Aristo made virtue one thing in its essence, and called it health; but in what it is somehow related to, he made the virtues differentiated and plural, just as if one wanted to call our vision in grasping light-colored things light-sight, but dark-sight in grasping dark-colored ones. For virtue in considering things to be done and not to be done is called wisdom, but it is called temperance in bringing order to our appetites and defining what is measured and timely in pleasures, and justice in busying itself with joint enterprises and contracts with other people.