This somewhat obscurely articulated chapter is a good example of the informal and semi-systematic way in which Aristotle’s thought is apt to move. I interpret as follows. Chapter xi (of Book IV) had concluded that in certain circumstances the best or preferable constitution, the ‘mixed’ one based on the ‘middle people’, may be abandoned in favour of one more ‘advantageous’. Aristotle now naturally, and in apparent abandonment of the subject of the ‘middle’ people, is prompted to ask the question: what constitution is ‘advantageous’ to what sort of person? Obviously democracy to the many poor, oligarchy to the wealthy few; but there will be no stability in such constitutions unless the element that wishes it to continue is ‘stronger’ than that which does not. Aristotle suggests, if I understand him aright, that the numbers of the poor may be ‘stronger’ than the ‘quality’ of the rich (their wealth, education, etc.); or this ‘quality’ may be ‘stronger’ (meaning ‘more influential’, presumably) than the numbers of the poor; in the former case, a democracy is natural, in the latter an oligarchy. There is some point, presumably varying from case to case, at which the ratio between number and quality shifts decisively one way or the other; and the greater the imbalance, the more extreme will be the democracy or oligarchy that results.
Now comes, at the beginning of the third paragraph, the crucial junction of thought: both democracy and oligarchy should always (sc. in spite of being, as surh, ‘advantageous’ to their respective adherents) somehow accommodate the ‘middle people’ – because thus the ‘stronger’ element will be even stronger, and the constitution will be more stable; and of course without stability the constitution will not be as advantageous to the ‘stronger’ element as it might be. Stability is therefore in a sense the key to the chapter, which turns out to have been concerned all along, like its predecessor, with the constitutional merits of an influential ‘middle people’. In effect it argues that even partisans of ‘extreme’ constitutions have or should have, on their own showing, an interest in cultivating the middle ground.
In the final paragraph, Aristotle notes that makers of aristocratic constitutions commit the mistake of trying to ensure stability not by ‘mixing’ their constitutions but by tricking the people. In the next chapter he proceeds to list some of the subterfuges employed.
1296b13 It is proper to follow what has been said by a discussion of the question of what constitution is advantageous for what persons, and what kind of constitution for what kind of men. First, we must grasp a principle which is universally applicable to them all: it is essential that that part of the state which desires the permanence of the constitution should be stronger than that which does not.
1296b17 Now every state can be measured either qualitatively – I mean by such qualities as freedom, wealth, education, and good birth – or quantitatively, that is by numerical superiority. Look at the parts which make up a state: it is possible that quality may be present in one, quantity in another (e.g. the non-noble may be numerically greater than the noble, the poor than the rich), but without quantitative superiority being enough to compensate for the qualitative inferiority. These must therefore be weighed one against the other. Where the number of the poor is sufficiently large to exceed the given ratio, there democracy naturally arises; and the type of democracy will depend on the type of people which has the numerical superiority in each case. Thus, if those who cultivate the soil make up the superior numbers, the democracy will come first1 on the scale; if those engaged in mechanical work and receiving pay for it predominate, then it will come last,1 and similarly with the rest in between. Where, on the other hand, the rich and notable people have a greater qualitative superiority than quantitative inferiority, there an oligarchy naturally arises, and once again its type will depend on the degree of superiority in those who form the oligarchical body.
1296b34 But at all times a legislator ought to endeavour to include the middle people in the constitution. If he is framing laws that are oligarchical in character, he should have the middle people always in view; if democratic, he should again make them attractive to those in the middle. Wherever the middle people outweigh a combination of the two extremes, or even one only, then there is a good chance of permanence for the constitution. There is no danger of rich and poor making common cause against them; for neither will want to be slaves to the other, and if they are looking for a constitution more acceptable2 to both, they will not find any better than this. Their mistrust of each other would make it impossible for them to accept alternation in office. But in all places the mediator is best trusted by the parties, and the one in the middle is a mediator.
1297a6 The better mixed a constitution is, the longer it will last. It is a mistake made by many, even by those seeking to make an aristocratic constitution, not only to give too great a preponderance to the rich, but to cheat the people. In the long run mistaken good inevitably gives rise to unmistakable evil; for the greedy grabbing of the rich does more harm to the constitution than that of the people.