Physics and medicine from antiquity to the medieval period

Abstract Medical physics is commonly held to have begun at the end of the nineteenth century following discoveries about radiation and radioactivity that were to transform medical diagnosis and the treatment of cancer. A wider perspective dates the origin of the relationship between physics and medicine to the scientific revolution of the sixteenth century when physics began to be applied to understanding the workings of the body and to the development of medical technology. This paper argues that the relationship is in fact much older, dating back several millennia. At the heart of ancient Greek φυσική (natural philosophy) was an attempt to understand the nature and composition of the Universe and a belief which remains valid today that the human body functions on the same principles as the Universe as a whole. This approach led to a corpus of medical teachings rooted in physics as it was then understood that remained dominant in Europe and the Islamic world until the sixteenth century. Furthermore, ancient and medieval sources provide evidence of physical principles being used in medical diagnosis, in treatment and as a means of understanding the functioning of the body in a range of ancient cultures including Greece, Egypt and Persia. This mirrors the different ways in which physics continues to contribute to medical science and clinical practice today. Examples described in this paper include the first technique to map body temperature (arguably also the first medical imaging technique), the use of fire and heat in surgery and other forms of treatment, and medieval attempts to understand vision and the physics of the eye.