Aristotle is not a big fan of what we might call “the social contract” theory of government. This is largely because he is interested in what is enduringly natural, but the social contract is merely a matter of changing convention.
For Aristotle, the social contractarian understanding of the city (polis) consists of two things: (1) association for residence on a common site, and (2) association for the sake of preventing mutual injustice and easing exchange (Politics III.ix.12). This differs from the polis because the polis is “an association of households and clans in a good life, for the sake of attaining a perfect and self-sufficing existence” (Politics III.ix.12). A social contract is not an association of friends and equals seeking the common good, but a mere alliance of strangers and unequals seeking protection and acquisition.
Here are some arguments against the social contractarian understanding of political order. First, a social contract city exists only for the sake of daily living, not for living well. It separates a man’s duties to the state from his duties to his larger social setting – in other words, it separates “politics” and “ethics.” But this sort of end is unnatural for human beings, for whom happiness is the final and most perfect end to which everything else is subordinated (Nicomachean Ethics I.vi.7; Politics VI.vii.1). The point of political order is the ethical training of the individual person (Politics III.vi.4, ix.7-9).
Second, a social contract city is based on a mere convention, a potentially changing compact, not a natural law and a desire to attain man’s natural end. The purpose of political life is to morally train the individual for living in association with free and equal people who are all aiming for the good life (Politics III.ix.13-14). But convention is not concerned with the good life, with the moral training of the individual. It is merely “a guarantor of men’s rights against one another” and a facilitator of trade, acquisition, and money-making (Politics III.ix.8).
Third, the social life of such a city is based on friendship, not justice. While friendship is not a bad thing on Aristotelian terms (see Nicomachean Ethics, Books VIII-IX), it is something that takes place within the city, not the very glue that holds the city together. The common interests of groups of friends might not always cohere with the common interest of the whole city. Rowers on a ship have interests common to rowing, look-out men to look-out men, and so forth, but all have the common interest of preserving the ship (cf. Politics III.iv.2). The ship of the state is about finding and preserving justice (Politics I.ii.11), but friendship is a relationship concerned with reciprocal quantitative exchange, and is not based on merit (Nicomachean Ethics VIII.7). Consequently, friendship, while a natural result of relations in the state, is an inadequate basis for the state.
Fourth, the broader relationships within such a city are between people who are fundamentally strangers and unequals, not free and equal persons involved in rational deliberation about the good (Politics III.ix.13-14). Is not most, if not all of the above, the very image of the Modern metropolis? Think of the crowded, zooming freeways full of comfortably anonymous people who shout curses at each other while ruthlessly jockeying for position because every single one of them has to get where he’s going yesterday. Think of the mechanistic and commercialistic view of provisioning food, shelter, and clothing. Only a machine could feed a modern metropolis, but that seems inevitably to entail transforming those living in the metropolis – especially those who work in “service industries” – into cogs. Think of the complete lack of concern for any purpose higher than a self-centered desire for only What Is Good For Today, and you have Aristotle’s objection to this form of life in a nutshell.
Given such considerations as these, on Aristotelian premises the social contract is not that great of an idea, and actually undermines man’s humanity and his pursuit of what is best for him.