In many respects Aristotle is considered Plato’s opposite, his words, ideas, and theories are informed by Plato’s in that they rebel against them. Aristotle seems to take the position of devil’s advocate on many subjects, Whereas Plato sees democracy as weak and chaotic as well as the killer of his mentor, Socrates. Aristotle feels that democracy, while not being the best of regimes is a reasonably fair a just structure for government.
Aristotle most likely takes this view because of his more rounded experience with government. Plato considered society as the “individual writ large”, and thusly drew his ideal structure for the polis from his ideal structure for the soul. Aristotle on the other hand saw that to understand how a regime work one must look at a regime and break it down scientifically; empirically; as a surgeon might perform an autopsy. This is why Aristotle is usually considered the first Political Scientist while Plato was the first Political Philosopher.
In a similar fashion Aristotle is often seen a pragmatist in comparison to Plato, who was concerned solely with the ideal forms and harmonies of the universe, Aristotle saw philosophy with in the physical world. Plato considered all physical things to be illusory as in his parable of the cave; to see the real world one must look beyond the physical and into “the great light” of truth. Plato also saw the world in a constant state of decay; Aristotle on the other hand saw everything as growing, with possibilities for improvement. This is how he approached all of his studies, including his studies of world regimes.
Aristotle first cataloged and classified all the regimes he could, over one hundred in all. Then he decided which were strongest and how they functioned and which serve their people best. Eventually he arrived at the conclusion that a middle constitution was for the greatest good. This polity, as he called it, balance aspects of a Democracy and an Oligarchy, as well as aspects from an Aristocracy, with a strong Middle class to mediate the Upper and lower classes, for the most stable and just society that he thought could be found.
A Democracy being a government run be the people and serving the people, An Aristocracy being a government run by the elite to serve the elite, and a Oligarchy being a government that is run by the elite but in the best interest of the people. Essentially he thought that it was important that a governing body be concerned with the peoples best interest but that since most people are ill equipped to pursue their own best interest, that it should be up to those that have the intelligence and power to ensure the peoples wellbeing.
Despite these strongly opposing views between Plato and Aristotle, I do think that their two styles of philosophy are not in complete opposition. Aristotle, for instance said that he thought that the best and most ideal regime would be a Kingship or an Aristocracy, but he considered the former near impossible and the latter very rare.
Also Aristotle’s obsession, it could be called, with the “Golden Mean” is a concept that I think Plato could relate to, at least in a broad sense, since Plato himself was always looking for a balance and a harmony. Aristotle eventually judged that the best of all possible regimes would be a middle regime, a balance of all the regimes, for greatest stability.
So even someone so practical as Aristotle saw the value of the ideal, though he also seemed to see the wisdom of living in the real world, as Aristotle saw it, not as Plato would describe it. To say that Plato’s Republic was an impracticality is an obvious critique. Does this view of his Ideal City mean that we are not to seek a better and more perfect regime? I think not, Aristotle saw that this was a necessity; to improve upon the current world and all of its regimes.
In the end both Aristotle and Plato believed in trying to better the world around them, if they are opposed in any sense it is in their approach. Plato prefer to start with logic and the idealized forms of the universe, and work backwards trying to bring the work close to that ideal. Where Aristotle started with the reality of the world and sought solutions that would make the world a better place to living, and therefore a more ideal place. In both cases their ends were the same, seeking to better the world through reason and logic.
And that’s my take on Aristotle vs Plato.