When quantum scattering theory is applied strictly from the point of view that the state of a system is completely described by the density matrix, whether pure or mixed, it is not possible to assume that colliding particles are at all times individually in pure states. Exact results are significantly different from conventionally accepted approximations. In particular, it turns out that the cross section as ordinarily defined in theS-matrix formalism is an adequate parameter for deciding the outcome of interactions only (...) when the particles are carefully prepared in matching pure states. In general the use of the cross section in studying pair collisions in a real gas is shown to be analogous to a repeated “collapse of the wave function” after each collision, and involves arbitrary removal of nondiagonal elements of the density matrix, thus violating the basic laws of quantum dynamical evolution. (shrink)

A common approach to quantum physics is enshrouded in a jargon which treats state vectors as attributes of physical systems and the concept of state preparation as a filtration scheme wherein a process involving measurement selects from a primordial assembly of systems those bearing some prescribed vector of interest. By contrast, the empirical experiences with which quantum theory is actually concerned relate measurement and preparation in quite an opposite manner. Reproducible preparation schemes are logically and temporally anterior to measurement acts. (...) Measurement extracts numbers from systems prepared in a specified manner; these data are then regularized by the theory by means of a state concept which is in turn used to characterize succinctly the given mode of preparation. The present paper offers, in a simple spin model, a method for determining the quantum state that represents any reproducible preparation. (shrink)

When the state of a physical system is not fully determined by available data, it should be possible nevertheless to make a systematic guess concerning the unknown state by applying the principles of information theory. The resulting theoretical blend of informational and mechanical constructs should then constitute a modern structure for statistical physics. Such a program has been attempted by a number of authors, most notably Jaynes, with seeming success. However, we demonstrated in a recent publication that the standard list (...) of so-called “mutually exclusive and exhaustive” quantum states that is commonly employed by these authors is in fact not exhaustive. It follows that the information-theoretic foundations of quantum statistics must be reformulated. The present paper discusses the fundamental problems involved and establishes a format for the correct application of information theory to quantum mechanical situations. (shrink)

A theorem is derived that enables a systematic enumeration of all the linear superoperators ℒ (associated with a two-level quantum system) that generate, via the law of motion ℒρ= $\dot \rho$ , mappings ρ(0) → ρ(t) restricted to the domain of statistical operators. Such dynamical evolutions include the usual Hamiltonian motion as a special case, but they also encompass more general motions, which are noncyclic and feature a destination state ρ(t → ∞) that is in some cases independent of ρ(0).

This note, in rejoinder to a paper by Newton critical of our analysis of certain limitations of quantum scattering theory, seeks to acknowledge and to clarify the disparate interests of the two conflicting articles.

Part I of the present work outlined the rigorous application of information theory to a quantum mechanical system in a thermodynamic equilibrium state. The general formula developed there for the best-guess density operator $\hat \rho$ was indeterminate because it involved in an essential way an unspecified prior probability distribution over the continuumD H of strong equilibrium density operators. In Part II mathematical evaluation of $\hat \rho$ is completed after an epistemological analysis which leads first to the discretization ofD H and (...) then to the adoption of a suitable indifference axiom to delimit the set of admissible prior distributions. Finally, quantal formulas for information-theoretic and thermodynamic entropies are contrasted, and the entire work is summarized. (shrink)

Here, we offer concrete illustrations of the state determination method developed abstractly in Part I of this work. Quorums are found for finite-dimensional magnetic multipole problems as well as for the harmonic oscillator with an energy cutoff. There is, in addition, a discussion of general procedures for empirically distinguishing pure states from mixed states.

This collection of essays focuses on the concepts of tolerance and intolerance as it commemorates the life of James Parkes - the man who pioneered the study of antisemitism and Jewish-non-Jewish relations. The essays analyse many different examples of antisemitism, ambivalence and philosemitism.

