In working out our true function, Aristotle looks to that feature that separatesman from other living animals. According to Aristotle, what separates mankindfrom the rest of the world is our ability not only to reason but to act onreasons. Thus, just as the function of a chair can be derived from its uniquelydifferentiating characteristic, so the function of a human being is related to ouruniquely differentiating characteristic and we achieve the good when we actin accordance with this true function or telos