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René Descartes (1596-1650) Sunday, October 6, 19

René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

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Page 1: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

René Descartes(1596-1650)

Sunday, October 6, 19

Page 2: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

René Descartes

Sunday, October 6, 19

Page 3: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

René Descartes

• Method of doubt

Sunday, October 6, 19

Page 4: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

René Descartes

• Method of doubt

• Things you believed that you now know to be false?

Sunday, October 6, 19

Page 5: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

René Descartes

• Method of doubt

• Skeptical arguments (illusion, dreams) —> doubt of senses

Sunday, October 6, 19

Page 6: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Possibility of Dreaming•Descartes: “In my sleep I

experience the same things as madmen do when they are awake— or sometimes even less probable things. How often have I been persuaded, in the quiet of the night, of familiar things— that I was here in my robe sitting near the fire— when in fact I was lying disrobed between the sheets!”

Sunday, October 6, 19

Page 7: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Possibility of Dreaming•Descartes: “It certainly seems to

me now that I am looking at this paper with waking eyes; that this head I move is not asleep; that I deliberately and knowingly extend my hand and feel it. What happens in sleep is not so distinct. No doubt! As if I do not remember being tricked while asleep by similar thoughts on other occasions!”

Sunday, October 6, 19

Page 8: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Possibility of Dreaming•Descartes: “While I think

about this more carefully, I see so plainly that there are no certain indications by which we may clearly distinguish being awake from being asleep that I am dumbfounded. And my astonishment almost persuades me that I am asleep.”

Sunday, October 6, 19

Page 9: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes’s Contribution

•Evil deceiver

Sunday, October 6, 19

Page 10: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Possibility of an Evil Deceiver

•Imagine an all-powerful but evil being out to deceive me

•It makes my mind skip every time I think or draw a conclusion

Sunday, October 6, 19

Page 11: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Evil Deceiver

•Descartes: “I shall therefore suppose not that God who is supremely good and the fountain of truth, but some evil genius of the greatest power and cunning, who has employed all his energies to deceive me.”

Sunday, October 6, 19

Page 12: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes’s Contribution

• Evil deceiver —>

• doubt of logic and mathematics

Sunday, October 6, 19

Page 13: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Classical Rationalism

• We are able to have knowledge of the world independently of experience because the structure of the mind matches the structure of the world

Sunday, October 6, 19

Page 14: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Classical Empiricism

Sunday, October 6, 19

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Classical Idealism

Sunday, October 6, 19

Page 16: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Classical Rationalism

Sunday, October 6, 19

Page 17: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Philo of Alexandria• Forms are ideas in the mind of God

• Our minds and the world are both stamped with the Word of God

WordWord

Sunday, October 6, 19

Page 18: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes• What if our minds and the world are stamped with

different stamps?

VerbumWord VerbumWord

Sunday, October 6, 19

Page 19: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes• What if our minds and the world are stamped with

different stamps?

Word λογος

Sunday, October 6, 19

Page 20: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes• What if our minds and the world are stamped with

different stamps?

Word अभिधा

Sunday, October 6, 19

Page 21: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes• What if our minds and the world are stamped with

different stamps?

Word ❡ϖ❄ð☃☜

Sunday, October 6, 19

Page 22: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes

• What if our minds and the world are stamped with different stamps?

Word ☀☄☻✌

Sunday, October 6, 19

Page 23: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Plato’s Philosophy of Mind

Form

Object

This is a triangle

Participation

Perception

Recollection

The Good

Sunday, October 6, 19

Page 24: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Augustine’s Philosophy of Mind

Form

Object

This is a triangle

Participation

Perception

Illumination

God

Sunday, October 6, 19

Page 25: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Descartes’s Philosophy of Mind

Innate Ideas

Object

This is a triangle

Why think they match?

Perception

God

Sunday, October 6, 19

Page 26: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Must I Doubt Everything?

• “I suppose, then, that all the things that I see are false; I persuade myself that nothing has ever existed of all that my fallacious memory represents to me. I consider that I possess no senses; I imagine that body, figure, extension, movement and place are but the fictions of my mind. What, then, can be esteemed as true? Perhaps nothing at all, unless that there is nothing in the world that is certain.”

Sunday, October 6, 19

Page 27: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Foundations

• Is there anything we can’t doubt?

• Foundation for the rest of knowledge

Sunday, October 6, 19

Page 28: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

• “But there is some deceiver or other, very powerful and very cunning, who ever employs his ingenuity in deceiving me. Then without doubt I exist also if he deceives me, and let him deceive me as much as he will, he can never cause me to be nothing so long as I think that I am something.”

