance and invariance. Other fundamental requests are that the theory allows the description of isolated physical systems as well as that it leads to a solution (in the same sense as Bohmian mechanics) of the measurement problem. We show that, even when all the above conditions are taken into account, there are infinitely many inequivalent (from the point of view of the trajectories) bohmian-like theories reproducing the predictions of quantum mechanics. This raises some interesting questions about the meaning of Bohmian mechanics. (shrink)

After reviewing the use of isolation in US prisons and public restrooms to confine transgender people in solitary cells and single‐occupancy bathrooms, I propose an explanatory theory of eliminative space. I argue that prisons and toilets are eliminative spaces: that is, spaces of waste management that use layers of isolation to sanctify social or individual waste, at the outer and inner limits of society. As such, they function according to an eliminative logic. Eliminative logic, as I develop it, involves three (...) distinct but interrelated mechanisms: 1) purification of the social center, through 2) iterative segregation, presuming and enforcing 3) the reduced relationality of marginal persons. By evaluating the historical development and contemporary function of prisons and restrooms, I demonstrate that both seek to protect the gender binary through waves of segregation by sex, race, disability, and gender identity. I further argue that both assume the thin relationality of, in this case, transgender people, who are conceived of as impervious to the effects of isolation and thus always already isolable. I conclude that, if we are to counter the violence of these isolation practices, we not only need to think holistically about eliminative spaces and logic, but also to richly reconceptualize relationality. (shrink)

Both philosophers and psychologists have argued for the existence of distinct kinds of explanations, including teleological explanations that cite functions or goals, and mechanistic explanations that cite causal mechanisms. Theories of causation, in contrast, have generally been unitary, with dominant theories focusing either on counterfactual dependence or on physical connections. This paper argues that both approaches to causation are psychologically real, with different modes of explanation promoting judgments more or less consistent with each approach. Two sets of experiments isolate (...) the contributions of counterfactual dependence and physical connections in causal ascriptions involving events with people, artifacts, or biological traits, and manipulate whether the events are construed teleologically or mechanistically. The findings suggest that when events are construed teleologically, causal ascriptions are sensitive to counterfactual dependence and relatively insensitive to the presence of physical connections, but when events are construed mechanistically, causal ascriptions are sensitive to both counterfactual dependence and physical connections. The conclusion introduces an account of causation, an "exportable dependence theory," that provides a way to understand the contributions of physical connections and teleology in terms of the functions of causal ascriptions. (shrink)

Despite the miraculous progress of science—it’s practitioners continue to run into mistakes, either discrediting research unduly or making leaps of causal inference where none are warranted. In this we isolate two of the reasons for such behavior involving the misplaced understanding of the role of mechanisms and mechanistic knowledge in the establishment of cause-effect relationships. We differentiate causal knowledge into causes, effects, mechanisms, cause-effect relationships, and causal stories. Failing to understand the role of mechanisms in this picture, (...) including their absence of knowledge or incorrect specification, leads to errors of wrongly excluding cause-effect relationships or wrongly inferring their existence. We highlight the primary of causality over mechanistic knowledge and causal stories in scientific reasoning. (shrink)

This article shows how the MISS account of models—as isolations and surrogate systems—accommodates and elaborates Sugden’s account of models as credible worlds and Hausman’s account of models as explorations. Theoretical models typically isolate by means of idealization, and they are representatives of some target system, which prompts issues of resemblance between the two to arise. Models as representations are constrained both ontologically (by their targets) and pragmatically (by the purposes and audiences of the modeller), and these relations are coordinated by (...) a model commentary. Surrogate models are often about single mechanisms. They are distinguishable from substitute models, which are examined without any concern about their connections with the target. Models as credible worlds are surrogate models that are believed to provide access to their targets on account of their credibility (of which a few senses are distinguished). (shrink)

