J.D. Trout

A fundamental goal of psychology is to describe how humans reason. A fundamental goal of epistemology -- the theory of knowledge -- is to set out how humans ought to reason, and so to acquire knowledge. There is no responsible way of answering the second question without accurately answering the first. So, how do humans reason? Once we have a psychological description of how we reason, it is natural to ask a normative question: How well do we reason? If our reasoning is suboptimal, what can we do, if anything, to improve? Various philosophers and psychologists have offered quite different answers to this question. By considering some of their views, we will explore some central issues about the evaluation of human reasoning: On what basis do we evaluate certain reasoning as good or bad, rational or irrational? On what basis do we evaluate certain beliefs as justified or unjustified? Along the way, we will explore decision aids, the nature of biases, accounts of knowledge in other cultures, and the prospects for philosophical naturalism regarding knowledge.