Final answer:
Aristotle argues that the ultimate human good, eudaimonia or flourishing, is achieved by fulfilling our unique function through the cultivation of virtues. Rationality is identified as the unique human function, and through habituation in virtues, we lead fulfilling lives. The social and political structure also influences our ability to develop and exercise these virtues for the common good.
Step-by-step explanation:
Aristotle's argument from function to the human good is predicated on the idea that everything has a purpose or function, and the 'good' of something is determined by how well it fulfills its function. When applied to humans, Aristotle contends that our unique function is rationality and thus human flourishing, or eudaimonia, is achieved through the cultivation of virtue. Virtue, in this context, means "excellence" in exercising reason and developing good character through consistent, well-reasoned actions.
In the Nicomachean Ethics, Aristotle illustrates that cultivating virtues allows us to achieve the highest good, eudaimonia, which is more than pleasure or power, but a state of flourishing. This flourishing is the telos, or the ultimate goal, of human life. By fostering habits of character that improve our ability to make good decisions, we lead a fulfilling life. In essence, through habituation, individuals possess and demonstrate virtue, which is essential for leading a life of excellence and ultimately achieves human flourishing.
Moreover, Aristotle highlights that humans as social beings evolve through social relations and political participation, implying that the structure of society and governance also plays a role in facilitating the virtuous development essential for eudaimonia. His ethical framework thus includes a social and political dimension where the cultivation of virtue goes hand in hand with the exercise of rational and public deliberation for the common good.