 Aristotle’s moral psychology has further implications for his account of happiness. In Book I, chapter 7, he said that human good is virtuous activity of the soul but was indefinite about the virtues. In most of the Nicomachean Ethics he talks about the moral virtues, leaving the impression that virtuous activity is the same as activity associated with moral virtues. In Book X, however, Aristotle revisits the issue of virtuous activity. If happiness, he says, is activity in accordance with virtue, it will be activity in accordance with the highest. The highest virtue belongs to the best part of the soul, i.e., the intellect (nous) or the part that governs in the soul and contemplates the fine and godly, being itself the divine part of the soul or that which is closest to the divine (1177a10–20). Up to this point, Aristotle has apparently been talking about the man of political action and the happiness that is suitable to rational, embodied human beings. Active in the life of the city, this person exercises courage, moderation, liberality, and justice in the public arena. Now, instead of the life of an effective and successful citizen, Aristotle is holding up the life of study and contemplation as the one that achieves happiness – that is, the highest human good, the activity of the highest virtue. Such a life would achieve the greatest possible self-sufficiency and invulnerability (1177a30). Indeed, at first he portrays these two lives as so opposite that they seem incompatible.