Transcript
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Possible examples of a
priori knowledgebachelors are unmarried
2+2=4
There cannot be a round square
Any logical truththe connectionbetween premises and conclusion in avalid argument
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The dream argument calls intoquestion knowledge based on
experience, but it leaves a prioriknowledge untouched
But the evil demon argument
questions also a priori knowledge
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The EVIL DEMON!
It is possible that there is a demon,with nearly godlike powers, who aims
to deceive me. Therefore it is possible that all my
beliefs, are the result of the deceptive
powers of a demon Therefore I cannot trust any of my
beliefs
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Meditation 2
Descartes now tries to discover somebelief or beliefs that can be known
with certainty. These beliefs wouldhave to be true even if there is ademon
He finds one: I exist. But could an evil demon deceive him
(or you) about your own existence?
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Descartes answers no. Deceptionrequires that there be something to be
deceived.Even if all my thoughts are mistaken,
the thoughts must exist in order for
them to be mistakenEverytime I reflect on my thinking I can
know with absolute certainty that I
exist.
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But what sort of thing isthis I
Am I a rational animal?
Am I a human being?
What is essential to this I that Iknow to exist?
Essentially, what I am is not humanbeing, not rational animal, but athinking thing
Why?
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The knowledge that I am human or ananimal, or even have any body, is still
in doubt. A demon can deceive meabout these things. So I cannot knowanything about my physical being. But
there is something I know. What Iknow is the residuum, it is what is leftover after all that can be doubted isdoubtedthinking, consciousness.
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Solipsism!
Solipsism is a view that can only bestated in the first person.
My mind is all that exists, everythingelse only exists as I experience it.
There are few if any solipsists. But is
there any way to refute solipsism?
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The piece of wax
Therefore we know the mind withmuch more clarity than we know the
body. But this is hard to believe. Its easy to
think that knowledge of the physical
world is much more concrete,tangible, and that the mind issomehow mysterious
The piece of wax example shows us
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Take a piece of wax, melt it.
All the sensible properties change
Yet we still believe, we still take thewax to be the same thing
This shows: [supposed] knowledge of
physical things is based on the mind.We need to think to know the physicalworld
Our concept of the physical world isnot a bundle of sensible qualities.
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What we understand when weunderstand that the piece of wax is
the same is a flexible, extendedsubstance
It is what underlies or causes our
perceptions, not what we directlyperceive
Descartes is foreshadowing future
conclusions in the Meditations.
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