What is the highest of all goods achievable by action? ...both the general run of man and people of superior refinement say that it is happiness ...but with regard to what happiness is they differ.
Special care should be taken of the health of the inhabitants, which will depend chiefly on the healthiness of the locality and of the quarter to which they are exposed, and secondly on the use of pure water; this latter point is by no means a secondary consideration. For the elements which we use the most and oftenest for the support of the body contribute most to health, and among those are water and air. Wherefore, in all wise states, if there is want of pure water, and the supply is not all equally good, the drinking water ought to be separated from that which is used for other purposes.
Nor was civil society founded merely to preserve the lives of its members; but that they might live well: for otherwise a state might be composed of slaves, or the animal creation... nor is it an alliance mutually to defend each other from injuries, or for a commercial intercourse. But whosoever endeavors to establish wholesome laws in a state, attends to the virtues and vices of each individual who composes it; from whence it is evident, that the first care of him who would found a city, truly deserving that name, and not nominally so, must be to have his citizens virtuous.
Nature herself, as has been often said, requires that we should be able, not only to work well, but to use leisure well; for, as I must repeat once again, the first principle of all action is leisure. Both are required, but leisure is better than occupation and is its end.
For both excessive and insufficient exercise destroy one's strength, and both eating and drinking too much or too little destroy health, whereas the right quantity produces, increases and preserves it. So it is the same with temperance, courage and the other virtues. This much then, is clear: in all our conduct it is the mean that is to be commended.
What is the highest good in all matters of action? To the name, there is almost complete agreement; for uneducated and educated alike call it happiness, and make happiness identical with the good life and successful living. They disagree, however, about the meaning of happiness.