[PhilPhys] Fwd: Workshop: Underdetermination and Quantum Physics (Leeds, 20-21 May)

[Juha Saatsi]

*‘Underdetermination and Quantum Physics’ – International Workshop *

20-21 May 2016


University of Leeds

Centre for the History and Philosophy of Science


This workshop examines the issue of underdetermination in the context of
quantum physics and realism debate. (See below for abstracts.)


The workshop is part of the ARHC Scientific Realism and the Quantum Project.

http://arts.leeds.ac.uk/raq


*Speakers*:


Elena Castellani (Florence)

Kevin Coffey (NYU)

Matthias Egg (Bern)

Steven French (Leeds)

Lina Jansson (Nottingham)

Laura Ruetsche (Michigan)

Karim Thébault (Bristol)

David Wallace (Oxford)


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*Programme:*



Friday 20th May


10:30 – 10:45  Coffee and Welcome


10:45 – 12:00  *Steven French*


12:00 – 12:45  Lunch


12:45 – 14:00  *David Wallace*


14:00 – 15:15  *Matthias Egg*


15:15 – 15:45  Coffee


15:45 – 17:00  *Lina Jansson*


17:00 –   Pub and workshop dinner




Saturday 27th


10:00 –11:15  *Karim Thébault*


11:15 - 11:30  Coffee


11:30 – 12:45  *Laura Ruetsche*


12:45 – 13:30  Lunch


13:30 – 14:45  *Elena Castellani*


14:45 - 15:00  Coffee


15:00 – 16:15  *Kevin Coffey*


16:30   Workshop ends.




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*Venue:*


Room G36, Baines Wing, School of PRHS, Woodhouse Lane, Leeds LS2 9JT

For directions see
http://www.teachingspace.leeds.ac.uk/building_details.asp?ID=1


There is no registration fee, but please contact Juha Saatsi (
J.T.Saatsi at leeds.ac.uk) by Friday 13th May if you plan to attend or have
any questions about the event.



------------------------


*ABSTRACTS:*



*Elena Castellani*

(University of Florence)


"Theoretical and physical equivalence: the case of weak/strong duality"


Dualities in field and string theories seem to provide new and interesting
cases to the philosophical debate on theoretical equivalence. In which
sense physical dualities are theoretical equivalences, what kind of
equivalence is indeed concerned and whether physical dualities can be seen
as genuine cases of underdetermination,

are the issues naturally discussed in this respect. Dualities are of
various types, and how to address the above issues depends on the type of
duality and the context considered. This paper's focus is on weak/strong
duality and the equivalence issue is discussed in the light of an
historical analysis of how this kind of duality developed in the framework
of quantum field theory in the 70s, to be successively extended to the
string context in the early 90s.



*Kevin Coffey*

(New York University / Abu Dhabi)


‘Can the Foundational Realist Be Agnostic?’


What does it mean to be a scientific realist about quantum mechanics in
light of the various persistent interpretive problems that beset the
theory? In particular, is it possible to be a realist about quantum theory
and yet remain agnostic regarding its correct interpretation? I consider
several ways one might try to implement such an idea, and examine how they
bear on the standard epistemological arguments for and against realism.



*Steven French*

(University of Leeds)


‘Realism About *That*: exploring the role of metaphysics in breaking
underdetermination’


Back in 1991, Jones drew on the different ‘formulations’ of Newtonian
mechanics (Hamiltonian, Lagrangian etc.) and the different
‘interpretations’ of quantum mechanics (Bohemian, Everettian etc.) to
construct forms of underdetermination that he claimed present a serious
challenge to the realist. Musgrave responded by invoking metaphysical
considerations to break the underdetermination in the classical case. Here
I shall evaluate that strategy in the context of recent work on the
relationship between metaphysics and science (particularly that of myself
and Kerry McKenzie) and consider the extent to which it might be extended
to the quantum case. When it comes to the latter I shall also explore the
possibility of adopting a metaphysically more minimal stance that focusses
on the relevant underlying structure (of course!).



*Matthias Egg*

(University of Bern)


‘3 or 3N Dimensions? Underdetermination about the Fundamental Space of
Quantum Mechanics’


The question concerning the dimensionality of our fundamental physical
space is arguably one of the most profound cases of underdetermination in
non-relativistic quantum mechanics. Those who take the wave function to
represent fundamental reality think that the world fundamentally has 3N
dimensions, where N is the total number of particles. Against this, various
versions of quantum mechanics postulate certain entities in 3-dimensional
space as fundamental. An important argument for the latter view suggests
that this is not strictly a case of underdetermination of theory by
evidence, because a view that does not include some entities in
3-dimensional space fails to explain how there can be empirical evidence
for quantum mechanics in the first place. A critical assessment of this
argument will clarify how the debate on dimensionality depends on the
evaluation of non-empirical virtues which is well-known from other debates
on underdetermination.



