Events Bulletin
Board
Abstracts, Philosophy of Physics Research Seminar, HT
2013
The
Philosophy of Physics seminar at Oxford will take place this Hilary term at the
usual time of 4.30pm, Thursdays, in the Lecture Room at the Philosophy Centre.
Please note the Centre's NEW ADDRESS: Radcliffe Humanities, Radcliffe
Observatory Quarter, Woodstock Road, Oxford OX2 6GG. (This is the old Radcliffe
Infirmary building.) The Lecture Room is on the second floor.
Week 1 (17 January): Dr David Wallace, Philosophy
Faculty, Oxford.
Title:
The nonquestion of Gibbs vs Boltzmann entropy
Abstract:
Contemporary philosophy of statistical mechanics is often set up as a
battle royale between Gibbsian and Boltzmannian conceptions of entropy, with
the Gibbsian approach generally regarded as philosophically suspect. I argue
that, although much is indeed conceptually wrong with Gibbsian
statistical mechanics as it is conventionally presented, the framework
itself is perfectly coherent. Furthermore, if the foundational assumptions
required by BoltzmannÕs approach are granted, they suffice to underpin the Gibbsian
approach equally well, and indeed the Boltzmannian approach can be understood
as a special case of the Gibbsian approach. In particular, the question of
which definition of entropy is right becomes essentially a matter of
terminology, of no great conceptual significance.
Week
2 (24 January): Dr Brian Pitts,
University of Cambridge
Title:
Energy and Change in Lagrangian and
Hamiltonian General Relativity
Abstract: The supposed lack of
localized gravitational energymomentum in General Relativity (GR) has inspired
both absurdities and objections to GR.
The Noether pseudotensor has components in every coordinate system, but
no transformation law relating them as equivalent faces of one thing (not a
geometric object). Bergmann noted that formally there are infinitely many
conserved gravitational energymomenta; any vector field (or basis) gives a
set. One should expect inequivalent
symmetries to yield inequivalent conserved quantities, so why not simply believe
the mathematicsÕ indication of an infinitecomponent localized entity?
Hamiltonian GR supposedly
defines change only asymptotically (if at all). But the completed DiracBergmann
constrained dynamics analysis of Castellani, Salisbury, Pons, and Shepley
implements HamiltonianLagrangian equivalence and distinguishes the
4dimensional gauge transformation generator ("t)G(t) from the Hamiltonian
H. 4dimensional Lagrangian change
is the lack of a timelike Killing vector field. Thus Hamiltonian change must be the
Hamiltonian equivalent, vindicating the changeaffirming common sense of
Maudlin and Kuchař from the technicalities of Earman et al. DiracÕs book
notwithstanding, firstclass primary constraints in GR do not always generate
gauge transformations.
Firstclass primaries appear both in H to help to generate time
evolution (the lapse and shift vector values at later times) and in ("t)G(t)
to help to generate coordinate transformations. Hence the conceptual side of the Dirac
conjecture also fails. Gauge
equivalence in GR must be understood in terms of histories, not instantaneous
states as Dirac envisagedthereby feeding in the idea that different stages
of history are physically equivalent by not adequately testing the formalism on
its chief example. More confusion
is avoided by not introducing primitive point identities into mathematical
physics. Demanding that the Lie
derivative vanish for ÒobservablesÓ is unmotivated by comparison with
4dimensional tensor calculus, at least if observables have something to do
with observations (as Bergmann held).
He developed the notion of observables in GR by analogy to Hamiltonian
electromagnetism, thus tacitly inclining toward invariance over covariance and
neglecting equivalence with Lagrangian GR.
Week
3 (Thu 31 January): Prof Dennis Dieks,
University of Utrecht
Title:
Indistinguishability and Individuality:
Classical and Quantum
Abstract:
In
classical physics the concept of a particle seems clear enough: we are dealing
with individuals, distinguished by individuating statedependent properties
(position, trajectory, etc.). However, even in classical physics there have
been arguments that particles of the same kind are indistinguishable. The situation
becomes more confusing in quantum mechanics. Here we have the famous symmetrization
and antisymmetrization postulates for bosons and fermions, respectively, which
seem to entail that all Òidentical particlesÓ of the same kind are in
literally the same state and must therefore be completely indistinguishable.
Still, in the classical limit they seem miraculously to emerge as individuals
with different states.
We
shall attempt to bring some order here, going from the Gibbs paradox to quantum
theory.
Week 4 (Thursday 7 February): Dr Terry Rudolph, Imperial College,
London
Title: Realism and the epistemic view of quantum states
The idea that
quantum states reflect only an observers knowledge/beliefs/information
about the world has a long history. The challenge for an advocate of this
position, however, is to identify what we can deduce is ``really going
on'' out there. There seem to three main paths proponents of the epistemic
view have followed in trying to extract such a narrative from quantum
theory. I will explain how the most na•ve such paththat quantum states
can be associated with standard (probabilistic) uncertainty about some
(arbitrary) real states of the worldis not tenable under some extremely
mild assumptions about how any theory of reality must treat independent
experiments. I will then overview the other two paths and what I see as
the challenges they face.
Week 5 (Thursday 14 February): Dr Jeffrey Ketland, Oxford
Title: Leibniz Equivalence
Abstract:
In this talk I discuss two topics.
First,
I will argue that the notion of a diffeomorphism is something of a red herring
in the usual debates about the hole argument and Leibniz equivalence. It seems
clear that, given a spacetime model, (M, g_{ab}, É), the application of an
arbitrary permutation of the base set of M generates a new isomorphic model
which represents the same physical possibility. There seems no genuine
requirement that such a permutation must also be a diffeomorphism (i.e.,
automorphism) of M. For if one is allowed to shift around the tensor fields,
why is one not allowed to shift around the open sets of the topology in M, so
long as the overall result is isomorphic? I believe that this suggestion is in
accord with R.M. WaldÕs formulation of the corresponding principle in his
standard textbook on General Relativity.
Second,
I will make some more tentative suggestions about how to think of possible
worlds as not having any domain at all: namely, as certain kinds of categorical
existentially quantified propositions (possibly infinitary), so that it is
automatically true that isomorphic models represent the same world. This may
also be of relevance to those are sympathetic to a version of structuralism,
whether scientific or mathematical, in which one has Òstructures without
relataÓno distinguished domain or base set.
Week
6 (Thursday 21 February): Dr Berry Groisman, D.A.M.T.P., Cambridge
Title:
Sleeping Beauty in Quantumland
Abstract: I
will discuss the treatment of the Sleeping Beauty Problem within the
framework of the ManyWorlds Interpretation of Quantum Theory. I will take
the view that the MWI is a fundamentally deterministic theory with full
information being available to observers before experiments are carried
out. The absence of objective uncertainty in this version of the MWI does
not contradict the fact that observers might experience an 'illusion of
probability'. I will argue, therefore, that the Sleeping Beauty Problem
fits naturally into this interpretation of probability in Many Worlds and
will demonstrate how this approach leads to the 'thirder' solution. I will
comment on alternative views on the probability in Many Worlds and on
alternative treatments of quantum Sleeping Beauty.
Week
7 (28 February): Dr Martin Sahlen, Astrophysics, Oxford.
Title:
Questions
in Philosophy of Cosmology
Abstract:
Within modern physical cosmology, a series of new discoveries over the last
100 years have paved the way for a new conception of the Universe. The
image has changed from a single, static galactic universe to a dynamically
forming universe arisen from quantum mechanical fluctuations, expanding in
size, and dominated by an unknown "dark" set of
constituents.
But
even as theoretical and observational discoveries have proceeded apace, a
number of philosophical questions have come increasingly to the fore. Cosmology
concerns a single timesituated system, vast parts of which, even at
the present epoch, are in principle unobservable: how is this limitation to be managed? Is cosmology a science, properly speaking, at
all?
I will
present the main current results in physical cosmology, future planned
observations, and some of the key recent theoretical developments, with an
eye to some of the inherent problems in the field: that the object of
cosmology comprises a single, unrepeatable system, studied from a single,
situated standpoint, observations of which may be subject to selection
effects consequent on our existence as observers, that may be vastly
larger than its visible part.
Abstracts,
Philosophy of Physics Research Seminar, MT 2012
The
Philosophy of Physics seminar at Oxford will take place this Michaelmas term at
the usual time of 4.30pm, Thursdays, in the Lecture Room at the Philosophy
Centre. Please note the Centre's NEW ADDRESS: Radcliffe Humanities, Radcliffe
Observatory Quarter, Woodstock Road, Oxford OX2 6GG. (This is the old Radcliffe
Infirmary building.) The Lecture Room is on the second floor.
Week 1 (11 October): Dr Owen Maroney, Philosophy Faculty,
Oxford.
Title: No go theorems and statistical states.
Abstract:
There has recently been a flurry of activity, proving limitations on
whether it is possible to understand the quantum wavefunction as just a
statistical (rather than physical) state. I will review the three most
recent nogo theorems, all focussed on the idea of `psiepistemic' hidden
variable theories. I will try to clarify the assumptions involved and what
possibilities they leave for a statistical interpretation of the quantum state.
Week 2 (18 October): Dr Olivier Darrigol, CNRS/UniversitŽ Paris
VII (Denis Diderot); University of California, Berkeley.
Title: Necessity or contingency of the laws of
classical mechanics.
Abstract: Nowadays,
the laws of ordinary mechanics are usually regarded as contingent: the motion
of macroscopic bodies could have obeyed other laws; it is only from experiment
that we could learn the true laws. There was no such consensus in the early
mechanical philosophy of the seventeenth century. Famously, Descartes and
Newton held opposite views on this matter. The two most important writers on
mechanics in the eighteenth century, d'Alembert and Euler, believed in the
rational necessity of the laws of mechanics. So did too the two most
influential philosophers of that century, Leibniz and Kant. Nineteenthcentury
physicists and critiques of science often held an intermediate position, in
which some mechanical laws were rational and others empirical. They nonetheless
approved mechanical reductionism. The purpose of this talk is to summarize
these debates, to investigate the nature and quality of the arguments, and to
question today's reigning antirationalism.
Week 3 (25
October): Dr. Adam Caulton,
Department of Philosophy, Logic and Scientific Method, LSE
Title: Hume's dictum as a
guide to physical ontology
Abstract: Quine's dictum that to
be is to be the value of a variable has become an enormously popular mantra for
ontologists of a regimenting disposition, but it is apt only on the assumption
of other Quinean doctrines that are, for good reason, more controversial.
In this talk, I will outline an alternative that takes its inspiration from
Hume's dictum that there are no necessary connections between distinct
existents. I will trace a brief history of the dictum within 20th Century
analytic philosophy, and argue that Hume's dictum provides a better guide than
Quine's for interpretative projects in the philosophy of physics. Finally
(and if there's time), I will attempt to use this application of Hume's dictum
to reconcile a Kuhnian notion of conceptual relativity with Davidson's apparent
scepticism about the possibility of rival conceptual schemes.
Week 4 (1
November): Dr. Gabor HoferSzabo, Institute
of Philosophy, Research Center for the Humanities, Hungarian Academy of
Sciences
Title: Bell Inequality and
Common Causal Explanation in Algebraic Quantum Field Theory
Abstract: In the
talk it will be argued that the violation of the Bell inequality in
algebraic quantum field theory does NOT exclude a common causal
explanation of a set of quantum correlations if we abandon
commutativity
between the common cause and the correlating events. Moreover, it will
turn out that the common cause is local, i.e. localizable in the
common
past of the correlating events. It will be argued furthermore that
giving
up commutativity helps to maintain the validity of Reichenbach's
Common
Cause Principle in algebraic quantum field theory.
Preprint: http://philsciarchive.pitt.edu/9101/
Week 5 (8 November): Dr. Eric Cavalcanti, Department of Computer Science, Oxford
University; School of Physics, University of Sydney
Title:
What Bohr could have told Einstein at Solvay had he known about Bell
Abstract: The 1964
theorem of John Bell shows that no model that reproduces the predictions of
quantum mechanics can simultaneously satisfy the assumptions of locality and
determinism. On the other hand, the assumptions of signal locality plus
predictability are also sufficient to derive Bell inequalities. This simple
theorem, previously noted but published only relatively recently by Masanes,
Acin and Gisin, has fundamental implications not entirely appreciated. Firstly,
nothing can be concluded about the ontological assumptions of locality or
determinism independently of each other—it is possible to reproduce
quantum mechanics with deterministic models that violate locality as well as
indeterministic models that satisfy locality. On the other hand, the
operational assumption of signal locality is an empirically testable (and
welltested) consequence of relativity. Thus Bell inequality violations imply
that we can trust that some events are fundamentally unpredictable, even if we
cannot trust that they are indeterministic. This result grounds the
quantummechanical prohibition of arbitrarily accurate predictions on the
assumption of no superluminal signalling, regardless of any postulates of
quantum mechanics, and underlies recent proposals for randomness generation
certified by Bell inequality violations. It also sheds a new light on an early
stage of the historical debate between Einstein and Bohr.
http://www.springerlink.com/content/160t806n89457104/
Week 7 (22 November): Dr. Tracy Lupher, Department of
Philosophy and Religion, James Madison University.
Title: The Limitations of Physical
Equivalence
Abstract: Some
physicists and philosophers argue that unitarily inequivalent representations
in quantum field theory are not physically significant because they are
physically equivalent. The heart of the argument relies on FellÕs theorem
and its deployment in the algebraic approach to quantum field theory.
That argument and its use as a criterion for physical equivalence is examined
in detail and it is proven that FellÕs theorem does not apply to the vast
number of representations used in the algebraic approach. Unitarily
inequivalent representations are not another case of theoretical
underdetermination, because they make different predictions about ÒclassicalÓ
operators. These results are applied to the Unruh effect where there is a
continuum of UIRs to which FellÕs theorem does not apply.
Week 8 (29 November): Dr. Juha Saatsi, Department of
Philosophy, University of Leeds.
"What is theoretical progress of science?"
I explore,
with examples from physics, the idea that science makes theoretical progress if
a better confirmed theory Ôlatches better onto realityÕ than its predecessor. I
compare this conception of theoretical progress with the 'epistemic conception'
advocated (inter alia) by Bird. According to Bird science makes progress
Ôprecisely when it shows accumulation of knowledgeÕ. I argue that BirdÕs
conception fails of accommodate some theoretical progress in science, and that
it leads to an impoverished conception of scientific realism.
Abstracts, Philosophy of Physics Research Seminar, MT
2011
October 13. William Harper, Department of Philosophy, University
of Western Ontario
ÒIsaac Newton's Scientific MethodÓ
Abstract:
On the basic hypotheticodeductive model hypothesized principles are
tested by experimental verification of observable consequences drawn from them.
Empirical success is limited to accurate prediction of observable phenomena.
NewtonÕs inferences from phenomena realize an ideal of empirical success
that is richer than prediction. To realize NewtonÕs richer conception of
empirical success a theory needs to do more than to accurately predict the
phenomena it purports to explain; in addition, it needs to have the phenomena
accurately measure parameters of the theory. NewtonÕs method aims to turn
theoretical questions into ones which can be empirically answered by
measurement from phenomena. Propositions inferred from phenomena are
provisionally accepted as guides to further research. Newton employs
theorymediated measurements to turn data into far more informative evidence
than can be achieved by hypotheticodeductive confirmation alone. On his method
deviations from the model developed so far count as new theorymediated
phenomena to be exploited as carrying information to aid in developing a more
accurate successor.
All of these enrichments are exemplified in the classical response to
MercuryÕs perihelion problem. Contrary to Kuhn, NewtonÕs method endorses the
radical transition from his theory to EinsteinÕs. These richer themes of
NewtonÕs method are, also, strikingly realized in the response to a challenge
to general relativity from a later problem posed by MercuryÕs perihelion.
We can also see NewtonÕs method at work in cosmology today in the
support afforded to the (dark energy) cosmic expansion from the agreeing
measurements from supernovae and cosmic microwave background radiation.
Oct 20. Matt Leifer, Quantum Information Group, Physics and Astronomy Department,
UCL, and Perimeter Institute for Theoretical Physics, Ontario, Canada.
"Quantum Theory as a Causally Neutral Theory of
Bayesian Inference"
Abstract:
Quantum theory can be viewed as a noncommutative
generalization of classical probability theory, but, as it stands, the analogy
is not complete. The basic rules of classical probabilistic inference are
independent of causal structure whereas the conventional quantum formalism
requires causal structure to be specified in advance.
In this talk, I outline an alternative formalism for
finitedimensional quantum theory, based on the idea of a quantum conditional
state, that unifies the quantum rules of inference in different causal
scenarios. In particular, quantum dynamics, the Born rule, ensemble averaging,
and the rules for inferences across spacelike separation can all be viewed as
special cases of a quantum generalization of the belief propagation rule P(Y) =
\sum_X P(YX)P(X). The formalism gives rise to a quantum generalization
of Bayes' theorem, and an associated notion of Bayesian conditioning.
These can be used to derive and generalize the retrodicitive formalism
for quantum theory of Pegg et. al. and provide an intuitive derivation of
ensemble steering in EPRtype experiments.
Our notion of quantum Bayesian conditioning differs
from the projection postulate, which several authors (e.g. Bub) have argued is
a quantum generalization of conditioning. I will explain why projection
cannot be viewed as a type of conditioning in our formalism and show that it
should instead be thought of as an instance of quantum belief propagation
followed by conditioning.
This talk is based on joint work with Rob Spekkens
arXiv:1107.5849
Oct 27. Simon Saunders, Faculty of Philosophy, Oxford University
ÒNewton's
theory of gravity in the light of cosmologyÓ.
Abstract:
Newton famously thought his theory of gravity required
the existence of absolute space and time. It was subsequently realized that
neoNewtonian or Galilean spacetime is sufficient, based on the concept of a
class of intertial frames rather than absolute space. But if we lived in a
'large enough' Newtonian universe, no such inertial frames could ever be
discovered by any operational method.
The privileged frames that can be operationally
defined in accordance with Newton's theory are rather nonrotating freelyfalling
frames. This raises the suspicion that the spacetime structure implicit in
Principia is weaker than Galilean spacetime, to be grounded on Corollary VI to
the Laws, whereas Galilean spacetime is grounded on Corollary V (the
relativity principle). Unlike the latter, this structure, for a theory of
particles, admits of a purely relational interpretation, in the sense of
Huygens, based only on the comparison of directions in space (as given by
particle pairs) at different times.
Nov 3. Matthew Pusey, Controlled Quantum Dynamics Centre for Doctoral Training, Imperial
College.
"Local realism for product states needs the
quantum state"
Abstract:
If the quantum state is a real thing then the
existence of entangled states shows that physical reality is not local. Before Bell's
theorem it was reasonable to hope that local realism could be saved by adopting
the view that quantum states are not real, but rather a representation of
knowledge. Based on joint work with Jonathan Barrett and Terry Rudolph, I will
argue that the failure of local realism is in fact qualitatively more dramatic
under this latter perspective. I will do this by describing a class of
experiments, involving unentangled states, for which the only local explanation
is that the quantum state is real.
Nov 10. Fotini Markopoulou, Perimeter Institute for Theoretical Physics,
Ontario.
ÔSpin systems as toy models for emergent gravityÕ
Abstract:
A number of recent proposals for a quantum theory of gravity are based
on the idea that spacetime geometry and gravity are derivative concepts and
only apply at an approximate level. Two fundamental challenges to any
such approach are, at the conceptual level, the role of time in the emergent
context and, technically, the fact that the lack of a fundamental spacetime
makes difficult the straightforward application of wellknown methods of
statistical physics and quantum field theory to the problem. We initiate
a study of such problems using spin systems as toy models for emergent geometry
and gravity. These are models of quantum networks with no a priori
geometric notions.
In this talk we present two models. The first is a model of emergent
(flat) space and matter and we show how to use methods from quantum information
theory to derive features such as speed of light from a nongeometric quantum
system. The second model exhibits interacting matter and geometry, with
the geometry defined by the behavior of matter. This is essentially a
Hubbard model on a dynamical lattice. We will see that regions of high
connectivity behave like analogue black holes. Particles in their
vicinity behave as if they are in a Schwarzchild geometry. Time
permitting, I will show our study of the entanglement entropy of the system,
which suggests particle localization near these traps.
Nov 17. Owen Maroney, Faculty of Philosophy, Oxford University
"What does violating the Leggett Garg Inequality actually tell us?
(Two ways to be a macrorealist, and one way not to be.)"
Abstract:
The Leggett Garg Inequalities were introduced with the intention
of providing a Bell Inequalitylike test of whether macroscopic
objects
like cats are always in one or another macroscopically distinct state, and
never in superpositions of such states. Leggett and Garg dubbed
this idea "macrorealism". Critics immediately argued that it
was an additional condition  noninvasive measureability  that was
really at
stake. Leggett, however, maintained that the noninvasiveness of
the relevant measurements was simply a natural consequence of
macrorealism
and the issue remained stalled.
Advances in quantum technology have led to a number of
experiments recently testing violations of the Leggett Garg Inequality,
albeit in
microscopic systems. It seemed a good idea, therefore, to revisit
the basis of the Inequality and ask what, if anything, these
experiments
might be revealing.
Surprisingly, perhaps, it turns out that a violation does do more that just
refute noninvasive measureability. Although
"macrorealist" theories can, and should, deny noninvasive
measureability, there remain additional nontrivial constraints they
must fulfil to account for a Leggett Garg Inequality violation.
Nov 24. Hasok Chang, Department of History and Philosophy of Science, University of Cambridge
ÒOperationalism and Realism in 19thcentury
Atomic ChemistryÓ
Abstract:
In this paper I offer a new philosophical interpretation of the
development of atomic chemistry in the 19th century. I argue that success
in this field owed much to a particular kind of operationalism, a key
component in an epistemic attitude which I call active realism (though
it is not so consonant with scientific realism as normally conceived). We
lose sight of crucial aspects of this history if we approach it through a preoccupation
with the question of whether atoms really exist, or whether statements we make
about the unobservable atoms and molecules are Òreally trueÓ. As Alan Rocke has
argued, chemical atomism was unhampered by the persisting doubts about
the real existence of physical atoms. Chemists devised various ways of
operationalizing the atom by incorporating it into clear and stable epistemic
activities, such as the tracking of combining weights, and decomposition by
electrolysis. Particularly striking is the midcentury success of atomic
chemistry based on operational methods of atomcounting, using combining
volumes and specific heat. On the other hand, different
operationalizations of the atom did often diverge, as manifested in the fact
that at least 4 different sets of atomic weights were in widespread use until
the 1860s. This is a reminder of a fundamental dilemma faced by Percy
Bridgman: when there are multiple methods purporting to measure the same
quantity, does each method really define a separate concept as his
operationalist philosophy dictated, or are we somehow justified in regarding
the different methods as different ways of getting at the same thing?
Ultimately Bridgman left this issue unresolved. Interestingly, the same
philosophical indecision was at the heart of the successful development of
19thcentury atomic chemistry. In the absence of unification, each
operationalization provided an independent window on reality.
Dec 1. Wayne Struyve, Institute for Theoretical
Physics, Catholic University of Leuven
ÒSpontaneous symmetry breaking and the Higgs
mechanismÓ
Abstract:
The Higgs mechanism gives mass to YangMills gauge
bosons. According to the conventional wisdom, this happens through the
spontaneous breaking of gauge symmetry. But if gauge symmetries merely
reflect a redundancy in the state description, what exactly does it mean
to break it? I want to address this question in the context of classical
field theory.
Abstracts, Philosophy of Physics Research Seminar, TT
2011
All talks are Thursdays 4:306:30, Lecture Room, 10 Merton Street,
followed by dinner for those who are interested.
May 5^{th} (Week 1): Frank Arntzenius and Cian Dorr (Faculty of
Philosophy, Oxford University) "The ontology of gauge theories and
differential geometry"
Abstract:
The first half of this talk will argue that gauge field theories should
be interpreted as talking about an ontology of 'fibre bunde substantivalism': one
in which every point of spacetime is associated with a real, concrete space
(the fibre over that point). The
second half will attempt to extend the programme of nominalising physical
theories initiated by Hartry Field in _Science Without Numbers_. We will show how an ontology of fibre
bundle substantivalism can provide us with a nominalistically acceptable
account of spacetime _qua_ differentiable manifold, thereby opening up a
straightforward route towards the nominalisation of any physical theory formulable
in differentialgeometric terms.
