rené descartes, meditations introduction to philosophy jason m. chang

René Descartes,MeditationsIntroduction to Philosophy

Jason M. Chang

Learning Outcomes

1. Background

2. Descartes’ project in the Meditations

3. Descartes’ method

4. “Cogito, ergo sum”

5. The appearance/reality gap

Background

• Biography

• Meditations on First Philosophy (1647)

Rene Descartes 1596-1650

Background

• Historical context

o Scientific revolution

o Expansion of human knowledge

Descartes’ project in the Meditations

Descartes project

Background

• Knowledge = justified true belief

• Foundationalism

o Definition

o Example1, Example 2

x

yz

I know that x + y = 90 degrees

Z = 90

x + y + 90 = 180

x + y = 90

x + y + z = 180

FOUNDATIONAL BELIEFS

C3 is 3

C2 = 1

C1 = 2A2 and B2 are

combo of 2 and 3

A1 = 1

B1 = 3

B2 = 2A1 = 3

B3 = 1A3 = 2Ken Ken Puzzle

Descartes project

• Problem of doubtful beliefs

• Descartes’ question

o What can serve as a foundation for scientific truths?

• Aim of MeditationsPublished in 1647

Descartes’ method

Descartes’ method

What scares Descartes

“It is now some years since I detected how many were the false beliefs that I had from my earliest youth admitted as true, and how doubtful was everything I had since constructed on this basis.”

Descartes’ method

Descartes’ method

• “If in doubt, throw it out”

• Method of “Cartesian doubt”

o What it iso Its aimo Methodological NOT genuine doubt

Are there any beliefs that cannot be doubted that can serve as a foundation for scientific knowledge?

Descartes’ method

Descartes’ method

Candidate #1: Beliefs derived from senses

• Senses are deceptive

• The dream argument

Descartes’ method

Descartes’ Dream Argument

(P1) I often have perceptions when I am dreaming like the ones I have now.

(P2) There is no definite signs to distinguish between dream experience and waking experience.

Therefore,

(C) It is possible that I am dreaming right now and that my perceptions are false.

Descartes’ method

Candidate #2: Beliefs derived from reason

• Evil demon argument

Descartes’ method

Descartes’ Evil Demon Argument

(P1) It is possible that an evil demon is deceiving me when I reason to conclusions.

Therefore,

(C) It is possible that the conclusions I derive from reason are false.

Descartes seems to have shown that there are no indubitable beliefs that can serve as a foundation for science.

Descartes’ method

Descartes’ method

What this means

• Wrong interpretation

• Right interpretation

o No solid foundation for knowledge

o Beliefs from science no better than beliefs from faith

o Skepticism (???)

“Cogito ergo sum”

“Cogito, ergo sum”

• Translation

• The passage

“Let [the evil demon] deceive me as much as he will, he can never cause me to be nothing so long as I think that I am something. So that after having reflected well and carefully examined all things, we must come to the conclusion that this proposition; I am, I exist, is necessarily truth each time that I pronounce it or that I mentally conceive of it.”

“Cogito, ergo sum”

• Descartes’ reasoning

(P1)  Even if we assume that there is a deceiver, from the very fact that I am deceived it follows that I exist.

(P2) More generally, whenever I think (e.g., feel, sense, imagine, reason), it is affirmed I exist.

(P3) I think.

Therefore,

(C) I exist.

“Cogito, ergo sum”

• Others things that cannot be doubted

o Experience claims vs. Reality claims

o Experience claims cannot be doubted

The appearance/reality gap

The appearance/reality gap

How can we know that objects as they appear to us is how objects

really are?

The appearance/reality gap

Clear and distinct ideas

• “Myself as an existing thing” is clear and distinct

• Ideas and perceptions that are clear and distinct are true

• I have a clear and distinct idea of perfection

The appearance/reality gap

Descartes’ argument for God

(P1) The idea of perfection must have a cause.(P2) I am an imperfect being.(P3) It is impossible for an imperfect being to be the source of the idea of perfection.So,(P4) I cannot be the source of the idea of perfection.

Therefore,

(C) The source of the idea of perfection must be a Perfect Being (God).

The appearance/reality gap

Descartes’ argument bridging the gap

(P1) God, who is perfect, cannot be a deceiver.

So,

(P2) God would not mislead me when I perceive something clearly and distinctly.

Therefore,

(C) Whenever I perceive something clearly and distinctly, it must be true.

The appearance/reality gap

Part of Descartes’ legacy

How can we know that objects as they appear to us is how objects

really are?