Earlier in the chapter we contrasted nature with art. In Aristotelian thought nature also contrasts with violence. Like art violence refers to an activity whose source or principle is outside the affected subject, but the source may be natural or artificial. In either case, however, violence and this is its distinctive featureis directly contrary to the natural tendencies of the receiving body. Thus, by the ancient physics the upward motion of a heavy body is "violent." Such a body moves naturally down.
In the Scholastic tradition these three notions, nature, art, and violence, have acquired each a formulation that is standard and well worth reproducing here:
( i ) Natura est principium et causa motus et quietis in eo in quo est primo et per se et non secundum accidens. (Nature is a principle and cause of motion and rest in the thing in which it inheres immediately and as an attribute that is essential and not accidental.)
(ii) ) Artificiale est cujus principium est extra, in ratione externam materiam disponente. (That is artificial whose principle is outside, namely, in reason disposing external matter.)
(iii) Violentum est cujus principium est extra, passo non conferente vim. (A "violent" action is one whose principle is outside, without active contribution from the affected subject.)