This article examines to what extent a particular case of cross-disciplinary research in the 1930s was structured by mechanistic reasoning. For this purpose, it identifies the interfield theories that allowed biologists and chemists to use each other’s techniques and findings, and that provided the basis for the experiments performed to identify plant growth hormones and to learn more about their role in the mechanism of plant growth. In 1930, chemists and biologists in Utrecht and Pasadena began to cooperatively study plant (...) growth. I will argue that these researchers decided to join forces because they believed to rely on each other’s findings and methods to solve their research problems adequately. In the course of the cooperation, organic chemists arrived at isolating plant growth hormones by using a test method developed in plant physiology. This achievement, in turn, facilitated biologists’ investigation of the mechanism of plant growth. Researchers eventually believed to have the means to study the relation between a substance’s molecular structure and its physiological activity. The way they conceptualized the problem of identifying hormones and unraveling the mechanism of plant growth, as well as their actual research actions are compatible with the new mechanists’ account of mechanism research. The study illustrates that focusing on researchers’ mechanistic reasoning can contribute considerably to explaining the structure of cross-disciplinary research projects. (shrink)

This article shows how the MISS account of models—as isolations and surrogate systems—accommodates and elaborates Sugden’s account of models as credible worlds and Hausman’s account of models as explorations. Theoretical models typically isolate by means of idealization, and they are representatives of some target system, which prompts issues of resemblance between the two to arise. Models as representations are constrained both ontologically (by their targets) and pragmatically (by the purposes and audiences of the modeller), and these relations are coordinated by (...) a model commentary. Surrogate models are often about single mechanisms. They are distinguishable from substitute models, which are examined without any concern about their connections with the target. Models as credible worlds are surrogate models that are believed to provide access to their targets on account of their credibility (of which a few senses are distinguished). (shrink)

For any choice of initial state and weak assumptions about the Hamiltonian, large isolated quantum systems undergoing Schrödinger evolution spend most of their time in macroscopic superposition states. The result follows from von Neumann’s 1929 Quantum Ergodic Theorem. As a specific example, we consider a box containing a solid ball and some gas molecules. Regardless of the initial state, the system will evolve into a quantum superposition of states with the ball in macroscopically different positions. Thus, despite their seeming fragility, (...) macroscopic superposition states are ubiquitous consequences of quantum evolution. We discuss the connection to many worlds quantum mechanics. (shrink)

This thesis is an attempt to reconstruct the conceptual foundations of quantum mechanics. First, we argue that the wave function in quantum mechanics is a description of random discontinuous motion of particles, and the modulus square of the wave function gives the probability density of the particles being in certain locations in space. Next, we show that the linear non-relativistic evolution of the wave function of an isolated system obeys the free Schrödinger equation due to the requirements of spacetime translation (...) invariance and relativistic invariance. Thirdly, we argue that the random discontinuous motion of particles may lead to a stochastic, nonlinear collapse evolution of the wave function. A discrete model of energy-conserved wavefunction collapse is proposed and shown to be consistent with existing experiments and our macroscopic experience. In addition, we also give a critical analysis of the de Broglie-Bohm theory, the many-worlds interpretation and other dynamical collapse theories, and briefly discuss the issue of unifying quantum mechanics and special relativity. (shrink)

In the context of a viral outbreak and necessary physical distancing, the emergence of new or the evolution of older artistic behavioural schemes becomes evident. We correlate the isolation space of the artist with the cockpit of a spaceship and the navigation and communication interfaces used by an astronaut. The cybernetic domain between physical space(s) and artist(s) can be thought of as consisting of many ‘organs’. It includes a core (black box), many-layered limits: skin, walls, mental and digital borders as (...) well as mechanisms of connectivity with external entities (other astronauts in art spaceships). This space could be a bedroom, a studio, an office or any different location the artist uses as an isolated bubble of information sharing and manipulation (material and immaterial). For the construction of such an (astronaut, artist) ontology we use metaphors, etymological references, transformed concepts and creative analogies between the actual and the subjective space. As one case study for this paradigm, we experimented with a telematic performance of Heiner Müller’s Hamlet Machine titled, I want to be 171. (shrink)

