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The Forum is open to everyone, including students, visitors, and faculty members from all departments and institutes!

The 60 minute lecture is followed by a 10 minute break and a 30-60 minute discussion. The language of presentation is English or Hungarian.

The scope of the Forum includes all aspects of theoretical philosophy, including:

  • logic and philosophy of formal sciences
  • philosophy of science
  • modern metaphysics
  • epistemology
  • philosophy of language
  • problems in history of philosophy and history of science, relevant to the above topics
  • particular issues in natural and social sciences, important for the discourses in the main scope of the Forum.


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 re-emerges 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 Evans-problem 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 Ben-Yami
Department of Philosophy, Central European University, Budapest
Truth and Proof without Models: A Development and Justification of the Truth-valuational 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 truth-valuational 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 truth-valuational 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 Gyenis1    Gábor Hofer-Szabó2     Miklós Rédei2,3
1 Alfréd Rényi Institute of Mathematics, Budapest
Institute of Philosophy, Research Centre for the Humanities, Budapest
3 Department of Philosophy, Logic and Scientific Method, LSE, London
The Borel-Kolmogorov Paradox and conditional expectations
The Borel-Kolmogorov 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 Borel-Kolmogorov 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.

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