2008-2-PHI130.Week03

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PHI130 Week 3: Plato's Doctrine of Forms

Lecture 5: Plato 1 - Doctrine of Forms

Book X: The three beds

While Socrates put philosophy on its way, Plato is the first real philosopher in the sense that he endeavours a systematic coverage of all aspects of reality. He offers an explanation for all the different spheres of reality with political, moral, scientific, and aesthetic implications.

We will look at two of the most famous aspects of his thinking:

  • His theory of ideas
  • His theory of love

Plato's doctrine of forms, or doctrine of ideas, asks a metaphysical question about what is real and how we can know it. He endeavours to answer this by trying to look beyond what is available to the senses to find the ultimate level of reality. Once defined he then seeks to determine how we can know about this ultimate level of reality.

Book X (Ten) of Plato's famous book The Republic is where we learn of his theory of forms. The Republic is his longest book, and it's a book of political philosophy that deals with what is a just city. In order to know what a good city is we need to know what reality is and how we can know about it. That is, we must answer the fundamental questions in order to know what a just city is.

In The Republic Plato speaks through Socrates, but we understand that these are likely Plato's ideas and not those of Socrates.

Two equivalent Greek words: eidos or idea = Form or Idea.

The thought is that we use the same name for different things. E.g. "chairs", even though they are all different in some respect.

What is beauty? Things, persons, emotions. We use it with the same meaning in all these contexts. How do we know the meaning of the adjective remains the same?

The concept that Plato draws out is that there are two levels of reality at the very least. There's the physical level in the material world, and above that the notions or concepts of these things.

Aristotle criticised Plato for his ideas (we get to that later).

Plato held the ideal world out as being more 'perfect' than the physical world. This is very similar to Pythagoras' idea that the material world is a world of corruption where the world of ideas is a world of perfection.

This is one of the most famous texts of Western philosophy, the simile of the three beds, drawing out the three levels of reality:

  • The ideal
  • The realisations of the ideal
  • The appearances of the realisations

These are held to have three corresponding levels of truth:

  • Truth in the realm of forms. Artisans aspire to move physical reality toward the forms.
  • Truth in the realm of physicality. This level of worldly reality is held to be less true, less real, than the intellectual realm.
  • Truth in the realm of appearances. This is the level of illusion and deception.

This all gives rise to three levels of quantity:

  • In the ideal there is one form.
  • In the physical there are many instances of a form.
  • In the apparent there are a multitude of aspects on a physical object.

See Plato's Republic, p.361, for an argument in favour of the Forms.

In a just city Plato would expel the poets, because they lie in representing things that they don't know about.

Book VII: the allegory of the Cave

Plato's Republic, pp.256-264.

With the allegory of the cave Plato introduces a fourth level of reality, higher than the Forms.

The allegory of the cave is Plato's way of explaining that appearances are only shadows of real things. The voices of images perceived by the prisoners in the cave are contingent properties. Appearances are an unstable reality which depend on the sensor. Plato's implications concerning reality and knowledge:

  • We can not trust sensory perception to gain knowledge.
  • Objects of perception and their properties are themselves only contingent, not "real".

Plato suggests to "move one's head" from experiential knowledge of physical reality toward actual causes. This is the migration to the "upper world" of the ideal, the intellectual world of pure form.

Plato's levels of reality in the cave:

  • The world of shadows and echo.
  • The world of physical objects giving rise to shadows.
  • The ideal objects giving rise to the physical.
  • The pure principles of knowledge -- the moon, the stars, the sun -- being reality.

The Sun is the one supreme idea, the Idea of the Good. Pure ideas are one in themselves, but there are many of them. The supreme idea is one in itself and single of its kind.

It's funny, but there is no mention of what he was smoking.

The Good as principle of order in the world and in knowledge.

The normative principle behind knowledge and reality: that order and beauty bring harmony amongst all other pure ideas. The Idea of the Good is principle order, functioning as the cosmos, and thus the ultimate principle of knowledge. To know truly is to understand how all principles and truths fit together.

Summary

The Divided Line.

DOXA (opinion) EPISTEME (science)
Knowledge Eikasia Pistis Dianoia Noesis
Objects Appearances Visible things Mathematical terms
First principles Ideas of things The Good
VISIBLE THINGS INTELLIGIBLE THINGS
Eikasia
illusion, conjecture about appearance of visible things.
Pistis
perceptual belief about visible things.
Dianoia
Knowledge that starts from a hypothesis and moves from it through analysis (i.e. without recourse to visible things, without empirical considerations), to conclusions. Model is mathematics, geometry, astronomy. This type of knowledge is unable to justify its own hypotheses.
Noesis
First it is a type of reasoning. Dianoia starts from hypotheses that are the Forms of physical things. In this sense, Dianoia still relies on the physical world. For example, the mathematician uses a triangle drawn in the sand.
By contrast, Noesis is pure thought which no longer uses images of the visible world. Hypotheses now are pure ideas. The mind ascends gradually to the first principle, the Idea of the Good, the normative principle of knowledge and reality. Once the first principle has been seen, after this ascending movement, reasoning can redescend and redefine the Ideas that were used as hypotheses, this time giving them absolute certainty. This "movement" is dialectic, which Plato learnt from Socrates.
Second, Noesis is also the intellectual intuition, the state of knowledge in which we see the Good, all the other pure Ideas, and their systematic interconnections made possible by our vision of the Good.

