In early modern times, the dream—which was defined as a product of the imagination during the nightly sleep as the soul stayed wide awake although the body rested, cut off from the external senses—aroused a large debate in the Holy Roman Empire that lay open to external influences (particularly the Italian and the French ones).
This discussion stemmed from the rival attempts to define the relationships between the soul and the body, the dead, and the living (with or without the purgatory), as well as between mankind and the supernatural powers (God or the devil). Because they allowed a direct relation with the divine, beyond any mediation of the established churches, dreams represented a potential danger for the authorities.
In the course of the confession, the debate was reoriented from the issue of the theological truth toward the sphere of knowledge: henceforth, the aim was to educate the young generations, i.e., to control the imagination of children. Consequently, pathological beliefs were defined. But where ran the frontiers between dream, daydream, or "Schwärmerei," possession, witchcraft, and madness, and how could dreams be used as proofs? A third aspect of the project concerned the rhetorical conventions and strategies mobilized to give an account of such a contravening phenomenon as dream. The final question concerned the epistemological as well as cultural and political status of dreams as truth was progressively being defined in terms of facts. The use of dreams in political, historiographical, and medical issues in the seventeenth and eighteenth centuries does not advocate a marginalization of dreams, but rather a new interest in all the consequences of a moral control of the imagination.
The story of the relationships between dream and knowledge exemplifies the different modes of knowledge and of belief that were developed while metaphysics tended to weaken, and while epistemology, which devoted itself to the study of the justification of belief, was being asserted.