“That which is unjust,” we must notice, is different from “an act of injustice,” and “that which is just” from “an act of justice:” for a thing is unjust either by nature or by ordinance; but this same thing when done is called “an act of injustice,” though before it was done it could only be called unjust. And so with “an act of justice” ( δικαίωμα ); though in the latter case we rather employ δικαιοπράγμα as the generic term, and restrict δικαίωμα to the correction of an act of injustice. But as to the several species of acts of justice and injustice, we must postpone for the present the inquiry into their nature and number and the ground which they cover.