 The later portions of the fourth treatise are grounded in an Aristotelian definition of nobility, as the perfection of a thing according to its nature [Conv. 4.16.7; Physics 7.3, 246a]. The human expression of this perfection is virtue, moral and intellectual. Electing to address the moral virtues, as more accessible to a lay understanding, Dante begins by describing how nobility is implanted in the nascent soul as the seed of virtue, from which spring the two branches of the active and the contemplative life. The final chapters of the Convivio show how the virtues that stem from nobility can direct the natural appetite of the mind, enabling it to evolve through love of them to the happiness which is the end of virtue [Conv. 4.17.8–9; NE 1.13, 1102a].