PIs: Prof. Dr. Gabriele Kern-Isberner, Dr. Dr. Niki Pfeifer
 Involved: Christian Eichhorn
 Institution: Technische Universität Dortmund, Ludwig-Maximilians-Universität München

Abstract
This project combines logic-based theories of rationality provided by nonmonotonic logics and approaches to conditional reasoning, and probabilistic theories of rationality based on coherence approaches and the principle of maximum entropy. Conditionals will serve as a common interface between all these approaches, since they encode crucial guidelines for rational reasoning and can be used both in a qualitative and in a probabilistic way. This provides a unifying perspective on rationality that helps to overcome the limits of specific frameworks and also allows for taking information from the environment into account. We aim to extend axiomatic systems of nonmonotonic logics (like system P) to better approximate rational reasoning. In particular, the theory of conditional structures shall be used to develop formal models of rational conditional reasoning, both in qualitative and probabilistic frameworks. On the probabilistic side, the coherence approach will be utilized and extended to investigate formally and empirically current psychologicial and philosophical theories of conditionals. The descriptive value of the formal models shall be evaluated with respect to people's understanding of and their commonsense reasoning with uncertain conditionals. Moreover, the relevance of the methods to be developed in this project to causal and counter-factual reasoning and for belief revision shall be investigated.

Projekt-Homepage: http://www.pfeifer-research.de/spp.html

Project-related Publications
Kern-Isberner, G., & Eichhorn, C. (2014). Structural inference from conditional knowledge bases. Studia Logica, 102(4), 751-769.
Pfeifer, N. (2014). Reasoning about uncertain conditionals. Studia Logica, 102, 849-866.
Pfeifer, N. & Douven, I. (2014). Formal epistemology and the new paradigm psychology of reasoning. The Review of Philosophy and Psychology, 5, 199-221.
Kern-Isberner, G. & Eichhorn, C. (2013). Intensional combination of rankings for OCF-networks. In Boonthum-Denecke, C. and Youngblood, M. (Eds.), Proceedings of the 26th International Florida Artificial Intelligence Research Society Conference (FLAIRS-2013) (pp. 615-620). AAAI Press.
Kern-Isberner, G. & Eichhorn, C. (2013). OCF-Networks with missing values. In Beierle, C. & Kern-Isberner, G. (eds.): Proceedings of th 4th Workshop on Dynamics of Knowledge and Belief (DKB-2013), 2013.
Pfeifer, N. (2013). The new psychology of reasoning: A mental probability logical perspective. Thinking & Reasoning, 19, 329-345.
Pfeifer, N. (2013). On argument strength. In F. Zenker (Ed.), Bayesian argumentation. The practical side of probability (p. 185-193). Dordrecht: Synthese Library Vol. 362 (Springer).
Kern-Isberner, G. & Eichhorn, C. (2012). A structural base for conditional reasoning. In: Human Reasoning and Automated Deduction (HRAD)—KI 2012 Workshop Proceedings.
Pfeifer, N. (2012). Experiments on Aristotle's Thesis: Towards an experimental philosophy of conditionals. The Monist, 95, 223-240.
More publications can be found on this page.