Psychological, social, political and pedagogical implications

If the ultimate principle is the principle of order and beauty, then every aspect of reality must be governed by the same rule:

3 parts + 1 principle beyond the parts, bringing them into harmony.

The three parts are characterised as follows, from the highest to the lowest:

  • Part 1: unity, singularity, ideality
  • Part 2: reality, diversity, regularity
  • Part 3: multitude, chaos, contradiction, change
  • Principle: harmony, beauty, order, justice

Apply this to (from the noblest to the basest part + principle):

  • SOUL: three parts of the soul: intelligence / courage / desires + well-ordered soul where intelligence governs courage which tames desires
  • TYPES OF PLEASURES: knowledge / honour / fulfillment of desires
  • VIRTUES: prudence / courage / temperance + just individual
  • LIFE: of meditation / of inner struggle / of pleasure
  • TYPES OF MEN: philosophers / ambitious / interested
  • IDEAL SOCIETY: three classes: leaders / warriors / workers + justice
  • PAEDAGOGY: love of knowledge / develop courage and ambition / rule over sensuous desires

Lecture 6: Platonic strands in modern science and art

Plato's mathematical view of the universe and modern science

Important features of Plato's thinking found in modern science:

  • Distrust of sense and opinion (doxa).
  • Anti-empiricism: to learn from pure reason, not experience.
  • Science does not originate in techniques.
  • Mathematics as fundamental to understanding nature.

Three types of mathematics in Plato:

  • Applied mathematics. Measuring, counting.
  • Mathematicians' mathematics. Dealing with inferior Ideas, a preparation for true knowledge.
  • Higher mathematics. Pythagorean harmony and music, reduced to their essence as a series of ratios. The Idea of the Good leads to beautiful mathematical order of the universe. The descending dialectic is the application of the simple principle of ordered beauty in a series of numbers and ratios.

"We must assume as a principle in all we say that god brought the elements to a state of the greatest possible perfection, in which they were not before." -- Plato, Timaeus


Platonic strands in history of Western art

Myth of the Golden Section, propagated by Rumanian art historian Matila Ghyka

Readings

Plato, Republic

Plato, Republic, Section VII, 514-521, p.376-383; Section X, 596-598, p.468-471. In The dialogues of Plato, vol.II, trans. by B. Jowett (Oxford: Clarendon Press, 1964).

Plato, Timaeus

Plato, Timaeus, trans. D. Lee (Harmondsworth: Penguin Books, 1977), p.72-79

L. Stevenson and H. Byerly, The many faces of science

L. Stevenson and H. Byerly, The many faces of science (Westview Press, 1995), p.52-63.

R. Eaton, Ideal cities

R. Eaton, Ideal cities (London: Thames and Hudson, 2001), p.196-204.

Reading Questions

  • Plato, The Republic, Extract 1, from Book 7 (The allegory of the cave)
    • What do the prisoners in the cave represent in the cave allegory? What does the ascent from imprisonment in the cave to liberation represent?
    • What is the significance of the fact that the prisoner mistakes the source of the voices he hears? What relationship, according to Plato, do things have with their sensuous properties?
    • Being 'cured' of his delusions is painful and dazzling for the prisoner in the story. Why would the ascent to the upper, intellectual world, to which the prisoner's ascent is analogous, be painful?
    • Eventually, the prisoner is able to look directly at the sun itself. To what is this state analogous?
    • In what way does the prisoner change, having been out of the cave? Why does he no longer desire the honour and glory he desired while imprisoned?
    • How is he received on his return to the cave? Why? Why should he, nevertheless, return? Why should those who have reached it not be allowed to remain in the upper world?
    • What does it mean to say that it is possible to be blinded in two ways, and what implications does this have for the study of the good?
    • Socrates claims that the capacity for knowledge is not learned, but innate. Why?
  • Plato, The Republic Extract 2, from Book 10 (The three beds)
    • In what sense is a carpenter's creation of a bed similar to a painter's representation of it? What is a bed really?
    • What is the relationship between the beds produced by god, the carpenter and the painter?
    • Why could there only be one Form of a bed, or bed-in-itself?
    • What are the levels of reality to which the three beds correspond?
  • Plato, extracts from Timaeus
    • On what basis are the four regular solids assigned to the four elements?
    • What distinguishes the dodecahedron from the other solids? What consequence does this have for its place in Plato's view of nature.
  • L. Stevenson, H. Byerly, extract from The Many Faces of Western Science
    • Why is mathematics central to understanding and representing nature?
    • Relate Plato's view of mathematics as involving the contemplation of things in themselves to his idea of the upper intellectual world as described in the Republic.
    • What is the relationship between Plato's view of nature as expressed in the Timaeus and the views that drove Copernicus, Kepler, Newton and Einstein?

Discussion

Andres links to God in Greek Philosophy.

Defining "science":

http://plato.stanford.edu/entries/religion-science/

http://plato.stanford.edu/entries/scientific-unity/

http://plato.stanford.edu/entries/scientific-explanation/