Abstracts, Philosophy of Physics Research Seminar, HT
2011
All talks are Thursdays 4:306:30, Lecture Room, 10 Merton Street,
followed by dinner for those who are interested.
Jan 27th (Week 2): Roman Frigg (LSE): ÒExplaining ThermodynamicLike
Behaviour In Terms of EpsilonErgodicityÓ
Abstract: Macroscopic systems such as gases reach equilibrium when left
to themselves. Why do they behave in this way? The canonical answer to this
question, originally proffered by Boltzmann, is that the systems have to be
ergodic. This answer has been criticised on different grounds and is now widely
regarded as flawed. In this paper we argue that some of the main arguments
against BoltzmannÕs answer, in particular, arguments based on the KAMtheorem
and the MarkusMeyer theorem, are beside the point or inconclusive. We then
argue that something close to BoltzmannÕs original proposal is true: systems
approach equilibrium if they are epsilonergodic, i.e. ergodic on the entire accessible
phase space except for a small region of measure epsilon. This answer is
promising because there are good reasons to believe that relevant systems in
statistical mechanics are epsilonergodic.
Feb 3 (Week 3): Carl Hoefer (Barcelona): TBC
Feb 10 (Week 4): David Wallace (Oxford): ÒSymmetry, locality, and spaceÓ
Abstract: I attempt to square the circle between (a) the view that two
situations, related by a symmetry, are the same situation differently described
(so that symmetry can seem like an inessential consequence of our choosing an
excessive mathematical formalism), and (b) the manifest fact that symmetries 
local and global  seem to play an absolutely essential role in physical
theories (so that they seem like features of the theory itself, not just of our
formulation of it). In doing so, I hope to cast some light on the relationship
between symmetries and the spaces of which they are symmetries, and also on the
gauge principle.
Feb 17 (Week 5): Jon Barrett (Royal Holloway): TBC
Feb24 (Week 6): Steven French (Leeds): ÒDoing Away with
Dispositions: Towards a LawBased View of ModalityÓ
Abstract: Most metaphysicians accept a form of possibility in actuality,
articulated through dispositional accounts of properties. Advocates of the dispositional
essentialist variant of such accounts have drawn on modern physics in support
of their programme. However I shall suggest that such support is equivocal at
best and that the recent development of this programme has led to the denial of
an appropriate role for laws and symmetries in physics. As an alternative I
shall defend the view that laws and symmetries themselves should be regarded as
part of the 'fundamental base' of reality, drawing on recent work in
metaphysics. This raises a number of issues to do with the relationship between
laws and properties, the modal nature of laws and the relationship between
determinable and determinate aspects of the fundamental base, which I hope to
explore.
Abstracts, Philosophy of Physics Research Seminar, MT
2010
All talks are Thursdays 4:306:30, Lecture Room, 10 Merton Street,
followed by dinner for those who are interested.
October 14th (week 1):
Prof Doreen Fraser, Department of Philosophy, University of Waterloo,
Canada.
"Emergence and Explanation in Quantum Field Theory and Statistical
Mechanics"
The insight that a formal, mathematical identification can be made
between the theory of critical phenomena in statistical mechanics (SM) and
renormalization methods in quantum field theory (QFT) has led to significant
advances in both fields in the decades since Kenneth Wilson and his
collaborators first published their results. An important question about these
developments has been raised and debated by structural realists: What is the physical basis for
this mathematical analogy? As a way
of exploring this issue, I will consider whether analogues of BattermanÕs
arguments that modern thermodynamics is an emergent theory apply to effective
QFTs. This investigation will
illuminate some important differences between the physical interpretations of
the similar mathematical formalisms employed in QFT and SM.
October 21st (week 2):
Steve Simon, Department of Physics, Oxford University.
"Knots, WorldLines, and Quantum Computation"
The talk will be an introduction to topological quantum computing, an
active field of research which aims to exploit the existence of 'topological
phases' of matter to achieve coherent manipulation of quantum information.
Sigma Club at LSE  Programme for Michaelmas Term
2010/11
Monday October 25. 5:157:00pm
Jeremy Butterfield, Trinity College, University of Cambridge
Particles as Properties (joint work with Adam Caulton, University of
London)
Abstract:
In this paper, we have two main aims: the first negative, the second
positive.
First, we show that what are usually called `particle labels' (labelling
a factor Hilbert space) do not correspond to the physical idea of a particle.
This point is widely recognized, especially in the practice of physics. But it
is worth developing in detail since almost all authors in the interpretive
literature take particles to correspond to labels (whatever their other
disagreements, e.g. about particles being indiscernible, or being individuals).
Our second aim is to develop a positive account of the physical idea of
a particle (in nonrelativistic quantum mechanics). Our main idea is that it is
a (higherorder) property of what is traditionally called `the assembly of
particles', and is an emergent or approximate feature of certain states. This conception
of particle is familiar from quantum field theory, where it is usually
motivated by the existence of superpositions of particlenumber. But we argue
that it is also well motivated for nonrelativistic quantum mechanics.

Monday November 1. 5:157:00pm
Bob Coecke, Oxford University
In the beginning God created tensor
Abstract
It is now exactly 75 years ago that John von Neumann denounced his own
Hilbert space formalism: ``I would like to make a confession which may seem
immoral: I do not believe absolutely in Hilbert space no more.''(sic) [1] His
reason was that Hilbert space does not elucidate in any direct manner the key
quantum behaviors. So what are
these key quantum behaviors then? [2,3]
For Schrodinger this is the behavior of compound quantum systems,
described by the tensor product [4, again 75 years ago]. While the quantum information endeavor
is to a great extend the result of exploiting this important insight, the
language of the field is still very much that of strings of complex numbers,
which is akin to the strings of 0's and 1's in the early days of computer
programming. If the manner in which
we describe compound quantum systems captures so much of the essence of quantum
theory, then it should be at the forefront of the presentation of the theory,
and not preceded by continuum structure, field of complex numbers, vector space
over the latter, etc, to only then pop up as some secondary construct.
Over the past couple of years we have played the following game: how much
quantum phenomena can be derived from `compoundness + epsilon'.
It turned out that epsilon can be taken to be `very little', surely not
involving anything like continuum, fields, vector spaces, but merely a
`twodimensional space' of temporal composition (cf `and then') and
compoundness (cf `while'), together with some very natural purely operational
assertion, including one which in a constructive manner asserts entanglement;
among many other things, trace structure (cf von Neumann above) then follow [5,
survey]. In a very short time, this
radically different approach has produced a universal graphical language for
quantum theory which helped to resolve some open problems. It also paved the
way to automate quantum reasoning [6] and has even helped to solve problems
outside physics, most notably in modeling meaning for natural languages
[7]. Meanwhile several researchers
aiming `beyond quantum theory' have taken up several of our ideas eg [8].
All of this gives a totally new conception about what's `logical'
about quantum theory.
[1] M Redei (1997) Why John von Neumann did not like the Hilbert space
formalism of quantum mechanics (and what he liked instead). Stud Hist Phil Mod Phys 27, 493510.
[2] For von Neumann, initially these were the propositions that one
could measure with certainty, an idea that he later abandoned in favor of the
trace structure, which generates probability [1].
[3] Still, today for most physicists `quantum' is synonym for `Hilbert
space', which of course is not unrelated to the dominant ``shut up and
calculate''conception of quantum theory.
[4] E Schroedinger, (1935) Discussion of probability relations between
separated systems. Proc Camb Phil
Soc 31, 555563; (1936) 32, 446451.
[5] B Coecke (2010) Quantum picturalism. Cont Phys 51, 5983.
arXiv:0908.1787
[6] L Dixon, R Duncan & A Kissinger.
dream.inf.ed.ac.uk/projects/quantomatic/
[7] B Coecke, S Clark & M Sadrzadeh (2010) Ling Anal 36.
Mathematical foundations for a compositional distributional model of meaning.
arXiv:1003.4394
[8] L Hardy (2010) A formalismlocal framework for general probabilistic
theories including quantum theory. arXiv:1005.5164

Monday November 15. 5:157:00pm
Chris L. Farmer, University of Oxford
Inverse Problems: Formulation, Computation and Interpretation.
Abstract:
Mathematical theories are used for making predictions in, for example,
weather forecasting, climate prediction and oil recovery from geological
formations.
Prediction involves setting wellposed problems using a state space and
equations evolving the system state through time. Some elements of the state,
the 'parameters', do not change in time. Other elements of the state, the
'variables', do change in time. To make predictions then requires knowing the
state at the initial time. This is 'forward modelling'. In practical problems
the initial values of the variables or the values of the parameters are usually
unknown. However, a few measurements of the state can be made, and so the
'inverse problem' is to infer the parameters and the variables from the
measurements and the forward model. With limited information a unique answer is
not possible, and thus inverse problems are generally illposed problems.
One framework for studying such problems is provided by Bayesian
statistics. The first part of the talk outlines how this is used. The second
part of the talk summarises our current ability to actually perform Bayesian
inference for realistic forward models. When carefully designed, a Bayesian
framework leads to a wellposed inverse problem and a solution in the form of a
probability measure.
When forward models are accurate, the Bayesian framework is
satisfactory; when models are inaccurate there are severe problems of
interpretation. One practical difficulty is to ascertain how accurate a theory
is from the sparse observations when they are needed to infer the parameters.
This is, possibly, the situation in climate prediction. A further difficulty is
that we usually know anyway, that the forward model is very far from accurate. So
how can forward and inverse problem solving be used in a defensible way as a
basis for decisionmaking and control? The third part of the talk will thus
discuss how inverse problems are involved in practical decisionmaking and
control. In control theory it is sometimes observed that by making sufficient
use of feedback one can be robust to model error. Perhaps then, we should
concentrate more on problems of decision and control and less upon problems of
prediction.
On Symmetry in Physics
A OneDay Conference
Saturday 30
October 2010
The Deighton Room, Blue Boar Court, Trinity College, Cambridge
This room is on the first floor at the intersection of Trinity Street and
Green Street, but is hard to find from within the College's Court
(accessed
via Whewell's Court). Therefore, at 09.50, 10.25 and at 13.50, there will
be a guide whom you can ask, who will be stationed on the cobblestones at
the front of Trinity College's main entrance, i.e. opposite Heffer's
bookshop, on Trinity Street.
10.00 Hilary Greaves, Oxford University
On the empirical significance of ("global" and "local")
symmetries
11.00 Coffee
11.30 David Wallace, Oxford University
Symmetry, locality, and space
12.30 Lunch
2.00 pm Adam Caulton, London University
Two ways to permute particles in quantum mechanics
3.00 pm Tea
3.45 pm
Nazim.Bouatta, Cambridge University
Symmetries, Infinities and Wilsonian Quantum Field Theory
4.45 Close
£2 registration: to be paid at the door. To help organize seating. please
email the organizers to say if you are coming.
Organized by:
J Butterfield (jb56@cam.ac.uk) and A Caulton (adam.caulton@googlemail.com)
ABSTRACTS
Hilary Greaves: On the empirical
significance of ("global" and "local") symmetries
There is something of a tension between two aspects of symmetry in
physics. On the one hand, there is a widespread consensus that 'two states
of affairs related by a symmetry transformation are really just the same
state of affairs differently described': that is, that if two mathematical
models
of a physical theory are related by a symmetry transformation, then
those models represent one and the same physical state of affairs. This
seems to give symmetry a purely formal role in physics: symmetries are not
features of the world, but merely features of our method of describing the
world.
On the other hand, it seems to be a matter of plain historical fact
that the observable consequences of symmetries have guided physicists
in their construction of theories ever since Galileo's ship
thought experiment. It is prima facie mysterious how this fact is
compatible with
the account of symmetries given above.
The usual story about how to reconcile the idea of symmetry
as surplus structure with the idea of symmetry as an empirical feature of
the
world gives a key role to the distinction between 'global' and
'local' symmetries: it is supposed to be the case that global symmetries
(e.g. the Lorentz invariance of special relativity) correspond to
Galileoship type experiments, while local symmetries (e.g. the
diffeomorphism invariance of general relativity, or the gauge invariance
of electromagnetism) do not. (This 'usual story' has recently been
defended by, among others, Katherine Brading, Harvey Brown and Richard
Healey.) In my talk, I will raise several puzzles that I don't think the
usual account can deal with.
