To investigate the best regime it is necessary to first investigate the best way of life. Virtue is more important for a good life than external things. The soul is more honorable than the body and possessions, because these things are for the sake of the soul, not vice versa. Happiness is the result of living according to virtue. Now, "the best city is happy and acts nobly." Therefore the best way of life both for individuals and for cities is a life of virtue.
Now we need to investigate which is the most choiceworthy way of life and which regime is the best. The best regime is the one in which a person can act in the best manner and live most happily. There is a dispute between those who assert that the political or active life is the most choiceworthy and those who assert that the philosophic way of life is the best.
Those who dislike the political way of life because it involves ruling make the mistake of equating every type of rule with mastery, while political rule is noble because it is rule over free persons. Inactivity is also not praiseworthy. For people who are similar, the noblest arrangement is to rule and be ruled in turn. Yet this is not to say that the active life is necessarily the best, because the philosophical life is in reality not inactive, and its actions are for the sake of goods which are ends in themselves.
In thinking about the best city, it is important to think about population and territory. A larger population is not always better, because quality of citizens is more important than quantity, and it is often more difficult for a populous city to be well-managed. Too few persons is also bad because the city will not be self-sufficient. Therefore the optimal number is just enough so that the city is self-sufficient.
As far as territory is concerned, one also needs to look for territory that is self-sufficient, and that it allows people to live at leisure but also with moderation. The territory should be readily surveyable so that it is easily defended.
The territory should be near a port so as to have access to trade, but not right on the sea so as to avoid the influx of foreigners.
Considering what quality of persons the political multitude should be, it is clear that they should be both spirited and endowed with thought, as the Greeks are.
"The city is a partnership of similar persons, for the sake of a life that is the best possible." There will need to be several sorts of cities and regimes because of the different sorts of people that make them up. This requirements for a city are as follows: sustenance, arts, arms, funds, priestcraft, and judgment concerning the advantageous and the just. Accordingly, the multitude must consist of farmers, artisans, warriors, a well-off element, priests and judges.
In the best regime, the citizens should not be merchants, because this way of life is ignoble. Further, they should not be farmers because leisure is necessary for virtue and political activity. The fighting element and the judges should be citizens, such that the young are warriors and then afterwards become judges.
The city should be divided among the separate types of persons. There should be common messes, but also a sphere for private property. Farmers should slaves.
The city should be in a place where the terrain and climate are favorable to people's health, and should be adequately fortified to safeguard against attack.
Common messes need to be arranged for the different classes in the city.
Since the best city is the happiest city, we need to review what happiness is before deciding what the regime of the best city should be. Happiness, as defined in the discourse on ethics, is "the actualization and complete practice of virtue." First and foremost, the city is excellent when its citizens are excellent. Men become excellent through nature, habit and reason.
Should the rulers and ruled be the same throughout life or should they alternate? Unless there is a person or group who so preeminent in virtue that they are like gods, the citizens should rule and be ruled in turn. A regime cannot last if it is contrary to justice. The older should rule the younger, because this is a natural distinction and a person rules more finely if he has been ruled first.
The soul has two partsone has reason, and the other does not have reason but can obey it. The reasonable part can also be divided into the active part and the studying part. Action directed toward necessary thing should always be for the sake of noble things. Citizens must be educated to act with a view toward noble things above all. They also must be sure that citizens do not view war as an end in itself, so that they will know how to be capable of being at leisure.
Should citizens be educated first by means of reason or by means of habits? The two should be consonant with one another, and since reason and intellect are the end of human nature habits should be formed with a view to these. The superintendence of the body is for the sake of the soul, and the control of the appetites is for the sake of the intellect.
The legislator needs to makes laws regarding marriage so as to ensure that procreation takes place at the best time both physically and with respect to capability of child-rearing.
Raising children should be regulated with a view to helping them grow strong physically and habituating them in virtue. They should not spend much time with slaves and foul speech should be banished from the city so that it doesn't negatively influence the children. It is also important to be careful about what young people watch. The young should be protected from all bad influences. Education should be split into two age groups: age seven until puberty, and puberty until age twenty-one.
In his discussion of the best city, it is natural that Aristotle would begin with an examination of the best life, since of course the aim of the city is living well. The happiest man would have all three kinds of goodsexternal goods, goods of the body, and goods of the soulbut goods of the soul are the most important. Aristotle argues that while external goods by nature have a limit and can be excessive, there is no possibility of excess with regard to goods of the soul. There is a natural hierarchy of beings to which a hierarchy of goods correspond, and goods of the soul are the highest. They are intrinsically choiceworthy, not chosen for the sake of something else.
Aristotle's discussion of the best life leads him to the debate between the practical life versus the contemplative life, a debate which recurs throughout the writings of both ancient and medieval philosophers, such as Plato, Cicero, and Aquinas. In Aristotle's view, the highest practical life is the political life, while the highest contemplative life is the philosophic life. While it is unclear, especially in the politics, whether the political or the philosophic life is best, texts on this subject in the Ethics, particularly in Book X, indicate that the philosophic life is the best because it engages the highest part of the soul in contemplation of the highest things, and is the most complete, continuous and self-sufficient activity.
Having established what the best life is, Aristotle then proceeds to work out the details for the best city. The best city brings together all of Aristotle's previous recommendations for a just regime. Aristotle often repeats that for a city to be well-managed, the citizens have to "similar in stock and free." Otherwise, there is discord with regard to varying ideas of justice and competing claims to rule based on numbers, wealth or virtue. At the same time, Aristotle recognizes that a city needs farmers, laborers and artisans if it is to be able to provide for the necessities of life. It is clear to Aristotle that these laboring classes are not fit to take part in ruling, because they do not have the necessary leisure time required for a proper education in virtue. However, all citizens ought to have a share in ruling, and if the citizens are similar they ought to rule and be ruled in turn. This problem of the demosthe people, or the multitudeis a recurrent theme throughout the Politics. The demos seems to be an insurmountable obstacle to the formation of a perfect regime. Perhaps that is why, in his best regime, Aristotle simply eliminates the demos. The laboring classes are all slaves, and the only citizens are an elite aristocracy of gentlemen, in which the young are soldiers and the old rule. This seems to be the only way for Aristotle to actualize his ideal political set-up, where citizens who are similar in stock and free rule and are ruled in turn.