What would it mean to apply quantum theory, without restriction and without involving any notion of measurement and state reduction, to the whole universe? What would realism about the quantum state then imply? This book brings together an illustrious team of philosophers and physicists to debate these questions. The contributors broadly agree on the need, or aspiration, for a realist theory that unites micro- and macro-worlds. But they disagree on what this implies. Some argue that if unitary quantum evolution has (...) unrestricted application, and if the quantum state is taken to be something physically real, then this universe emerges from the quantum state as one of countless others, constantly branching in time, all of which are real. The result, they argue, is many worlds quantum theory, also known as the Everett interpretation of quantum mechanics. No other realist interpretation of unitary quantum theory has ever been found. Others argue in reply that this picture of many worlds is in no sense inherent to quantum theory, or fails to make physical sense, or is scientifically inadequate. The stuff of these worlds, what they are made of, is never adequately explained, nor are the worlds precisely defined; ordinary ideas about time and identity over time are compromised; no satisfactory role or substitute for probability can be found in many worlds theories; they can't explain experimental data; anyway, there are attractive realist alternatives to many worlds. Twenty original essays, accompanied by commentaries and discussions, examine these claims and counterclaims in depth. They consider questions of ontology - the existence of worlds; probability - whether and how probability can be related to the branching structure of the quantum state; alternatives to many worlds - whether there are one-world realist interpretations of quantum theory that leave quantum dynamics unchanged; and open questions even given many worlds, including the multiverse concept as it has arisen elsewhere in modern cosmology. A comprehensive introduction lays out the main arguments of the book, which provides a state-of-the-art guide to many worlds quantum theory and its problems. (shrink)
Following a proposal of Vaidman The Stanford encyclopaedia of philosophy, 2014) The probable and the improbable: understanding probability in physics, essays in memory of Itamar Pitowsky, 2011), Sebens and Carroll , have argued that in Everettian quantum theory, observers are uncertain, before they complete their observation, about which Everettian branch they are on. They argue further that this solves the problem of making sense of probabilities within Everettian quantum theory, even though the theory itself is deterministic. We note some problems (...) with these arguments. (shrink)
I sketch a line of thought about consciousness and physics that gives some motivation for the hypothesis that conscious observers deviate—perhaps only very subtly and slightly—from quantum dynamics. Although it is hard to know just how much credence to give this line of thought, it does add motivation for a stronger and more comprehensive programme of quantum experiments involving quantum observers.
I propose a new class of interpretations, real world interpretations, of the quantum theory of closed systems. These interpretations postulate a preferred factorization of Hilbert space and preferred projective measurements on one factor. They give a mathematical characterisation of the different possible worlds arising in an evolving closed quantum system, in which each possible world corresponds to a (generally mixed) evolving quantum state. In a realistic model, the states corresponding to different worlds should be expected to tend towards orthogonality as (...) different possible quasiclassical structures emerge or as measurement-like interactions produce different classical outcomes. However, as the worlds have a precise mathematical definition, real world interpretations need no definition of quasiclassicality, measurement, or other concepts whose imprecision is problematic in other interpretational approaches. It is natural to postulate that precisely one world is chosen randomly, using the natural probability distribution, as the world realised in Nature, and that this world’s mathematical characterisation is a complete description of reality. (shrink)
A quantum measurement-like event can produce any of a number of macroscopically distinct results, with corresponding macroscopically distinct gravitational fields, from the same initial state. Hence the probabilistically evolving large-scale structure of space-time is not precisely or even always approximately described by the deterministic Einstein equations.Since the standard treatment of gravitational wave propagation assumes the validity of the Einstein equations, it is questionable whether we should expect all its predictions to be empirically verified. In particular, one might expect the stochasticity (...) of amplified quantum indeterminacy to cause coherent gravitational wave signals to decay faster than standard predictions suggest. This need not imply that the radiated energy flux from gravitational wave sources differs from standard theoretical predictions. An underappreciated bonus of gravitational wave astronomy is that either detecting or failing to detect predicted gravitational wave signals would constrain the form of the semi-classical theory of gravity that we presently lack. (shrink)
