But they disagree about what happiness is, and the many do not give the same answer as the wise. We say that this ultimate supreme good is happiness , but hold different opinions on how one is to know when one has attained it. Since there are evidently more ends than one, and of these we choose some as means to something else, it is clear that not all of them are final ends, whereas the supreme good is obviously something final. Therefore, if there is only one final end, this will be what we are seeking, and if there are more than one, the most final of these will be what we are seeking. Therefore we call final without qualification that which is always desirable in itself and never for the sake of something else.
Happiness is defined as the final end .
Now happiness more than anything else seems unconditionally complete, since we always choose it because of itself, never because of something else. Happiness is so complete that we choose it for its own sake. Happiness, then, is apparently something complete and self-sufficient, since it is the end of the things pursued in action. Happiness is the most fulfilling end, the sum of all other ends. Now we take the human function to be a certain kind of life, and take this life to be the soul's activity and actions that express reason, and the function of a good man to be the good and noble performance of these.