Philosophy as Adventures of Ideas

Week5

Descartes

in the Pyrrhonian Crisis

Kazuyoshi KAMIYAMANIT, Ibaraki College

2016/1/11

CONTENTS

Descartes

Descartes’ Project

The Meditation

Ontology

Ontology1

Ontology2

Mind-Body Dualism

References

RENÉ DESCARTES (1596-1650)

French mathematician, scientist, and philosopher

the “father of modern philosophy”

DESCARTES’ PROJECT

Distrust to the Scholasticism (a Medieval school of philosophy

taught by the academics of medieval universities and cathedrals

in the period from the 12th to 16th Century)

In ”the Pyrrhonian Crisis“ (Hopkin,2003)

→

Descartes’ Project: to reconstruct the whole philosophy on the

firm, certain ground

Meditations on First Philosophy(1641)

THE MEDITATION

I need to find a absolutely certain proposition, only on

which I can rebuild philosophy as the set of certain

propositions.

How to find the certain proposition(s) or an

epistemological ground-zero?

Answer

Through methodic doubt

searching for certainty by systematically though

tentatively doubting everything

DOUBT STEP1

What Senses report

They are not certain.

Because

The senses sometimes deceive.

ex. Objects at a distance appear to be quite small

(the Illusion Argument)

DOUBT STEP2

Survivors of the step1

“I am here, sitting by the fire, wearing a winter dressing gown,

holding this piece of paper in my hands, and so on.”

They are not certain.

Because

they might all be a dream.

(the Dreaming Argument)

DOUBT STEP3

Survivors of step2: mathematical beliefs such as 2 + 3 = 5

Not certain.

Because

there could be an evil demon with supreme power and cunning

（悪知恵）that puts all his efforts into deceiving him so that he is

always mistaken about everything, including mathematics.

(the Evil Demon Argument)

THE FINAL SURVIVOR OF DOUBTS

I cannot doubt my own existence. In order to doubt or to think, there

must be someone doing the doubting or thinking. Deceived as I may

be about other things, I cannot help but conclude that I exists.

“I must finally conclude that the proposition, ‘I am,’ ‘I exist,’ is

necessarily true whenever it is put forward by me or conceived in

my mind”

Cogito, ergo sum or “I think, therefore I am.”

ONTOLOGY1

I exist.

Next question: Does World exist?

BASIC LINE OF REASONING

God exists.[by the ontological argument(see next file)]

God is not a deceiver. [by the notion of God itself, God is

perfect.]

→We can dispel three doubts: doubts on senses, reason,

mathematics. We can rely on them.

Clear and distinct perceptions are indubitable.

→

World exists.

THE ONTOLOGICAL ARGUMENTOF THE EXISTENCE OF GOD

It is apparent that the idea of God is that of a supremely perfect being, that

is, a being with all perfections to the highest degree. Moreover, actual

existence is a perfection, at least insofar as most would agree that it is better

to actually exist than not. Now, if the idea of God did not contain actual

existence, then it would lack a perfection. Accordingly, it would no longer be

the idea of a supremely perfect being but the idea of something with an

imperfection, namely non-existence, and, therefore, it would no longer be

the idea of God. Hence, the idea of a supremely perfect being or God

without existence is unintelligible. This means that existence is contained in

the essence of an infinite substance, and therefore God must exist by his

very nature. (www.iep.utm.edu/descarte/ )

ONTOLOGY2

Which entities, if any, are fundamental?

Decartes’ answer:

Cogitatio(pensee, thought) and Extensio(etendue, extension）

Thought and Extension are two substances of the world,

where a substance is something that does not require any other

creature to exist—it can exist with only the help of God’s

concurrence.

MIND-BODY DUALISM

What is the difference between human and animal?

Animal: just Extension, Automaton

Human: Automaton with rational soul

Humans are the union of these two substances: mind and body.

MIND-BODY PROBLEM

How do mind and body communicate?

(Descartes’ suggestion : through the pineal

gland松果腺)

REFERENCES

J. Skirry, “Descartes, Rene” Internet Encyclopedia of

Philosophy(www.iep.utm.edu/descarte/), 2008

“René Descartes” (http://philosophy.about.com/od/Major-

Philosophers/a/Ren-E-Descartes.htm)

Richard Popkin, The History of Scepticism from Savonarola to Bayle.

Third enlarged edition, Oxford University Press, 2003.