The purpose of the present study is not as it is in other inquiries, the attainment of knowledge, we are not conducting this inquiry in order to know what virtue is, but in order to become good, else there would be no advantage in studying it. For that reason, it becomes necessary to examine the problem of our actions and to ask how they are to be performed. For as we have said, the actions determine what kind of characteristics are developed.
Xenophanes states that the fire in Lipara once failed for sixteen years, but returned in the seventeenth year. They say that the lava-stream in Etna is neither flaming nor continuous, but returns only after an interval of many years.
The same thing may have all the kinds of causes, e.g. the moving cause of a house is the art or the builder, the final cause is the function it fulfils, the matter is earth and stones, and the form is the definitory formula.