The Enlightenment was an eighteenth-century European cultural movement which emphasized the power of reason as a way of defining reality over against the authority of tradition—particularly, a religious one. It is, however, not always an optimistic phenomenon in a sense that its over-confidence in reason has brought about, to some extent, the destruction of humanity. Defoe’s Robinson Crusoe was written during the time of the Enlightenment, and the novel implies a possibility of how reason and faith can be understood not in a dualistic but an interrelated way. First, it is clear that the power of reason as a key element of Enlightenment is crucial for Crusoe to create the necessities of daily life—a kind of microcosmic civilization or culture. Second, Crusoe demonstrates some counter-arguments against the Enlightenment in terms of imperialism and slavery. Third, both reason and faith are interrelated with each other in his conversion experience and in the process of overcoming fear.