I will then go on to sketch an alternative account,
carefully drawing out the precise consequences of the (wellknown) idea
that, to realise a symmetry empirically, one must be symmetrytransforming
only a subsystem of the universe, and not the universe as a whole.
According to this alternative account, both global and local symmetries
can correspond to Galileoship type phenomena; in particular, there are
such phenomena corresponding to both the (local) gauge invariance of
classical electromagnetism and the (local) diffeomorphism invariance of
general relativity. The key distinction, which I will draw in the talk, is
rather between 'interior' and 'noninterior' symmetries.
This talk is based on a forthcoming joint paper with David Wallace.
David Wallace: Symmetry, locality, and
space
I attempt to square the circle between (a) the view that two
situations, related by a symmetry, are the same situation differently
described (so
that symmetry can seem like an inessential consequence of our choosing
an excessive mathematical formalism), and (b) the manifest fact that
symmetries  local and global  seem to play an absolutely essential
role in physical theories (so that they seem like features of the theory
itself,
not just of our formulation of it). In doing so, I hope to cast some
light on the relationship between symmetries and the spaces of which they
are
symmetries, and also on the gauge principle.
Adam Caulton: Two ways to permute
particles in quantum mechanics
Broadly speaking, particle statistics in elementary quantum mechanics
have been given two origins, which are apparently in tension. According to
one account, one quantizes using the usual classical configuration space,
and the resulting Hilbert space is broken into superselection "symmetry
sectors" corresponding to inequivalent representations of the
symmetric group, owing to the Indistinguishability Postulate. Fermions and
bosons arise alongside paraparticles as possible particle statistics.
According to another account, a reduced configuration space is first
obtained by
quotienting the classical configuration space by the symmetric group,
and then one quantizes. But nontrivial topological features of the
reduced
configuration space allow for multivalued wavefunctions. In three
spatial dimensions, fermions and bosons arise (but not paraparticles); in
two
spatial dimensions, particles with statistics somewhere between
fermions and bosons arisethe anyons. The two accounts are in tension
because
anyonic states apparently do not lie within symmetry sectors.
In response to this situation, I will first argue that there is
no real conflict between anyonic "statistics" and the
Indistinguishability Postulate. Rather, confusion arises from the fact
that unitary representations of the symmetric group ambiguously represent
both synchronic permutations of labels within a state and
diachronic transpositions of particles. Further, the diachronic
transpositions admit a different group of representations (namely, the
braid group) when the transpositions are governed by pathdependent
dynamicswhich is exactly what to expect in two but no more spatial
dimensions.
Finally, I will argue that two issues remain for
philosophical antihaecceitists about quantum particles. First, the formal
resources necessary to mark the synchronic/diachronic difference appears
to mean trouble for antihaecceitists who also wish time to be an emergent
feature of dynamics, in the sense advocated by Barbour. Second, given that
the two proceduresquotienting under the symmetric group and
quantizationdo not commute, it is indeterminate which order an
antihaecceitist ought to favour.
Nazim Bouatta: Symmetries, Infinities
and Wilsonian Quantum Field Theory
Wilson's renormalization group (RG) approach gives a new point of
view about the meaning of quantum field theory. In this context, I
will
conceptually analyze the status of "nonrenormalizable" gauge
theories, viz. nonrenormalizable theories in the Dyson power counting
sense. I will
examine the nature of the "infinities" in these gauge theories by
means of the BRST symmetry and the BatalinVilkovisky (BV) formalism.
Finally, I
will discuss the idea of emergent "accidental" symmetries in the
framework of effective field theories. I will illustrate our discussion by
an example
in particle physics: baryon number conservation.
Abstracts, Philosophy of Physics Research Seminar, TT
2010
1^{st} Week (29 April) Alastair Wilson ÒMetaphysics in light of
Everettian Quantum MechanicsÓ
Abstract: If an Everettstyle interpretation of quantum theory is
correct, what are the metaphysical implications? In this talk I argue that
Everettian quantum mechanics (EQM), taken seriously, licenses a variety of
arguments for distinctively metaphysical conclusions. After explaining the
nature of my project, and defending the propriety and feasibility of appealing
to evidence from physics in metaphysics, I outline my preferred version of EQM,
which includes a postulate connecting variation amongst Everett branches with
objective modality in nature. I argue that this postulate is required if
Everettians are to make sense of objective probability; and I use it to provide
support for a number of metaphysical doctrines in the context of EQM, including
the reducibility of the modal to the nonmodal, the necessity of existence, the
indexicality of actuality, and the necessity of laws of nature.
2^{nd} Week (6 May) Andreas Doering ÒSome basics of the topos
approach to the formulation of physical theoriesÓ
Abstract: The topos approach, which is motivated by the stillopen
question of finding a theory of quantum gravity, aims to provide a framework
for the formulation of physical theories in general, and a new mathematical
formulation of quantum theory in particular. The latter includes a novel
geometric underpinning by suitable pointless spaces and a new form of quantum
logic. A procedure called ÒdaseinisationÓ is the bridge between the usual
Hilbert space formalism and the topos form of quantum theory. I will present
the basics of the topos approach, with some emphasis on conceptual aspects.
3^{rd} Week (13 May) Keith Hannabuss ÒSome recent developments
in Quantum ElectrodynamicsÓ
Abstract: This talk will review the history of electrodynamics and the
problem of divergences, together with some of the more recent ideas on how
those can be tamed. It will not assume any detailed knowledge of QED.
4^{th} Week (20 May) Harvey Brown ÒBoltzmannÕs Htheorem and its
discontentsÓ
Abstract: A comparison is made of the traditional Loschmidt
(reversibility) and Zermelo (recurrence) objections to Boltzmann's Htheorem,
and its simplified variant in the Ehrenfests' 1912 windtree model. The
littlecited 1896 (measuretheoretic) objection of Zermelo (similar to an 1889
argument due to PoincarŽ) is also analysed. Significant differences between the
objections are highlighted, and several old and modern misconceptions
concerning both them and the Htheorem are clarified. Particular emphasis is
given to the radical nature of PoincarŽ's and Zermelo's attack, and the
importance of the shift in Boltzmann's thinking in response to the objections
taken together.
5^{th} Week (27 May) Nancy Cartwright (LSE) ÒWhoÕs afraid of
external validity?Ó
6^{th} Week (3 June) Darrell Rowbottom ÒConfirmation and the intersubjective
interpretation of probabilityÓ
7^{th} Week (10 June) David Wallace ÒThe logic of the Past
HypothesisÓ
Abstract: I attempt to get as clear as possible on the chain of
reasoning by which irreversible macrodynamics is derivable from timereversible
microdynamics, and in particular, to clarify just what kinds of assumptions
about the initial state of the Universe, and about the nature of the
microdynamics, are needed in those derivations. I conclude that while a ÒPast
HypothesisÓ about the early Universe does seem necessary to carry out such
derivations, that Hypothesis is not correctly understood as a constraint on the
early UniverseÕs entropy.
8^{th} Week (17 June) Adam Caulton (Cambridge) ÒInterpreting
physical theories with symmetriesÓ
Abstracts,
Philosophy of Physics Research Seminar, TT 2008
All talks are thursdays 4:306:30, Lecture Room, 10 Merton Street,
followed by dinner for those who are interested.
30 April: Luke Glynn (Philosophy, Oxford)
ÒProbabilityLowering Causes and ProbabilityRaising NonCausesÓ
Abstract:
The starting point in the development of probabilistic analyses of token
causation has usually been the naive intuition that, in some relevant sense, a
cause raises the probability of its effect. But there are wellknown examples
both of nonprobabilityraising causation and of probabilityraising
noncausation. Sophisticated extant probabilistic analyses treat some such
cases correctly, but only at the cost of excluding the possibilities of direct
nonprobabilityraising causation, failures of causal transitivity,
actionatadistance, prevention, and causation by absence and omission. I show
that an examination of the structure of these problem cases – facilitated
by the use of causal graphs – suggests a different treatment, one which
avoids the costs of extant analyses.
7 May: Guido Bacciagaluppi
Title: Heisenberg on hidden variables
14 May
No talk.
21 May: Peter Byrne
Title: The Devil's Pitchfork: Multiple Universes, Mutually Assured
Destruction, and the Meltdown of a Nuclear Family  The Life of Hugh Everett
III
28 May: Jos Uffink
Title: Entanglement, entropy
and utility: the analogy between
axiomatic approaches to quantitative measures thereof.
4 June: Cian Dorr
Title: Expressivism about chance
11 June: Oliver Pooley
Title: Relativity, Branching Spacetimes and the Passage of Time
18 June: Tien Cao
Title: TBA
Abstracts,
Philosophy of Physics Research Seminar, MT 2008
22 January (1 Week) – Jonathan
Barrett (Physics, Bristol): Processing Information: Is Quantum Theory Special?
29 January (2^{nd} week) –
David Wallace (Philosophy, Oxford):
ÒThe irrelevance of gravitational entropy in cosmological
thermodynamicsÓ
Abstract:
There is a widespread view that (i) in the presence of gravity, highly
concentrated systems are actually higherentropy than more dispersed systems,
and (ii) that – because it makes the early universe low rather than
highentropy – this is the ultimate explanation of the second law of thermodynamics.
This view has recently been sharply criticised by Earman, who argues that (iii)
gravitational entropy is too illdefined to play a foundational role of this
kind. I will review this discussion and argue that (i)(iii) are all either
flat wrong or at any rate often understood in a confused fashion. I will argue
that (a) we have a perfectly satisfactory understanding of the consequences of
gravity for entropy at the energy scales relevant to classical cosmology; (b)
that understanding does lead to the conclusion that uniform dispersed systems
are relatively lowentropy, but this is not really because squeezing those
systems into smaller spaces increases their entropy; (c) that spatial
uniformity is not, as far as thermodynamics is concerned, the real explanation
for the lowness of the entropy of the early universe and hence for the 2^{nd}
law in our present epoch.
5 February (3^{rd} Week)
– Jonathan Tallant (Philosophy, Nottingham):
ÒExistence PresentismÓ.
Abstract:
Grant the presentist that everything exists now: what is it about the
world that makes a moment ÔnowÕ? It turns out that this is a difficult
question to answer and a number of concerns arise in discussion of the various
options. To deal with these concerns, IÕll put forward and defend a new
version of presentism: Existence Presentism.
Existence presentism, I argue, turns out to have particular modal consequences.
Namely, that it is necessarily true if true at all. Although the conclusion
isnÕt novel, it is (I think) a conclusion for which we donÕt typically see an
argument. However, the modal result itself then turns out to be problematic
since we have the appearance of the genuine possibility of eternalism. To
square the circle I spend the latter portions of the paper arguing that
eternalism has the mere appearance of possibility.
The result is this: we have a new variety of presentism on our hands, one that
is able to solve certain problems that afflict traditional strains of
presentism. We can also explain away the seeming possibility of eternalism.
This, it seems to me, is to put presentism on a stronger (if not yet strong)
footing.
12 February (4^{th} Week)
– Bob Coecke (Comlab, Oxford):
ÒHighlevel reasoning about the lowlevel scaleÓ
Abstract:
We report on progress in an approach which aims to provide quantum
theory with a purely diagrammatic calculus, a logical foundation, and increased
degrees of axiomatic freedom, while still retaining full expressiveness.
Key to this approach is the fact that monoidal categories provide a
natural framework to reason about systems, processes and their interactions of
any kind. We provide two applications of this framework.
An axiomatization of the notion of complementary observables exposes the
flows of information in sophisticated quantum informatic protocols involving
complex entanglements, and an axiomatization of relative phases provides new
insights in the origin and peculiarity of quantum nonlocality.
The applications are drawn from the following papers:
[1] Bob Coecke & Ross Duncan. "Interacting quantum
observables". ICALP'08.
[2] Bob Coecke, Bill Edwards and Rob Spekkens. "The grouptheoretic
origin of nonlocality". Hopefully available by the date of the
talk.
19 February (5^{th} Week)
– Dennis Lehmkuhl (Philosophy, Oxford): Is matter an aspect of spacetime
structure? On Classical Unified Field Theories
26 February (6^{th} Week)
– Katherine Brading (Philosophy, Notre Dame), title TBC
5 March (7^{th} Week) – Mark
Sprevak (History and Philosophy of Science, Cambridge): Are computations
objective features of the world?
