Taken from Quora from a post by Spencer McDaniel in answer to this question: Why were most Greek philosophers against democracy?

First of all, it is a grave mistake to say that “most” Greek philosophers were opposed to democracy, because that is not actually true. Most Greek philosophers were either in favor of democracy or had no opinion on it. The philosophers that most people see as having been opposed to democracy are Socrates, Plato, and Aristotle, but, as we shall see in a moment, this common perception is actually rather inaccurate.

For one thing, we actually know very little about what the historical Socrates (lived c. 470–399 BC) thought of democracy because everything we know about Socrates’s opinions comes from the writings of his two students Plato and Xenophon. Plato in particular seems to have used the character of Socrates in his dialogues as a sort of “sounding board” for various ideas and opinions, so, in most cases, when Plato attributes an idea to Socrates, it is very difficult to tell if it is really one of Socrates’s ideas, one of Plato’s own, some combination thereof, or just an idea Plato was experimenting with.

Plato (lived c. 423–c. 347 BC) makes it very clear in his Republic that he does not have much liking for the particular form of democracy that was instituted in his native city-state of Athens. Instead, in this dialogue, Plato argues that the ideal, perfect government should be ruled by a “philosopher-king,” a man who is supremely wise, intelligent, and rational and who makes all decisions for the benefit of everyone. This, however, is an idealistic vision and it is unlikely that Plato ever expected anything resembling his ideal republic to actually be implemented.

Plato would probably have much admiration for the government of most modern democratic countries, which operate on a very different form of democracy than the one that existed in Athens during Plato’s time. Athens in the fourth century BC was a direct democracy, meaning citizens voted directly on all the issues. This was a problem because most people did not understand the issues and were unable to make informed decisions on them. Modern representative democracies would probably be more palatable to Plato’s sensibilities.

Aristotle (lived c. 384–322 BC) has sometimes been portrayed as hostile to democracy, but, in fact, this is an egregious misunderstanding of Aristotle’s complex and erudite political theory. In his Politics, Aristotle explains that there are three major forms of ideal government: a monarchy (which he defined as a government ruled by a man very much along the lines of Plato’s “philosopher-king”: one who is supremely qualified and rules for the betterment of everyone), an aristocracy (which he defined as a small group of the best and most qualified people ruling for the betterment of everyone), and a constitutional government (which he defined as a government ruled by all the free citizens on behalf of and for the betterment of everyone).

Aristotle held that, of the three ideal forms, a monarchy is the best because it is the most efficient, but he contended that all three ideal forms of government will inevitably become perverted and corrupted over time. He explains that a monarchy becomes perverted into a tyranny, a government ruled by one man for solely his own benefit. An aristocracy becomes perverted into an oligarchy, a government ruled by a few people for solely their own benefit. Finally, a constitutional government becomes perverted into a democracy, a government ruled by the majority of the population for solely their own benefit.

Aristotle reasoned that a democracy is the least terrible of these three forms of government because it results in the most number of people being happy; whereas a tyranny is the worst form of government because it results in only one man (the tyrant) being happy. Aristotle was therefore in favor of democracy, not because he necessarily liked it in and of itself, but rather because it was the least awful form of government that he could think of.