Theoretical rationality is often called “epistemic” rationality, since it is concerned with the question of obtaining knowledge. An agent can be said to know that p only if, apart from believing that p and p being true, he or she is able to give reasons for his or her belief that p. Theoretical rationality, hence, can be understood as that capacity of cognitive agents that allows them to adopt beliefs about the world on the basis of reasons. This raises at least two problems. First, what are the grounds on which a rational agent may adopt such beliefs? ...