Philosophy as Adventures of Ideas

Week3

What We See Are Shadows of Ideas

Kazuyoshi KAMIYAMA

2017/4/04

CONTENTS

Thales

Pre-Socratic Philosophy

From what is everything created?

From where does everything come?

Permanence: Parmenides

Change: Heraclitus

Plato

The theory of Ideas 1

The theory of Ideas 2

Plato’s Realism (Platonism)

Rationalism

Plato’s Academy

References

ANCIENT GREEK ONTOLOGY: AN INTRODUCTION

MILETUSBEFORE THE 6TH CENTURY BC, MILETUS WAS CONSIDERED

THE GREATEST AND WEALTHIEST OF GREEK CITIES.

THALES(624-546BC)

from Miletus in Asia Minor

A pre-Socratic Greek philosopher and mathematician

“the first philosopher” in the Greek tradition

（Aristotle）

What is the Arche (the originating principle of nature

and the nature of matter)?

His answer: water

Aristotle “the riddle of existence”

Philosophy begins with a sense of wonder,

the wonder that there are things, rather than no

things.

"It was their wonder, astonishment, that first

led men to philosophise and still leads them.”

(Metaphysics (982b12) )

PRE-SOCRATIC PHILOSOPHY

The Pre-Socratic philosophers (or natural philosophers) asked

questions about "the essence of things“(Arche):

A. From where does everything come?

B. From what is everything created?

Ontology（Metaphysics): the discussions of these questions

B. FROM WHAT IS EVERYTHING CREATED?

Types of Answers

Monism（一元論）: there is only one kind of ultimate

substance.

Pluralism（多元論）: reality consists of two or more

independent elements.

Dualism（二元論）: there are just two mutually

irreducible substances.

…

A. FROM WHERE DOES EVERYTHING COME?

(“THE ULTIMATE WHY QUESTION”)

Permanence vs. Change

PERMANENCE

Parmenides (of Elea): 514-460 BC

"Is" could not have "come into being" because

"nothing comes from nothing".

Existence is necessarily eternal.

Moreover, he argued that movement was impossible

because it requires moving into “the void”空虚, and

Parmenides identified "the void" with nothing, and

therefore (by definition) it does not exist.

That which does exist is The Parmenidean One, which

is timeless, uniform, and unchanging.

ZENO OF ELEA （490–430 BC)THE INVENTOR OF THE DIALECTIC（ARISTOTLE）

Zeno’s paradoxes

Achilles and the tortoise

Let us suppose that

movement is possible.

Achilles cannot catch up with

the tortoise (as shown in a right

picture), which contradicts

the facts. Therefore movement is

impossible.

NOTEDIALECTIC (ALSO DIALECTICS AND THEDIALECTICAL METHOD） 問答法（弁証法）

A method of argument for resolving disagreement that

has been central to European and Indian philosophy

since antiquity. The word dialectic originated

in ancient Greece, and was made popular by Plato in

the Socratic dialogues. The dialectical method

is discourse between two or more people holding

different points of view about a subject, who wish to

establish the truth of the matter guided by reasoned

arguments.

Zeno shows the Doors to Truth and Falsity (Veritas et

Falsitas)

CHANGE

Heraclitus （of Ephesus）（535–475 BC)

Panta rhei, “Everything flows“

"Everything changes and nothing remains still ...

and ... you cannot step twice into the same stream."

PLATO(428/427–348/347BC)

Dialogues対話篇: The Apology of Socrates, Meno,

Theaetetus, Republic

Theory of Ideas (Forms) イデア論

What is Circle?

Answer: Circle is …..

The Idea(or Form) of circle 円のイデア（形相） is the

description which applies to the blank ….. .

LOTS OF QUESTIONS

What is equilateral triangle?

What is natural number?

What is human being?

What is courage?

What is virtue?

What is justice?

・・・

LOTS OF IDEAS (FORMS)

the idea of equilateral triangle

the idea of natural number

the idea of human being

the idea of courage

the idea of virtue

the idea of justice

・・・

THE THEORY OD IDEAS 1

There is a correct answer in each question.

Various ideas exist objectively.

The ideas exist, and the activity that tries to

discover them by reasoned arguments

(philosophy) is possible and meaningful.

THE THEORY OD IDEAS 2

The changing material world as it seems to us (the

world of appearance) is not the real world, but only an

"image" or "copy" of the real never-changing world

(the world of existence, the world of Ideas).

The Allegory of the Cave

(洞窟の比喩)

What we see are shadows of real things

(https://www.youtube.com/watch?v=ivY8nmJ05ns)

PLATONIC REALISM(PLATONISM)

Ideas (Forms) exist independently of human beings

and are the only true objects of study that can provide

us with genuine knowledge.

Note: This has been the most fundamental philosophy

of many western mathematicians and physicists.

RATIONALISM

In epistemology, rationalism is the view that regards

"reason as the chief source and test of knowledge.“

(Wikipedia) Plato's ideas possess the highest and

most fundamental kind of reality and are accessible

only to reason and not to sense. Plato is a rationalist

philosopher. cf. empiricism

PLATO’S ACADEMY（３８７BC－529AD）

"Let no one ignorant of geometry enter here."

The Academy (Ancient Greek: Ἀκαδημία) was founded by Plato in ca.

387 BC in Athens. Aristotle studied there for twenty years (367 BC –

347 BC) before founding his own school, the Lyceum. The Academy

persisted throughout the Hellenistic period as a skeptical school,

until coming to an end after the death of Philo of Larissa in 83 BC.

Although philosophers continued to teach Plato's philosophy in

Athens during the Roman era, it was not until AD 410 that a revived

Academy was established as a center for Neoplatonism, persisting

until 529 AD when it was finally closed by Justinian I.

The Platonic Academy has been cited by historians as the first

higher learning institution in the Western world. (Wikipedia)

THE SCHOOL OF ATHENS BY RAPHAEL (1509–1510)

REFERENCES

広川洋一『プラトンの学園アカデメイア』講談社学術文庫、 1999年

Nothingness - Why is there something rather than nothing?

Plato (https://en.wikipedia.org/wiki/Plato)

Pre-Socratic philosophers

(https://en.wikipedia.org/wiki/Pre-Socratic_philosophy)

KEYWORDS

the riddle of existence

Thales

arche

ontology

monism

pluralism

Permanence vs. Change

Zeno’s paradoxes

dialectic

Ideas (Forms)

the allegory of the cave

realism(Plato’s realism, Platonism)

rationalism

Plato’s Academy