The fifth book fulfils one of the promises made in IV ii – to discuss both the preservation and the dissolution of constitutions, and the respective causes. Minor changes not amounting to dissolution are mentioned briefly; but Aristotle is thinking chiefly of revolutions, carried through by violence or trickery (see V iv ad fin.), and resulting in a new constitution. This was the type of change most familiar and most feared; hence Aristotle shows some anxiety to avoid all change and to cultivate stability. Discontent is a constant threat to stability; and inequality, being a kind of injustice, is a potent cause of discontent; and as there is more equality in democracy than in oligarchy, the former is generally the more stable. The Greek word stasis, which bulks large in this book, is not exactly ‘revolution’, but the state of affairs that leads to it, when tension has become so great that an outbreak of violence occurs between the opposing sides. My usual translation of stasis is ‘faction’.
It is worth noting here a crucial point about stasis and constitutional change in ancient Greece. The aim of those who wished for change was usually not simply to replace one policy by another within the same constitutional arrangements; it was to replace one complete constitution by another – to recast the whole set of rules by which political decisions were made.
The first four chapters of the book discuss constitutional changes and their causes in fairly general terms, and the opening chapter is a fine example of Aristotle’s shrewd analysis. He is here concerned not merely to list what circumstances lead to what changes, but to penetrate to the psychological or intellectual or ‘ideological’ sources of social conflict. These sources he locates in differing notions of distributive justice, which in turn depend on different criteria for measuring the equality and inequality of men. True to his intention to give practical advice, he counsels (as did Plato in the Laws 756e) the use of a judicious combination of ‘arithmetical’ equality and equality by ratio (logos), i.e. according to axia, value (i.e. merit or desert). For a discussion of these ideas in Greek thought, see F. D. Harvey, ‘Two concepts of equality’, Classica et Mediaevalia, 26 (1965), pp. 101–46, and 27 (1966), 99–100.
1301a19 We have now dealt with nearly all the matters that we promised, but we have still to discuss (a) what the sources are of change in constitutions, and the nature and number of these sources; (b) what the destructive agencies are that affect each constitution, and (c) from what kinds into what kinds they generally change. We must likewise consider (d) what factors make for the preservation of constitutions, both in general and of each kind separately, and also (e) by what means each of the constitutions could best be preserved.
1301a25 We should begin by assuming the fundamental starting point. Many constitutions have come about because although everyone agrees on justice, i.e. proportionate equality, they go wrong in achieving it, as mentioned before.1 Democracy arose from the idea that those who are equal in any respect are equal absolutely. All are alike free, therefore they claim that they are all equal absolutely. Oligarchy arose from the assumption that those who are unequal2 in some one respect are completely unequal: being unequal in wealth they assume themselves to be unequal2 absolutely. The next step is when the democrats, on the ground that they are equal, claim equal participation in everything; while the oligarchs, on the ground that they are unequal, seek to get a larger share, because ‘larger’ is unequal. Now all these constitutions have a sort of justice in them, but from an absolute stand-point they have gone wrong. And this is why, whenever either side does not share in the constitution according to their fundamental assumption in each case, they form factions. Those who are of outstanding virtue would have by far the greatest justification for forming factions (they are the only people to whom the term ‘absolutely unequal’ can be properly applied), but they least often do so. Then there are those who being superior in birth claim that they are too good for mere equality, just because of this inequality of birth; for those who have inherited virtue and wealth from their forbears are commonly reckoned nobly-born. These are, generally speaking, the origins of factions, the founts from which they spring.
1301b6 Hence the changes which take place may be of two kinds, according to whether they involve a complete abandonment of an existing constitution for another, or not. Examples of the former are from democracy to oligarchy, from oligarchy to democracy, from these to polity and aristocracy, or the reverse. In the other case they prefer the established arrangement (oligarchy or monarchy, for instance), but want to run it themselves. Or again it may be a matter of degree: they may wish an existing oligarchy to become more broadly or less broadly based, an existing democracy to become more democratic or less, and similarly with the other constitutions, either a relaxation or a tightening up. There are also attempts to change only a part of the constitution – the establishment or abolition of a particular office, for example the alleged attempt by Lysander to abolish the monarchy,3 or of King Pausanias to abolish the Ephorate. In Epidamnus too there was a partial change in the constitution: they instituted a council in place of the tribe leaders, and it is still the rule that whenever any officer is appointed by vote, the existing officers, out of all the members of the citizen-body, must be present at the public gathering. The sole archon too was an oligarchical feature of this constitution.
1301b26 Inequality is everywhere at the bottom of faction, for in general faction arises from men’s striving for what is equal. I am speaking of states where there is no proportion in the unequals’ inequality (a perpetual monarchy ruling over equals, for instance, is unequal). Now there are two kinds of equality, the one being numerical, the other of value. I use ‘numerically equal’ to cover that which is equal and the same in respect of either size or quantity, and ‘equal in value’ for that which is equal by ratio. Thus numerically the difference between three and two is the same as the difference between two and one, so that the amounts of difference are numerically equal. But the relationship of four to two is, by ratio, equal to the relationship of two to one: two is exactly the same fraction of four as one is of two, namely a half. But while men agree that absolute justice is justice based on value, they differ, as has been said before, in that one group believes that if they are equal in any respect, they are equal all round; while the others claim that if they are not equal in any respect, they ought to have unequal treatment in all matters. It is for this reason that there are, broadly speaking, two kinds of constitution, democracy and oligarchy. The number of people in whom noble birth and virtue are found is very small, but those other features are present in a larger number, so that while you could not find anywhere a hundred good men of noble birth, you could in many places find many rich and poor.4
1302a2 To lay it down that the equality shall be exclusively of one kind or the other is a bad thing, as is shown by what happens in practice: no constitution that is constructed on such a basis lasts long. The reason for this is that to start from an initial and fundamental error makes it impossible not to run into disaster at the end. Therefore we must make use both of numerical equality and of equality of value. Nevertheless democracy is safer and less liable to faction than oligarchy. In oligarchies, two factions arise, one between the oligarchs and the people, and one of the oligarchs among themselves. In democracies, on the other hand, the only faction that arises is against oligarchy;5 internal faction within a democracy virtually never occurs. Also, a constitution of the middle people is nearer to democracy than is a constitution of the few, and is of all such constitutions the safest.