The identification of a set of mutually exclusive and exhaustive propositions concerning the states of quantum systems is a corner stone of the information-theoretic foundations of quantum statistics; but the set which is conventionally adopted is in fact incomplete, and is customarily deduced from numerous misconceptions of basic quantum mechanical principles. This paper exposes and corrects these common misstatements. It then identifies a new set of quantum state propositions which is truly exhaustive and mutually exclusive, and which is compatible with (...) the foundations of quantum theory. (shrink)

This communication is part I of a series of papers which explore the theoretical possibility of generalizing quantum dynamics in such a way that the predicted motions of an isolated system would include the irreversible (entropy-increasing) state evolutions that seem essential if the second law of thermodynamics is ever to become a theorem of mechanics. In this first paper, the general mathematical framework for describing linear but not necessarily Hamiltonian mappings of the statistical operator is reviewed, with particular attention to (...) detailed representations of the Kossakowski conditions for the case of a two-level system. (shrink)

To honor Henry Margenau on the occasion of his 90th birthday, we attempt in this essay to integrate certain aspects of the physics, philosophy, and pedagogy of quantum mechanics in a manner very much inspired by Margenau's idealist scientific epistemology. Over half a century ago, Margenau was perhaps the first philosopher of science to recognize and elaborate upon the essential distinction between thepreparation of a quantum state and themeasurement of an observable associated with a system in that state; yet in (...) contemporary quantum texts that distinction rarely receives adequate emphasis even though, as we demonstrate, it may be explicated through a series of simple illustrations. (shrink)

In previous publications we have criticized the usual application of information theory to quantal situations and proposed a new version of information-theoretic quantum statistics. This paper is the first in a two-part series in which our new approach is applied to the fundamental problem of thermodynamic equilibrium. Part I deals in particular with informational definitions of equilibrium and the identification of thermodynamic analogs in our modified quantum statistics formalism.

If the ordinary quantal Liouville equation ℒρ= $\dot \rho $ is generalized by discarding the customary stricture that ℒ be of the standard Hamiltonian commutator form, the new quantum dynamics that emerges has sufficient theoretical fertility to permit description even of a thermodynamically irreversible process in an isolated system, i.e., a motion ρ(t) in which entropy increases but energy is conserved. For a two-level quantum system, the complete family of time-independent linear superoperators ℒ that generate such motions is derived; and (...) a physically interesting example is presented in detail. (shrink)

This paper develops a method for extracting from data the quantum theoretical state representation belonging to any reproducible empirical scheme for preparing a physical system, provided only that at least one observable has its possible values limited to a finite set. In Part I, we formulate a general systematic procedure, based on the concept of irreducible tensor operators, for the selection of sets of observables sufficiently large to permit the unambiguous determination of an unknown quantum state.

Introduction.--The Puritan heresy.--Emerson.--Paul Elmer More.--William James.--John Dewey.--Nietzsche.--Bergson.--The limitations of Marxism.--T. S. Eliot.--Christopher Dawson.--Kenneth Burke.--Jeffersonian democracy.

Noted psychologist and philosopher develops his own brand of pragmatism, based on theories of C. S. Peirce. Emphasis on "radical empiricism," versus the transcendental and rationalist tradition. One of the most important books in American philosophy. Note.

Animal behaviour and welfare research are part of a wider endeavour to optimize the health and wellbeing of humans, animals and ecosystems. As such, it is part of the One Health research agenda. This article applies ethical principles described by the One Health High Level Expert Panel to animal behaviour and welfare research. These principles entail that animal behaviour and welfare research should be valued equitably alongside other research in transdisciplinary and multisectoral collaboration. It should include and promote a multiplicity (...) of marginalized voices, including those of animals, and it should apply and describe a harmonious balance between human—animal-environment interactions. Lastly, it should describe how humans need to change behaviour, adopt sustainable solutions and recognize the importance of animal welfare and the integrity of the whole ecosystem. (shrink)

Two books bound together, from the religious period of one of the most renowned and representative thinkers. Written for laymen, thus easy to understand, it is penetrating and brilliant as well. Illuminations of age-old religious questions from a pragmatic perspective, written in a luminous style.

Introduction.--The Puritan heresy.--Emerson.--Paul Elmer More.--William James.--John Dewey.--Nietzsche.--Bergson.--The limitations of Marxism.--T. S. Eliot.--Christopher Dawson.--Kenneth Burke.--Jeffersonian democracy.

First published in 1909 (one year before his death), philosopher William James collected several essays into this volume, meant as a sequel to his book "Pragmatism." He wanted to clarify his definition of the truth, and respond to criticism of his previous book.

This first volume contains discussions of the brain, methods for analyzing behavior, thought, consciousness, attention, association, time, and memory.