Hugh Everett III died of a heart attack in July 1982 at the age of 51. Almost 26 years later, a New York Times obituary for his PhD advisor, John Wheeler, mentioned him and Richard Feynman as Wheeler’s most prominent students. Everett’s PhD thesis on the relative state formulation of quantum mechanics, later known as the “Many Worlds Interpretation”, was published (in its edited form) in 1957, and later (in its original, unedited form) in 1973, and since then has given (...) rise to one of the most radical schools of thought in the foundations of quantum theory. Several years ago two conferences held in Oxford and in the Perimeter Institute celebrated the occasion of 50 years to the first publication of Everett’s thesis. The book Many worlds? grew out from contributions to these conferences, but, as its editors emphasize, it is more than mere conference proceedings. Instead, an attempt was made to assemble an impressive collection of papers which together illustrate the promise of the many worlds interpretation and the obstacles it faces. 23 papers divided into six sections follow an introduction by Simon Saunders, one of Oxford’s fiercest Everettians. The first four sections cover two thorny issues that have been flagged by contemporary opponents to the many worlds interpretation, namely, the problem of ontology and the problem of probability, while the fifth discusses alternatives to Everett such as Bohmian mechanics and information–theoretic approaches to quantum theory. The sixth section seems to be a wild card, hosting several papers unrelated to each other, including one of the most interesting contributions to this volume on the history of Everett’s thesis and his (some may say all too) short academic career. Each section concludes with transcripts of the discussion session that took place after the talks, thus giving an additional emphasis to the points of contention. Apart from general comments on the volume, in what follows I would like to concentrate on few papers I found especially illuminating. Start with ontology.. (shrink)
C.S. Peirce, the American philosopher and a principal figure in the development of the modern study of semiotics, struggled, mostly during his later years, to work out a systematic method for classifying sciences. By doing this, he hoped to define more clearly the various tasks of these sciences by showing how their individual effects are interrelated and how these effects, considered in their interrelations, establish pragmatic meanings for each individual science. Much of his work was centered on the meaning and (...) function of logic in relation to other areas of human knowledge. By rightly defining the work of logic, Peirce argued, the work of the other sciences could be pursued with more rigorous reasoning. Beverley Kent closely examines the published and unpublished writings of Peirce and carefully attends to the chronological development of his systems of classification; she thereby shows for the first time in the scholarly literature how seeming contradictions in Peirce's evolving classification are really part of an increasingly clear position. Logic, Peirce came to understand, is actually dependent on ethics and aesthetics for its principles. Kent shows how Peirce's working out of the classification of logic in relation to other sciences is a clue to the significant differences between his early and late philosophy and, perhaps even more important, to a reading of his more general claims for a philosophy of "pragmaticism." This work will be of interest to readers of Peirce and American philosophy, to historians of logic and semiotics, and to those more generally interested in the history of systems of knowledge-classification. (shrink)
[Abstract and PDF at the Pittsburgh PhilSci Archive] A slightly shorter version of this paper is to appear in a volume edited by Jonathan Barrett, AdrianKent, David Wallace and Simon Saunders, containing papers presented at the Everett@50 conference in Oxford in July 2007, and the Many Worlds@50 meeting at the Perimeter Institute in September 2007. The paper is based on my talk at the latter meeting (audio, video and slides of which are accessible here).
BACKGROUND: It can be argued that the ethical conduct of research involves achieving a balance between the rights and needs of three parties-potential research participants, society, and researchers. Local Research Ethics Committees (LRECs) have a number of roles and functions in the research enterprise, but there have been some indications that LREC members, researchers and the public can have different views about these responsibilities. Any such differences are potential sources of disagreement and misunderstanding. OBJECTIVES: To compare the views of LREC (...) members, researchers and the public towards the roles and functions of LRECs. DESIGN: A questionnaire that contained items concerned with a variety of such roles was distributed to general practice patients (as proxies for potential research participants), researchers and LREC members. FINDINGS: While general practice patients believed that the main function of LRECs is to ensure that research participants come to no harm, LREC members were more concerned with the protection of participants' rights. There was also some disagreement between members and researchers with regard to the consideration of proposals on the grounds of scientific merit. CONCLUSIONS: Local Research Ethics Committee members need to be aware of potential differences in views, that they ought to make their priorities clear, and that membership of LRECs ought to reflect the views of both researchers and potential research participants. (shrink)
This essay presents a critical review of recent literature on evil in medieval philosophy, as understood by thinkers from Anselm of Canterbury onward. "Evil" is taken to include not only serious, deliberate wrongdoing, but also everyday sins done from ignorance or passion. Special attention is paid to Aquinas's De Malo, Giles of Rome and the aftermath of the 1277 Condemnation, scholarly disputes about Scotus's teachings, and commentaries on the Nicomachean Ethics by Walter Burley, Gerald Odonis, and John Buridan.
