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# Descartes' Meditations

Last updated January 12, 2022

## First Meditation → skeptical doubts

• descartes wants to find a foundation of knowledge that will still stand strong even after doubting the most basic facts about the world
• everything descartes has accepted has true has come through senses, but senses can deceive
• First Argument
1. Some experiences are deceptive (e.g. visual illusions, mirages)
2. Any particular experience I have might be deceptive
3. It is possible that all my experiences are deceptive
• Counterexample to first argument
• Some paintings are forgegeries
• Any particular painting might be a forgery
• It is possible that all paintings are forgeries
• can’t be possible because all paintings if all paintings are forgeries, what are they based off of?
• Descartes' objection to First Argument
• premise 2 doesn’t work → any particular experience I have might be deceptive
• I am sure of my own thoughts
• And yet to have these doubts, he must exist. For an evil demon to mislead him in all these insidious ways, he must exist in order to be misled.
• Therefore, thought above all else is inseparable from being. The Meditator concludes that, in the strict sense, he is only a thing that thinks.

## Dream Argument

• Premises
1. i have dreamt at being at my desk
2. when i dreamt it, i believed it was true
3. when i dreamt it, it was false
4. there is no way to tell whether you are dreaming or awake
• Conclusion → i don’t know that I am here at my desk right now
• as premise 4 is roughly equivalent to the conclusion, this argument is invalid
• begs the question → argument which has a premise as a conclusion (circular reasoning)

### The God argument

• suppose there exists an evil demon, just as powerful as God, but which deceives me about everything he can
• descartes refutation
• it seems possible for there to be such a person
• if there were such a person, then everything I believe would be false
• I can’t tell that there isn’t such a person
• so, I don’t really know anything I thought i knew