Still-vital lectures on teaching deal with psychology and the teaching art, the stream of consciousness, the child as a behaving organism, education and behavior, native and acquired reactions, habit, association of ideas, attention, memory, acquisition of ideas, perception, will, and more. The three addresses to students are "The Gospel of Relaxation," "On a Certain Blindness in Human Beings," and "What Makes a Life Significant?" Preface. 2 black-and-white illustrations.

A perfectly matched layer (PML) absorbing material composed of a uniaxial anisotropic material is presented for the truncation of finite-difference time-domain (FDTD) lattices. It is shown that the uniaxial PML material formulation is mathematically equivalent to the perfectly matched layer method published by Berenger (see J. Computat. Phys., Oct. 1994). However, unlike Berenger's technique, the uniaxial PML absorbing medium presented in this paper is based on a Maxwellian formulation. Numerical examples demonstrate that the FDTD implementation of the uniaxial PML medium (...) is stable, equal in effectiveness as compared to Berenger's PML medium, while being more computationally efficient. (shrink)

A pioneer in early studies of the human mind and founder of that peculiarly American philosophy called Pragmatism, William James remains America's most widely read philosopher. Generations of students have been drawn to his lucid presentations of philosophical problems. His works, now being made available for the first time in a definitive edition, have a permanent place in American letters and a continuing influence in philosophy and psychology. The essays gathered in the posthumously published Essays in Radical Empiricism (...) formulate ideas that had brewed in James's mind for thirty years as he sought a way out of the philosophical dilemmas generated by the new psychology of the late nineteenth century. They constitute the explanatory core of his doctrine of radical empiricism, a doctrine that charts his course between the absolute idealism he could not accept and, at the other extreme, the law of associationism, which reduces knowledge to sheer contiguity of ideas. In his introduction John J. McDermott describes the historical background and the genesis of James's theory and considers the objections raised by its opponents. (shrink)

The Gifford Lectures were established in 1885 at the universities of St Andrews, Glasgow, Aberdeen and Edinburgh to promote the discussion of 'Natural Theology in the widest sense of the term - in other words, the knowledge of God', and some of the world's most influential thinkers have delivered them. The 1901–2 lectures given in Edinburgh by American philosopher William James are considered by many to be the greatest in the series. The lectures were published in book form (...) in 1902 and have been reprinted many times. James, who was educated in the United States and Europe, and spent much of his career teaching philosophy at Harvard, was very influential in the development of modern psychology, and in these twenty lectures he explores the personal experience of religion. Some of the topics include religion and neurology, 'the sick soul', saintliness, and mysticism. (shrink)

The first systematic study of the aesthetic evaluations that scientists pass on their theories.

One of the great American pragmatic philosophers alongside Peirce and Dewey, William James (1842–1910) delivered these eight lectures in Boston and New York in the winter of 1906–7. Though he credits Peirce with coining the term 'pragmatism', James highlights in his subtitle that this 'new name' describes a philosophical temperament as old as Socrates. The pragmatic approach, he says, takes a middle way between rationalism's airy principles and empiricism's hard facts. James' pragmatism is both a method (...) of interpreting ideas by their practical consequences and an epistemology which identifies truths according to their useful outcomes. Furnished with many examples, the lectures illustrate pragmatism's response to classic problems such as the question of free will versus determinism. Published in 1907, this work further develops James's approach to religion and morality, introduced in The Will to Believe (1897) and The Varieties of Religious Experience (1902), both reissued in this series. (shrink)

When does a person qualify for protected and continuing life? At a time when technology can sustain marginal life, it is ever more important to understand what constitutes a person.

For this 1897 publication, the American philosopher William James brought together ten essays, some of which were originally talks given to Ivy League societies. Accessible to a broader audience, these non-technical essays illustrate the author's pragmatic approach to belief and morality, arguing for faith and action in spite of uncertainty. James thought his audiences suffered 'paralysis of their native capacity for faith' while awaiting scientific grounds for belief. His response consisted in an attitude of 'radical empiricism', which (...) deals practically rather than ideologically with real-world phenomena. When facing a 'momentous' decision about belief, he says, we both can and must choose the best hypothesis. The first four essays apply this principle to religious faith, and the rest explore the pragmatic approach to such topics as determinism, ethics and individual achievement. James developed his ideas further in The Varieties of Religious Experience and Pragmatism, both of which are reissued in this series. (shrink)