Many studies of the labour market spatial mismatch rely on the deductivenomological model of causation to test the theory that low-skilled, inner-city residents have been isolated from the knowledge of job opportunities by the suburbanization of jobs. The logic of this approach follows the deductivenomological model of explanation which establishes causation by measuring the constant conjunctions between ‘causes’ and ‘effects’. As an alternative, I have used a realist approach to the study of the labour market spatial mismatch that uses a (...) ‘causal-explanatory’ method. This approach entails the qualitative description of the causal mechanism in order to discover and conceptualize its causal properties. The results suggest that the spatial mismatch theory could be refined in order to accommodate the finding that workers in excluded ghettos do not necessarily rely solely on local social networks to find out about job vacancies. Instead, workers with employment experience have strong workplace-based social networks. Since employers recruit workers by relying on referrals from trusted workers, these workplacebased social networks can put job seekers at the front of the hiring queue, regardless of where they live. (shrink)

This paper asks how, in science in general and in economics in particular, theoretical models aid the understanding of real-world phenomena. Using specific models in economics and biology as test cases, it considers three alternative answers: that models are tools for isolating the ‘capacities’ of causal factors in the real world; that modelling is ‘conceptual exploration’ which ultimately contributes to the development of genuinely explanatory theories; and that models are credible counterfactual worlds from which inductive inferences can be made. (...) The paper argues that the ‘credible worlds’ account captures significant aspects of scientific practice, even if many modellers see their work as conceptual exploration. (shrink)

Consider a gas that is adiabatically isolated from its environment and confined to the left half of a container. Then remove the wall separating the two parts. The gas will immediately start spreading and soon be evenly distributed over the entire available space. The gas has approached equilibrium. Thermodynamics (TD) characterizes this process in terms of an increase of thermodynamic entropy, which attains its maximum value at equilibrium. The second law of thermodynamics captures the irreversibility of this process by positing (...) that in an isolated system such as the gas entropy cannot decrease. The aim of statistical mechanics (SM) is to explain the behavior of the gas and, in particular, its conformity with the second law in terms of the dynamical laws governing the individual molecules of which the gas is made up. In what follows these laws are assumed to be the ones of Hamiltonian classical mechanics. We should not, however, ask for an explanation of the second law literally construed. This law is a universal law and as such cannot be explained by a statistical theory. But this is not a problem because we.. (shrink)

If we follow a traditional reading of Descartes and throw in some of our favorite German philosophers (Kant, Husserl and Heidegger, for instance) we can isolate a doctrinal current that says that the pure intellect has no immediate access to the extra-mental world. This reduction of experience to reason forces the question of the external world’s existence, leading to Heidegger’s assertion that the scandal of philosophy was not that it had yet to furnish a proof for the external world’s existence, (...) as Kant thought, but that the question emerged in the first place. Prior to representing realities, the human being dwells in the world. Knowing is, thus, founded on Being-in-the-world. Once this is remembered, it seems quite extraneous to inquire about the existence of the external world, since it is given as part of the structure of human experience. But, if the question of the external world's existence arises when we reduce experience to rational experience, then we have learned something important about the structures involved in knowing the world. Knowing succeeds by breaking away from Being-in-theworld. As Levinas says, "it is still and always a solitude" (EI 60). Though knowledge might begin as a mode of Being-in-the-world, it succeeds by turning its back on these origins and entering upon another terrain. Thus, Heidegger's recourse to the external world could not be within knowledge. Instead, he grounded it in concern, the primordial way in which the human being dwells in the world. Knowing is but one way in which the human being exhibits this concern. Where Husserl showed the limits of representation to be within the parameters of the transcendental ego, Heidegger pushed the frontiers of the world down to another level, the level of function. On this level, the human being dwells as a worker; things are construed as implements for-the-sake-of something else. These implements refer to other implements in a referential totality guided by "circumspection." The world of function is held together as a totality by an intricate web of references, each pointing to others.. (shrink)

