When we say that a dog is good or that a car runs badly, we are often using these value terms (good, bad, etc.) in neither an aesthetic nor a moral sense. When we say that a car runs badly, we mean that there is something mechanically (but not morally or aesthetically) wrong with the car’s engine.
Similarly, in calling a dog good, we do not mean that the dog is morally good or even beautiful, we mean that it does not bite or that it barks only when strangers threaten us. In short, what we usually mean by such a statement is that the thing in question is good because it can be used to fulfil some kind of function.
Aristotle argued that being moral has to do with the function of a human being and in developing his argument he moved from the non-moral to the moral uses of good and bad. He suggested that anything that is good or bad is so because it functions well or poorly. If we could discover what the function of a human being is, then we would know how the term good or bad can be applied to human life. Since reason is the proper function of human being, he concluded that being moral essentially means “reasoning well for a complete life”.
