This chapter examines how justification is transmitted from one belief to another, as where one acquires justification for believing a proposition by inferring it from something else that one already justifiedly believes. An account of theoretical reason must also consider knowledge. Knowledge is not merely justified true belief, and its relation both to theoretical justification and to practical rationality is quite complicated. It is argued that rationality, justification, and knowledge are all based on reasons, and several kinds of reasons we must understand in order to see how they are so based are discussed.
Keywords: rationality, justification, knowledge, belief, theoretical reason