This paper discusses the problem of finding and defining chaos in quantum mechanics. While chaotic time evolution appears to be ubiquitous in classical mechanics, it is apparently absent in quantum mechanics in part because for a bound, isolated quantum system, the evolution of its state is multiply periodic. This has led a number of investigators to search for semiclassical signatures of chaos. Here I am concerned with the status of semiclassical mechanics as a distinct third theory of the asymptotic domain (...) between classical and quantum mechanics. I discuss in some detail the meaning of such crucial locutions as the " classical counterpart to a quantum system " and a quantum system ' s " underlying classical motion ". A proper elucidation of these concepts requires a semiclassical association between phase space surfaces and wave - functions. This significance of this association is discussed in some detail. (shrink)

The standard view is that the Lagrangian and Hamiltonian formulations of classical mechanics are theoretically equivalent. Jill North, however, argues that they are not. In particular, she argues that the state-space of Hamiltonian mechanics has less structure than the state-space of Lagrangian mechanics. I will isolate two arguments that North puts forward for this conclusion and argue that neither yet succeeds. 1 Introduction2 Hamiltonian State-space Has less Structure than Lagrangian State-space2.1 Lagrangian state-space is metrical2.2 Hamiltonian state-space is symplectic2.3 Metric > (...) symplectic3 Hamiltonian State-space Does Not Have Less Structure than Lagrangian State-space3.1 Lagrangian state-space has less than metric structure3.1.1 A potential worry3.1.2 General Lagrangians3.2 Hamiltonian state-space has more than symplectic structure3.2.1 A dual structure on the Hamiltonian state-space3.2.2 Simple Hamiltonians3.3 Comparing Lagrangian and Hamiltonian structures3.3.1 Counting mathematical structure3.3.2 Symplectic and metric structure are incomparable4 An Alternative Argument for LS4.1 The argument for P3*4.2 Symplectic manifold vs. tangent bundle structure4.3 Trying to patch up the argument for P3*5 Interpreting Mathematical Structure5.1 State-space realism5.2 Model isomorphism and theoretical equivalence6 Conclusion. (shrink)

In this article, I provide phenomenological reflections on patients’ experiences of undergoing extreme isolation protocols while admitted to Intensive Care Units [ICU] during the first wave of COVID-19. Based on observation studies from within the patient isolation rooms and retrospective, in-depth phenomenological interviews with patients, I characterize this exceptional experience as one of becoming anonymous. To illustrate this, I start by establishing a perspective on embodied existence as constituted on a scale between anonymous embodiment and being enrooted into a personal (...) niche. Against the backdrop of this framework, I illustrate how being admitted to the ICU under strict isolation protocols produced extraordinary experiences of becoming anonymous. Sources of the anonymization were: (1) Mechanical expropriation, pacification and disownership of the visceral-kinaesthetic body; (2) Objectification; (3) Spatial and intercorporeal anonymity (4) Surrealism: the intermingling of objective impressions and dream-like interpretations. Finally, I illustrate how anonymization induced an experience of embodiment as raw materiality, confronting the patient with what Martin Heidegger called the facticity of naked existence. This experience is discussed against Levinas’ critique of Heidegger, while I propose that insights from this exceptional case may substantiate Heidegger’s account. (shrink)

The model presented by Lee and Schwarz provides a novel explanation for the elementary mechanisms of psychological cleansing. I argue that the model could be extended to account for complex instances of psychological cleansing where the grounded procedures are not isolated and the opposing motives of separation and connection are entangled in a strategic interplay.

