# Descartes "Meditations"
## January 13th, 2020
- Pre-class scribblings:
above the sea
below the sky
as so much snow
or newt's eyes
we lie
living
dead
- We have a Georgia Tech emails] for Professor Culbreth! `aculbreth6@gatech.edu` should be used for all official emails with him
- We'll also start being able to use the Canvas site to take attendance, etc.
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- Alright, Descartes! Initially he can seem *crazy,* but he actually has very good arguments if you understand his ways of thinking
- Studying him, we'll get to the core of what philosophy means and what is truly needed as "first principles" for doing philosophy
- First, though, let's wrap up last week
- We were talking about Galileo's corpuscularianism, and he makes a distinction:
- PRIMARY qualities are things he thinks are inherent in objects themselves, like position, matter, shape, taking up space, etc.
- SECONDARY qualities are things that are subjective and (he thinks) are only inside our own heads, like color, taste, feel, sound, etc.
- Galileo's argument for this is that he can't imagine an object without primary qualities like position, but he CAN imagine ones without colors, tastes, etc.
- "He sees this as similar to the idea that you can't have a 'married bachelor;' he thinks primary qualities are INHERENT in the definition of an object"
- This is a good example of a RATIONALISTIC argument; some rationalists believe there are ideas we innately believe to be true, and that we can correctly deduce or intuit new beliefs through our reason
- In contrast, EMPIRICISTS are skeptical of such claims and believe we can *only* rely on our senses to get correct information about the world
- Finally, from last time, let's talk about the problem of perception
- PERCEPTUAL SUBJECTIVISM is the idea that we don't directly experience the world, but only experience it through our senses
- Galileo thinks this, that we only subjectively experience the secondary qualities of objects and never their primary qualities directly
- Why, then, do our senses match up with the outside world? Do they? How can we know?
- REPRESENTATIONAL REALISM is the position that our senses "represent" actual stuff in the world
- There are other positions, like phenomenalism, but we'll return to them later
- Okay - now, I have 1 hour to convince you that Descartes isn't doing a crazy thing by doubting everything, but is actually trying to do something really cool
- At the time Descartes wrote these "Meditations" (1641), 2 big historical things had happened:
- ~1517, the Protestant Reformation began, causing people to start questioning the authority of the Catholic church and who's right about *everything*
- ~1543, Copernicus published his heliocentric model, kicking off the modern scientific revolution
- Galileo started doing empirical research in the 1600s, too, and was questioning our image of the universe as we knew it
- So, at the time there were a LOT of competing ideas about who was right, and at the time people didn't know who to trust for their source of truth
- Into this, Descartes, a brilliant mathematician and philosopher, steps onto the scene of radical doubt
- His project: to come up with a system of things we KNOW to be true, making rational thought possible
- Alright; let's look at Meditation 1
- We see immediately he's trying to "raze everything he knows to the ground," and then trying to go from there
- This is known as FOUNDATIONALISM, the idea that we have to come up with solid axioms as a foundation before we can do any further thought, science, or study
- Descartes' method for getting to these foundations is to *doubt,* and to try and ignore anything he isn't *certain* of
- "The burden of proof for showing something is definitely false can be high, but to show something *might* be false is much easier"
- Descartes did NOT think his beliefs were false, but for this project he wanted to ignore anything he wasn't 100% certain he could prove
- As readers, then, we're simultaneously invited to question our own beliefs in the hope of finding fundamental truths and then building our way back up
- "His general structure here is to offer a belief, give a reason he believes it, and then provide a counter-example to show it can be doubted"
- So, Descartes doubts a lot of stuff, and in particular 3 big, related things:
- The truth of his sensory experience
- Descartes' senses have previously deceived him, like when he looks at something far away and thinks it's close to him!
- So, not ALL senses are reliable, but aren't there some that are? "Immediate sensory beliefs," for example (e.g. "I am holding this pen")?
- BUT, I could be dreaming! I often think dreams are real when they aren't! Therefore, Descartes thinks even THIS is subject to doubt!
- "Again, Descartes doesn't say he really is dreaming, but that it's *possible* - he just has to show there's some doubt here, however small"
- Basic sensory beliefs (e.g. colors, sounds, etc.)
- "But," Descartes says, "even if I am dreaming, the parts in my dream must come from something I've really seen, since dreams are combinations or exaggerations of stuff I've seen before"
- However, Descartes rejects THIS because his imagination might be so good that he really can make all this stuff up! He isn't sure!
- Therefore, Descartes thinks we can't be certain of even basic sensory beliefs
- Mathematical truths
- Descartes then says, though, that at least mathematical, axiomatic truths must be correct, right? A square by definition has 4 sides, and it's *inconceivable* that we could get something so obvious wrong
- ...however, Descartes imagines that maybe an evil demon or genius could be deceiving him, and that he's actually been taught lies about ALL this stuff!
- Not even logic helps us here, since those logical rules might've been taught to use by this deceiver! We can't be certain of it!
- So, if Descartes has shown even logic itself can be doubted, how can we prove anything is true?
- Let's look at Meditation 2:
- Descartes says that even without logic, there's 1 thing we can still be sure of: "I exist!"
- Why? Because *even if* all his perceptions are false, he's still perceiving, and that must mean there's something there to do the perceiving!
- "Notice he NEVER uses the word 'therefore' in this section, since that would require logic"
- Even if I doubt, then, I'm doing something!
- So, we know we exist - but what are "we"?
- Read Meditation 3 ("warning: it's difficult"), and we'll go from there