  In his De natura logicae (part of the Opera logica) Zabarella attacks writers who put medicine alongside the philosophy of nature among the sciences. Contemplative philosophy appropriates nothing from the productive arts, but instead the arts adopt everything from philosophy. No matter how valuable and precise medicine may be, it could never be a science because it is practised not for the sake of knowledge, but for an end product: that is, the maintenance or restoration of health. If knowledge of the human body is considered purely for its own sake, rather than for curative purposes, it should be called natural philosophy rather than medicine. Even if it were admitted that medicine could be practised for the sake of knowledge, it could not be called a pure science, because it does not explain the first causes, and without this comprehension the other causes cannot be clearly apprehended. Health cannot be fully comprehended and the goal of medicine cannot be achieved, if a physician does not comprehend all the parst of a human body and their nature, composition, purpose, and function.