selections from aristotle, nicomachean ethics (Crisp translation)
Knowledge of the good would seem to be the concern of the most authoritative science, the highest master science. And this is obviously the science of politics, because it lays down which of the sciences there should be in cities, and which each class of person should learn and up to what level. And we see that even the most honourable of faculties, such as military science, domestic economy, and rhetoric, come under it. Since political science employs the other sciences, and also lays down laws about what we should do and refrain from, its end will include the ends of the others, and will therefore be the human good. For even if the good is the same for an individual as for a city, that of the city is obviously a greater and more complete thing to obtain and preserve. For while the good of an individual is a desirable thing, what is good for a people or for cities is a nobler and more godlike thing. Our enquiry, then, is a kind of political science, since these are the ends it is aiming at (1094a-b).
Since, then, our predecessors have left the question of legislation unexamined, it is presumably better that we study it, and the question of political systems in general, so that our philosophy of humanity might be as complete as possible. First, then, if any part of what has been said by those before us is plausible, let us try to go through it. Then, in the light of the political systems we have collected, let us try to consider what sorts of things preserve and destroy cities and each type of political system, and what causes some cities to be well run, and others badly run. For when these issues have been considered, we shall perhaps be more likely to see which political system is best, how each must be arranged, and what laws and habits it should employ. Let us, then, discuss these matters from the beginning (1181b).