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2008. Pruning Some Branches from 'Branching Spacetimes'
CHAPTER 10 Pruning Some Branches from “Branching Spacetimes” John Earman* Abstract Discussions of branching time and branching spacetime have become com- mon in the philosophical literature. If properly understood, these concep- tions can be harmless. But they are sometimes used in the service of debat- able and even downright pernicious doctrines. The purpose of this chapter is to identify the pernicious branching and prune it back. 1. INTRODUCTION Talk of “branching time” and “branching spacetime” is wide spread in the philo- sophical literature. Such expressions, if properly understood, can be innocuous. But they are sometimes used in the service of debatable and even downright per- nicious doctrines. The purpose of this paper is to identify the pernicious branching and prune it back. Section 2 distinguishes three types of spacetime branching: individual branch- ing, ensemble branching, and Belnap branching. Individual branching, as the name indicates, involves a branching structure in individual spacetime models. It is argued that such branching is neither necessary nor sufficient for indeterminism, which is explicated in terms of the branching in the ensemble of spacetime mod- els satisfying the laws of physics. Belnap branching refers to the sort of branching used by the Belnap school of branching spacetimes. An attempt is made to sit- uate this sort of branching with respect to ensemble branching and individual branching. Section 3 is a sustained critique of various ways of trying to imple- ment individual branching for relativistic spacetimes. Conclusions are given in Section 4. * Department of History and Philosophy of Science, University of Pittsburgh, Pittsburgh, USA The Ontology of Spacetime II © Elsevier BV ISSN 1871-1774, DOI: 10.1016/S1871-1774(08)00010-7 All rights reserved 187 188 Pruning Some Branches from “Branching Spacetimes” 2. -
Lost in the Tensors: Einstein's Struggles with Covariance Principles 1912-1916"
JOHN EARMAN and CLARK GL YMOUR LOST IN THE TENSORS: EINSTEIN'S STRUGGLES WITH COVARIANCE PRINCIPLES 1912-1916" Introduction IN 1912 Einstein began to devote a major portion of his time and energy to an attempt to construct a relativistic theory of gravitation. A strong intimation of the struggle that lay ahead is contained in a letter to Arnold Sommerfeld dated October 29, 1912: At the moment I am working solely on the problem of gravitation and believe 1 will be able to overcome all difficulties with the help of a local, friendly mathemat- ician. But one thing is certain, that I have never worked so hard in my life, and that I have been injected with a great awe of mathematics, which in my naivet~ until now I only viewed as a pure luxury in its subtler forms! Compared to this problem the original theory of relativity is mere child's play.' Einstein's letter contained only a perfunctory reply to a query from Sommerfeld about the Debye-Born theory of specific heats. Obviously disappointed, Som- merfeld wrote to Hilbert: 'My letter to Einstein was in vain . Einstein is evidently so deeply mired in gravitation that he is deaf to everything else? Sommerfeld's words were more prophetic than he could possibly have known; the next three years were to see Einstein deeply mired in gravitation, sometimes seemingly hopelessly so. In large measure, Einstein's struggle resulted from his use and his misuse, his understanding and his misunderstanding of the nature and implications of covariance principles. In brief, considerations of general covariance were bound up with Einstein's motive for seeking a 'generalized' theory of relativity; mis- understandings about the meaning and implementation of this motivation threatened to wreck the search; and in the end, the desire for general covariance helped to bring Einstein back onto the track which led to what we now recognize *Present address c/o Department of Philosophy, University of Minnesota, Minneapolis, Minn, U.S.A. -
The Oberlin Colloquium in Philosophy: Program History
