

3 April (Wednesday)
5:00
PM
Room
226 
Elias
Zafiris

Department
of Logic,
Institute of
Philosophy,
Eötvös
University
on
leave from
Institute
of Mathematics, National
University of Athens


The Role of Topology in the Interpretation of Quantum Event Structures

One of
the deepest insights of quantum theory is that
although the totality of all
experimental/empirical facts can only be
represented globally as a nonBoolean event structure,
the acquisition of every single fact
depends on a local Boolean frame. This is tied with
the particular formalization of the notion of an observable in quantum
theory, namely a selfadjoint operator. More precisely, each
selfadjoint operator has associated with it a Boolean frame which is
identiﬁed with the complete Boolean algebra of projection operators
belonging to its spectral decomposition. In this way, complete Boolean
algebras of projection operators can be considered as local Boolean
logical recognition frames for the individuation of events. We claim
that the current settheoretic models of quantum event structures
underscore the functional role of interconnected families of local
Boolean frames in the global formation of quantum structures. We propose
to remedy this deficiency in terms of a localtoglobal sheaftheoretic
model, where the global information of a quantum algebra can be
topologically localized to covering systems of local Boolean frames, and
inversely induced by them via gluing. We discuss the application of
this topological scheme in relation to quantum nonseparability.

10 April (Wednesday)
5:00
PM
Room
226 
Jenő Pöntör

Institute of Philosophy, Eötvös University, Budapest


Mi
a baj a nemreduktív fizikalizmussal?
(What's wrong with nonreductive physicalism?)

Előadásomban először felvázolom a kortárs fizikalizmus három
fő formájának – az antirealista, a reduktív, illetve a
nemreduktív fizikalizmusnak – legfontosabb állításait, majd a
mellett érvelek, hogy az antirealista és reduktív fizikalista
elméletek empirikusan jól megalapozott hipotézisek, ezzel szemben
a nemreduktív fizikalizmus elvileg igazolhatatlan tézis.

17 April (Wednesday)
5:00
PM
Room
226 
Attila Molnár

Department of Logic, Institute of Philosophy
Eötvös University, Budapest


Mass and Modality

The
Logic and Theory of Relativity group lead by Andréka, H. and Németi, I.
developed several axiom systems for relativity theory to investigate it
within mathematical logic.
One of the simplest and most commonly used axiom system is an axiom
system of kinematics, the socalled SpecRel. Although this axiom system
is very simple, it implies all the main predictions (theorems) of
special relativity theory. However, as it is proposed by the group in
many articles, sometimes the classical firstorder logic framework of
SpecRel does not seem to be sufficient to give back the appropriate
physical meaning. For example, the main axiom of SpecRel, the axiom
which is about the possibility of sending out light signals, states that
there could be a photon which crosses certain points. This "could be"
indicates some kind of notion of possibility, which is barely accessible
from a classical firstorder logic.
This problem becomes more serious when we try to expand the system
SpecRel by certain dynamical axioms (to get SpecRelDyn). For example, we
would like to postulate that for every observer, everywhere, any kind
of possible collision is realizable. It is worth to investigate this
type of axioms, because this way leads to an experimental understanding
of the notion of possibility.
We will investigate axiom systems of special relativity based on modal
logic, which is the standard tool for formally handle dynamical notions –
such as performing a (thought) experiment, for instance "send out a
light signal" or "realize a collision".
Our axiom systems will be built with the following goals:
 Give a plausible but formal notion of possibility/experimentation
based on the informal explanations of the classical SpecRel and
SpecRelDyn.
 Save the theorems and the ideas of their proofs from SpecRel and SpecRelDyn.
 Show that in a modal framework the mass can be explicitly defined
essentially in the language of kinematics. This can be viewed as the
formal interpretation of the operational definition of mass.

24 April (Wednesday)
5:00
PM
Room
226 
Péter Mekis

Department of Logic, Institute of Philosophy
Eötvös University, Budapest


Thought Experiments as Semantic Arguments

In the
last couple of decades, there has been an intensive debate concerning
the epistemological status of thought experiments. Whether in science or
in philosophy, these tools of investigation apparently provide
important new knowledge in spite of being entirely a priori, and thus
they pose a serious challenge to empiricism. One of the crucial
questions of this debate is: Are thought experiments
indispensable, or are they reducible to ordinary arguments within a
given theory?
One characteristic point of view regarding this question is that the
phenomenon of thought experiments does actually falsify empiricism,
providing quasiperceptional, yet a priori knowledge. Thought
experiments are experimental in nature; the only difference between them
and actual experiments is that the objects of observation are abstract
entities, instead of physical ones.This view rules out the possibility
that thought experiments could be reduced to arguments. Another extreme
is the reductionist view, according to which a thought experiment is an
argument in a fictional disguise, which can be left out without any
theoretical loss.
My suggestion is that a great deal of thought experiments function as
semantic arguments concerning the satisfiability or categoricity of
scientific or philosophical theories. They are not experimental in
nature; but they are not arguments within a (scientific or
philosophical) theory either. Rather, these arguments serve as tests for
theory choice. Being about (rather than part of) theories, they differ
genuinely from the deductive arguments which prove the theories' facts.
But, on the other hand, no appeal to quasiperceptional knowledge is
required to account for their correctness.



