Abstract
Traditionally, an important class of empirical investigations on the justification of beliefs consists of experimental studies on the evaluation of argument forms w. r. t. logical validity and the truth of the conclusion given sure premises. Recently, probabilistic approaches became popular in the psychology of reasoning. There is a similar trend in formal epistemology to use probabilistic models. In my talk I survey this development in both fields and show how philosophy and psychology can fruitfully interact. I argue that coherence based probability logic is an appropriate rationality framework for investigating formally and empirically the justification of beliefs. Specifically, I defend a probabilistic measure of argument strength. Moreover, I discuss how probability logical formalizations of everyday life arguments make reasons for inferring beliefs from evidence and background knowledge explicit. Finally, I illustrate the psychological plausibility of the proposed rationality norms with the help of some of my psychological experiments.
