My dissertation explores the dramatic merit of encounters between supernatural and human characters on the early modern English stage. I argue that the psychological disturbance these encounters engender allows for a re-evaluation of the process and nature of belief formation. Rather than dismiss representations of the supernatural in English theatre as theatrical spectacles void of critical significance, I argue that the supernatural can be productive conduits for exploring the psychological complexities of the human mind. I demonstrate that because ghosts, devils and witches are products of the same theological and philosophical systems which conceptualize the workings of the early modern mind, they are able to infiltrate and influence the aspects of human psychology which are particularly susceptible to doubt and desire. These encounters then result in the psychological unravelling of human characters, who must navigate conflicting ideals in order to move towards action. However, the experience of this internal struggle is significant not only for revealing the competing influences characters must reconcile in the process of forming beliefs and opinions, but also for emphasizing the importance of critical evaluation of the discourses of belief that surround them, regardless of external pressure to blindly accept them. As ghosts, devils and witches are supernatural figures rooted in widespread theological doctrine, and whose function is determined by the religious, social and political authorities that shape early modern English belief, so are they imbued with a powerful potential to shake the foundations of those belief systems of which they themselves are part. I analyze supernatural representations of these figures in plays by Shakespeare, Middleton, Marston, Chapman, Goffe and Marlowe, and the psychological effects of their encounters with human characters, in order to examine how they can facilitate alternative perceptions of beliefs around gender and power in sixteenth and seventeenth-century England.