12 March (8^{th} Week) – Dennis
Dieks (Institute for History and Foundations of Science, Utrecht), title TBC
Abstracts,
Philosophy of Physics Research Seminar, MT 2008
October 23. Prof Michel Janssen, Program in the History of Science,
Technology, and Medicine, University of Minnesota/Max Planck Institute for the
History of Science (MPIWG), Berlin
Title: Pascual JordanÕs Resolution of the Conundrum of the WaveParticle
Duality of Light
Abstract: In a key contribution to the 1926 Dreimaennerarbeit with Born and
Heisenberg, Jordan showed for a simple model of quantized waves how one
recovers both the wave and the particle term of Einstein's famous 1909 formula
for the meansquareenergyfluctuation in blackbody radiation. So the two
terms do not require separate mechanisms, as Einstein thought, but arise from a
unified dynamical framework (which can be expressed in terms of particles or
waves). I give a detailed reconstruction of JordanÕs derivation of this result
and tell the curious story of its reception. I defend Jordan's argument against
various criticisms in the literature, but I also argue that the argument is
incomplete. In modern terms, Jordan calculated the quantum uncertainty in the energy
of a subsystem in an energy eigenstate of the system as a whole, whereas the
thermal fluctuation is the average of this quantity over an ensemble of such
states. This talk is based on a recent paper I wrote together with Tony Duncan
(SHPMP 39 (2008): 634666) in the context of a larger history of quantum
project led by Juergen Renn and his group in Berlin (http://quantumhistory.mpiwgberlin.mpg.de/main).
October 30. Prof DŽcio Krause, Department of Philosophy, Federal University of
Santa Catarina, Brazil.
Title: Quantum (Non) Individuality  Logical aspects
Abstract: In this talk I discuss in a general way some reasons which
would sustain a metaphysics of nonindividuals, based on a possible
interpretation of quantum objects. I emphasize some of the involved
foundational problems that appear when we consider the underlying logic
(mathematics included) used to approach the subject.
November 6. Dr Alexei Grinbaum, LARSIM laboratory, CEA (French Atomic Energy
Commission)Saclay, France
Title: Which finetuning arguments are fine?
Abstract. Arguments from naturalness are much used in quantum field theory in
the last 25 years. Still naturalness can be understood in several nonequivalent
ways. We review the role of fine tuning/naturalness in the purported solution
of QFT problems and we oppose 'can this be true' evaluations of models solving
the hierarchy problem to the unsound use of fine tuning for preferring one
model over another.
November 13. Prof Lane Hughston,
Department of Mathematics, Imperial College
Title: Do we really need dynamical models for quantum state reduction ?
Abstract: This talk will present an overview of dynamical models for the
"collapse of the wave function", and will discuss some of the
foundational issues arising in connection with such models.
In nonrelativistic quantum mechanics the expectation value of the energy is a
conserved quantity. It is possible to extend the dynamical law associated with the
evolution of a quantum state to include a nonlinear stochastic component,
while respecting the conservation law. In accordance with the dynamics thus
obtained, referred to as the energybased stochastic Schrodinger equation, it
can be shown that an arbitrary initial state collapses spontaneously to one of
the energy eigenstates, with the Bornrule probabilities. Two such models will
be analyzed in this talk: one that achieves state reduction in infinite time,
and the other in finite time. Closedform solutions can be obtained for both of
these models. With these solutions at hand it is possible in principle to
simulate explicitly the dynamics of the quantum states of even complicated
physical systems. An interesting byproduct of the investigation is the resolution
of an important issue concerning the "tail problem" in the collapse
of the wave function.
Do we really need dynamic reduction models? I shall argue that such models do
not really "solve" the problem of the collapse of the wave function,
at least perhaps not in the original sense envisaged two decades ago by Diosi,
Ghirardi, Gisin, Pearle, Percival and others  but may nevertheless be valid
as dynamical models for the evolution of a quantum state.
(Based in part on work carried out in collaboration with D. C. Brody.)
November 20. Prof Simon Saunders, Faculty of Philosophy, Oxford University.
Title: Chance in the Everett Interpretation
Abstract: In the Everett interpretation of quantum mechanics, the wave
function of the universe has the macroscopic structure of innumerable branches,
in each of which quasiclassical equations hold to high accuracy. I argue that
ratios in the squared norms of branch amplitudes fulfil the three key roles of
objective chance: (i) the statistical inference role (chance is manifested in
statistics); (ii) the decision theory role (chance as a guide to credence); and
(iii) the link with uncertainty (chance events are uncertain). (i) is easily
demonstrated, whilst (ii), granted the structure to the wavefunction, is established
by the Bornrule theorem due to Deutsch and Wallace. This talk is concerned
with (iii), considered by many the 'Achilles heel' of the Everett
interpretation. It can be relegated to a semantic problem, but it can also be
given a more substantive basis given the atemporal representation of the
wavefunction in terms of quantum histories. Vaidman's recent proposal, that
uncertainty in the Everett interpretation be anchored to Aharonov's 2vector
formalism, is also considered. On either count, Everettian worlds have a
natural representation as divergent worlds, rather than overlapping worlds (in
Lewis' sense), whereupon quantum mechanical uncertainty reflects selflocating
ignorance.
November 27. Dr David Frame, Department of
Physics, Oxford University
Title, Abstract TBA
December 4. Prof Nick E.
Mavromatos, Department of Physics, King's College London
Title: Quantum Gravity, Microscopic Time Irreversibility and EPR
Correlations
Abstract: I discuss the concept of time in some (stringy) versions of space
timefoam models of quantum gravity, and discuss the conditions under which
the induced decoherence of matter in such models may imply a microscopic
time irreversibility, due to the fact that the CPT operator is illdefined
(intrinsic CPT symmetry violation). I discuss ``perturbative'' situations, i.e.
situations in which the concept of antiparticle is still in place, but its
properties in connection with the particle are affected by the abovementioned
breakdown of CPT. I will explain how spacetime foam may affect (modify)
EinsteinPodolskyRosen (EPR) correlations in entangled particle states of
mesons, yielding effects that, depsite being attributed to quantum gravity, may
have a chance of being falsified in upcoming experimental facilities. The
key point, which leads to an enhancment of the magnitude of such effects in
lowenergy experiments (as compared to Planck scale), is the neardegeneracy of
the mass states of the involved mesons.
Abstracts,
Philosophy of Physics Research Seminar, TT 2008
Th
24^{th} April:
Title:
ÒIn what sense does Ònothing make sense except in the light of evolutionÓ
Speaker:
Paul Griffiths (philosophy department, University of Sydney; and ESRC Centre
for Genomics in Society, University of Exeter):
Abstract:
Dobzhansky argued that biology only makes sense if life on earth has a shared
history. But his dictum is often reinterpreted to mean that biology only makes
sense in the light of adaptation. Some philosophers of science have argued in
this spirit that all work in ÔproximalÕ biosciences such as anatomy, physiology
and molecular biology must be framed, at least implicitly, by the selection
histories of the organisms under study. Others have denied this and have
proposed nonevolutionary ways in which biologists can frame these
investigations. This paper argues that an evolutionary perspective is indeed
necessary, but that it must be a forwardlooking perspective informed by a
general understanding of the evolutionary process, not a backwardlooking
perspective informed by the specific evolutionary history of the species being
studied. Interestingly, it turns out that there are aspects of proximal biology
that even a creationist cannot study except in the light of a theory of their
effect on future evolution.
****************************************************************************************************************************************************
Th
1^{st} May
Title:
Geometrizing gravity and vice versa: the force of a formulation
Speaker:
Eleanor Knox (philosophy department, Oxford University)
Abstract:
It is wellknown that NewtonÕs theory of gravity, commonly held to describe a
gravitational force, can be recast in a geometrical form: NewtonCartan theory.
It is less wellknown that general relativity, an apparently geometrical
theory, can be reformulated in such a way that it resembles a force theory;
teleparallel gravity does just this. This raises questions. One of these
concerns theoretical underdetermination. I argue that we should see NewtonCartan
and teleparallel theory as reformulations of Newtonian gravity and general
relativity and not independent theories. However, if the same gravitational
theory may be formulated in geometrical and nongeometrical terms, this raises
conceptual problems of its own. I argue that these formulations do not wear
their interpretations on their sleeves. The geometrical nature of a
gravitational theory is not a straightforward consequence of anything internal
to that theory as a theory of gravity. Rather, it essentially relies on the
rest of nature (the nongravitational interactions) conspiring to choose the
appropriate set of inertial frames.
********************************************************************************
Everett@50:
The Everett interpretation of quantum mechanics, 50 years on.
Oxford
University, July 19July 21, 2007
Organisers:
Simon Saunders
David Wallace
Peter Taylor
Full schedule: http://users.ox.ac.uk/~everett/schedule.htm
Website: http://users.ox.ac.uk/~everett/
Schedule
10.30  11.00 
Coffee 
11.00  1.00 
The Everett interpretation: 50 years on. Simon Saunders Decoherence and ontology. David
Wallace 
1.00  2.00 
Sandwich lunch, Ryle Room, 10 Merton St. 
2.00  3.30 
Can the world be only wavefunction? Tim Maudlin 
3.30  4.00 
Tea 
4.00  5.30 
Two Dogmas About Quantum Mechanics. Jeffrey Bub and Itamar Pitowsky 
6.30  10.00 
Evening drinks and dinner, Cherwell Boathouse 
9.30  11.00 
Probability in the Everett picture. David Z. Albert 
11.00  11.30 
Coffee 
11.30  1.00 
Everett and Evidence. Wayne Myrvold and Hilary Greaves 
1.00  3.00 
Lunch at the Head of the River 
3.00  4.30 
Apart from universes. David Deutsch The time symmetric QM and the MWI. Lev Vaidman 
4.30  5.00 
Tea 
5.00  6.30 
Quantum cosmology. James B. Hartle Some remarkable implications of probabilities without time. Andreas J. Albrecht 
7.00  10.00 
Conference dinner, Oriel College 
9.30  11.00 
A metaphysician looks at the Everett interpretation. John Hawthorne 
11.00  11.30 
Coffee 
11.30  1.00 
Explaining probability. Simon Saunders 
1.00  2.30 
Lunch, local restaurants 
2.30  4.00 
Pilotwave theory: Everett in denial? Antony Valentini 
4.00  4.30 
Tea 
4.30  6.00 
Round table discussion: David Wallace, Jeremy Butterfield, David Z. Albert 
7.00 
Drinks, Old Cloisters, New College 
8.30 
Farewell dinner, The Undercroft, New College 
Abstracts,
Philosophy of Physics Research Seminar, TT 2007
PROF RICHARD HEALEY, Arizona
26 April: ÔGauge Symmetry
and the ThetavacuumÕ
Abstract. According to conventional wisdom, local gauge symmetry is not
a symmetry of nature, but an artifact of how our theories represent nature. But
a study of the socalled thetavacuum appears to refute this view. The ground
state of a quantized nonAbelian YangMills gauge theory is characterized by a
realvalued parameter ө (theta)—a fundamental new constant
of nature. The structure of this vacuum state is often said to arise from a
degeneracy of the vacuum of the corresponding classical theory: this degeneracy
allegedly arises from the fact that ÒlargeÓ (but not ÒsmallÓ) local gauge
transformations connect physically distinct states of zero field energy. If
that is right, then some local gauge transformations do generate
empirical symmetries. In defending conventional wisdom against this challenge I
hope to clarify the meaning of empirical symmetry while deepening our
understanding of gauge transformations.
DR SIMON BENJAMIN, Oxford
10 May: "Measurement as the fundamental mechanism in a quantum
computer."
Abstract: The paradigm of measurement based quantum computing (MBQC)
has proven to be very rich. It is both simple to apply and very
flexible, allowing it to be employed for many different physical
implementation schemes. Yet at the same time it offers deep insights
into the structure of quantum computational tasks. I'll give a basic
review of the essential ideas in the paradigm, including graph states
and cluster states: these are the manyqubit entangled states which
MBQC consumes as a kind of resource. I will then go on to discuss a
set of schemes for large scale QIP which I consider to be the most
promising and exciting proposals todate; they use measurements both
to _create_ and to _consume_ the graph state resource, so that
measurements alone form the essential mechanism of the device. The
measurements required to create entanglement are interesting in their
own right: the key is not to learn too much about the system being
measured, so that one is tempted to apply slogans like, "Ignorance
is
power"!
