Lecture 07 Notes

Plato's Theory of Knowledge

Plan of the Lecture

I.    Knowledge in Citizens
II.   The Simile of the Divided Line
III. The Simile of the Cave
IV.   Brief Summary

I. Knowledge in Citizens

**This discussion picks up at the very end of the previous lecture**

Consider, for a moment, the classes in a good society and the occupations associated with each.

A. The Commercial Class

The commercial class includes carpenters, merchants, sea captains, and so on. Notice the following contrasts:

Knowing how to build vs. principles of carpentry
Knowing how to sell vs. principles of finance
Knowing how to sail vs. prniciples of navigation

Questions: (i) What do carpenters, merchants sailors need to know? (ii) What do those who teach them need to know?

B. Military Class

The military class (the auxiliaries) include the soldiers. Notice the following contrasts:

Knowing how to fight vs. principles of strategy
Knowing what to fear vs. principles of psychology

Questions: (i) What do soldiers need to know? (ii) What do those who teach soldiers need to know?

C. Governing Class

The governing class includes the rulers (the guardians).
Question: What do they need to know?
Answer: The most abstract principles and objects.

II. The Simile of the Divided Line

A. Imagine a spectrum of objects from less abstract to more abstract:

Less	_______________	\|_______________	\|__________________	More
		\|	\|

	Actual Shelf	Ideal Shelf	Mathematical Plane
	Actual Sales	Ideal Market	Calculus
	"3 Hour Tour"	Ideal Voyage	Trigonometry

Now consider a corresponding spectrum:

Changeable	___A___	\|___B___	\|\|___C___	\|___D___	Unchanging
Corruptible		\|	\|\|	\|	Eternal
[Less Actual]					[More Actual]

B. These Spectra Correspond to Plato's Divided Line:

Segment A represents pictures, shadows, reflections in the water, mirror.
Segment B represents all material objects of which we’re aware by sensation.
Segment C represents all ideals of which material objects are likenesses
Segment D represents mathematical objects which describe ideal structures
Segments A+B represent the visible realm, accessible to the faculty of sense, of which we have opinion.
Segments C+D represent the intelligible realm, accessible to the faculty of reason, of which we have knowledge.
Plato thinks that those who teach must know objects in segments C and D.

C. Areas C and D Represent the Realm of the Forms, or Ideas.

Plato therefore ascribes to these ideas a number of properties.
They are eternal, unchangeable, independently existing, objects of knowledge (rather than opinion), and resembled by particular objects.

III. The Simile of the Cave

Recall: Plato thinks those who teach must know the Forms

Question: How do they come to know them? What sort of education do they get?

A. Progress of Education is:

...from what is most familiar and vivid, e.g., footballs
...to what is less vivid and more abstract: the Forms
When learn to think abstractly, we think about the Forms. This will sound foolish and confused to everyone else, just as a football commentator who talked about math will sound foolish and confused.

B. Those Who Teach Must Know the Forms

Given (A), we can see why the Cave is an apt simile for this education.

IV. Brief Summary

A. Those in the ruling class are society’s teachers

They frame laws which teach rabble self-discipline.
They frame laws which teach soldiers courage.
In order to teach, they must think abstractly about the skills and virtues they impart.
They must know objects at right end of the Divided Line.
They must therefore know the Forms.

B. Their education is allegorized by Simile of the Cave.

C. The rationale for teaching as they do is partially communicable.

Citation: Weithman, P. (2006, September 19). Lecture 07 Notes. Retrieved February 12, 2012, from Notre Dame OpenCourseWare Web site: http://ocw.nd.edu/philosophy/introduction-to-philosophy/lectures/lecture-07-notes.