In his commentary upon Aristotle’s politics, St. Thomas writes that “the polity (civitas) is the end of the previously mentioned societies, which were shown to be natural. Therefore, the polity is natural. […] Since the polity is a society that has of itself what is sufficient for life, it is itself the end of the previously mentioned societies.” He concludes, “since a polity is nothing other than a congregation of men, it follows that man is a naturally political animal.”
As a political animal, Thomas notes that “men desire to live with one another and not be alone. Even if one man did not have need of another for anything in order to lead a political life, there is nevertheless a great common benefit in the sharing of social life.” This great common benefit stems from two things; first, he says, it helps the people who are living together live better, for each person contributes their own share to the common good of all. As an example, he notes the benefits of the division of labor that come with society – when lots of people can live together, one person can do one thing and another can do another. This division and pursuit of individual goods which contribute to the good of all, Thomas claims, is the highest purpose, or the end, of the polity and the government. He is careful to say that this end is for the sake both of the individuals and also for the sake of the whole community.
The second reason Thomas gives for the benefits of society and common life is that is valuable not only for living well, but also for living at all – for “mere existence.” People who are able to live in community can help contribute to each other’s happiness and fulfillment, but they can also come to each other’s aid and help preserve the lives of one another “against the dangers that threaten [them].” It is this second reason, Thomas explains, that initially brings people together to live in community in the first place. Living well and being happy is a great thing which people desire, but living life at all is desirable as well. People know that if they live together and trust each other and come to the aid of the other, regardless of whether they can help each other live well, they can at least gain a little security for their own life. Thomas seems here to be almost anticipating the rather different and more pessimistic theories of another fellow of the same first name, Hobbes, about 300 years later. Thomas even comments that life can be very miserable and one can suffer many evils outside – echoed later by Hobbes (as he famously said in his book Leviathan, life outside of community is possessed of “no society, and which is worst of all, continual fear and danger of violent death, and the life of man, solitary, poor, nasty, brutish, and short”) without losing the “certain natural sweetness” it seems to possess which drives men together into communities in order to preserve it. It is as if, Thomas says, “life possessed in itself a certain solace and natural sweetness.” Indeed, it is more than mere appearance and “as if” – it is so. For Hobbes, though, there is no real equivalent to living well, which is central to the Angelic Doctor’s thought here.
It is particularly important to note the purpose of society which Thomas declares in his first reason for the great benefit of community – it is, in his words, that
[O]ne person serves the society by performing one function, another by performing another function, and in this manner all live well together. This, then, namely, to live well, is above all else the end of the polity or of the regime, both collectively with reference to all and severally with reference to each individual.
Observe carefully the last clause of the last sentence: “both collectively with reference to all and severally with reference to each individual.” For Thomas, there exists a separate thing called society which is not simply the sum of its individual constituents. Every person pursues their own good life and contributes to that same pursuit in the lives of others, but also contributes to a whole which sits atop the members and exists as a thing in its own right with its own goods and excellences. Thomas says, following Aristotle, “the good to which the polity is ordered is the highest human good.”
To support this argument, Thomas explains that every society exists for some purpose beyond its own mere existence – it has some goal, which he calls the good. He then notes that while polities and societies are not the synonymous, polities are a certain kind of society, so polities, too, are “ordered towards” or exist for the purpose of some greater good. Thomas describes how every person naturally does things which they think will bring about the good in their lives. Whether they’ve got things right or not, and whether the things they do are actually good or not, they still do what they do because they think that it is for the sake of the good. Seeing that every polity is ordered towards some good, that is, that it exists for a purpose, the polity which is best will necessarily be one that “seeks in the highest degree” the greatest good. So we see that the best polity is the one which seeks the highest good, and furthermore, Thomas tells us “the importance of the means to an end is determined according to the importance of the ends.” What does this indicate? It indicates that if we can agree on the importance of the “greatest human good,” we ought to be able to agree that the thing that brings it about is extremely important as well – the polity.
Thomas’s defense of the polity as being ordered towards the highest human good is buttressed from every side by the underlying principle that he is about to expound: namely, that the whole is higher than its parts. He gives the example of a wall, which is indeed a whole composed of bricks, but also a part of a house, and states that the house is clearly the higher of the two wholes. In this same sense, society is a whole composed of parts – of families and households, towns and villages. Therefore, the good of the polity which contains all these parts is greater than any individual part which is its constituent.