Philosophy 4610Philosophy 4610Philosophy of MindPhilosophy of Mind

Week 2: Descartes and DualismWeek 2: Descartes and Dualism

Rene DescartesRene Descartes

1596-16501596-1650 Born in France, travels Born in France, travels

as a young man to as a young man to Holland and Germany Holland and Germany to serve in the armyto serve in the army

In 1618, has a series In 1618, has a series of dreams that he of dreams that he interprets as telling interprets as telling him he will found a him he will found a new sciencenew science

Descartes and MeditationDescartes and Meditation

Descartes undertakes to Descartes undertakes to testtest all of his all of his opinions to see if they are really opinions to see if they are really knowledge. To do so, he will ask himself if knowledge. To do so, he will ask himself if they are based on a they are based on a securesecure foundation: foundation: that is, whether they are certain and that is, whether they are certain and immune to doubt.immune to doubt.

He considers various possibilities of doubt He considers various possibilities of doubt or or skeptical scenariosskeptical scenarios to see whether he to see whether he really knows what he thinks he knowsreally knows what he thinks he knows

Descartes: Radical DoubtDescartes: Radical Doubt

Descartes considers three Descartes considers three skeptical skeptical scenariosscenarios or possibilities of radical doubt: or possibilities of radical doubt: 1) Senses can be deceptive, for instance 1) Senses can be deceptive, for instance

when I mistake something far awaywhen I mistake something far away 2) I could be dreaming2) I could be dreaming 3) God, or an “evil genius,” could be 3) God, or an “evil genius,” could be

deceiving me by “feeding in” my thoughts deceiving me by “feeding in” my thoughts and experiencesand experiences

The Brain in a VatThe Brain in a Vat(a modern version of skepticism)(a modern version of skepticism)

If we are brains in vats, we If we are brains in vats, we may may thinkthink we are having we are having experiences such as being experiences such as being outside, walking in the sun, outside, walking in the sun, feeling the warmth on our feeling the warmth on our faces, etc.faces, etc.

But we are really just But we are really just brains wired up to electrical brains wired up to electrical stimulators, perhaps stimulators, perhaps controlled by a computercontrolled by a computer

Philosophy: Philosophy: The MatrixThe Matrix

NEO: This isn’t real?NEO: This isn’t real? MORPHEUS: What is MORPHEUS: What is

real? How do you define real? How do you define ‘real’? If you're talking ‘real’? If you're talking about your senses, what about your senses, what you feel, taste, smell, or you feel, taste, smell, or see, then all you're talking see, then all you're talking about are electrical about are electrical signals interpreted by signals interpreted by your brain. your brain.

How do we know that we are not dreaming?How do we know that we are not dreaming? How do we know that we are not being How do we know that we are not being

deceived by an evil genius more powerful deceived by an evil genius more powerful than ourselves?than ourselves?

How do we know that we are not brains in How do we know that we are not brains in vats?vats?

IF any of these SKEPTICAL SCENARIOS IF any of these SKEPTICAL SCENARIOS are TRUE, then what (if anything) might we are TRUE, then what (if anything) might we STILL know and hold on to?STILL know and hold on to?

Descartes and Subjectivity: Descartes and Subjectivity: Re-building KnowledgeRe-building Knowledge

“…“…I have convinced myself that there is I have convinced myself that there is absolutely nothing in the world, no sky, no earth, absolutely nothing in the world, no sky, no earth, no minds, no bodies. Does it now follow that I no minds, no bodies. Does it now follow that I too do not exist? No; if I convinced myself of too do not exist? No; if I convinced myself of something then I certainly existed… So after something then I certainly existed… So after considering everything very thoroughly, I must considering everything very thoroughly, I must finally conclude that this proposition, finally conclude that this proposition, I am, I I am, I existexist, is necessarily true whenever it is put , is necessarily true whenever it is put forward by me or conceived in my mind.” (p. 10, forward by me or conceived in my mind.” (p. 10, col. 2)col. 2)

Descartes and Subjectivity: Descartes and Subjectivity: Re-building knowledgeRe-building knowledge

Having undertaken to doubt everything he Having undertaken to doubt everything he can, Descartes finds that he cannot doubt can, Descartes finds that he cannot doubt that he exists as a that he exists as a thinking thing:thinking thing:

““I am, then, in the strict sense only a thing I am, then, in the strict sense only a thing that thinks; that is, I am a mind, or that thinks; that is, I am a mind, or intelligence, or reason” (p. 11, 1intelligence, or reason” (p. 11, 1stst-2-2ndnd column)column)

Descartes and Subjectivity: Descartes and Subjectivity: Re-building knowledgeRe-building knowledge

By the end of the Second Meditation, By the end of the Second Meditation, Descartes has discovered that he exists Descartes has discovered that he exists as a as a thinkingthinking thing or a thing or a subjectsubject:: ““But what then am I? A thing that thinks. But what then am I? A thing that thinks.

What is that? A thing that doubts, What is that? A thing that doubts, understands, affirms, denies, is willing, is understands, affirms, denies, is willing, is unwilling, and also imagines and has sensory unwilling, and also imagines and has sensory perceptions.” (p. 11, second column)perceptions.” (p. 11, second column)

““Seemings:” The Way of IdeasSeemings:” The Way of Ideas “…“…Lastly, it is also the same ‘I’ who has Lastly, it is also the same ‘I’ who has

sensory perceptions, or is aware of bodily sensory perceptions, or is aware of bodily things as it were through the senses. For things as it were through the senses. For example, I am now seeing light, hearing a example, I am now seeing light, hearing a noise, feeling heat. But I am asleep, so all noise, feeling heat. But I am asleep, so all this is false. Yet I certainly seem to see, to this is false. Yet I certainly seem to see, to hear, and to be warmed. This cannot be hear, and to be warmed. This cannot be false; what is called ‘having a sensory false; what is called ‘having a sensory perception’ is strictly just this, and in this perception’ is strictly just this, and in this restricted sense of the term it is simply restricted sense of the term it is simply thinking.” (p. 12, 1thinking.” (p. 12, 1stst column) column)

Descartes and Subjectivity: Descartes and Subjectivity: The Way Of IdeasThe Way Of Ideas

At this stage, Descartes does not know At this stage, Descartes does not know whether anything outside him exists, but whether anything outside him exists, but he knows that he himself and his own he knows that he himself and his own processes of thinking do existprocesses of thinking do exist

These processes of thinking – the way These processes of thinking – the way things seem – can be called “things seem – can be called “ideasideas.” For .” For instance, Descartes does not know that instance, Descartes does not know that the sun really exists, but he does know at the sun really exists, but he does know at least that his least that his ideaidea or or impressionimpression of the sun of the sun does.does.