As in natural bodies those things are not admitted to be parts of them without which the whole would not exist, so also it is evident that in a political state everything that is necessary thereunto is not to be considered as a part of it, nor any other community from whence one whole is made; for one thing ought to be common and the same to the community, whether they partake of it equally or unequally, as, for instance, food, land, or the like; but when one thing is for the benefit of one person, and another for the benefit of another, in this there is nothing like a community, excepting that one makes it and the other uses it; as, for instance, between any instrument employed in making any work, and the workmen, as there is nothing common between the house and the builder, but the art of the builder is employed on the house. Thus property is necessary for states, but property is no part of the state, though many species of it have life; but a city is a community of equals, for the purpose of enjoying the best life possible: but the happiest life is the best which consists in the perfect practice of virtuous energies: as therefore some persons have great, others little or no opportunity of being employed in these, it is evident that this is the cause of the difference there is between the different cities and communities there are to be found; for while each of these endeavour to acquire what is best by various and different means, they give [1328b] rise to different modes of living and different forms of government. We are now to consider what those things are without which a city cannot possibly exist; for what we call parts of the city must of necessity inhere in it: and this we shall plainly understand, if we know the number of things necessary to a city: first, the inhabitants must have food: secondly, arts, for many instruments are necessary in life: thirdly, arms, for it is necessary that the community should have an armed force within themselves, both to support their government against those of their own body who might refuse obedience to it, and also to defend it from those who might attempt to attack it from without: fourthly, a certain revenue, as well for the internal necessities of the state as for the business of war: fifthly, which is indeed the chief concern, a religious establishment: sixthly in order, but first of all in necessity, a court to determine both criminal and civil causes. These things are absolutely necessary, so to speak, in every state; for a city is a number of people not accidentally met together, but with a purpose of ensuring to themselves sufficient independency and self-protection; and if anything necessary for these purposes is wanting, it is impossible that in such a situation these ends can be obtained. It is necessary therefore that a city should be capable of acquiring all these things: for this purpose a proper number of husbandmen are necessary to procure food, also artificers and soldiers, and rich men, and priests and judges, to determine what is right and proper.