[PhilPhys] Lisbon Philosophy of Physics Seminars: Ryan Miller (May 3 on Zoom)

[Andrea Oldofredi]

Dear List Members,

On Wednesday May 3 Ryan Miller (University of Geneva) will give a talk at
the Lisbon Philosophy of Physics Seminars titled "*Aristotelian Grounding
for GRW’s Flash Ontology*" (abstract below).

These events are organized in the context of the activities of the LanCog
Research Group <https://cful.letras.ulisboa.pt/lancog/> at the Centre of
Philosophy of the University of Lisbon, and they will focus on the
foundations of quantum and spacetime physics.

The meeting will be held on Zoom (17:00-19:00 CEST). If you have not
registered yet, you can do so here
<https://docs.google.com/forms/d/1pe9-CUZwKFA_uS0j-wD7bRQatIO-SdzxBqKlmkM6XOY/edit?usp=drive_web>
.

You can address any question to Andrea Oldofredi (
aoldofredi at letras.ulisboa.pt).

ABSTRACT:
The flash (i.e., event) ontology for the Ghirardi, Rimini, and Weber (GRW)
objective-collapse formulation of quantum mechanics (Goldstein et al.,
2012) has become increasingly popular. In this interpretation, a
wave-function evolving in a high-dimensional configuration space
“collapses” at probabilistic interval λ by multiplication with a Gaussian
function of width σ—both empirically chosen parameters (Feldmann & Tumulka,
2012). The flash ontology advances on previous versions of the GRW
mechanics by avoiding the paradoxes associated with GRW wavefunction monism
and the GRW matter density ontology (McQueen, 2015) and opening the door to
a multi-time wavefunction with interaction (Tumulka, 2021). Flashy GRW
combines complete Lorentz-invariance with a well-understood 4D ontology
(Tumulka, 2018) and explains thermodynamics (Albert, 2000). Valia Allori’s
(Allori et al., 2008) straightforward reading of this ontology suggests
that the flashes are fundamental, wholly grounding both the wavefunction
and our everyday macro-scale ontology. This view has come under pressure on
both points, however: Tim Maudlin (2010, 2019) argues that the GRW
wavefunction cannot be wholly grounded in the flashes, while Elizabeth
Miller (2022) argues that flashes are an inadequate ground for everyday
macro-scale ontology. Difficulties also arise in treating a sparse set of
events as the distributional base for the ontology of other sciences. If a
chemist places a mole of a compound in a flask, surely that flask should
contain Avogadro’s number of particles of that compound, not just some
vastly smaller number of discrete events. Yet neither
can the wavefunction wholly ground the flashes, since the collapse dynamics
requires some initial input set of flashes in order to predict future
flashes at all.
I suggest resolving these difficulties with the GRW flash ontology by
grounding both the flashes and the wavefunction in the objects specified by
the special sciences. On this broadly Aristotelian proposal, it is the
chemical and biological substances of the special sciences rather than the
wavefunctions or flashes of physics that are fundamental. Such substances
have proper times (the ordering of their own alterations) which can serve
as the times of a local quantum wavefunction, which is then understood
dispositionally as the evolution of the physical properties of those
substances (Dorato & Esfeld, 2010; Lorenzetti, 2021). The flashes, in turn,
would be events in an ordinary sense—the interactions of substances with
spacetime—even if sparser than supposed prior to quantum theory. This
approach requires that substances maintain entanglement among the flash
families of their parts, but the special sciences provide mechanisms (e.g.
bonding energies and metabolisms) by which such homeostasis of entanglement
is maintained, even though wavefunction collapse ordinarily promotes
disentanglement.
Unlike theories of strong emergence for the special sciences (Wilson,
2021), this grounding-based approach does not posit downward causation or
the incompleteness of physics. Given the physical facts about wavefunctions
and flashes, all the further physical facts (stochastically) follow
according to the multi-time GRW formalism. Any qualitatively distinct
powers posited by the special sciences must be inert with respect to the
physical world. Only the order of grounding is reversed, with entangled
macro-wholes grounding their dispositions for physical evolution and
micro-events, rather than vice versa. The Aristotelian approach is
therefore reminiscent of Jonathan Schaffer’s priority monism (Schaffer,
2010; Ismael & Schaffer, 2020), but unlike Schaffer’s assumption of a
single totally entangled wavefunction for the universe, the multi-time GRW
approach insists that wavefunctions and entanglement are largely (though
not exclusively) local affairs. While entanglement can persist non-locally,
as shown in the Bell experiments, collapses promote disentanglement, and
the macro-processes which cause entanglement operate locally. This
Aristotelian approach therefore recovers not only realism about the objects
of the special sciences but also explains (contra Schaffer and Bohm) why we
normally observe a high degree of separability and locality. Aristotelian
grounding for the GRW flash ontology should thus be taken seriously in
contemporary disputes about the metaphysics of quantum mechanics.

Best regards,

Andrea Oldofredi
----------

Dr. Andrea Oldofredi

Postdoc FCT

Internet Resources:
https://unil.academia.edu/AndreaOldofredi
https://www.researchgate.net/profile/Andrea_Oldofredi

Mailing Address:
University of Lisbon
Centre of Philosophy
Alameda da Universidade, 1600-214, Lisbon
Portugal
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