Medicine

At the start of the first book of The Canon of Medicine, Ibn Sina defines medicine as the science by which the conditions of the human body are known, in terms of what becomes sound and what departs from soundness, so that the health that is present may be kept and what has been lost may be recovered. ¹

Ibn Sina explains that medicine is divided into theoretical and practical. What he means by this is not a division into teaching the science and carrying out the work; rather, one of its two parts is the science of its principles, and the other is the science of how to practise it. ¹

Among the subjects of medicine in his account are the elements, the temperaments, the humours, the organs, the spirits, the faculties and the actions, together with the states of the body of health, sickness and balance, and their causes. The causes of health and sickness are of four kinds: material, efficient, formal and final. As Ibn Sina mentions in the margin, these are the four causes that Aristotle discussed. ^{2 3}

The physician takes from the science of nature some principles, such as the elements and the essence of the temperaments and humours, and is not required to prove them within his craft. ⁴ On the temperaments, he says that the physician must take from the natural philosopher what concerns moderation. ⁵