okay um so we're moving sort of out of the middle ages into rene descartes and rene descartes is a significant figure from many different arenas part of why i think it is very important to study rene descartes is in some ways he is emblematic of this thing that we mentioned earlier this thing called modernity okay so he he actually has a title he is known as the father of modern philosophy okay we have a bunch of fathers in the history of western philosophy and he is one of them um father father of modern philosophy um and so some of the themes that we're going to be picking up on including the way that he talks about the self um as a kind of rational individuated kind of isolated being is going to be very very important and very um informative to the modern imagination about who we are as human beings okay um rene descartes um dies in 1650 um to give you um that context there he is from france um he is um interesting in that um whenever he's doing philosophy he he does philosophy and writes not only in latin but also in french um and that's sort of also like one of those kind of moves within modernity where um where even sort of academic or intellectual work is done in local vernacular um and so that's kind of cool and interesting kind of move sort of like that move to sort of locality as opposed to sort of like universality anyway so descartes from france um he is um one of the most influential philosophers in in the history of philosophy all right he probably would go in everybody's top 10 like most influential um philosophers but he's also and this is an interesting piece he's also very significant um in the history of mathematics um his day job basically is as a geometer so for any of y'all that remember your geometry remember that old x y axis well that's from rene descartes um just to sort of indicate his significance um some of what we're going to be talking about today is his approach to philosophy right um in other words the way that he does philosophy is almost as important as the has his conclusions as the sort of content of what he says um i think the biggest analogy to this would be someone like socrates where socrates comes to be sort of known and regarded not so much for what he says but sort of how he engages philosophically and so as we get into descartes i think sort of having this um sort of opposition or contrast with socrates i think will be helpful and so kind of getting into the mindset thinking sort of remembering about socrates um sort of picturing him if you will um just as a reminder socrates doing philosophy always with other people really big deal right it's this dynamic conversation a dialogue right where he's sort of trying to draw out of his interlocutor something that is within them but hidden they've forgotten it right remember all that recollection stuff so socrates in conversation with another out in public right placed him over and over again in the agora out in the marketplace um barefoot with his thread bear cloak right engaging in this very public manner um where what he does is interpret it as something political right because it's not it's not some private act that happens down in somebody's basement somewhere right it's something that happens out in public with other people dynamic centered around inquiry um and examination okay so that's socrates um i also sort of think like the balminess of the athenian agora is also a helpful sort of thing to think about because we're gonna have a contrast with that with poor renee descartes okay renee descartes um suffers his entire life um with pretty severe health issues um including um a very severe respiratory disorder that will eventually end his life um early um and yet descartes is the tutor to the royal family in sweden okay not the awesomest place for somebody to live who is suffering uh respiratory issues and vulnerabilities and so renee renee descartes is living somewhere that is literally like the air is killing him okay which i think kind of works as a pretty good metaphor for thinking thinking about rene descartes um and so i wanted to picture him sort of finishing his his day job okay they are with the royal family um in particular the princess of sweden a pretty huge and monumental intellect on her own right um leaving um his day job uh getting all bundled up like prepared i don't know if any of y'all like lived in cold climates but i lived in chicago for five years and so i feel like i can picture this really really well just the necessity of like many layers of warm clothing right so i want you to picture rene descartes just like as bundled up as possible many layers boots uh muffler thick cap thick gloves heavy coat right and i want you to sort of picture him fighting the snow and the sleet and getting to finally his boudoir opening the door closing that painful shards of ice air closing that door taking off his gloves immediately going to the fire um lighting the fire lighting the candle on his riding desk changing out of his many layers of clothing i also like to picture the like little brother in a christmas story right where he like can't quite put his arms down like like he's all bundled up like getting getting changed out of out of his outside clothes putting on his like heavy flannel pajamas putting on his heavy velvet winter dressing gown i like to give him some like fancy tassels to like tie up and like a like a stocking cap right because it's so cold a little guy and with like the little pom-pom on the ends and like maybe bob cratchit fingerless gloves right because he he's cold but he still has work to do like that kind of thing okay like changing like into his cozy pajamas and his winter dressing gown seated next to the fire okay closed off from the outside world absolutely alone okay bolstered from the outside world okay takes a deep breath as the room begins to warm okay and only then does descartes begin to do philosophy only as he is utterly and absolutely alone okay and not just kind of physically alone and not only physically bolstered