ABSTRACT
The new Bayesian paradigm in the psychology of reasoning is truly psychological in focusing on inferences from beliefs, or strictly degrees of belief, and on how these beliefs are extended, revised, and updated in reasoning, and on inferences relevant to decision making. The new Bayesian paradigm has changed the focus in the psychology of reasoning to degrees of belief and utility, making the field properly psychological, and opening up the possibly of integrating the psychology of reasoning with judgement and decision making. Traditional psychology of reasoning, whether of the mental logic or mental models varieties, concentrated on inferences from assumptions, often abstract, arbitrary, unrealistic, and primarily from degrees of belief. A related topic for the Bayesian approach of the new paradigm is the speech act of assertion. The Bayesian approach has much to discover about indicative and counterfactual conditionals in natural language, belief revision and updating, and the human action of assertion.
