The conference is held in conjunction with ESSLLI 2014.

# Topic

Hypothetical reasoning or reasoning under assumptions is a key concept of logic, philosophy of science and mathematics. This conference focusses on its logical aspects, such as

- assumption-based calculi and their proof theory
- logical consequence from a proof-theoretic or model-theoretic point of view
- logics of conditionals
- proof systems
- structure of assumption-based proofs
- hypotheses in proof-theoretic semantics
- notions of implication
- substructural logics
- hypotheses in categorial logic
- logical aspects of scientific explanation
- hypothetical reasoning in mathematics
- reasoning from definitions and axioms

The conference is organised as part of the French-German ANR-DFG project HYPOTHESES.

The program committee consists of the members of this project.

# Invited speakers

- Arnon Avron (Tel Aviv University):
*Using Assumptions in Gentzen-type Systems* - Michel Bourdeau (CNRS, IHPST, Université Paris 1):
*Comte's « Théorie fondamentale des hypothèses »* - Kosta Došen (Mathematical Institute, SANU):
*An introduction to deduction* - Paul Egré (CNRS, Institut Jean-Nicod, Paris):
*Negating indicative conditionals* - Andrzej Indrzejczak (Institute of Philosophy UŁ, Łódź):
*Hypersequents and Linear Time* - Zoran Petrić (Mathematical Institute, SANU):
*Cuts and Graphs* - Francesca Poggiolesi (CNRS, CEPERC, Aix-en-Provence):
*Counterfactual logics: natural deduction calculi and sequent calculi*

# Contributing speakers

- Torben Braüner (Roskilde University):
*Seligman-style deduction for hybrid modal logic* - Michael Cohen (Munich):
*Explanatory Justice: The Case of Disjunctive Explanations* - Nissim Francez (Technion) and Julien Murzi (University of Kent):
*On a dogma of Proof-Theoretic Semantics: generalising canonicity of derivations* - Reinhard Kahle (Universidade Nova de Lisboa):
*Axioms as Hypotheses* - Sergey Melikhov (Steklov Mathematical Institute):
*A joint logic of problems and propositions, a modified BHK-interpretation and proof-relevant topological models of intuitionistic logic* - Grigory Olkhovikov (Ural Federal University):
*Truth-value gaps and paradoxes of material implication* - Paolo Pistone (Università di Roma Tre):
*Rules, types and the transcendence of second order logic* - Erdinç Sayan (Middle East Technical University):
*How do vacuous truths become laws?* - Guillaume Schlaepfer (Université de Genève):
*Scientific modeling: a two layer based hypothetical reasoning*