The Oberlin Colloquium in Philosophy: Program History 1960 FIRST COLLOQUIUM Wilfrid Sellars, "On Looking at Something and Seeing it" Ronald Hepburn, "God and Ambiguity" Comments: Dennis O'Brien Kurt Baier, "Itching and Scratching" Comments: David Falk/Bruce Aune Annette Baier, "Motives" Comments: Jerome Schneewind 1961 SECOND COLLOQUIUM W.D. Falk, "Hegel, Hare and the Existential Malady" Richard Cartwright, "Propositions" Comments: Ruth Barcan Marcus D.A.T. Casking, "Avowals" Comments: Martin Lean Zeno Vendler, "Consequences, Effects and Results" Comments: William Dray/Sylvan Bromberger PUBLISHED: Analytical Philosophy, First Series, R.J. Butler (ed.), Oxford, Blackwell's, 1962. 1962 THIRD COLLOQUIUM C.J. Warnock, "Truth" Arthur Prior, "Some Exercises in Epistemic Logic" Newton Garver, "Criteria" Comments: Carl Ginet/Paul Ziff Hector-Neri Castenada, "The Private Language Argument" Comments: Vere Chappell/James Thomson John Searle, "Meaning and Speech Acts" Comments: Paul Benacerraf/Zeno Vendler PUBLISHED: Knowledge and Experience, C.D. Rollins (ed.), University of Pittsburgh Press, 1964. 1963 FOURTH COLLOQUIUM Michael Scriven, "Insanity" Frederick Will, "The Preferability of Probable Beliefs" Norman Malcolm, "Criteria" Comments: Peter Geach/George Pitcher Terrence Penelhum, "Pleasure and Falsity" Comments: William Kennick/Arnold Isenberg 1964 FIFTH COLLOQUIUM Stephen Korner, "Some Remarks on Deductivism" J.J.C. Smart, "Nonsense" Joel Feinberg, "Causing Voluntary Actions" Comments: Keith Donnellan/Keith Lehrer Nicholas Rescher, "Evaluative Metaphysics" Comments: Lewis W. Beck/Thomas E. Patton Herbert Hochberg, "Qualities" Comments: Richard Severens/J.M. Shorter PUBLISHED: Metaphysics and Explanation, W.H. Capitan and D.D. Merrill (eds.), University of Pittsburgh Press, 1966. 1965 SIXTH COLLOQUIUM Patrick Nowell-Smith, "Acts and Locutions" George Nakhnikian, "St. Anselm's Four Ontological Arguments" Hilary Putnam, "Psychological Predicates" Comments: Bruce Aune/U.T. -
Determinism and General Relativity
Determinism and General Relativity Chris Smeenk and Christian W¨uthrich∗ 16 September 2020 Abstract We investigate the fate of determinism in general relativity (GR), comparing the philosopher's account with the physicist's well-posed initial value formulations. The fate of determinism is interwoven with the question of what it is for a spacetime to be `physically reasonable'. A central concern is the status of global hyperbolicity, a putatively necessary condition for determinism in GR. While global hyperbolicity may fail to be true of all physically reasonable models, we analyze whether global hyperbolicity should be (i) imposed by fiat; (ii) established from weaker assumptions, as in cosmic censorship theorems; or (iii) justified by beyond-GR physics. 1 Introduction Two foundational questions one might ask about any physical theory bring out particularly subtle and interesting features of general relativity (GR). First, is GR a deterministic theory? Second, do all mathematical models of the theory represent physically possible spacetimes? There is a tight connection in GR between these two questions, i.e., between an assessment of what spacetimes are physically possible or reasonable and of whether determinism holds. It is this connection that we explore in this essay. Determinism holds if specifying the state of a system uniquely fixes its dynamical evolution. Spacetimes with exotic causal structure raise a distinctive set of questions regarding the status of determinism in GR, differing from those raised by the (in)famous hole argument. Below we will bypass the hole argument by assuming that the existence of a unique solution `up to diffeomor- phism invariance' is sufficient for determinism in GR. -
Indeterminism Is a Modal Notion: Branching Spacetimes and Earman’S Pruning
Indeterminism is a modal notion: branching spacetimes and Earman’s pruning Tomasz Placek and Nuel Belnap Contents 1 Three types of branching 4 1.1 Ensemble and individual branching defined . 5 1.2 BST branching . 6 2 BT/BST branching 8 2.1 BST: Our World and its point events . 8 2.2 BST: histories . 9 2.3 BST: axioms . 10 2.4 BST: space-like relatedness . 10 2.5 BST: modal thickness and thinness . 10 2.6 BST: applications . 11 2.7 Spatiotemporal locations . 12 3 Physically-motivated BST models 13 3.1 Minkowskian Branching Structures . 13 3.2 Defining MBS’s . 18 3.3 Takingstock............................ 22 3.4 Historical remarks . 23 4 Further replies to Earman 24 4.1 BST: Hausdorffproperty..................... 24 4.2 The thin red line . 31 4.3 Semantic rule (R)......................... 33 4.4 Past/future asymmetry . 