Looking by turns at the history of concepts, knowledge and scholarly practice in the 18th century, the study traces the changes undergone in the course of the first half of that period by ideas on imagination as an intermediary faculty between the bodily and the spiritual. Whereas the early Enlightenment regarded imagination as a 'lower faculty' subordinate to the logic of reason, the rehabilitation of sensual perception brought with it a massive reinstatement of imagination as a 'way of knowing'. In the course of this process, it gained central status as a case in point for the investigation of interrelations between psychic and physiological processes representing a major challenge for philosophers and medical scholars alike. By contrast, poetics and aesthetics advocated formal education in aesthetic and sensual perception as a way of channelling and curbing potential extravagances in the use of the imaginative faculty.