DR SIMON SAUNDERS, Oxford
17 May: Probability and semantics for branching worlds
Abstract: According to Everettian quantum mechanics, we live in an emergent
branching multiverse. This is a structure that has been partially
anticipated by contemporary metaphysicians, save for two crucial features:
(i) branches come with quantities (squared amplitudes) whose sum is constant
under branching (ii) branches are emergent structures, defined in a suitable
approximation. Both features matter when it comes to the semantics of
branching  to truthconditions for ordinary utterances, including talk of
probability. Here I shall deal (almost) exclusively with the latter, and
with the explanation, more broadly, of why physical probability has the
characteristics it does  why it cannot be directly measured, and why it is
manifested in statistics.
PROF SANDU POPESCU, Bristol
24 May.: 'Entanglement and the Foundations of Statistical Mechanics'
Abstract:
Statistical mechanics is one of the most successful areas of physics. Yet,
almost 150 years since its inception, its foundations and basic postulates
are still the subject of debate. Here we suggest that the main postulate
of statistical mechanics, the equal a priori probability postulate, should
be abandoned as misleading and unnecessary. We argue that it should
be replaced by a general canonical principle, whose physical content
is fundamentally different from the postulate it replaces: it refers to
individual states, rather than to ensemble or time averages. Furthermore,
whereas the original postulate is an unprovable assumption, the principle
we propose is mathematically proven. The key element in this proof is the
quantum entanglement between the system and its environment. Our
approach separates the issue of finding the canonical state from finding
out how close a system is to it, allowing us to go even beyond the usual
boltzmannian situation.
Abstracts,
Philosophy of Physics Research Seminar, HT 2007
PROF SANDU POPESCU, Bristol
18 Jan.: 'Entanglement and the Foundations of Statistical Mechanics'
CANCELLED due to bad weather
Abstract:
Statistical mechanics is one of the most successful areas of physics. Yet,
almost 150 years since its inception, its foundations and basic postulates
are still the subject of debate. Here we suggest that the main postulate
of statistical mechanics, the equal a priori probability postulate, should
be abandoned as misleading and unnecessary. We argue that it should
be replaced by a general canonical principle, whose physical content
is fundamentally different from the postulate it replaces: it refers to
individual states, rather than to ensemble or time averages. Furthermore,
whereas the original postulate is an unprovable assumption, the principle
we propose is mathematically proven. The key element in this proof is the
quantum entanglement between the system and its environment. Our
approach separates the issue of finding the canonical state from finding
out how close a system is to it, allowing us to go even beyond the usual
boltzmannian situation.
DR DAVID WALLACE, Oxford
25th Jan.: 'The Ontology of the Quantum State'
Abstract: What ontology does realism about the
quantum state suggest? The main extant view is \textit{wavefunction realism}. I elaborate the sense in which wavefunction realism does
provide an ontological picture; and defend it from certain objections that have
been raised against it. However, there are good reasons to be dissatisfied with
wavefunction realism, as I go on to elaborate. This motivates the development
of an opposing picture: what I call \textit{spacetime state
realism}; a view which takes the states associated to spacetime
regions as fundamental. This approach enjoys a number of beneficial features,
although, unlike wavefunction realism, it involves nonseparability at the
level of fundamental ontology. I will investigate the pros and cons of this
nonseparability, arguing that it is a quite acceptable feature; even one that
proves fruitful in the context of relativistic covariance.
PROF DAVID DEUTSCH, Oxford
1 Feb.: 'Physics as Quantum Constructor Theory'
Abstract:: Constructor theory is the (as yet largely nonexistent)
general theory of what can be constructed from what. It can be regarded
as the ultimate generalisation of the theory of computation (the
theory of what *information* can be constructed from what other
information, and using what resources). But, more fundamentally, it can 
and for various reasons should  also be regarded as a way of expressing
the whole of physics (and the whole of science).
DR JAN BROEKAERT, Vrije Universiteit, Brussels
8 Feb.: 'Towards a LorentzPoincarŽ type interpretation of General
Relativity Theory.'
Abstract: The geometric interpretation of General Relativity
Theory reduces gravitation to a mass and energy induced curvature
of the metric of the spacetime continuum. This geometrical approach to
gravitation is seamlessly adjusted to the EinsteinMinkowski interpretation of
Special Relativity and inherits the Parmenidian ontology of the Minkowskian
block universe.
In the physical interpretation of Special Relativity
Theory; Lorentz and PoincarŽ inter alia conceived consistent
electromagnetic processes as rod contractions, clock slowing and light
synchronization to conjure the Lorentz transformations, proper to a
classical space and time ontology with a less exotic temporal
becoming. There is no completed correspondence with a similar ''physical"
interpretation in General Relativity Theory; however some elements are present
in various alternative developments of relativistic gravitation (Wilson 1921,
Dicke 1957, Dehnen et. al. 1960, Thirring 1961). Another recurrent argument for
the possibility of a ''LorentzPoincarŽ"type development of
gravitation is found in geometric conventionalism (e.g. Sexl 1970, Dieks
1987); leaving underdetermined the intrinsic nature of space and time at the
expense of modifications of the physical laws that go with it. We
have shown, at the hand of a relativistic gravitation model with
Euclidean coordinate space and coinciding till first PostNewtonian order
with General Relativity Theory, that it is indeed possible to maintain an
explicit LorentzPoincarŽ type interpretation to this extent (Broekaert
2005). While in principle this description allows a cosmological time and
a priorgeometric space, the latter remains fundamentally non observable
because of the implemented PoincarŽ Principle of Relativity, prohibiting the
perception of a preferred frame (e.g. PoincarŽ 1904). We will discuss
some of the conceptual advantages of this type of interpretation in terms of
the physics of gravitation, other than attraction.
PROF STEPHAN HARTMANN, LSE and Tilburg
15 Feb.: 'Probability and decoherence'
PROF IAN PERCIVAL, Queen Mary, London
22 Feb.: 'Newton, Berkeley and quantum theory'
DR PIETER KOK, Oxford and Sheffield
1 Mar.: 'Cluster states: a new class of entanglement'
PROF JEFFREY BUB, Maryland
8 Mar.: 'Two dogmas about quantum mechanics'
Abstract: I discuss what Pitowsky (2007) has called two 'dogmas' about
quantum mechanics. The first dogma is Bell's assertion that measurement should
never be introduced as a primitive in a fundamental mechanical theory like
classical or quantum mechanics, but should always be open to a dynamical
analysis in principle. The second dogma is the view that the quantum state has
an ontological significance analogous to the ontological significance of the
classical state (which specifies a complete catalogue of a system's
properties), i.e., that the quantum state is a (perhaps incomplete)
representation of physical reality. I argue that both dogmas are called into
question by a 'no cloning' principle that distinguishes quantum information
from classical information. I distinguish two measurement problems: a problem
about individual events, which I argue is a pseudoproblem, and a tractable
problem about probabilities, which finds a solution in the phenomenon of
decoherence.
Structuralism about Physics and Mathematics Conference
Department of Philosophy, University of Bristol
Saturday 2^{nd} and Sunday 3^{rd}
December 2006
Organisers: James Ladyman and ¯ystein Linnebo
Programme
Saturday
12.00pm – registration
12.30pm – 2.10pm
James
Ladyman (Bristol) ÔOn the Identity and
Diversity of Objects in a StructureÕ
reply: John Mayberry (Bristol)
2.30pm Tea and Coffee
2.30pm – 4.10pm
¯ystein Linnebo (Bristol)
reply: Katherine Hawley (St. Andrews)
4.20pm – 6.00pm
Stewart Shapiro (Ohio State and St. Andrews)
reply: Richard Pettigrew (Bristol)
Sunday
9.00am – 10.40am
Oliver Pooley (Oxford)
reply: David Wallace (Oxford)
10.40am – 11.00am Tea and Coffee
11.00am – 12.40 pm
Simon Saunders (Oxford) ÔIndistinguishabilityÕ
reply: James
Ladyman (Bristol)
12.40pm – 1.20pm
1.20pm –2.40pm
Steven French (Leeds)
2.40pm – 3.00pm Tea and Coffee
3.00pm – 4.20pm
Fred MŸller (Utrecht)
4.20pm – Concluding Discussion
***************************
OneDay Conference on Foundations
of Physics
in Memory of Jeeva Anandan
Convenor: Harvey Brown
The
meeting will take place on Saturday, 25 November 2006, in the Lecture Room of
the Philosophy Centre, 10 Merton Street, Oxford OX1 4JJ.
10.00–10.15
Opening remarks by Harvey Brown
10.15–11.30
Dr Dharamvir AhluwaliaKhalilova (Department of Physics and Astronomy, University of
Canterbury, New Zealand)
A new
fermionic quantum field for dark matter
11.30–12.45
Dr Jos Uffink (Institute
for History and Foundations of Mathematics and Natural Sciences,
Utrecht University)
Protective
measurement revisited
2.15–3.30
Prof Erik Sjšqvist (Department
of Quantum Chemistry, Uppsala University)
Quantum
Holonomies
3.30–4.45
Prof Leo Stodolsky (Max
Planck institute for Physics, Munich)
Why the
best wavefunction is no wavefunction
4.45–5.15
Tea/Coffee
5.15–6.30
Prof Sir Roger Penrose (Mathematical Institute, Oxford University)
TBA
Abstracts, Philosophy of Physics Research Seminar, MT 2006
12 October: Dr. Pedro Ferreira, Oxford University:
Modifying gravity: an alternative to
dark matter.
19 October: Dr Guido Bacciagaluppi, Institut d'Histoire et de
Philosophie des Sciences et des Techniques, CNRS, Paris.
Nonequilibrium, Nonlocality and Nonlinearity
Abstract: Nonequilibrium solutions are investigated in a Nelsonlike
framework of
diffusion processes on configuration space (more precisely, solutions
with initial or final constraints). Even if the framework is restricted,
to local theories, imposing initial (or final) constraints on particle
distributions can mimic nonlocal behaviour at the level of the
probability distribution and probability current. Specifically, one can
show that a nonlinear Schršdinger equation for noninteracting (but
generally entangled) particles can be derived from such a local theory
with constraints.
26 October: Dr. Rob Spekkens, Department of Applied Mathematics and
Theoretical Physics, Cambridge University
Quantum coherence: fact or fiction?
Abstract: A controversy that has arisen many times
over in disparate contexts is whether quantum coherences between eigenstates of
additively conserved quantities are fact or fiction. I present a pedagogical
introduction to the debate in the form of a hypothetical dialogue between
proponents from each of the two camps: a factist and a fictionist. A resolution
of the debate can be achieved, I argue, by recognizing that quantum states do
not only contain information about the intrinsic properties of a system but about
its extrinsic properties as well, that is, about its relation to other systems
external to it. Specifically, the coherent quantum state of the factist is the
appropriate description of the relation of the system to one reference frame,
while the incoherent quantum state of the fictionist is the appropriate
description of the relation of the system to another, uncorrelated, reference
frame. The two views, I conclude, are alternative but equally valid paradigms
of description. This conclusion has implications for a variety of
conceptual puzzles including whether it is possible to lift superselection
rules, whether synchronized clocks and aligned Cartesian frames are a source of
entanglement, and whether a single particle can exhibit Bell correlations.
2 November: Professor John Mayberry, University of Bristol.
Extensional structuralism and the problem of indiscernibles
Abstract: Extensional structuralism is the standard method that
mathematicians use in expounding mathematics. The simplest kind of
extensional structure is a set equipped with a morphology, which consists
of various functions and relations taken in extension (i.e., as sets of
ordered pairs). Such familiar mathematical structures as groups, rings, and
ordered fields are extensional structures of this sort.
In this talk I shall define the notion of indiscernibility in extensional
structures and discuss its relation to the traditional Kantian problem of
enantiomorphs.
