Aristotle defines virtues as the things that “cause [their] possessors to be in a good state and to perform their functions well.” So, the virtues of a knife are those qualities that make it good at being a knife, and the virtues of a horse are the horse’s inherent qualities that make it good at galloping and other horsey stuff. The human virtues he listed, then, are the things that make us good at being human.