Arguments about the morality of the use of deception in patient care have been conducted largely in an empirical vacuum, with few data about the situations in which deception occurs. Do staff frequently deceive their patients and, if so, under what conditions? Can the consequences of deception always be foreseen? What justifications do staff use to explain their behaviour? The small-scale study reported here on the uses of deception by nurses when attempting to reassure patients provides information on these questions. (...) The results suggest that deception can have deleterious effects on trust and increase the emotional distance between patients and staff. (shrink)
Against a background of increasing regulation regarding access to medical information and the presentation of patients' confidentiality, the case of genetic information raises interesting questions about whether the application of general rules is appropriate in all situations. Whilst all genetic information is not equally sensitive, some of it is highly predictive. It also allows deductions to be made about other family members. It may not be regarded as particularly sensitive when compared to other types of medical information and those to (...) whom it applies may not be as anxious about preserving their confidentiality as compared with—for example, the prospect of seeing research into cause and cures for rare diseases put in hand. These distinctions also find resonance with the general public. Resolving conflicting tensions will require subtlety, not a blunt “one size fits all” model. (shrink)
BACKGROUND: There is relatively little research concerning the processes whereby Local Research Ethics Committees discharge their responsibilities towards society, potential participants and investigators. OBJECTIVES: To examine the criteria used by LRECs in arriving at their decisions concerning approval of research protocols through an analysis of letters sent to investigators. DESIGN: Four LRECs each provided copies of 50 letters sent to investigators after their submitted proposals had been considered by the committees. These letters were subjected to a content analysis, in which (...) specific comments and requests for additional information and changes in the protocols were recorded and compared. FINDINGS: Overall 24% of proposals were approved without request for changes or clarifications, but this varied by committee: one committee approved only 6% of proposals without change or clarification while the others ranged from 26% to 32%. The content analyses of responses indicated that they could be placed into four categories: (i) further information for the committee to aid in their deliberations; (ii) requests for changes to the design or justification for the design used; (iii) changes to the information sheets provided to potential participants; and (iv) changes to consent procedures. Of these, alterations to information sheets were the most common type of request. These four types of response could be seen as safeguarding the wellbeing of potential participants (the principle of non-maleficence), of promoting the scientific validity of the research (the principle of beneficence), and of enhancing the rights of potential participants (the principle of autonomy). CONCLUSIONS: The committees were consistent in the types of requests they made of investigators, which can be seen as attempts to protect participants' rights and ensure the scientific validity of studies. Without an analysis of the proposals sent to the committees, however, it is difficult to account for the variation in the requirements set by the committees before approval was given. (shrink)
This paper identifies the legal and policy framework relating to the use of aborted fetuses in stem cell research and therapies and contrasts this with the collection of embryos for research. It suggests that more attention should be given to questions about the kind of consent sought by researchers from women and that there should be more transparency about how aborted fetuses are used. It reports on variability in current practices of research ethics committees and researchers and uncertainty about the (...) guidance available to them. It argues that there is a need for wide public discussion about the policy issues relating to fetal tissue use in stem cell research and the need for clarification of the law in this area. (shrink)
Aquinas’s admirers, reacting against Donald Davidson’s criticisms of hirn, commonly argue (a) that the will does play a role in Aquinas’s account of incontinence, and (b) that his explanation of incontinent action turns on the weakness of the will. The first part of this paper argues that they are correct about (a) but wholly mistaken about (b). Aquinas rarely even mentions the weakness of the will, and he neverinvokes it to explain why someone acts counter to her own better judgment. (...) In his view, such a person has the capacity for self-control but fails to exercise it. The second part of the paper considers Gary Watson’s account of incontinence, including and especially his objections to analyzing it as the failure to exercise one’s capacity for self-control. Here I argue that Aquinas’s account better serves the purposesof moral discourse and that it should not be expected to provide the kind of causal explanation Watson seeks. (shrink)
What is consciousness? brentano suggests that consciousness is a simple binary relation between a self and an object. in this paper, i offer a textual clarification and a qualified philosophical defense of brentano's suggestion. in part i, i indicate the ordinary facts of subjective experience that any adequate theory of consciousness must account for. in part ii, i argue on textual grounds that brentano's theory has been misunderstood by chisholm. in part iii, i argue that brentano's theory meets the conditions (...) of an adequate theory. (shrink)
This is an Essay Review of "Many Worlds? Everett, Quantum Theory, & Reality", edited by Simon Saunders, Jonathan Barrett, AdrianKent, and David Wallace. A much shortened version of this review is appearing in "Metascience" under the title "The Many Facets of Everett’s Many Worlds".
