Therefore in medicine we ought to know the causes of sickness and health. And because health and sickness and their causes are sometimes manifest, and sometimes hidden and not to be comprehended except by the study of symptoms, we must also study the symptoms of health and disease. And these two are subjects that, according to their mixing together, alter. In the composition and alteration of the substance which is thus composed, a certain unity is attained. Formal causes are physical constitutions, and combinations and virtues which result from them.
Final causes are operations.
And in the science of operations lies the science of virtues, as we have set forth. Medieval Arabia , pp. Scanned by Jerome S. Arkenberg, Cal. The text has been modernized by Prof. Arkenberg. This text is part of the Internet Medieval Source Book .