what each of these means, consider a classic example used by both Aristotle and St. Thomas Aquinas.9 A ship captain is out at sea. A terrible storm arises, such that the lives of his crew as well as the safety of the cargo are dangerously threatened. When it seems the ship may indeed sink, the captain orders the crew to throw all the cargo overboard to lighten the ship and keep it afloat. Though Aristotle and Aquinas use this case to make a slightly different point, it perfectly illustrates our three