I defend the idea that the fact that no system is entirely isolated can be used to explain the successful use of the microcanonical distribution in statistical mechanics. The argument turns on claims about what is needed for an adequate explanation of this fact: I argue in particular that various competing explanations do not meet reasonable conditions of adequacy, and that the most striking lacuna in Interventionism – its failure to explain the ‘arrow of time’ – is no real defect.

This thesis makes the issue of reconciling the existence of thermodynamically irreversible processes with underlying reversible dynamics clear, so as to help explain what philosophers mean when they say that an aim of nonequilibrium statistical mechanics is to underpin aspects of thermodynamics. Many of the leading attempts to reconcile the existence of thermodynamically irreversible processes with underlying reversible dynamics proceed by way of discussions that attempt to underpin the following qualitative facts: (i) that isolated macroscopic systems that begin away from (...) equilibrium spontaneously approach equilibrium, and (ii) that they remain in equilibrium for incredibly long periods of time. These attempts standardly appeal to phase space considerations and notions of typicality. This thesis considers and evaluates leading typicality accounts, and, in particular, highlights their limitations. Importantly, these accounts do not underpin a large and important set of facts. They do not, for example, underpin facts about the rates in which systems approach equilibrium, or facts about the kinds of states they pass through on their way to equilibrium, or facts about fluctuation phenomena. To remedy these and other shortfalls, this thesis promotes an alternative, and arguably more important, line of research: understanding and accounting for the success of the techniques and equations physicists use to model the behaviour of systems that begin away from equilibrium. Accounting for their success would help underpin not just the qualitative facts the literature has focused on, but also many of the important quantitative facts that typicality accounts cannot. This thesis also takes steps in this promising direction. It outlines and examines a technique commonly used to model the behaviour of an interesting and important kind of system: a Brownian particle that's been introduced to an isolated homogeneous fluid at equilibrium. As this thesis highlights, the technique returns a wealth of quantitative and qualitative information. This thesis also attempts to account for the success of the model and technique, by identifying and grounding the technique's key assumptions. (shrink)

Traditional accounts of explanation fail to illuminate the explanatory relevance of “models that are descriptively false” in the sense that the regularities they entail fail to obtain. In this paper, I propose an account of explanation, which I call ‘explanation by concretization’, that serves to explicate the explanatory relevance of such models. Starting from a highly abstract and idealized model, causal explanations of the absence of regularities are sought by adding complexity to the model or by concretizing it. Whether this (...) process is successful depends on whether the abstractions and idealizations in the basic model succeed in isolating a mechanism, i.e. in representing how it operates when interfering factors are absent. This account is developed in the context of economics and contrasted to those of Daniel Hausman and Nancy Cartwright. I go on to provide an account of how unrealistic models can be used for providing understanding of the way mechanisms work. (shrink)

Recent discussion of mechanism has suggested new approaches to several issues in the philosophy of science, including theory structure, causal explanation, and reductionism. Here, I apply what I take to be the fruits of the 'new mechanical philosophy' to an analysis of a contemporary debate in evolutionary biology about the role of natural selection in speciation. Traditional accounts of that debate focus on the geographic context of genetic divergence--namely, whether divergence in the absence of geographic isolation is possible (or significant). (...) Those accounts are at best incomplete, I argue, because they ignore the mechanisms producing divergence and miss what is at stake in the biological debate. I argue that the biological debate instead concerns the scope of particular speciation mechanisms which assign different roles to natural selection at various stages of divergence. The upshot is a new interpretation of the crux of that debate--namely, whether divergence with gene flow is possible (or significant) and whether the isolating mechanisms producing it are adaptive. (shrink)

The textbook presentation of quantum mechanics, in a nutshell, is this. The physical state of any isolated system evolves deterministically in accordance with Schrödinger's equation until a "measurement" of some physical magnitude M (e.g. position, energy, spin) is made. Restricting attention to the case where the values of M are discrete, the system's pre-measurement state-vector f is a linear combination, or "superposition", of vectors f1, f2,... that individually represent states that..

The aim of the article was to develop the thesis that patient’s decisions about truth and responsibility are central to the process of psychotherapy and yet they are rarely explicitly articulated. In the first part of the text, I outlined the anthropological context of the thesis, according to which human intentionality and psychological mechanisms have the status of domains of objective reality that are ontologically separate, although in the patient’s experience they combine with one another. Next, with reference to (...) the classical opinions of psychotherapy, I identified two aspects of patient decisions related to her/his psychopathology: adaptive (more pronounced in childhood) and moral (more pronounced in adulthood). I went on to isolate groups of psychological operating mechanisms involved in both truth- and responsibility-avoidance choices and, using clinical illustration, showed how the therapist can support alternative decisions. Finally, I further clarified the understanding of the proposed working model by indicating the different therapeutic consequences of revealing psychological mechanisms vs. decision-making based on the type of patient disorder and the anthropological-moral character of his/her choices. (shrink)

Chronic pain affects a large part of the population causing functional disability, being often associated with coexisting psychological disorders, such as depression and anxiety, besides cognitive deficits, and sleep disturbance. The world elderly population has been growing over the last decades and the negative consequences of chronic pain for these individuals represent a current clinical challenge. The main painful complaints in the elderly are related to neurodegenerative and musculoskeletal conditions, peripheral vascular diseases, arthritis, and osteoarthritis, contributing toward poorly life quality, (...) social isolation, impaired physical activity, and dependence to carry out daily activities. Organ dysfunction and other existing diseases can significantly affect the perception and responses to chronic pain in this group. It has been proposed that elderly people have an altered pain experience, with changes in pain processing mechanisms, which might be associated with the degeneration of circuits that modulate the descending inhibitory pathways of pain. Aging has also been linked to an increase in the pain threshold, a decline of painful sensations, and a decrease in pain tolerance. Still, elderly patients with chronic pain show an increased risk for dementia and cognitive impairment. The present review article is aimed to provide the state-of-art of pre-clinical and clinical research about chronic pain in elderly, emphasizing the altered mechanisms, comorbidities, challenges, and potential therapeutic alternatives. (shrink)

Pérez Laraudogoitia (1996) presented an isolated system of infinitely many particles with infinite total mass whose total classical energy and momentum are not necessarily conserved in some particular inertial frame of reference. With a more generalized model Atkinson (2007) proved that a system of infinitely many balls with finite total mass may evolve so that its total classical energy and total relativistic energy and momentum are not conserved in any inertial frame of reference, and yet concluded that its total classical (...) momentum is necessarily conserved. Contrary to this conclusion of Atkinson, I show that Atkinson's model has a solution in which the total momentum fails to be conserved in every inertial frame of reference. This result, combined with Atkinson's, demonstrates that both classical and relativistic mechanics allow the energy and momentum of a system of infinitely many components to fail to be conserved in every inertial frame of reference. (shrink)

It is argued that quantum mechanics is fundamentally a geometric theory. This is illustrated by means of the connection and symplectic structures associated with the projective Hilbert space, using which the geometric phase can be understood. A prescription is given for obtaining the geometric phase from the motion of a time dependent invariant along a closed curve in a parameter space, which may be finite dimensional even for nonadiabatic cyclic evolutions in an infinite dimensional Hilbert space. Using the natural metric (...) on the projective space, we reformulate Schrödinger's equation for an isolated system. This metric is generalized to the space of all density matrices, and a physical meaning is proposed. (shrink)

The many-worlds interpretation of quantum mechanics predicts the formation of distinct parallel worlds as a result, of a quantum mechanical measurement. Communication among these parallel worlds would experimentally rule out alternatives to this interpretation. A possible procedure for “interworld” exchange of information and energy, using only state of the art quantum optical equipement, is described. A single ion is isolated from its environment in an ion trap. Then a quantum mechanical measurement with two discrete outcomes is performed on another system, (...) resulting in the formation of two parallel worlds. Depending on the outcome of this measurement the ion is excited from only one of the parallel worlds before the ion decoheres through its interaction with the environment. A detection of this excitation in the other parallel world is direct evidence for the many-worlds interpretation. This method could have important practical applications in physics and beyond. (shrink)

