Aristotle: Politics, Book IV & V (Varieties, Stability, and Change)

Books IV and V analyze the variations of democracy and oligarchy, proposing the "middle constitution" as the most stable and examining the causes and means of constitutional preservation.

Grading of pervasions

Tyranny is the worst perversion; Oligarchy is the next worst; and Democracy is the least bad/most moderate.

Polity (Constitutional Government)

A mixture of oligarchy and democracy. A sign of a good mixture is that the constitution can be described indifferently as either.

The Best Practicable Constitution (The Mean)

Since goodness consists in a mean, the best way of life and the best constitution for the majority are based on the middle condition.

    ◦ The city is composed of three parts: the very rich, the very poor, and the middle class.

The Middle Class is Best

They are the most ready to listen to reason, least prone to arrogant or petty offenses, and are the most secure.

Stability

A political association where power is vested in a large middle class (stronger than either the rich or the poor singly) is the best and most free from faction.

General cause of faction

Political conflict is always the result of inequality. This arises from the conflict between those seeking numerical equality (Democrats) and those seeking proportionate equality (Oligarchs).

Causes of change

Revolutions are caused by psychological motives (passion for equality/superiority), objects at stake (profit and honor), and specific origins (arrogance, fear, contempt, disproportionate increase). 

Change of democracies

Chiefly due to the wanton license of demagogues who attack the rich individually or collectively, forcing the notables to combine.

Change in oligarchies

Due to the unjust treatment of the masses or internal faction among the rulers (e.g., when members waste their possessions or create an exclusive inner ring).

Methods of Preservation (Stability):

1. Guard against all forms of petty lawlessness, as it creeps in unperceived and ruins the whole.

2. Do not use deceptive devices to hoodwink the masses.

3. Prevent officials from using their office for private gain. This is the only possible way to combine democracy with aristocracy, as the poor will not desire office if it offers no profit, and the rich can afford to take office.

4. In democracies, spare the rich (secure their estates and property); in oligarchies, pay attention to the poor (assign them profitable offices, punish violence against them heavily).

The Greatest Means of Stability

The most important rule for stability is the education of citizens in the spirit of their constitution. Extreme democracies neglect this, promoting a false conception of liberty as "doing what one likes," which should instead be viewed as salvation.