Plato’s Philosophy

Detail of The School of Athens painting by Raphael with Plato (left) & Aristotle (right)

The ancient Greek philosopher Plato asked the most important questions of his time, and from these questions, he developed his philosophy that influenced the modern western world. He asked about what beauty is, what justice is, and what love is. Philosophers after him tried to answer all these simple yet difficult ideas, but Plato was the first to attempt to clarify these ideas in his various works.


Ethics is the study of what is right and wrong within society’s context. In Plato’s Republic, he discussed several ideas, including aesthetics, metaphysics, and epistemology, but largely focused on ethics and his political theories. At the beginning of this work, he had the character of Socrates ask what justice is. This work also features the character of Thrasymachus, who believes that justice is the business of the strong. Thrasymachus claimed that it is natural for a strong person to cheat others and steal from them as long as they can avoid punishment. In ancient Greece, this was not a shocking opinion. Ancient Greeks were used to treating strength as the highest value. Thrasymachus’ sentiments eventually bring up the question of why a person should choose to be just. If a person’s good choices enable him to live a good life, then there should be no problem with choosing courses of action. Later in the book, it is argued that people are only just because they can be caught, and they are unjust if they could get away with an unjust deed. Therefore, it is unjust for a man to do wrong to his fellow man without punishment.

Plato’s ethics is founded on virtue. The ethics of virtue is based on the belief that a person who knows what is good will do good and that a person does not simply do good because he avoids punishment. Plato asserts that the human soul comprises three parts: reason, spirit, and appetite. The reason is the human ability to think. Spirit is the ability to feel, while appetite represents worldly desires. Plato claims that these three parts of the soul should be balanced for a person to make good choices and lead a good life. He believes morality is the constant balance of these three soul components. If one of these becomes dominant, then it leads the person to make bad decisions and, consequently, may lead to a bad life.

Political Philosophy

Athenian democracy was responsible for the death of Plato’s most admired person, Socrates. Therefore, Plato hated democracy and viewed people as incompetent to choose the right leaders. Plato also did not like the Athenian state because it did not allow women to vote. In Plato’s ideal society, everyone was assigned to work in his proper sphere. Those who had an aptitude for the military were assigned to be soldiers. Those who were good at any trade were assigned to be workers. Finally, those who are the most intelligent and are educated by the state and therefore most qualified to rule are the philosopher-kings. Plato assigns power to his philosopher-kings to censor artists because Plato believes that any artist can distort reality and present it to the public. This distortion of reality is dangerous, according to Plato, because it can mislead many citizens.

Metaphysics and Epistemology

Epistemology is the study of the sources and nature of knowledge, while metaphysics deals with the ultimate causes of things. Plato expressed his ideas on these matters using the Allegory of the Cave. In the story, Plato makes the reader imagine a group of people inside a cave. These people’s legs and arms, and necks are chained to the wall, and they cannot look behind them. They can only see the wall in front of them on which shadows are constantly being projected. These shadows are cast by objects that are held in front of a fire behind them. The chained people cannot see the people holding the objects behind them but can hear them and mistakenly believe that the conversations are coming from the objects themselves. 

Consequently, these people believe that the shadows are reality itself and that the light behind them is the only light in the world. Then, Plato makes us imagine that one prisoner manages to free himself from the chains and is able to look at the fire behind him. At that moment, the brightness of the fire hurt his eyes, and he could barely see the objects that cast the shadows on the wall. If he were told that the shadows are not real and that the objects are real, he would be shocked and would not believe what he was told. Eventually, the pain in his eyes caused by the brightness of the fire would make him return to his place facing the wall and the shadows. There, he would convince himself that the shadows are indeed reality. 

At this point, Plato presents us with a turning point in the story. He makes us suppose that a person forcefully takes this prisoner and drags him out into the entrance of the cave, and then exposes him to the real world under the sun. The freed prisoner would then be shocked and in pain, because the brightness of the sun was hurting his eyes more than the fire inside the cave did. However, his eyes would eventually adjust to the brightness of the real world, and he would be able to see people, the stars, and the moon. Finally, he would be able to look straight at the sun. Plato asserts that when the freed prisoner is able to look at the sun, he will be able to think about truth. He would feel pity for the other prisoners in the cave and how they mistakenly think that shadows are real objects. This allegory presents Plato’s belief that the shadows inside the cave are the interpretations of artists who hold the object in front of the fire and that these shadows are not reality itself.

Plato claimed that there is a realm where perfect copies of objects exist and that this realm is the realm of ideas. The physical world contains objects that are poor copies of the perfect sources in the realm of ideas, and he called the perfect copies the forms. Plato’s Theory of Forms claims that the physical world is always changing and cannot be real, whereas the world of forms is where the truth lies and can only be accessed by pure reason.