and protecting himself from the world but he does a mental exercise where he says he frees his mind of all cares frees his mind of all prejudice okay only as he engages in this kind of meditative releasement again does he begin to do philosophy philosophy for descartes is not something that takes place with other people philosophy is not something that takes place out in public out in the world philosophy for descartes almost in a certain sense doesn't engage the world at all okay descartes is a rationalist okay this is like the kind of philosopher that he is he's a rationalist he's also a dualist and so we talked a ton about that all semester long um he's a modern duelist he's not just sort of a repetition of what we heard from from plato where for plato you've got the body that's like the shell and then you've got like the ghost like soul that's absolutely separable from the substance of the body descartes is more complicated than that the body is a certain kind of machine for him but just like for plato the body is not essential to who renee descartes is the thing that's essential to who renee descartes is is his mind okay so whereas plato would talk about the soul for for descartes he will will mark that at the mind the mind is essentially who we are right that kernel of a self um is going to be our mind our reason in particular okay um and so as we're we're sort of getting into that cartesian mindset i mentioned earlier that descartes is well known for his methodology right we talked about his method um he writes a book um prior to the meditations that um i sort of think of as like the rule book for philosophy like when you do philosophy like do these things okay and so he sets up in the discourse on method um for rules of method okay um some of these rules are more important than other rules but i will mention them all to you just so you kind of have a good sense of where he's coming from and his again approach to doing philosophy which is really important um let me talk for a second about the idea of a method okay this again as we're getting into questions about what constitutes the modern world the modern age modernity this notion of methodology um comes to be one of the most important ideas that sort of demarcate a differentiation uh sort of from the ancient and medieval way of thinking to the modern way of thinking um and so probably most famously um y'all should be thinking of the modern scientific method okay um that uh during a descartes time sort of um as we get the tail end of the renaissance with descartes um the sort of development of the modern scientific method and that yields results that are themselves reliable and repeatable that require testing and rigor and consistency and efficacy right descartes recognizes in the sciences that something interesting is happening right the results that are are occurring from the explosion of science during his time right is very impressive to him okay and he is wondering to himself if something like that reliability and consistency yielded by the scientific method if that could be replicated in philosophy okay and so he likes again that reliability that consistency wonders if that can happen with philosophy because when descartes thinks about the history of philosophy he thinks it's a big old mess he thinks it's a big inconsistent mess that's built upon shaky foundations okay he will very consistently um use the language of edifice of construction of building okay and so this sort of foundational language sort of comes back to the sort of notion of sort of building on firm found foundations and if you're not building on firm foundations whatever you're building no matter how beautiful it is or how impressive it is it's going to come tumbling down unsafe you shouldn't go in there right and so so he's sort of using this idea of of the shaky foundations of the history of philosophy and and he doesn't want that for philosophy because he thinks philosophy is super dang important and so the questions that are addressed in philosophy deserve better they deserve a certain kind of certainty and security and consistency okay now it might turn out that philosophy is the kind of thing that can't be reliable can't be consistent maybe it always will just be opinion and conjecture and if so he's not interested in it okay um maybe uh we then move from the philosophers being the arbiters of truth right to something like the scientists should take over okay um that's again like um a modernity alert okay turns out something like that has actually gone down right like if we in a contemporary way sort of think through like like who are the arbiters of truth where is truth housed right we tend within the modern world to think in terms of of techno-scientific truth right that's where truth lies philosophers you know are sort of like sort of slouchy um like like like dark cigarette smoking folks you know drinking too strong coffee in france or something like like that that's adorable and cute or whatever and they're true bohemians but like arbiters of truth maybe not so much right we the scientists um are the are the sort of folk that we look to to find the truth um but this is just sort of a move after descartes i'm sort of getting getting ahead in the history there but whatever but just just so you know he raises this question maybe philosophy is not up to this challenge and if philosophy is not up to this challenge we need to sort of seed this realm of truth or at least truth truthfulness to the scientists because they at least are equipped quit to deal with this now for descartes the difference between the kind of truth he's looking for and what's already going on in science like why he would look to philosophy and not just be like science can have it is that science deals in the realm of probability right science deals always in the realm of probability that's why it's sort of built into the scientific method a certain kind of adaptability right you're not looking for timeless eternal truths with the scientific