Physiological Introduction or Principles of the Human Body

privation could be counted among the internal principles of natural bodies, if it is a non-entity, not a part of a natural body, nor its cause, and only pertains to the natural body by accident and not by itself, and cannot remain, which is nevertheless required for an internal principle. By the Peripatetics followers of the Aristotelian school, the internal principles of a natural body are distinguished into those "in being" original: "in fieri" and "in fact" original: "in facto". Principles "in being" are three: matter, form, and privation. Principles "in fact" are two: matter and form. To prove this number, they cite Aristotle lib. 1. phys. t. 67., who says that there can be both two principles and three. Yet, although to those weighing it more strictly, only matter seems to be called an internal principle according to Aristotle, since it is the first subject for each thing and that from which something is made while it does not exist; nevertheless, it seems to matter little whether the number of internal principles of a natural body is stated as one, two, or three, and everything from which a composite manifestly owes its origin is called a principle. Since, therefore, matter alone cannot constitute a natural body but seeks a "companion" for itself, such as another component, and finally an "aptitude" is pre-required for this, for example, for the form to be received and joined, which according to Aristotle is called privation with respect to the still absent form, it seems evident that this exists; for even without this aptitude, there would never be any composition of a body.

Prænot. 4. Internal principles are finally said to be either essential, which compose the essence of a natural body, such as matter and form, or integral, which do not concern the essence but the mixture of some body, and are themselves supposed to be already composed from essential principles. Thus, Peripatetic elements constitute a mixture as integral principles, but they themselves are already composed as natural bodies essentially from matter and form. With these noted: