Ren© Descartes, Meditations Introduction to Philosophy Jason M. Chang

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Smiths Invisible Hand

Ren Descartes,MeditationsIntroduction to PhilosophyJason M. ChangKen Ken puzzle1Learning OutcomesBackground

Descartes project in the Meditations

Descartes method

Cogito, ergo sum

The appearance/reality gap

2BackgroundBiography

Meditations on First Philosophy (1647)

Rene Descartes 1596-1650

Biography

1596-1650Born in France and educated by the JesuitsContributed to mathematics, physics, physiology, philosophy (Renaissance man)Regarded as the father to modern philosophyMost famous philosophical work is his Discourse on Methods (1637) and his Meditations on First Philosophy (1647)

Meditation on First Philosophy (1647)

Arguably Descartes most famous philosophical work and classic in the Western canonWritten almost like a diary that spans over 6 days

3

BackgroundHistorical context

Scientific revolution

Expansion of human knowledge

Historical context

In Descartes time, time-honored ideas, established religious doctrines, and traditional attitudes were being called into question by new discoveries in the sciences. This was the era of Galileo, Copernicus, Kepler, Bacon, and Newton thinkers who were dismantling hundreds of years of beliefs dating back to the ancient Greeks.

Copernicus proposed a heliocentric theory of the universeGalileo provided evidence for this model through observations using a telescopeKepler proposed elliptical (not circular) planetary orbitsNewton proposed his theory of gravityVesalius published drawings of the human body based on his dissections

It appeared that human beings were greatly expanding their knowledge of the world.

4Descartes project in the Meditations

5Descartes projectBackground

Knowledge = justified true belief

Foundationalism

Definition

Example1, Example 2

Knowledge = justified true belief

What does justification mean?When are we justified in believing something?

FoundationalismDefinition

Definition A theory that says that beliefs are justified by appealing to more fundamental beliefs (which are justified by more foundational beliefs, which are justified by more foundational beliefs, etc.)

Examples

Example #1: Ken Ken

Example #2: Math proof

Descartes and foundationalismDescartes believes that knowledge is derived from more fundamental beliefs we have

Implications

Scientific knowledge is derived from more fundamental beliefs we have

6xyzI know that x + y = 90 degreesZ = 90x + y + 90 = 180x + y = 90x + y + z = 180FOUNDATIONAL BELIEFSMy belief that x+y=90 is justified by the belief x+y+90 = 180

My belief that x+y+90=180 is justified by the beliefs z = 90 and x+y+z=180

7C3 is 3C2 = 1C1 = 2A2 and B2 are combo of 2 and 3A1 = 1B1 = 3B2 = 2A1 = 3B3 = 1A3 = 2Ken Ken Puzzle8Descartes projectProblem of doubtful beliefs

Descartes question

What can serve as a foundation for scientific truths?

Aim of Meditations

Published in 1647

Problem of doubtful beliefs

Q What problems do doubtful beliefs (i.e., beliefs we are not sure whether they are true) pose for foundationalism?

A Doubtful beliefs can disrupt and ruin the entire foundation

Descartes question

What can serve as a foundation for scientific truths?

Aim of Meditations To arrive at a foundation for scientific truths

9Descartes method

10Descartes methodWhat 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.

What scares Descartes

Many beliefs he held true as a young man were shown to be false

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

11Descartes methodDescartes method

If in doubt, throw it out

Method of Cartesian doubt

What it isIts aimMethodological NOT genuine doubt

Descartes method

If in doubt, throw it out

Q If we go by foundationalism, what should we do with beliefs that we can doubt?

A When in doubt, throw it out

Method of Cartesian doubt

What it isA method of inquiry that rejects any belief that can be doubted

Descartes If I am able to find in each one some reason to doubt, this will suffice to justify my rejecting the whole

The aimTo arrive at a solid foundation for scientific knowledge

Methodological doubt NOT genuine doubt

This leads Descartes down a radical path of doubting.12Are there any beliefs that cannot be doubted that can serve as a foundation for scientific knowledge?

Descartes method13Descartes methodCandidate #1: Beliefs derived from senses

Senses are deceptive

The dream argument

Doubt #1: Beliefs derived from senses

Senses are deceptive

Examples

Earth appears to be stillPlane moves slowlyObjects look smaller at a distanceA pencil in a glass of water appears bent

The dream argument

Q Have you ever had a dream in which you were sure that it was real?

Descartes claim There are no definite signs to distinguish dream experience from waking experience14Descartes methodDescartes 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.

Q Is (P2) acceptable?15Descartes methodCandidate #2: Beliefs derived from reason

Evil demon argument

Doubt #2: Beliefs derived from reason

Evil demon argument16Descartes methodDescartes 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.

Q Is (P2) acceptable?17Descartes seems to have shown that there are no indubitable beliefs that can serve as a foundation for science.

Descartes method18Descartes methodWhat this means

Wrong interpretation

Right interpretation

No solid foundation for knowledge

Beliefs from science no better than beliefs from faith

Skepticism (???)

What this means

Wrong interpretation Descartes has proven and actually thinks that all his beliefs are false

Right interpretation

No solid foundation for scientific and philosophical knowledge

Beliefs from science have no better basis than beliefs from faith?

SKEPTICISM (???)

We can still believe and live our daily lives

BUT we must admit that the aim of scientists, mathematicians and philosophers of arriving at knowledge about the world is impossible (Mans desire to know will be left unfulfilled)

19Cogito ergo sum

20Cogito, ergo sumTranslation

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.

Translation

I think, therefore, I am21Cogito, ergo sumDescartes 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.

22Cogito, ergo sumOthers things that cannot be doubted

Experience claims vs. Reality claims

Experience claims cannot be doubted

Other beliefs that cannot be doubted Beliefs about experience vs. beliefs about reality

Experience claims beliefs about our own personal experience

Example I seem to see a brown, rectangular desk

Reality claims beliefs about how the world really is

Example There is a brown, rectangular desk in front of me

Experience claims cannot be doubted

Belief about reality can be doubted

Example I can doubt whether there actually is a brown desk in front of me

Belief about my own personal experience cannot be doubted

Example I cannot doubt that I am seeing a brown desk in front of me. Even if I am dreaming or being deceived, I am still having an experience of a brown desk.

23The appearance/reality gap

24The appearance/reality gapHow can we know that objects as they appear to us is how objects really are?

25The appearance/reality gapClear 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

Descartes on clear and distinct ideas

Idea of 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 perfection26The appearance/reality gapDescartes 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 sourc