Kirby and Paris have exhibited combinatorial algorithms whose computations always terminate, but for which termination is not provable in elementary arithmetic. However, termination of these computations can be proved by adding an axiom first introduced by Goodstein in 1944. Our purpose is to investigate this axiom of Goodstein, and some of its variants, and to show that these are potentially adequate to prove termination of computations of a wide class of algorithms. We prove that many variations of Goodstein's axiom are (...) equivalent, over elementary arithmetic, and contrast these results with those recently obtained for Kruskal's theorem. (shrink)
‘ The Development of Ethics’ proves a rather misleading title for Terence Irwin’s latest book. He describes it more accurately as “a selective historical and critical study in the Socratic tradition, with special attention to Aristotelian naturalism, its formation, elaboration, criticism, and defence” . ‘Socratic’ refers to Irwin’s method: not merely describing “a collective Socratic inquiry” historically but also evaluating it and taking part in it . Unlike Alasdair MacIntyre and J. B. Schneewind, who think that “a moral theory cannot (...) be assessed timelessly, and there are no timelessly appropriate questions that different moral theories try to answer,” Irwin declares that history reveals substantial agreement on the main principles of ethics. The historian’s task is to discover them . Small wonder, then, that Development does so little to illuminate how ethics changed over time. When an author seeks unity among moral philosophers of the past, or at least all the good ones, he can hardly be expected to highlight significantly new issues or approaches, let alone differences in historical context. (shrink)
This is a Critical Notice for the general philosophical journal, Philosophy, of the anthology 'Many Worlds? Everett, Quantum Theory and Reality', edited by Simon Saunders, Jonathan Barrett, AdrianKent and David Wallace.
The last decade has witnessed a dramatic revival of interest in Hellenistic philosophy. No longer can one complain that scholars pitch their tents on Aristotelian turf and refuse to move beyond it. Indeed, the burgeoning literature on Hellenistic philosophy might now raise doubts about whether an author breaks any new ground. Sorabji's latest book analyzes many of the same texts and issues explored in Martha Nussbaum's The Therapy of Desire ; and he, too, argues that ancient philosophical therapy can be (...) useful to ordinary people in our own overstressed, post-industrial age. Emotions and Peace of Mind nonetheless has its own fascinating story to tell. Roughly the first two thirds of the book, devoted to the Stoics and their pagan critics, set the stage for an account of how early Christians revised Stoic teachings. Central to the tale is an aspect of Stoicism probably unfamiliar to most readers: the theory of “pre-passions” or “first movements”. According to Sorabji, the distinction between these involuntary movements and genuine emotions was muddied by Origen and other Christian thinkers, who reshaped the Stoic theory of how to avoid agitation into a theory of how to avoid temptation. The first movements so important to Seneca's thought became in the fourth-century hermit Evagrius the eight bad thoughts that monks must work especially hard to vanquish. With some modest transformations, these eight bad thoughts ultimately emerged as the seven deadly sins of Dante's Purgatorio. (shrink)