The philosophical problems discussed by the author of this scientifically erudite work concern the usual and much debated questions of the role of causality in microphysics and the "completeness" and "indeterminism" of statistical theories in natural science. Blokhintsev, the author of a highly-regarded Russian text on quantum theory, advocates the direct opposite of the Einsteinian thesis; and furthermore, he seems to interpret the alleged irreducibly statistical nature of physical theory in a quite literal ontological sense. "We must now accept," he (...) says, "that we cannot ignore the element of games of chance in the behavior of the universe." The materials adduced in support of this thesis consist almost entirely of various essays in theoretical physics, which, while undoubtedly relevant to the question at issue, will be accessible in their details and content only to those philosophers with better than average mathematical acumen, particularly in classical analysis. Unfortunately, as so often happens in discussions of this type, the author's scientific expertise is not matched by his degree of philosophical rigor and awareness of important conceptual distinctions. Thus, although the concept of measurement in quantum mechanics and the differences between "direct" and "derived" measurement play a central role in his argument, the author seems unaware of the important logical differences which are brought out by rigorous postulational treatments of measurement theory. Moreover, when the author argues, convincingly enough, that even classical Newtonian mechanics is not a fit candidate for the label of "deterministic theory" if such factors as random fluctuations in the initial conditions and lack of isolation of actual physical systems are taken into account, he seems to forget that this is not the basis on which deterministic status is properly assigned to classical physical theory in the first place. It is physical theory as applied to suitably idealized physical systems which is held to be deterministic, and the same sort of idealizations are commonly assumed when quantum mechanics is said to be indeterministic.--H. P. K. (shrink)

By probability theory the probability space to underlie the set of statistical data described by the squared modulus of a coherent superposition of microscopically distinct (sub)states (CSMDS) is non-Kolmogorovian and, thus, such data are mutually incompatible. For us this fact means that the squared modulus of a CSMDS cannot be unambiguously interpreted as the probability density and quantum mechanics itself, with its current approach to CSMDSs, does not allow a correct statistical interpretation. By the example of a 1D completed scattering (...) and double slit diffraction we develop a new quantum-mechanical approach to CSMDSs, which requires the decomposition of the non-Kolmogorovian probability space associated with the squared modulus of a CSMDS into the sum of Kolmogorovian ones. We adapt to CSMDSs the presented by Khrennikov (Found. Phys. 35(10):1655, 2005) concept of real contexts (complexes of physical conditions) to determine uniquely the properties of quantum ensembles. Namely we treat the context to create a time-dependent CSMDS as a complex one consisting of elementary (sub)contexts to create alternative subprocesses. For example, in the two-slit experiment each slit generates its own elementary context and corresponding subprocess. We show that quantum mechanics, with a new approach to CSMDSs, allows a correct statistical interpretation and becomes compatible with classical physics. (shrink)

This paper examines the contribution of Gabrio Piola to continuum mechanics.Though he was undoubtably a skilled mathematician and a good mechanician, little is commonly known about his papers within the international scientific community, principally because a large part of the Italian school of mechanics was isolated in the first half of the XIXth century.We examine and comment on Piola’s most important papers, and compare them with those of his contemporaries Cauchy, Poisson and Kirchhoff.

