The aim of the paper is to shed light on the difference between two Aristotelian notions of the just by nature, one is to be found in the Nicomachean Ethics, the other in the Magna Moralia. I shall concentrate on the definitions because they seem to be the core of their divergence. Without any commitment to authorship one has to see that the account in Magna Moralia differs in two important points. First, in general, as a virtue justice contains a non-rational element, a certain kind of impulse (ὁρμή). It is a non-rational force that constitutes natural virtue. In order to become complete virtue such as justice it has to embrace reason and choice as well. Second, natural justice is established by usage. If a custom or habit has become settled it turns into a part of our nature or character and therefore actions based on such intentions can rightly be called actions in accordance with natural justice.