35 5 Indeterminism 37 1 6 Final 40 2 Abstract The paper defends an Aristotelian notion of indeterminism, as rig- orously formulated in the framework of branching space-times (BST) of Belnap (1992), against criticism by Earman (2008) based on a model-theoretic characterization of indeterminism. It delineates BST branching against the background provided by Earman’s (2008) dis- tinction between individual vs. ensemble branching. Partly in order to motivate our responses to Earman, it describes a construction of physically-motivated BST models, in which histories are isomorphic to Minkowski spacetime. Finally it responds to Earman’s criticisms leveled against BST by addressing a topological issue, the question of an actual future, the past/future asymmetry, and some semantical questions. -
Aspects of Determinism in Modern Physics
ASPECTS OF DETERMINISM IN MODERN PHYSICS John Earman 1 INTRODUCTION The aims of this chapter are to review some aspects of determinism that are famil- iar to physicists but are little discussed in the philosophical literature and to show how these aspects connect determinism to issues about symmetries in physics, the structure and ontological status of spacetime, predictability, and computability.1 It will emerge that in some respects determinism is a robust doctrine and is quite hard to kill, while in other respects it is fragile and requires various enabling as- sumptions to give it a fighting chance. It will also be seen that determinism is far from a dead issue. Whether or not ordinary non-relativistic quantum mechanics (QM) admits a viable deterministic underpinning is still a matter of debate. Less well known is the fact that in some cases QM turns out to be more deterministic than its classical counterpart. Quantum field theory (QFT) assumes determinism, at least at the classical level, in order to construct the field algebra of quantum observables. Determinism is at the heart of the cosmic censorship hypothesis, the most important unsolved issue in classical general relativity theory (GTR). And issues about the nature and status of determinism lie at the heart of key foundation issues in the search for a theory of quantum gravity. 2 PRELIMINARIES 2.1 The metaphysics of determinism The proposal is to begin by getting a grip on the doctrine of determinism as it was understood pre-GTR and pre-QM, and then subsequently to try to understand how the doctrine has to be adjusted to accommodate these theories. -
Tim W. E. Maudlin Curriculum Vitae
Tim W. E. Maudlin curriculum vitae Dep't of Philosophy Davison Hall Douglass College Rutgers University New Brunswick, NJ 08903 (732) 932-9861 Education 1986 Ph.D., University of Pittsburgh, History & Philosophy of Science 1982 M.A., University of Pittsburgh, History & Philosophy of Science 1980 B.A., Yale University, Physics & Philosophy 1976 Diploma, The Sidwell Friends School, Washington DC Employment and Teaching Experience 2005- present Professor II, Rutgers University 1996-2005 Professor, Rutgers University 1996 Visiting Associate Professor, Harvard University 1992- 96 Associate Professor, Rutgers University 1986-92 Assistant Professor, Rutgers University 1985-86 Visiting Lecturer, Carnegie-Mellon University 1984-85 Teaching Fellow, University of Pittsburgh 1982-83 Teaching Fellow, University of Pittsburgh Academic Awards, Honors, and Fellowships 2008 Guggenheim Fellowship 2007 Elected to Academie Internationale de Philosophie des Sciences 1992 Rutgers University Board of Trustees Research Fellowship for Scholarly Excellence 1992 NEH Summer Stipend to complete book manuscript Quantum Non-Locality and Relativity 1989 Invited participant, Sixty-two Years of Uncertainty: Historical, Philosophical and Physics Inquiries into the Foundations of Quantum Mechanics , International School of History of Science,Ettore Majorana Centre for Scientific Culture, Erice, Italy 1988 Participant in National Endowment for the Humanities Summer Institute on Aristotle's Metaphysics, Biology and Ethics 1986-88 Henry Rutgers Research Fellowship, Rutgers -
Intermediate Philosophy of Physics Reading List
