IV. Plato: The first comprehensive philosophical system
A. Theory of Knowledge
1. Against relativism
a. Relativism is self-refuting
b. Everyone recognizes the difference between belief and knowledge. Ex. If hurt our foot, does anyone think their own opinion is as good as that a trained physician in determining whether or not the foot is sprained or broken
2. Against empiricism (the claim that all knowledge comes from experience
a. The world of experience is in flux
b. Objects in experience are relative to the observers
c. What is real knowledge must be something universal that we can capture in a universal definition. Consider the concept of justice.
1. Either justice is something real and objective, or it is a mere word.
2. If the second alternative is true, then our moral judgments have no value. There is no real difference between Hitler and a saint except certain sounds we conventionally apply to them.
3. But this is absurd. There is a difference between Hitler and a saint.
4. So justice is something real and objective.
5. That which is real must by physical or nonphysical.
6. Clearly, justice cannot be physical.
7. Therefore justice must be something real, objective, and nonphysical.
3. Knowledge is more than just true belief.—must be justified.
4. Universal forms are the basis of knowledge. Forms are
b. Unavailable to the senses
e. Grounded in a rational understanding
5. Knowledge comes through recollection
a. Before we were born we had access to the forms
b. When we became encased in fleshly bodies we lost that knowledge
c. Knowledge of the forms can be recovered through a process of recollection.
d. Slave boy argument-Socrates by questioning a slave boy leads him to prove a mathematical theorem. Since Socrates didn’t pump anything into his head, he had to have had the knowledge inside all along, waiting to come out.
6. The divided line
a. Imagination or conjecture-knows shadows, images and reflections
b. Belief-knows things and objects
c. Thinking-knows lower forms
d. Rational intuition or pure knowledge, knows the higher forms.