Aristotle's Nicomachean Ethics grapples with a fundamental question: what constitutes the good life for a human being? His distinctive approach, centered on the "function argument," posits that understanding a thing's purpose or characteristic activity is key to determining its excellence and, by extension, its good. This argument, which concludes that the human good is virtuous activity of the soul, remains a powerful framework for understanding human flourishing, or eudaimonia. By examining what makes a thing function well, Aristotle establishes a compelling, albeit debated, foundation for ethical inquiry, suggesting that our good is not arbitrary but deeply rooted in our nature.
The function argument begins by observing that objects, from a cobbler's tools to an eye's sight, have a specific function or characteristic activity. A knife's function is to cut; a good knife cuts well. Similarly, Aristotle argues, humans must have a characteristic activity. He dismisses mere life, which we share with plants, and perception, which we share with animals, as insufficient to define our unique human function. What distinguishes us, he contends, is our capacity for reason. Therefore, our characteristic activity, our ergon, must involve the exercise of this rational faculty. A good human, then, is one who performs this rational activity well, which Aristotle identifies as acting virtuously.
This connection between function and virtue is central. Just as a skilled musician plays their instrument with excellence, a virtuous person exercises their reason with excellence. Virtue, for Aristotle, isn't merely a disposition but an activity that aligns with reason and leads to good outcomes. He distinguishes between intellectual virtues, like wisdom and understanding, cultivated through teaching, and moral virtues, such as courage, temperance, and justice, developed through habit. Courage, for instance, is the mean between the extremes of cowardice and rashness, a state achieved by habituating oneself to act rationally in fearful situations. These moral virtues, when consistently practiced, allow us to fulfill our rational function effectively, leading us closer to eudaimonia.
The ultimate aim of this virtuous activity, Aristotle argues, is eudaimonia, often translated as happiness or flourishing. This is not a fleeting emotional state but a state of living well and doing well, a life of sustained, excellent activity. Eudaimonia is the highest good, pursued for its own sake, and all other goods are pursued because they contribute to it. By grounding eudaimonia in the exercise of our uniquely human rational capacity, Aristotle offers a teleological understanding of ethics: our good is tied to our purpose. The function argument provides the logical scaffolding for this, demonstrating that living according to reason, i.e., virtuously, is the most fitting way for a human being to achieve their ultimate end.
While the function argument has faced criticism, particularly from modern perspectives that question inherent human purposes, its strength lies in its coherence and its comprehensive vision of a well-lived life. It offers a framework where ethics is not a matter of arbitrary rules but an investigation into what it means to be a good human. By linking our nature to our moral and intellectual development, Aristotle provides a compelling case for the pursuit of virtue as the path to genuine human flourishing, a vision that continues to resonate in philosophical discourse today.