Intermediate Philosophy of Physics Reading List James Read [email protected] This is James Read’s reading list for the Finals paper, Intermediate Philosophy of Physics. If you have any questions, comments, or suggestions, please email me at the above address. 1 1 Special Relativity As preparation for the special relativity section of the paper, you might consider reading: (Warning: All of these books are stellar, but some of the later entries are very technical!) 1. N. David Mermin, It’s About Time: Understanding Einstein’s Relativity, Princeton: Prince- ton University Press, 2009. 2. Tim Maudlin, Philosophy of Physics Volume I: Space and Time, Princeton: Princeton Uni- versity Press, 2012. 3. Hans Reichenbach, The Philosophy of Space and Time, New York: Dover, 1957. 4. Harvey R. Brown, Physical Relativity: Spacetime Structure from a Dynamical Perspective, Oxford: Oxford University Press, 2005. 5. Roberto Torretti, Relativity and Geometry, New York: Dover, 1996. 6. Michael Friedman, Foundations of Space-Time Theories, Princeton: Princeton University Press, 1983. 2 1.1 Newton’s laws State Newton’s laws of motion and define all terms therein. How (if at all) do the laws depend upon one another? Do the laws together imply that Newtonian mechanics is Galilean invariant? Core reading 1. Herbert Pfister and Markus King, Inertia and Gravitation, Heidelberg: Springer, 2015. xx1.1-1.3. 2. Roberto Torretti, Relativity and Geometry, New York: Dover, 1996. Ch. 1. 3. Harvey R. Brown, Physical Relativity: Spacetime Structure from a Dynamical Perspective, Oxford: Oxford University Press, 2005. xx2.2, 3.1, 3.2. 4. Michael Friedman, Foundations of Space-Time Theories, Princeton, NJ: Princeton Univer- sity Press, 1983. -
Space, Time, and Ontology in Classical and Quantum Gravity
WHATEVER IS NEVER AND NOWHERE IS NOT: SPACE, TIME, AND ONTOLOGY IN CLASSICAL AND QUANTUM GRAVITY by Gordon Belot B.Sc., University of Toronto, 1991 M.Sc., University of Toronto, 1993 Submitted to the Graduate Faculty of University of Pittsburgh in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Pittsburgh 1996 John Earman Joseph Camp Adolf Grünbaum John Norton Carlo Rovelli ii WHATEVER IS NEVER AND NOWHERE IS NOT: SPACE, TIME, AND ONTOLOGY IN CLASSICAL AND QUANTUM GRAVITY Gordon Belot, Ph.D. University of Pittsburgh, 1996 Substantivalists claim that spacetime enjoys an existence analogous to that of material bodies, while relationalists seek to reduce spacetime to sets of possible spatiotemporal relations. The resulting debate has been central to the philosophy of space and time since the Scientific Revolution. Recently, many philosophers of physics have turned away from the debate, claiming that it is no longer of any relevance to physics. At the same time, there has been renewed interest in the debate among physicists working on quantum gravity, who claim that the conceptual problems which they face are intimately related to interpretative questions concerning general relativity (GR). My goal is to show that the physicists are correct—there is a close relationship between the interpretative issues of classical and quantum gravity. In the first part of the dissertation I challenge the received view that substantivalism has a commanding advantage over relationalism on grounds internal to GR. I argue that this view is based on a misconception of the relationships between realism and substantivalism, and between empiricism and relationalism. -
The Berlin School of Logical Empiricism and Its Legacy
Nicholas Rescher July 6, 2006 THE BERLIN SCHOOL OF LOGICAL EMPIRICISM AND ITS LEGACY 1. BACKGROUND What has become generally known as the Berlin School of Logical Empiricism constitutes a philosophical movement that was based in Berlin’s Gesellschaft fuer empirische Philosophie and erected on foundations laid by Albert Einstein. His revolutionary work in physics had a profound impact on philosophers interested in scientific issues, prominent among them Paul Oppenheim and Hans Reichenbach, the founding fathers of the school, who joined in viewing him as their hero among philosopher-scientists. Overall the membership of this school falls into three groups, as per Display 1.1 The founding generation was linked by the circumstance that both Grelling and Reichenbach were collaborators of Oppenheim; the middle generation by the fact that both Hempel and Helmer were students of Reichenbach’s in Berlin; and the younger generation by the fact that all of its members were students and (at least in their early years) disciples either of Reichenbach or of Hempel in the USA. Three stages are thus at issue: an initial phase in Berlin, a transatlantic migration, and a continuation in the U.S.A.—principally in Pittsburgh. 1 Various other people were involved in the Berlin School in a more peripheral way. A detailed account of its early days in Berlin (roughly 1927 to 1933) is given in Dieter Hoffman’s contribution to Dannenberg et. al. 1994, entitled “Zur Geschichte der Berliner Gesellschaft für empirisch/wissenschaftliche Philosophie.” 2 ___________________________________________________ Display 1 THE BERLIN SCHOOL I. THE FOUNDING GENERATION • Paul Oppenheim (1885-1977) • Kurt Grelling (1886-1942) • Hans Reichenbach (1891-1953) • Walter Dubislav (1895-1937) II. -