This book is divided into two sections. The first section is concerned with the emergence and expansion of a form of mechanical knowledge defined by us as pre-classical mechanics. The definition purports to the period roughly between the 15th and the 17th century, before classical mechanics was formulated as a coherent and comprehensive mechanical theory in the sequel of Newton's work. The investigation of problems that were isolated from each other at the time but cohered into some kind of stable (...) broad intellectual framework characterizes pre-classical mechanics. The second section is dedicated to specific case studies that present the application of a pre-classical framework to determined problems and to the investigation of specific natural phenomena. It consists of five case studies that illustrate in detail a reconstruction of pre-classical mechanics in particular constellations. Early modern theoretical, technical and social contexts transformed ancient and medieval mechanical knowledge in the course of its transmission. (shrink)

How eukaryotic genomes are packaged into compact cylindrical chromosomes in preparation for cell divisions has remained one of the major unsolved questions of cell biology. Novel approaches to study the topology of DNA helices inside the nuclei of intact cells, paired with computational modeling and precise biomechanical measurements of isolated chromosomes, have advanced our understanding of mitotic chromosome architecture. In this Review Essay, we discuss – in light of these recent insights – the role of chromatin architecture and the functions (...) and possible mechanisms of SMC protein complexes and other molecular machines in the formation of mitotic chromosomes. Based on the information available, we propose a stepwise model of mitotic chromosome condensation that envisions the sequential generation of intra‐chromosomal linkages by condensin complexes in the context of cohesin‐mediated inter‐chromosomal linkages, assisted by topoisomerase II. The described scenario results in rod‐shaped metaphase chromosomes ready for their segregation to the cell poles. (shrink)

The ascidian embryo has long provided a model system for ‘mosaic’ development. This article reviews recent advances in the study of ascidian developmental biology. These include: (a) the re‐analysis of cell lineages in ascidian embryos with the ascertainment of developmental fates of every blastomere of a 110‐cell embryo; (b) the development of several tissue‐specific monoclonal antibodies; (c) the investigation and description of cell cycle requirements for differentiation; it has been found that neither cytokinesis nor nuclear division is required for differentiation, (...) but that several rounds of DNA replication are essential for the expression of certain tissue‐specific genes; and (d) the demonstration by new descriptive and experimental studies of the presence of cytoplasmic factors or determinants responsible for specification of embryonic cell features; myoplasm which is thought to contain muscle determinants has been isolated, and immunological attempts to elucidate the molecular nature of the factors have begun. (shrink)

The analysis of the play "The Seagull" undertaken in the article is based on an unusual assumption. Chekhov's phrase is known that "after writing a story, you should cross out its beginning and end." What if we apply this "formula" to the dramatic works of Anton Pavlovich and assume that when finishing the plays, Chekhov "left out some part of the text"? The analysis of the "Seagull" is performed directly by the classic tool of directors – the method of effective (...) analysis. The work involved a wide range of facts about the social and everyday realities of the Russian Empire of the late XIX - early XX century. The choice of the play "The Seagull" is due to two reasons. Firstly, it is one of Chekhov's most famous and popular dramas. Interest in it has not waned for many decades, neither the audience nor the directors. Secondly, it is believed that the "Seagull" is read inside and out, and working with it is a challenge for the researcher. The analysis of "The Seagull" allows us to state that Chekhov's formula about "crossing out the beginning and the end" of the story is also applicable to his plays. Moreover, this "crossing out" is made taking into account the principles of classical drama. As a result, the reader is faced with the fact that the "Seagull" can be read in at least two – almost opposite in meaning – ways. The results obtained during the analysis, firstly, give grounds to assume that the case of the "Seagull" is not an isolated one, and Chekhov resorted to similar techniques in his other dramas. Secondly, to conclude that the "dramatic mechanism" of The Seagull is not just an attribute of the author's voice, but actually the path of evolution of classical drama proposed by Chekhov. (shrink)

Despite growing consumerism and skepticism about authority in the culture as a whole, most patients continue to be pliant. If there is a serious threat to physician autonomy, it is more likely to come from third‐party payers and new forms of medical practice, particularly the rise of for‐profit hospital chains, than from patients. Though physicians are restless, they will learn to adapt to the new conditions of practice.