 Aristotle is persuasive when he argues that children need adult supervision because their rationality is “imperfect” (ateles) or immature. But he is unconvincing to modern readers when he alleges (without substantiation) that, although women have a deliberative faculty, it is “without authority” (akuron), so that females require male supervision (I.13.1260a13–14). (Aristotle’s arguments about slaves and women appear so weak that some commentators take them to be ironic. However, what is obvious to a modern reader need not have been so to an ancient Greek, so that it is not necessary to suppose Aristotle’s discussion is disingenuous.) It is noteworthy, however, that paternal and marital rule are properly practiced for the sake of the ruled (for the sake of the child and of the wife respectively), just as arts like medicine or gymnastics are practiced for the sake of the patient (III.6.1278b37–1279a1). In this respect they resemble political rule, which is the form of rule appropriate when the ruler and the subject have equal and similar rational capacities. This is exemplified by naturally equal citizens who take turns at ruling for one another’s advantage (1279a8–13). This sets the stage for the fundamental claim of Aristotle’s constitutional theory: “constitutions which aim at the common advantage are correct and just without qualification, whereas those which aim only at the advantage of the rulers are deviant and unjust, because they involve despotic rule which is inappropriate for a community of free persons” (1279a17–21).