at a cause necessitates effect. However, the Unmoved Mover is a special case. Since motion is necessary, the Unmoved Mover must exist, and it must at all times produce motion. Aristotle makes an important distinction, between necessity-as-compulsion, and simple necessity. Nothing compels the Unmoved Mover to exist or to cause motion—He is an absolute first principle, unaffected by anything else. The unmoved mover exists and acts with necessity, in the sense that it is impossible that the mover not exist or not act. Simple necessity is a condition that “could not be otherwise.”Aristotle argues that the Unmoved Mover must be immaterial, since if He were material, He could move other things only by moving Himself, which would raise the necessity of explaining the motion of the Mover. Like Plato, Aristotle quickly concludes that this immaterial being must be a mind. The most interesting inference about the Unmoved Mover that Aristotle draws concerns the issues of potentiality and actuality. Aristotle explains the possibility of enduring substances that endure through time by distinguishing potentiality and actuality. An enduring thing is called a (primary) substance. Each substance has a fixed essence, which determines which properties or attributes it can possess, either potentially or actually. Aristotle uses the word “potentially” in two different ways. Sometimes it means “merely potentially”. The potential properties of a substance are constant over time: What changes is which of these properties are actual and which are not. These variable properties are called “accidents”. All change is change in the accidents of a substance.ETHICSAristotle viewed ethics as an attempt to find out our chief end or highest good. Aspirations and desires must have some final object or pursuit. The chief end, according to Aristotle, is happiness. Unlike Plato’s self-existing good, A...