From the $700 billion bailout of the banking industry to president Barack Obama’s $787 billion stimulus package to the highly controversial passage of federal health-care reform, conservatives and concerned citizens alike have grown increasingly fearful of big government. Enter Nobel Prize–winning economist and political theorist F. A. Hayek, whose passionate warning against empowering states with greater economic control, The Road to Serfdom, became an overnight sensation last summer when it was endorsed by Glenn Beck. The book has since sold over (...) 150,000 copies. The latest entry in the University of Chicago Press’s series of newly edited editions of Hayek’s works, The Constitution of Liberty is, like Serfdom, just as relevant to our present moment. The book is considered Hayek’s classic statement on the ideals of freedom and liberty, ideals that he believes have guided—and must continue to guide—the growth of Western civilization. Here Hayek defends the principles of a free society, casting a skeptical eye on the growth of the welfare state and examining the challenges to freedom posed by an ever expanding government—as well as its corrosive effect on the creation, preservation, and utilization of knowledge. In opposition to those who call for the state to play a greater role in society, Hayek puts forward a nuanced argument for prudence. Guided by this quality, he elegantly demonstrates that a free market system in a democratic polity—under the rule of law and with strong constitutional protections of individual rights—represents the best chance for the continuing existence of liberty. Striking a balance between skepticism and hope, Hayek’s profound insights are timelier and more welcome than ever before. This definitive edition of The Constitution of Liberty will give a new generation the opportunity to learn from his enduring wisdom. (shrink)

The will to believe.--Is life worth living?--The sentiment of rationality.--Reflex action and theism.--The dilemma of determinism.--The moral philosopher and the moral life.--Great men and their environment.--The importance of individuals.--On some Hegelisms.--What psychical research has accomplished.

His final set of lectures at the College de France, described here by Thomas Flynn, focused on the concept of truth-telling as a moral virtue in the ancient ...

The will to believe.--Is life worth living?--The sentiment of rationality.--Reflex action and theism.--The dilemma of determinism.--The moral philosopher and the moral life.--Great men and their environment.--The importance of individuals.--On some Hegelisms.--What psychical research has accomplished.

The title of our collection is owed to Hannah Arendt herself. Writing to Karl Jaspers on August 6, 1955, she spoke of how she had only just begun to really love the world and expressed her desire to testify to that love in the title of what came to be published as The Human Condition: "Out of gratitude, I want to call my book about political theories Arnor Mundi. "t In retrospect, it was fitting that amor mundi, love of the (...) world, never became the title of only one of Arendt's studies, for it is the theme which permeates all of her thought. The purpose of this volume's a- ticles is to pay a critical tribute to this theme by exploring its meaning, the cultural and intellectual sources from which it derives, as well as its resources for conte- porary thought and action. We are privileged to include as part of the collection two previously unpu- lished lectures by Arendt as well as a rarely noticed essay which she wrote in 1964. Taken together, they engrave the central features of her vision of amor mundi. Arendt presented "Labor, Work, Action" on November 10, 1964, at a conference "Christianity and Economic Man:Moral Decisions in an Affluent Society," which 2 was held at the Divinity School of the University of Chicago. (shrink)

One of the most influential men of his time, philosopher, psychologist, educator, and author William James (1842-1910) helped lead the transition from a predominantly European-centered nineteenth-century philosophy to a new "pragmatic" American philosophy. Helping to pave the way was his seminal book Pragmatism (1907), in which he included a chapter on "Truth," an essay which provoked severe criticism. In response, he wrote the present work, an attempt to bring together all he had ever written on the theory of (...) knowledge, including an article on the function of cognition, later polemic and expository contributions, and some replies to previous criticism. The result was a full and definitive expression of the pragmatist "epistemology" from James' point of view. In the book, he urges the reader to "turn away from abstractions, verbal solutions, fixed principles, and pretended absolutes and look for concreteness and facts, action and power," arguing that "the ultimate test for us of what a truth means is the conduct it dictates or inspires." For students, scholars--anyone interested in William James or the history of American philosophical thought--this book offers an in-depth exposition of the influential ideas of one of the greatest American thinkers. Unabridged republication of the edition originally published by Longmans, Green and Co., New York and London, 1909. (shrink)

Michel Foucault and Theology brings together a selection of essays by leading Foucault scholars on a variety of themes within the history, thought and practice of theology. Revealing the diverse ways that the work of Michel Foucault (1926-1984) has been.