Somewhat unexpectedly, in view of the ‘programme’ of IV i–ii, Aristotle now tells us briefly why there are several different constitutions. States have various ‘parts’ (households, professional groups, etc.) in various combinations, and the resulting variety of economic and social pressures inevitably produces a variety of constitutions. Aristotle considers unsatisfactory the popular view that there are fundamentally only two constitutions, democracy and oligarchy, the others being grouped roughly under one or other of these headings; it would be truer, he suggests, to think of one or two ‘well-formed’ constitutions, the others being ‘deviations’ from them. He thus prefers a classification based on ‘value judgements’ to a purely descriptive one. In effect the chapter prepares us for the several different kinds of constitution we shall meet in subsequent chapters, by contrasting a popular classification with a philosophical, which looks for the reasons for the complexity of constitutional forms and seeks to grade them on moral criteria.
1289b27 The reason for the plurality of constitutions lies in the plurality of parts in every state. We observe in the first place that all states are composed of households, and then that of this total number of persons some must be wealthy, others poor, others in the middle between them; furthermore the rich and the poor are respectively armed and unarmed. We also observe that the people are divided into three classes, agricultural, commercial, and mechanical workers. There are also differences among the upper classes, according to their wealth and the extent of their possessions. We ask, for example, how many horses a man keeps. (Horse-rearing is always difficult without wealth. Hence in ancient times the states whose power lay in their horses had oligarchies, and they made use of their horses in war against states whose borders were contiguous. We see this in Chalcis and Eretria and, on the Asiatic side, Magnesia on the Maeander, and other areas.) In addition to wealth there are other differentiae, of family, virtue, and any other similar feature we described as ‘part’ of a state, when in our discussion of aristocracy we were analysing the essential parts of any state.1
1290a3 Sometimes all these parts have a share in the constitution, sometimes a large number of them, sometimes fewer. It thus becomes clear that there must be several constitutions differing in kind from each other, since the parts differ in kind among themselves. For a constitution is the arrangement of the offices, which are everywhere distributed either according to the power of the participants, or on an equal basis, that is, equality as between the propertyless, for example, or as between the propertied, or some other equality as between them both. There must therefore be as many constitutions as there are arrangements of the superiorities and differences between the parts.
1290a13 But they are commonly reckoned to be two: in the same way as the winds are sometimes classified into northerly and southerly, the rest being deviations from these, so there are supposed to be two constitutions – democracy and oligarchy. For people treat aristocracy as a type of oligarchy, it being oligarchy in a way, and polity, as we call it, as a type of democracy, as the west wind is taken to be a sort of north wind and the east a sort of south wind. The same kind of duality some people find also in music; they lay down two types of mode, Dorian and Phrygian,2 and give one or other of these names to all the other arrangements of notes. People have therefore formed a firm habit of looking at constitutions in this way. But our own classification is better, as well as more accurate, because the well-formed constitutions are two (or perhaps only one), and all others are deviations, either from the absolutely best or from the harmonious and well-balanced mixture.3 These deviations we label oligarchical, if they are too strict and master-like,4 but democratic if they are loose and relaxed.