Determinism and General Relativity
Determinism and General Relativity Chris Smeenk and Christian W¨uthrich∗ 16 September 2020 Abstract We investigate the fate of determinism in general relativity (GR), comparing the philosopher's account with the physicist's well-posed initial value formulations. The fate of determinism is interwoven with the question of what it is for a spacetime to be `physically reasonable'. A central concern is the status of global hyperbolicity, a putatively necessary condition for determinism in GR. While global hyperbolicity may fail to be true of all physically reasonable models, we analyze whether global hyperbolicity should be (i) imposed by fiat; (ii) established from weaker assumptions, as in cosmic censorship theorems; or (iii) justified by beyond-GR physics. 1 Introduction Two foundational questions one might ask about any physical theory bring out particularly subtle and interesting features of general relativity (GR). First, is GR a deterministic theory? Second, do all mathematical models of the theory represent physically possible spacetimes? There is a tight connection in GR between these two questions, i.e., between an assessment of what spacetimes are physically possible or reasonable and of whether determinism holds. It is this connection that we explore in this essay. Determinism holds if specifying the state of a system uniquely fixes its dynamical evolution. Spacetimes with exotic causal structure raise a distinctive set of questions regarding the status of determinism in GR, differing from those raised by the (in)famous hole argument. Below we will bypass the hole argument by assuming that the existence of a unique solution `up to diffeomor- phism invariance' is sufficient for determinism in GR. -
Experiment Month: Helping Philosophers to Engage Empirically June 30, 2009
Experiment Month: Helping Philosophers to Engage Empirically June 30, 2009 Overview: Although there has been a growing interest in experimental research among young philosophers, especially undergraduate and graduate students, many find that they don’t have the resources or expertise required to conduct rigorous experimental research. These budding philosophers often have exciting and original ideas; they simply lack the support they would need to turn those visions into real philosophical research. The aim of the proposed Experiment Month program is to provide these philosophers with resources, encouragement and technical assistance to realize the potential of their own ideas. To attain these objectives, we propose, in conjunction with a consortium of prominent philosophers and under the auspices of the Yale University Program in Cognitive Science, to implement a program that will provide philosophers (especially students) with: x ‘Experiment buddies’ who can help them to correctly design studies and think through the implications of their data x On-line educational videos that guide them through the process of developing philosophically relevant experiments x The resources necessary to put together online studies, attract a large sample of subjects, and analyze the resulting data. Above all, we aim to encourage and inspire young philosophers through the organization of a community-wide event that will enable broad participation in a friendly and supportive atmosphere. Summary of Project: Fall 2010 Proposals for experiments due. Winter 2010 Team of volunteers select the most viable proposals for inclusion in the Experiment Month and provide helpful comments on selected submissions. Winter 2010— Each winning project is assigned an ‘experiment buddy’ who works Spring 2011 with the philosopher to help refine the proposed study, enabling research that successfully engages with the key philosophical questions in the relevant area.