Formal Epistemology and the New Paradigm Psychology of Reasoning

This position paper advocates combining formal epistemology and the new paradigm psychology of reasoning in the studies of conditionals and reasoning with uncertainty. The new paradigm psychology of reasoning is characterized by the use of probability theory as a rationality framework instead of classical logic, used by more traditional approaches to the psychology of reasoning. This paper presents a new interdisciplinary research program which involves both formal and experimental work. To illustrate the program, the paper discusses recent work on the paradoxes of the material conditional, nonmonotonic reasoning, and Adams’ Thesis. It also identifies the issue of updating on conditionals as an area which seems to call for a combined formal and empirical approach. This paper highlights the emergence of a new research program concerning uncertain reasoning. The program—henceforth simply referred to as “the newprogram”— is situated at the intersection of formal epistemology and experimental psychology of reasoning, and combines formal and empirical methods to address issues that call for the participation of both philosophers and psychologists. Probabilistic approaches to conditionals have been popular in philosophy for some decades now (e.g., [2, 6, 22]). Current contributions on conditionals by philosophers working in the probabilistic paradigm mostly fall within the relatively young discipline of formal epistemology. The traditional paradigm psychology of reasoning used logic as the rationality framework. Over the past ten years, however, psychologists of reasoning have also become increasingly interested in studying conditionals from a probabilistic perspective (e.g., [71, 76, 78, 84]). This shift from logic to probability theory as the rationality framework paved the way for the “new paradigm psychology of reasoning” [35, 73]. We note that Oaksford and Chater have argued since the early 1990s against classical logic as the correct normative standard