We've now come to Plato, Socrates’ greatest student. Plato’s most famous work, The Republic, continues to be read today by both philosophers and non-philosophers. Much of the information in the textbook comes from The Republic.

Plato eventually formed his own school called “The Academy.” He was led to do this by several changes in Athenian society brought about by the Peloponnesian Wars between Athens and Sparta. He saw what the mob (in this case, the jury members swayed by sophists) had done to Socrates (sentenced him to death). Plato also disliked the general mentality of greed of the elitists. Torn between the mob and the elitists, after leaving Athens and possibly going to Egypt, Plato eventually started the Academy. The Academy was built in a garden Plato owned. It's not that much of a stretch to say that the Academy was the first Western university, from which we derive the term "academia."

Plato's Dualism

Plato divided reality into two; he proposed dualism as opposed to monism. One part of reality is the sensible world of change: trees, people, skin cells, etc. Plato thought of this world as the way things appear to us. Sophists are only concerned with the realm of appearances, thought Plato, because they only argue back and forth, manipulating the appearance of knowledge but not knowledge itself. This second world—not the one of appearances—is one of truth, and truth cannot change. This second world is eternal and outside of the realm of space and time.

The Forms         

Notice that Plato was asserting the existence of a separate world that transcends our ordinary reality, that transcends the world of appearances. This separate, transcendental world is the home of Plato’s Forms. As Soccio explains, Plato believed that we can only know this eternal world of forms, while we only have opinions of the world of appearances. That is, any knowledge is knowledge of forms. Remember that epistemology is theory of knowledge, so Plato's epistemology is that we can know forms and nothing else.

While it’s true that philosophers are still arguing over what Plato really meant by forms, one way to think about them is through geometry. Can you draw a triangle where all the sides are perfectly equal? Is that possible? You can draw a triangle that looks perfect, but if you were to put your drawn triangle under a microscope there would be subtle imperfections, not every line would be exactly equal. But surely this perfect triangle exists somewhere. But where? The answer for Plato was in the unchanging world of forms. There is not a perfect triangle in the world of appearances, but there is a form of triangle that is perfect in the world of forms. Just as there is a form of square, parallelogram, and cube.

But there are non-geometrical forms as well. There are forms for love and wisdom, for example. There is a form for each color. Consider someone you know whom you also consider to be a wise person. According to Plato, this person is only partaking in the form of wisdom, and he/she is only a shadow of true wisdom. Just as a couple in love is only partaking in the form of love. Plato says that there is an ultimate form--the form of the good. The form of the good is the source of every other form, just as the sun is the source of life.

One other thing to keep in mind is that if forms are eternal, then they exist independently of humans. Think about math. Is it true that 2+2=4 in the absence of human thought? Yes, says Plato. We don't need a human to verify such truths.

The AHA! Moment

Plato wanted to show that true knowledge is possible, that everything is not just a matter of opinion. He thought that when we have true knowledge of something we are catching a glimpse of the form of that thing. By finally seeing that 2+2 is 4, we have caught a glimpse of that form, and we now understand it. But in order really know this, you must see why this is the case; someone cannot simply tell you. You must understand that 2 things added to 2 things will give you 4 things. Have you ever had the AHA! moment? That point when something clicks? Plato might say that this means you have just caught a glimpse of a form.

The Allegory (Myth) of the Cave

In The Republic, Plato gave three illustrations for the theory of forms. I will let you read about the Divided Line and the Simile of the Sun in the textbook. The divided line gives a visual example of Plato’s dualism. But I will say a bit about the allegory of the cave, probably the most famous part of The Republic. Soccio gives a brief passage from the allegory in the book, and the picture to the right is a contemporary illustration of the allegory. Here is a link to an online version: http://webspace.ship.edu/cgboer/platoscave.html

The allegory of the cave has been used as a metaphor for religious truth, scientific truth, the existence of a soul, and more. It is a timeless tale. One of the ideas from the allegory that has appeal is the idea that we are prisoners and we don’t know it. For this is one of the lessons: we humans are like the people in the cave, chained in, looking at shadows on the wall that we think are real. Is everything around you a shadow? Sometimes escaping the cave is equated with the Buddhist idea of “enlightenment,” going through levels of understanding until some final stage is reached. Sometimes it is said that we can’t escape the cave even if we want to. Are we prisoners by nature?

The Philosopher King

It isn't surprising that when Plato talked about the ideal society (as outlined in The Republic), he saw the head of that society as a philosopher. Plato thought that only a person who had escaped the cave and seen the good would be qualified to rule. This ruler, this philosopher king, would not rule because he/she wanted to, but because he/she was best suited to rule.

In Plato's society, everyone would serve a particular role, like a well-functioning machine with many parts. Philosopher kings and other members of society were to be trained from birth to fill their role. Plato thought that some people simply couldn't escape the cave (or were too comfortable in the cave), and that these people were destined to fill "lower" roles in society. The philosopher king would supposedly go through rigorous training in theory and practice, only being allowed to rule once he reached the highest level of understanding. Surprisingly (especially since women were denied citizenship at the time in Athens, despite a democracy) Plato did not exclude women from becoming philosopher kings. A person who had escaped the cave and seen the form of the good was fit to rule, regardless of anything else.

You may already have recognized some problems with Plato's ideas here. For one thing, how do we know that the philosopher king has really escaped the cave? Is it possible to go through all the requisite training and lie effectively about your "enlightenment?" And also, isn't it a little elitist to assume that only certain people are good enough to be philosophers, escape the cave? Plato didn't think so. He thought there were clear differences between people, and that unless certain activities were left to certain people who could perform them well, then there could be no ideal society. Plato even says that democracy is not a staple of the ideal society because a democracy grows out of the love for land and wealth and is swayed by opinion rather than truth or wisdom. Moreover, members of a democracy have too much freedom and individuality, causing them to lose sight of their own responsibilities and connections with society. We live in a democracy. Is Plato correct here?

Virtue for Plato

Plato said that something is virtuous when it functions excellently. The ideal society is virtuous when all its parts are working together in harmony. The same is true for the ideal human being. Whereas Socrates thought that virtue is knowledge (see Socrates lecture), Plato understood that sometimes we want to do the right thing, but our wills are too weak.

There are three parts of the soul for Plato: reason, spirit, and appetite. Plato thought that reason is what should rule the other two, though that's not always the case. The philosopher king will have developed his reason to such a high point that the other two are hardly relevant. This relationship is often represented by a horseman pulling two horses in chariot. One horse is unruly and difficult to control--it represents appetite. The other horse can be controlled with a wisper--it represents spirit. And the horseman himself is reason. The idea is to keep reason in control of the other two horses.