*Lina Jansson*

(University of Nottingham)


‘Can A Pragmatist Interpretation of Quantum Theory Explain?’


Typically, realist interpretations claim the explanatory advantage over
non-realist interpretations of theories. Recently, Healey (2015) has
proposed an account of how quantum theory can be used to explain without
taking quantum states to represent physical properties of the systems in
question.  The argument relies on both the notion of explanations providing
expectability and satisfying Woodward’s criterion of answering
what-if-things-had-been-different questions.  I argue that Healey’s
proposal is not stringent enough to distinguish explanatory from
non-explanatory inferences.  I will suggest a way to do so for pragmatist
interpretations, and I will outline what it forces us to give up.



*Laura **Ruetsche*

(University of Michigan)


‘Effective Theories and Ineffective Interpretations’


In physics, an effective theory is one that has a limited range of
application and that succeeds within that range because it incorporates
elements that encapsulate the implications, for phenomena within that
range, of physics outside that range. The quantum field theories of the
standard model are a widely held to be examples.  Despite failing to
describe physics at very high energies/very short length scales (aka Planck
scale physics), these theories manage to save lower energy phenomena
because they include a finite number of parameters (typically coupling
constants whose values are determined experimentally) that summarize the
empirical constraints Planck-scale physics exerts on lower energy
phenomena.  Let us entertain the possibility that our best quantum theories
are merely effective. How, if at all, should that transform our connected
understandings of what it is to interpret such theories and whether we’re
warranted in believing them? Good work is being done mining the terrain of
effective theories for resources congenial to realists.  I’ll try instead
to identify resources for the anti-realist, including similarities between
a theory’s status as merely effective and its status as (i) merely
empirically adequate, in something like van Fraassen’s sense, and (ii)
underdetermined with respect to something like unconceived alternatives in
Stanford’s sense.



*Karim Thébault *

(University of Bristol)


‘Three Degrees of Underdetermination in Canonical Quantum Cosmology’


In this talk I will distinguish three degrees of underdetermination drawing
upon the example of mini-superspace models of canonical quantum cosmology.
The first `representational degree’ is benign, and relates to the surplus
structure inherent in the parametrisation of the classical phase space
solutions of a `totally constrained’ globally reparametrization invariant
model.


The second `physical degree’ is more significant, and relates to a choice
as to how we motivate and apply the constraint quantization procedure. On
one view, radical relationalism, time is merely relative variation and
quantum mini-superspace models should feature a `wavefunction of the
universe’ trapped in an energy eigenstate. On a second view, Machian
relationalism, time ordering is non-relational and quantum mini-superspace
models should feature `Schrödinger evolution for the universe’.
Significantly, although this underdetermination stems from an
interpretational question, it leads to models that are in principle
observationally distinguishable.


The third `pernicious degree’ of underdetermination relates to an ambiguity
in the procedure for defining self-adjoint extensions to the
mini-superspace Hamiltonian operator. It has features in common with each
of the first two degrees in that there is a sense in which it is both
representational and physical. However, unlike the other two degrees,
pernicious underdetermination appears to imply a potential breakdown in the
`realism’ of our modelling procedure: a mathematical rather than
interpretational choice leads to models that are in principle
observationally distinguishable.




*David Wallace*

(University of Oxford)


‘What is "orthodox quantum mechanics”?’


Abstract: Philosophers of physics and metaphysicians often speak about the
"orthodox" interpretation of quantum mechanics, by which they mean
something like the Schrodinger dynamics supplemented with the
eigenvector-eigenvalue link and the Dirac-von Neumann projection
postulate.  But if "orthodox" means "standard amongst physicists" then the
orthodox interpretation is not orthodox at all: orthodoxy is something much
more minimal, from which the philosophers' orthodoxy is obtained by adding
substantive metaphysical assumptions and by trying to clear up
philosophical confusion in the physicists' approach. Since virtually no-one
actually thinks the (philosophers') "orthodox interpretation" is any good
as an interpretation of quantum mechanics, it might be better to take the
more minimal physics version as a starting point from which to formulate
the measurement problem.
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