I. Plato’s theory of knowledge
A. The nature of the forms
1. They are universal objects
2. They are not in space and time
3. they are objective, unavailable to the sense, universal, unchanging and grounded in a rational understanding
4. Circular objects, for example, have the Universal of Circularity in common
B. They are known through a process of recollection
1. Dialectical reasoning triggers the recollection of the Forms
C. The divided line
D. The form of the good
II. Plato’s metaphysics
A. The reality of the forms
B. The problem of change
1. Platonic dualism: The realm of particulars is subject to change
2. The realm of forms is not
C. Particulars and forms
1. The forms are what is most real
2. Particulars are real insofar as they resemble the forms
3. Therefore some things can be more real than others
D. The Allegory of the Cave
1. People are like the slaves who see only shadows on the cave wall
2. If someone were to somehow be thrust outside the cave s/he might come to see that the people inside the cave are living in illusion; thinking that the particular occurrences of their lives represent ultimate reality, when they do not.
3. If s/he, out of compassion for the people inside the cave, were to go in and try to show them that they were living in an illusion, they might no like it. In fact, they might kill him (like they did Socrates).
III. Plato’s Moral Theory
A. Against moral relativism
1. In ethics we are concerned with the Form of Justice and the Form of the Good. For example, we might want to say that laws of Arizona in 2004 are more just in the area of racial equality than the laws of Alabama in 1954. What does this mean? What is the standard? For Plato, the standard would be the Form of Justice. The laws of Arizona in 2004 more closely resemble the Form of Justice than do the laws of Alabama in 1954, at least insofar as race is concerned.
2. What this means is that the question of justice is not settled because everyone in a culture thinks it’s just, or even if everyone in the world thinks it’s just. Suppose Hitler had won WWII and taken over the world, killing all of the Jews and having an annual holiday, with lots of celebrations, on the day the last Jew died. Everyone would agree that Nazi anti-Semitism and the Holocaust was a good thing, and, for Plato, everyone would be wrong.
B. Why be moral?
1. Would everyone be immoral if it were to their advantage to do so?
2. The ring of Gyges. Plato’s brothers asked whether everyone wouldn’t do wrong if they knew it would be advantageous to them to do so.
C. The three parts of the soul. The answer to this is found in an analysis of human nature. If a person is just the sum total of their appetites, then one should do what will satisfy those appetites. But there are three parts of the soul
1. Reason-the desire for the Form of the Good
2. The Spirited Part, which is the part of you that seeks interpersonal satisfaction.
3. The appetites
Plato argues that a soul is properly ordered just in case reason commands and spirit and appetite obey.
D. The Four Cardinal Virtues are wisdom, courage, temperance, and justice.
1. Wisdom is being controlled and guided by reason.
2. Under the influence of reason, the spirited part generates the virtue of courage.
3. If the appetites are under control, then the person possesses the virtue of temperance or self-control
4. Justice is being a properly ordered person, with reason in command and spirit and appetite in obedience
E. So why be just or moral? Once we understand how the person is put together, the question ends up sounding something like “Why be well as opposed to sick?” The only reason you wouldn’t want to be moral is if you were confused about what your true good is and thought that you could achieve that good by cheating others for the sake of satisfying one’s appetites. Not only does this harm others, but most importantly, it harms yourself.