What are the necessary bases for the construction of the ideal state? An ideal constitution is bound to require an equipment appropriate to its nature. We must therefore assume, as its basis, a number of ideal conditions, which must be capable of fulfillment as well as being ideal. These conditions include, among others, a citizen body and a territory. All producers–weavers, for instance or shipwrights–must have the materials proper to their particular branch of production; and the better prepared these materials are, the better will be the products of their skill. Like other produces, the statesman and the lawmaker must have their proper materials, and they must have them in a condition that is suited to their needs.The primary factor necessary, in the equipment of a state, is the human material; and this involves us in considering the quality, as well as the quantity, of the population naturally required.
The second factor is territory; and here too we have to consider quality as well as quantity. Most men think that the happiness of a state depends on its being great. They may be right; but even if they are, they do not know what it is that makes a state great or small. They judge greatness in numerical terms, by the size of the population; but it is capacity, rather than size, which should properly be the criterion. States, like other things, have a function to perform and the state which shows the highest capacity for performing the function of a state is therefore the one which should be counted greatest…If we judge a state by the standard of its population, we ought to limit the population to those who are members of the state which sends into the field a large force of mere mechanics and can only raise a handful of heavily-armed infantry, cannot possibly be great. A great state is not the same as a populous state.
There is a further consideration. Experience shows that it is difficult, if not indeed impossible, for a very populous state to secure a general habit of obedience to law. Observation tells us that none of the states which have a reputation for being well governed are without some limit of population. But the point can also be established on the strength of philosophical grounds. Law is a system of order; and a general habit of obedience to law must therefore involve a general system of orderliness. Order, however, is the one thing which is impossible for an excessive number. The creation of order for an infinite number is a task for the divine power which holds together [and reduces to order] the whole of the universe, where beauty [which goes with order] is usually found attending on number and magnitude. We may therefore conclude that the state with the greatest beauty will be one which combines magnitude with the standard of order suggested above. But we must also note [apart from this general rule] that states, like all other things (animals, plants, and inanimate instruments) have a definite measure of size. Any object will lose its power of performing its function if it is either excessively small or of an excessive size. Sometimes it will wholly forfeit its nature; sometimes, short of that it will merely be defective….[Example of a ship]. The same is true of states. A state composed of too few members is a state without self-sufficiency (and the state by its definition is a self-sufficient society.) A state composed of too many will indeed be self-sufficient in the matter of material necessities (as an uncivilized people may equally be); but it will not be a true state, for the simple reason that it can hardly have a true constitution. Who can be the general of a mass so excessively large? And who can give it orders, unless he has Stentor’s voice? The initial stage of the state may therefore be said to require such an initial amount of population as will be self-sufficient for the purpose of achieving a good way of life in the shape and form of a political association. A state which exceeds this initial amount may be a still greater state; but such increase of size, as has already been noticed, cannot continue indefinitely. What the limit of increase should be is a question easily answered if we look at the actual facts. The activities of a state are partly the activities of its governors, and partly those of the governed. The function of governors is to issue commands and give decisions [the function of the governed is to elect the governors]; both in order to give decisions in matters of disputed rights, and to distribute the offices of government according to the merit of candidates, the citizens of a state must know one another’s characters. Where this is not the case, the distribution of offices and the giving of decisions will suffer. Both are matters in which it is wrong to act on the spur of the moment; but that is what obviously happens where the population is overlarge. Another thing also happens under these conditions. Foreigners and resident aliens readily assume a share in the exercise of political rights: it is easy for them to go undetected among the crowd.
These considerations indicate clearly the optimum standard of population. It is, in a word,‘the greatest surveyable number required for achieving a life of self-sufficiency.’