9 November: Dr. Ioannis Votsis, Philosophisches Institut
HeinrichHeineUniversitŠt DŸsseldorf
Structural realism 2.0
Abstract: In
this talk, I focus on the epistemic variety of structural realism. The aim is
to explore new sources of support, tackle certain threats, suggest various
adjustments, discuss neglected issues, and, finally, try to put things in
perspective. In more detail, I will look at: (1) the argument from transmission
(found in PoincarŽ, Russell, Carnap and Quine), (2) the argument from the
increased mathematisation of science, (3) the tenability of the structure vs.
nature distinction, (4) a particular version of the nonisomorphic models
problem, (5) the relationship between the foundations of science and the
foundations of mathematics and (6) a roundup of the main challenges. By
discussing these issues, I hope that a clearer picture will emerge of the
merits, desiderata and limits of epistemic structural realism.
16 November: Professor Samir Okasha
Where Rational Choice and Evolution
Part Ways
Abstract: Abstract: The paper has two parts. Firstly, I examine the
phenomenon of riskaverse behaviour, a long standing puzzle for the theory of
rational choice. I argue that interesting light can be shed on the phenomenon
by considering it from the viewpoint of evolutionary, rather than rational
choice, theory. Secondly, I examine Brian Skyrms' recent ideas on the general
relationship between evolution and rational choice. Skyrms argues that in
certain contexts, evolution and rational choice 'part ways', i.e. strategies
that are ruled out by considerations of rational selfinterest
may nonetheless be favoured by natural selection. I show that the phenomenon of
riskaversion demonstrates a more radical 'parting of ways' than those
discussed by Skyrms.
23 November: Dr. Antony Valentini, Perimeter Institute for Theoretical
Physics, Waterloo
Inflationary cosmology as a probe of
primordial quantum mechanics
Abstract: We show that inflationary cosmology may be used to test the
statistical predictions of quantum theory at short distances and early times.
Hiddenvariables theories, such as de BroglieBohm pilotwave theory, allow the
existence of vacuum states with nonstandard field fluctuations (Òquantum
nonequilibriumÓ). We show that inflationary expansion will transfer any
primordial nonequilibrium to cosmological scales, resulting in anomalous power
spectra, nonrandom phases, and nonGaussianity in the cosmic microwave
background. The conclusions depend only weakly on the details of the de
BroglieBohm dynamics. Here we discuss, in particular, nonequilibrium breaking
of scale invariance for the primordial power spectrum, as well as
nonequilibrium violation of the scalartensor consistency relation. Recent
observations are used to set limits on violations of quantum theory in the
early universe.
30 November: Dr. Simon Saunders, University of Oxford
NewtonÕs Corollary VI, and all that:
why absolute rotation is relational
Abstract: Corollary VI of Principia, Book I, Axioms, anticipated
– or was identical to  EinsteinÕs equivalence principle, yet its role in
NTG, historically and conceptually, has received very little attention. It
implies that gravitational acceleration (and hence the gravitational force) is
purely relational, a point about NTG stated as a paradox (or an inconsistency)
by Norton in 1992. I shall review the relevant history and show how to answer
NortonÕs paradox without the more elaborate apparatus of NewtonCartan theory,
used by Malament in his 1995 reply to Norton. I shall also consider how, in the
light of it, absolute rotation should have been analysed as relative motion
(and nearly was, by Huygens, Euler, and Maxwell), and how MachÕs principle
should have been framed in consequence.
***********************************************************************************
History and Philosophy of
Mathematics Day
Tuesday 23 May 2006
University of Bristol, 9 Woodland Road, Bristol BS8 1TB
PROGRAMME
10.30  12.30 Dr Hannes Leitgeb (University of Bristol) "Formal and
Informal Provability"
2.00  4.00 Professor Hartry Field (New York University) "Truth and
the Unprovability of Consistency"
4.00  5.00 tea
5.00  7.00 Dr Eleanor Robson (HPS, Cambridge) "A Short History of
Numbers in the Middle East"
7.00 dinner
for further information contact Hannes Leitgeb or Alexander Bird:
<http://www.bris.ac.uk/philosophy/department/staff/>
<http://www.bris.ac.uk/philosophy/department/events/
history_phil_maths.html>
********************
Professor Alexander Bird
Head of Department of Philosophy
University of Bristol
9 Woodland Road
Bristol BS8 1TB, United Kingdom
Tel: +44 (0)117 928 7826
Fax: +44 (0)117 928 7825
Web: http://eis.bris.ac.uk/~plajb/
Oxford, Michaelmas Term 2004
Interdisciplinary seminar "The Oxford Advanced Seminar on
Informatic
Structures"  nine lectures on "CONCEPTS OF SPACE"
Mathematical foundations of physics talks in it are:
Friday 15 October (week 1) Jonathan
Gratus (University of Wales at
Bangor) title TBA (discrete spacetime, quantum groups, fractafolds)
Friday 29 October (week 3) Basil
Hiley (Birkbeck College)  coauthor of
David Bohm of the The Undivided Universe: Ontological Interpretation of
Quantum Theory. TITLE: The role of noncommutative geometry in
algebraic
quantum mechanics: a physicist's perspective.
week 7 and 8 yet unconfirmed
Friday 17 December (week 10) Frank
Valckenborgh (Macquarie University,
Sydney) title TBA (Hilbert space representation theorems from projective
geometry)
All seminars are at:
http://se10.comlab.ox.ac.uk:8080/InformaticPhenomena/index.html
Trinity Term 2004
LSE
Unless otherwise noted, all seminars and events are
held in T206 and are open to the public.
Monday, 26 April 2:004:00 pm
SIGMA CLUB
PUBLIC LECTURE
Margaret Brown
Professor of Mathematics Education, King's College
London
Chair: Anthony O'Hear
CPNSS, LSE
Mathematics for the Millions
Thursday, 29 April 5.307:30 pm
LAKATOS AWARD LECTURE
Patrick Suppes
Winner of the 2003 award
Why are the Concepts of Representation and Invariance
Important in Science
Venue: Old Theatre
Friday, 30 April 11:001:00pm
LAKATOS AWARD SPECIALIST LECTURE
Patrick Suppes
Winner of the 2003 Award
Where do Bayesian Priors Come From?
Wednesday, 12 May 4:006:00 pm
SPECIAL LECTURE (organised by Roman Frigg and Stephan
Hartmann)
Paul HoyningenHuene
Hanover
On the Nature of Science
Monday, 24 May 5:307:00 pm
POPPER DEBATE
Science and Religion  Conflict or Peaceful
Coexistence?
Peter Atkins
Professor of Chemistry
University of Oxford
Peter Lipton
Hans Rausing Professor of History and Philosophy of
Science
University of Cambridge
Keith Ward
Emeritus Regius Professor of Divinity
University of Oxford
Chair: Michael Redhead
CoDirector, CPNSS, LSE
Venue: Old Theatre, Old Building
TUESDAY, 1 June 2:004:00 pm
POPPER SEMINAR
Harvey Brown
Oxford
The Arrow of Time in Thermodynamics
Monday, 7 June 5:157:00 pm (Tea at 4:45 in T116)
BRITISH SOCIETY FOR THE PHILOSOPHY OF SCIENCE
Helen Billinge
LSE
Constructive Mathematics and Pragmatism
Wednesday, 9 June
2:004:00 pm
RESEARCH SEMINARS IN THE PHILOSOPHY OF NATURAL
SCIENCES (PHYSICS, PH 551)
Roman Frigg and Stephan Hartmann
Guest Speaker
TBA
Information in Biology
Wednesdays, 16 June 11:001:00 pm
RESEARCH METHODS IN PHILOSOPHY (PH500)
Elliott Sober
University of WisconsinMadison
Probability in the Philosophy of Biology
Wednesday, 23 June 2:004:00 pm
RESEARCH SEMINARS IN THE PHILOSOPHY OF NATURAL
SCIENCES (PHYSICS, PH 551)
Vladko Vedral
Imperial College London
Quantum Information
FridaySaturday, 2526 June
'RISK, UNCERTAINTY AND DISSENT' CONFERENCE
Seville, Spain
Organisers: CPNSS jointly with GOPA (Group of Policy
Advisers, European
Commission) and IPTS (Institute for Prospective and
Technological Studies,
Seville)
Programme Under Construction
TUESDAY, 29 June 2:004:00 pm
POPPER SEMINAR
Branden Fitelson
UC Berkeley
Ravens, Emeralds, and Bayesianism Revisited
The University
of Bristol Philosophy of Physics Seminar
11th May Dr
Peter Morgan (Oxford)
"An understanding of QFT"
18th May Dr
Patrick Enfield (Bristol)
"Tributaries, rivers, and Chinese boxes: physicists and
philosophers on realism and the progress of science"
1st June
Professor Peter Landsberg (Southampton)
"Pauli and an ergodic theorem"
8th June
Professor Basil Hiley (Birkbeck)
"TBA"
The seminars will take place at 5.00 p.m. in room
3.27, physics department, University of Bristol, Tyndall Avenue, Bristol. All
Welcome
For further information, or if you would like to give
a talk, please contact: James Ladyman (james.ladyman@bristol.ac.uk), Department
of Philosophy,
University of Bristol, 9 Woodland Road, Bristol BS8 1TB,
0117 928 7609
LouvainlaNeuve, Belgium
The Arrow of Time: Physics and Philosophy, 78 May 2004
supported by the European Science Foundation (Network
on Philosophical and Foundational Problems of Modern Physics),
Institut SupŽrieur de Philosophie, Place du cardinal
Mercier 14, Auditorium Socrate 240.
See http://www.lofs.ucl.ac.be/recherche/colloques/time.html, and
www.philphys.nl
Instructions on how to get there can be found at:
http://www.adcp.ucl.ac.be/cartes.html
If you wish to spend some nights in LouvainlaNeuve,
I suggest that you directly contact the Hotel Le Relais, where most speakers
will stay during the Workshop. http://www.relais.ucl.ac.be/eng/accueil.htm
Attendance and coffee breaks are free. If you wish to
attend, please confirm your participation with Ms. Virginie Haulotte.
haulotte@sisp.ucl.ac.be
Talks will begin at 9:30 on Friday 7th and will be
over on Saturday 8th at 5:00 pm Speakers are by invitation only. The following
speakers have confirmed
their participation (some titles are provisional). You
will receive the final program and schedule shortly.
List of speakers:
David Atkinson
(UniversitŽ de Groningen)
Does Quantum Electrodynamics have an Arrow of Time?
Gennaro Auletta (UniversitŽ GrŽgorienne, Rome)
Reversibility and Irreversibility in Quantum Mechanics
Jean Bricmont (UniversitŽ Catholique de Louvain)
Boltzmann's explanation of the arrow of time
Harvey Brown (UniversitŽ d'Oxford)
Time and relativity
Marisa Dalla Chiara (UniversitŽ de Florence)
Quantum histories and quantum computations
Dennis
Dieks (UniversitŽ d'Utrecht)
Becoming, relativity and locality
Mauro
Dorato (UniversitŽ de Rome III)
Is becoming accessible to physical theories
Vincenzo
Fano (UniversitŽ d'Urbino)
The direction of time: Why is it a problem?
Mathias
Frisch (UniversitŽ du Maryland)
Entropy and the Arrow Radiation
Pierre
Gaspard (UniversitŽ Libre de Bruxelles)
Statisticalmechanical explanations of the
thermodynamic arrow of time
Michel
Paty (UniversitŽ de Paris VII)
The flow of time: physical time and cosmological time
Huw Price
(UniversitŽ de Sidney)
Sommerfeld's Puzzling Prescription: New Thoughts on
the Arrow of Radiation
Jos
Uffink (UniversitŽ d'Utrecht)
Irreversibility in thermodynamics
ESF Conference on Philosophical and
Foundational Issues in Spacetime Theories,
Oxford, 24–27 March 2004
PROGRAMME (as of March 22th 2004)
Wednesday 24 March 

9.00 
Dr Harvey Brown 
Relativity as a "constructive" theory: a
defence of the PauliEddingtonBell interpretation 
10.15 
Dr Henrik Zinkernagel 
Cosmology and the Meaning of Time 
11.15 
Coffee 

11.45 
Dr Edward Anderson 
Plausible first principles for geometrodynamics? 
14.00 
Dr Simon Saunders 
Framedependence: pros and cons 
15.15 
Prof Andreas Bartels and Prof Holger Lyre 
Structural realism and the generality of the hole
argument 
16.15 
Tea 

16.45 
Dr Oliver Pooley 
What is Observable in Special and General
Relativity? 
