Sleep and dreams in ancient medical diagnosis and prognosis

Abstract

This thesis aims to improve our understanding of sleep and dreams in ancient medicine, and allot dreams their own place among ancient diagnostic and prognostic procedures. First, a systematic overview of Hippocratic and Galenic diagnostic and prognostic procedures is provided. As yet, no such overview is available for the Hippocratic Corpus. To form a diagnosis or prognosis, the Hippocratics and Galen apply observation and semiotic inference, combining universal, external information concerning matters like the weather and the environment, with individual information such as a patient's symptoms and regimen and, occasionally, his dreams. Secondly, the (physiological) processes, which, according to the Hippocratics, Galen and Aristotle pertain to sleep and waking, are described in detail. A systematic account of Galen's theory of sleep is offered here for the first time. In Galen and Aristotle's accounts especially, digestion takes a central position. In all three approaches, the primary qualities - hot, cold, wet, and dry - play an important role. Lastly, the discussion of the Hippocratic and Galenic approaches to dreams is taken beyond the standard treatises, and Aristotle's views are also examined in detail. The various Hippocratic ideas on dreams show much greater consistency than has previously been suggested. In a broad spectrum of views, On Regimen most strongly emphasises the role of dreams as significant indicators of the dreamer's physical condition. Galen, elaborating Hippocratic ideas, prominently includes factors outside of the dream in the medical interpretation of dreams. Aristotle offers the most fully fledged physiological account of the occurrence of dreams. As in On Regimen, he provides a theoretical basis for the use of dreams as a source of information about the condition of the body. This thesis shows that sleep and dreams were duly considered in ancient medical thought.