I am

Sunday, October 6, 19

Page 29: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

I am

• “...we must come to the definite conclusion that this proposition: I am, I exist, is necessarily true each time that I pronounce it, or that I mentally conceive it....”

Sunday, October 6, 19

Page 30: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

‘I am’ (Sum)

• What makes ‘I am’ special?

Sunday, October 6, 19

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‘I am’ (Sum)

• What makes ‘I am’ special?

• I can’t think it without existing

• I can’t think it without it being true

Sunday, October 6, 19

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‘I am’ (Sum)

• What makes ‘I am’ special?

• I can’t think it without existing

• ‘I doubt whether I am’?

• But if I doubt, I am

Sunday, October 6, 19

Page 33: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Foundations

• Is there anything we can’t doubt?

• Foundation for the rest of knowledge

I am

Sunday, October 6, 19

Page 34: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

I think

• “What of thinking? I find here that thought is an attribute that belongs to me; it alone cannot be separated from me.”

Sunday, October 6, 19

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I think• “to speak accurately I am not more

than a thing that thinks, that is to say a mind or a soul, or an understanding, or a reason, which are terms whose significance was formerly unknown to me. I am, however, a real thing and really exist; but what thing? I have answered: a thing that thinks.”

Sunday, October 6, 19

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Cogito, Ergo Sum

• “I think, I am”

• True every time they are thought or uttered

Sunday, October 6, 19

Page 37: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

I Think (Cogito)

• What makes ‘I think’ special?

Sunday, October 6, 19

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I Think (Cogito)• What makes ‘I think’ special?

• The thought ‘I think’ is self-justifying

• It can’t be thought without being true

• It makes itself true

Sunday, October 6, 19

Page 39: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

I Think (Cogito)

• What makes ‘I think’ special?

• The thought ‘I think’ is self-justifying

• It makes itself true

• ‘I doubt whether I think’?

• But doubting is thinking

Sunday, October 6, 19

Page 40: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Foundations

• Is there anything we can’t doubt?

• Foundation for the rest of knowledge

I think, I am

Sunday, October 6, 19

Page 41: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

A Thing That Thinks

• “But what then am I? A thing that thinks. What is a thing that thinks? It is a thing which doubts, understands, [conceives], affirms, denies, wills, refuses, that also imagines and feels.”

Sunday, October 6, 19

Page 42: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Appearances

• “Finally, I am the same who feels, that is to say, who perceives certain things, as by the organs of sense, since it truth I see light, I hear noise, I feel heat. But it will be said that these phenomena are false and that I am dreaming. Let it be so; still it is at least quite certain that it seems to me that I see light, that I hear noise and that I feel heat. That cannot be false; properly speaking it is what is in me called feeling; and used in this precise sense that is no other thing than thinking.”

Sunday, October 6, 19

Page 43: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Conclusions

• I am a thing that thinks

• I am essentially a thing that thinks

• I can know my own mind more securely than I can know anything else: “I see clearly that there is nothing that is easier for me to know than my mind.”

Sunday, October 6, 19

Page 44: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Anything else?

• “I am certain that I am a thinking being; but do I not therefore likewise know what is required to make me certain of something?”

Sunday, October 6, 19

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Transcendental Argument• Argument concerning the conditions of the

possibility of something

• A is possible

• But A could be possible only if B

• Therefore, B

Sunday, October 6, 19

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Clear and Distinct Perceptions

• “Certainly in this first knowledge there is nothing that assures me of its truth, excepting the clear and distinct perception of what I state, which would not indeed suffice to assure me that what I say is true, if it could ever happen that a thing that I conceived so clearly and distinctly could be false; and accordingly it seems to me that already I can establish as a general rule that all things that I perceive very clearly and very distinctly are true.”

Sunday, October 6, 19

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Descartes’s Argument

• Argument concerning the conditions of the possibility of certainty

• It is possible for me to be certain of something

• But that could be possible only if I could trust what appears to me clearly and distinctly to be true

• Therefore, I can trust what appears to me clearly and distinctly to be true

Sunday, October 6, 19

Page 48: René Descartes - Daniel Bonevacphilosophical.space/philosophy/Descartes.pdfRené Descartes • Method of doubt • Skeptical arguments (illusion, dreams) —> doubt of senses Sunday,

Clarity and Distinctness

• But can I doubt the premises?

• Can I doubt the conclusion?

• Can I doubt whether it follows?

• Note the caution: ‘seems’ (Latin: ‘videor’)

Sunday, October 6, 19