Thursday 25 March 

9.00 
Prof Gerard Emch 
Symmetry and the Symplectic Geometry of
Gravitational Wave Causality 
10.15 
Prof Dennis Dieks 
Another look at general covariance and the
equivalence of frames of reference 
11.15 
Coffee 

11.45 
Prof Massimo Pauri 
General Covariance and the Objectivity of Spacetime
Pointevents 
14.00 
Prof Istvan Nemeti and Prof Hajnal Andreka 
On the logical foundation of spacetime theories References: 
15.15 
Prof Sir Roger Penrose 
Quantum Superpositions of Spacetimes: do they Reduce
Because of a Clash of Principles? 
16.15 
Tea 

16.45 
Dr Nick Bostrom 
SelfLocating Belief in an Infinite Spacetime 
Friday 26 March 

9.00 
Dr Fay Dowker 
The Causal Set as the Deep Structure of Spacetime 
10.15 
Dr Carl Dolby 
Life in an Energy Eigenstate: The Problem of Time in
Quantum Gravity 
11.15 
Coffee 

11.45 
Dr Joy Christian 
Passage of Time in a Planck Scale Rooted Local
Inertial Structure 
AFTERNOON
FREE 

Saturday 27 March 

9.00 
Prof Don Howard 
Spin, Space, Symmetries, and Statistics: Some
Questions about Covariance, Nonseparability, and Particle Identity in the
1920s 
10.15 
Prof Michel Ghins 
Revisiting the Equivalence Principle in General
Relativity 
11.15 
Coffee 

11.45 
Dr Julian Barbour 
Absolute and Relative Motion: A Review 
Trinity Term 2003
A OneDay Conference
In Memory of Jim Cushing
Faculty of
Philosophy, 10 Merton St., Oxford
Thursday June
26th 2003, 10.15–17.30
10.15 – 10.45 Registration and Coffee
10.45 – 11.45: Michael Redhead (LSE)
Broken Bootstraps: the Rise and Fall of a Research
Programme
11.45 – 12.45: Michael Dickson (Indiana, and
Oxford)
Dirac on Mathematical Beauty and Scientific Progress
12.45 – 2.00 Sandwich Lunch
2.00 – 3.00: Antony Valentini (Perimeter
Institute, Waterloo)
Quantum Theory as an Equilibrium Physics: Some New
Results
3.00 – 4.00: Mara Beller (Hebrew University,
Jerusalem)
Jim Cushing's Quest for UnderstandingPhysics,
Philosophy, History
4.00 – 4.30 Tea
Registration (covering
coffee, sandwich lunch, tea): £ 6, £ 3 for students;
to be paid on arrival on the day.
Contact details; To enable us to estimate numbers, please email Jeremy Butterfield, jb56@cus.cam.ac.uk, between Monday 23 and Wednesday 25 June, just to say
you (and how many of you!) are coming.
The organizers gratefully acknowledge sponsorship by
the British Society for the Philosophy of Science
A OneDay
Conference:
Friday 25^{th}
April 2003
Faculty of Philosophy, 10 Merton St., Oxford
10.1517.30
10.15  10.45
Registration and Coffee
10.45  11.45: Owen
Maroney (Bristol): Measurement, Entropy and the Szilard Engine
11.45  12.45: Chris Isham (Imperial
College London): Quantising on a Category: A new approach to quantum
spacetime.
12.45  2.00
Sandwich Lunch
2.00  3.00: Julian
Barbour (Oxford): Time and Relativity
3.00  4.00: Richard
Healey (Arizona, and LSE): Change without Change, and How to Observe it
in General Relativity
4.00  4.30 Tea
4.30  5.30:
Steven French (Leeds): From Groups to Gestalt: Varieties of Structuralism as
a Response to Quantum Physics
Registration
(covering coffee, sandwich lunch, tea): £ 6, £ 3 for students; to be paid on
arrival on the day.
Note: If you have not already registered, and plan to attend, please
contact Harvey Brown (Ox.276930 and harvey.brown@philosophy.ox.ac.uk) (by Thursday
April 24 at latest).
Hilary Term 2003
Philosophy of Mathematics Seminar
These lectures, followed by discussion, will take
place on Mondays at 4.30 p.m. in the
Ryle Room at the Philosophy Faculty, 10 Merton Street.
week 1 (20
January): Daniel Isaacson (Oxford),
ÒPhilosophical significance of complex conjugation.Ó
week 2 (27
January): Marcus Giaquinto
(University College London), ÒThe distinction between geometrical and algebraic
thinking.Ó
week 3 (3
February): John Mayberry (Bristol),
ÒHow to think about natural numbers.Ó
week 4 (10
February): Mary Leng (St JohnÕs
College, Cambridge), ÒNaturalism and linguistic frameworks: mathematical ontology in a postQuinean
setting.Ó
week 5 (17
February): Michael Potter
(Fitzwilliam College, Cambridge),
ÒHow far can you go? Some
reflections on limitation of size.Ó
week 6 (24
February): John Lucas (Merton
College, Oxford), ÒPrototopology: the fourth volume of Principia Mathematica that never was.Ó (See J.R. Lucas, The Conceptual Roots of Mathematics,
Routledge, London, 2000, Chapter 10, for background to this talk.)
week 7 (3 March):
Philip Scowcroft (Wesleyan University and Oxford), ÒBrouwerÕs creative
subject and variants of KripkeÕs schema.Ó
week 8 (10 March): No meeting, to avoid clashing with a
lecture by Adam Rieger (Glasgow), ÒSet theory and secondorder logicÓ, at a
meeting of the British Society for the Philosophy of Science, LSE, 5.157.00
(tea at 4.45 in T16).
Convener:
Daniel Isaacson, Faculty of Philosophy, 10 Merton Street Oxford OX1 4JJ (01865)
276929
******************************************************************
SYMMETRY AND
STRUCTURES IN PHYSICS
A OneDay
Conference
Faculty of
Philosophy, University of Oxford
Friday
January 10^{th} 2003, 11.00 – 17.00
Programme: (Coffee from 10.30)
11.00  11.45:
Harvey Brown, Oxford: Aspects of the Role of Symmetry in Physics
11.45 12.30:
Katherine Brading, Oxford: Some Variations on a Noether Theme
12.30 1.15:
David Wallace, Oxford: Quantum Probability and Decision Theory,
Revisited
1.15
 2.15: Sandwich Lunch
2.15 – 3.00:
James Ladyman, Bristol: Symmetry and Modality
3.00 – 3.45:
Oliver Pooley, Oxford: Should we be Sophisticated Substantivalists?
3.45
– 4.15: Tea
4.15 – 5.00:
Simon Saunders, Oxford: Global
Descriptivism
Registration (covering coffee, sandwich lunch, tea): £
6, £ 3 for students;
to
be paid on arrival on the day.
Contact details; To enable us to estimate numbers, please email Jeremy Butterfield, jb56@cus.cam.ac.uk, between Monday 6 and Wednesday 8
January, just to say you (and how many of you!) are coming.
******************************************************************************
Michaelmas Term 2002
Reverse Sokal Hoax
Anyone
interested in following the trauma following the Bogdanov brothers 'reverse
Sokal hoax might like to read along with the rest of the mathematical physics
community on the website set up for it:
http://www.lns.cornell.edu/spr/200210/thrd10.html
There you will
also find a denial by the Bogdanov brothers that it is in fact a hoax:.
Friday 5^{th}
Week Theoretical Physics Colloquium (2.15 Dennis Sciama Lecture Room, Nuclear
Physics)
Our very own Simon
Saunders is speaking on
ÒDerivation of the Born Rule from Operational AssumptionsÓ
Abstract:
Whence the Born rule? It is fundamental to quantum
mechanics; it is the essential link between probability and a formalism which
is otherwise deterministic; it encapsulates the measurement postulates.
Gleason's theorem does of course throw light on it, but it is a purely
mathematical theorem, and its premise is too strong to have any operational
meaning. Here the Born rule is derived
much more simply, from purely operational assumptions.
The argument is related to Deutsch's derivation of the
Born rule from decision theory. The latter was criticized by Barnum et al, but
their objections have recently been countered by Wallace. The argument from
decision theory that Wallace has presented is sound. However, it draws heavily
on the Everett interpretation; this case is of particular interest, as the
interpretation of probability has long been considered a weakness of Everett's
approach, but the key ideas of the derivation are of more general application,
and, in other contexts, his focus on a purely subjective notion of probability
is unduly restrictive.
In contrast, the derivation of the Born rule that we
shall present is independent of decision theory, and independent of any
assumptions about the measuring process. As such it applies to all the major
foundational approaches to quantum mechanics. We assume the conventional scheme
for the description of experiments, in terms of an initial state, measured
observable, and macroscopic outcomes. We assume there is a general algorithm,
given a description of this form, for the probabilities of the observable
outcomes. (The Born rule is such an algorithm.) Our argument then takes the following form:
for a certain class of experiments, there are definite rules for determining
such descriptions, based on simple operational prescriptions and theoretical
assumptions that concern only the statepreparation device, not the measurement
device. In particular cases, these rules imply that the experiment can be
described in two different ways. But the algorithm we are looking for concerns
the probabilities of the observed outcomes, so in such cases it must yield the
same probabilities, when applied to these different descriptions. Constraints
of this form are in fact sufficient to force the Born rule.
____________________________________________________________________
This term we
are running our first weekly research seminar in Philosophy of Science, replacing
our usual weekly philosophy of physics seminar (which will be back in Hilary
and Trinity terms):
Thurs 17 Oct K
Wilkes: Models and Realism; the animal model in the brain and behavioural
sciences
Thurs 24 Oct N
Jardine: Whigs and Stories: Herbert Butterfield and the historiography of
the sciences
Thurs 31
Oct D Papineau: Decisions and
Many Minds
Thurs 7 Nov : J
Campbell Causal vs Epiphenomenal Progressions
Thurs 14 Nov:
Tim Williamson, Evidential Probability
Thurs 21 Nov:
Frank Jackson The How and Why of Narrow Content
Thurs 28 Nov R
Harre: Science as model making: two roles for iconic representations
Thurs 5 Dec N
Cartwright: Causes and
Probabilities
All meetings will take place at 4.00 pm, The Old
Library, All Souls College.
_______________________________________________________________________
This termÕs Philosophy
of Mathematics research seminar series, convened by Dan Isaacson, features:
Week 1: Tuesday,
15 October. Professor Elaine
Landry (Calgary),
Category theory
as a framework for an in re interpretation of mathematical structuralism
Week 2: Thursday,
24 October. Dr David Corfield
(Oxford),
Towards a
philosophy of real mathematics
Week 3: Tuesday,
29 October. Professor Brian Davies
(King's College London),
Empiricism in
arithmetic and analysis
Week 4: Thursday,
7 November. Dr Gianluigi Oliveri
(Oxford and Palermo),
Mathematics, a
quasiempirical science?
Week 6: Thursday,
21 November. Professor Robert Thomas (Manitoba and Oxford)
The Comparison of Mathematics with Narrative
Week 8: Thursday,
5 December. Dr. Daniel Isaacson (Oxford)
Philosophical
Significance of Complex Conjugation.
All meetings,
whether on Tuesday or on Thursday, will take place in the Lecture Room, 10
Merton Street.
____________________________________________________________
Bruno Latour will be giving
this year's Clarendon Lectures in Oxford:
Professor Bruno
Latour (Centre de Sociologie de l'Innovation, Ecole Nationale SupŽrieure des
Mines de Paris) will give three lectures on INFORMATION AND ORGANIZATION
Lecture 1:
Tuesday 22 October 2002
Four New
Uncertainties in the Social Sciences
Lecture 2:
Wednesday 23 October 2002
For a Critique
of Pure Reason
Lecture 3:
Thursday 24 October 2002
The Trouble
with Organisation
All lectures
take place at 5 pm at the Said Business School, Park End Street, Oxford, OX4
1HP (next to Oxford rail station).
All lectures
are free and open to the public. The first lecture will be followed by a drinks
reception.
For further
information, contact Liz Buckle, Marketing Coordinator,
liz.buckle@sbs.ox.ac.uk, 01865 288852 Said Business School