

4
March (Wednesday)
5:00 PM Room
226

Ákos
Gyarmathy

Department
of Philosophy and
History of Science
Budapest University of
Technology and Economics


On the
problematic relation
of ontic vagueness
and models of
identity through
time

In
this talk I will discuss the
scope of Gareth Evans'
argument of vague identity
for different theories of
persistence. There are three
types of vagueness: ontic,
epistemic and semantic. As
Gareth Evans argues vague
identity is a serious
problem for the defenders of
ontic vagueness. I show
arguments for the claim that
the problem of ontic
vagueness reemerges for
vague objects that preserve
their identity through time.
Different theories about
persistence through time
(e.g. endurantism,
perdurantism, stage theory)
react differently to this
problem. My main argument
shows examples of definite
objects that gain and then
lose their vagueness
(assumed by the defenders of
ontic vagueness). These
objects will reproduce the
Evansproblem via their
identity through time in
most of the theories dealing
with persistence through
time. My suggestion is that
the concept of ontic
vagueness should be
abandoned in order to
preserve the concept of
persistence (this of course
does not mean that vague
identity would be the only
serious problem for these
theories).

11
March (Wednesday)
5:00 PM
Room 226

Balázs
Gyenis

Institute
of Philosophy,
Research Centre
for the
Humanities,
Budapest


The
first good bad
proof of
tendency
towards
equilibrium

When
two gases mix their
temperatures equalize.
In the talk we take a
look at a simple proof
that aims to
demonstrate this
phenomena from
historical,
philosophical, and
pedagogical
perspectives. We argue
that the proof can be
viewed as a charitable
reconstruction of
Maxwell's own 1860
argument, and if so,
then Maxwell preceded
Boltzmann's first
attempt to give a
mechanical explanation
of tendency towards
equilibrium with at
least 6 years. Albeit
the proof makes a
fallacious
probabilistic
independence
assumption, in this
regard it does not
fare worse than other
later attempts. On the
other hand this
probabilistic
independence
assumption is
geometrically
intuitive and even
invites some
speculation about the
physical basis of
irreversibility. The
proof is also simpler
than many later
attempts and could
reasonably be included
in a course on
classical mechanics.

18
March (Wednesday)
5:00 PM Room
226

Hanoch
BenYami

Department
of Philosophy, Central
European University,
Budapest


Truth and
Proof without
Models: A
Development and
Justification of the
Truthvaluational
Approach

I
explain why Model Theory
is unsatisfactory both as
a semantic theory and as a
tool for proofs on logic
systems. I then motivate
and develop an
alternative, a
truthvaluational
substitutional approach,
which uses no models. The
first order Predicate
Calculus with identity as
well as of Modal
Propositional Logic are
sound and complete on this
approach. This treatment
of Modal Logic does not
involve possible worlds.
Along the way I answer a
variety of difficulties
that have been raised
against the
truthvaluational
substitutional approach. A
conclusion of this work is
that logic needs no
semantics and provides no
basis for metaphysics. 
25
March (Wednesday)
5:00 PM
Room 226

Zalán Gyenis^{1}
Gábor
HoferSzabó^{2}
Miklós Rédei^{2,3}

^{1
Alfréd Rényi
Institute of
Mathematics,
Budapest
2 }Institute
of Philosophy,
Research Centre
for the
Humanities,
Budapest
^{3 }Department
of Philosophy,
Logic and
Scientific Method,
LSE, London 

The
BorelKolmogorov
Paradox and
conditional
expectations

The
BorelKolmogorov
Paradox is typically
taken to highlight a
tension between our
intuition that certain
conditional
probabilities with
respect to probability
zero conditioning
events are well
defined and the
definition of
conditional
probability by Bayes
formula, which is
meaningless when the
conditioning event has
probability zero. We
argue that the theory
of conditional
expectations is the
proper mathematical
device to
conditionalize, and
this theory allows
conditionalization
with respect to
probability zero
events. The
conditional
probabilities on
probability zero
events in the
BorelKolmogorov also
can be calculated
using conditional
expectations. The
alleged clash arising
from the fact that the
conditional
probabilities on
probability zero
events depend on what
condi tional
expectation one uses
to calculate them is
resolved by showing
that the different
conditional
probabilities obtained
using different
conditional
expectations cannot be
interpreted as
calculating in
different
parametrizations of
the conditional
probabilities of the
same event with
respect to the same
conditioning
conditions. Thus there
is no clash between
the correct intuition
about what the condi
tional probabilities
with respect to
probability zero
events are and the
technically proper
concept of
conditionalization via
conditional
expectations.
Related paper: http://philsciarchive.pitt.edu/11377/