method right you're looking for that which can be verified right which demands a certain kind of testing and retesting so that verifiability can be confirmed or denied right and if it is denied we adjust right the sort of theoretical sort of looseness right is very important to the scientific method okay it need we need to adapt if the evidence shows that what we thought to be the case isn't the case then we have to follow the evidence right within science okay and so we we deal in science in probability but descartes is wondering if it is possible to have something like absolute certainty that's what he's wondering can we have absolute certainty is it possible to ever arrive at something um that is at a foundational level absolutely indubitably secure okay and so his method sort of um provides a kind of i don't know like a testing mechanism for this question okay and so the first rule of method for descartes is this if we're if we're claiming that something is true okay we're saying something like it is true that i am holding this coffee mug in my hand something like that okay something simple it is true that i'm holding this coffee mug in my hand if i'm asserting that this is true whatever it is right two plus three equals five a square cannot have more than four sides etc whatever that thing that we're asserting to be true must present itself with such clarity and distinctness that it's impossible to doubt it okay i'll say that again like three times okay if we are asserting something to be true you're saying it's true that thing that we're asserting must present itself with such clarity and distinctness as the descartes like big words okay clarity and distinctness that it is impossible to doubt that thing and when he says impossible like those of y'all that have done your reading which hopefully is all of you you will know like he means like this in an extreme sense okay like if i think i exist i have to prove that i exist even if i don't have a body or i'm asleep and dreaming or if there's an evil all-powerful being creating me to be deceived right like like he means like to an extreme level of doubt right it has to withstand that kind of challenge okay so if we're asserting something is true it cannot admit of the least amount of doubt okay the least amount of doubt so this is this quest for certainty again right so if we are starting something is true it must present itself with such clarity and distinctness that it's impossible to doubt it so clarity distinctness and radical indubitability okay the best descarte word okay clarity distinctness and indubitability in order to ask the question regarding its and indubitability descartes says we have to consider whatever it is we are considering with the mind alone okay we have to consider it with the mind alone right i mentioned he was a dualist and that sort of like true self is going to be the mind right because our senses are going to mess with us they're radically unreliable this is why he thinks the history of philosophy is so messed up it's been reliant upon the shape the shaky foundation of sensation okay and so our senses are are absolutely unreliable and so if we think this is going to yield some kind of certain truth right if i say i am certain i am holding this cup in my hand because i see the cup or i feel the cup right that's not the kind of certainty that descartes is looking for that's that's fake certainty that is by definition uncertain because i'm experiencing that with my senses and basing my conclusion upon that experience okay so if something is considered true it must present itself to my mind alone to be clear distinct and indubitable okay so that's the first rule of method in some and it's the most important one y'all the other ones i'm going to list for you but it's certainly the the most significant um and the one that you should sort of be keeping in your mind throughout our conversation today okay the kind of truth he's looking for is that kind of truth that he described in in the first rule of method um the other three of this start with the simple and move to the complex okay start with the simple and move to the complex so if i'm wondering if i in fact have a body um i can start with the question of do i have hand okay and i move to the more complex my body okay rather than just like is there a world something like is there this room you understand okay so start with the simple move to the complex the second one is very similar but it has an important distinction start with the easy and move to the more difficult okay so we might start with a question of like is it indubitably true that two plus three equals five um and then build up to the question uh does god exist and is god good okay um so there is again um this kind of approach to philosophical questions that i would characterize as like it makes sense this is coming from a geometry right like it feels in some sense is like a geometric proof okay the way that you sort of like begin with certain kinds of foundational securities simple things that you can then build upon to get to something much more complex okay all right so so um something must present itself with such clarity and distinctness that it cannot be doubted start with the simple move to the complex start with the easy and move to the more difficult and then finally this isn't really a rule but it's still so descartes i want to mention it um make rules that are complete and detailed okay make rules that are complete and detailed again this kind of method the process um is this very modern way of thinking modern way of being where you kind of build this external structure that then becomes the boss of you right even if you're kind of the author of the structure right you're building these sets of rules that then are external to you that then govern you and rule you okay all right so um um let's shift there let's see um let's shift from the um the discourse on method to the meditations explicitly okay um so here we are in the meditations um this is um one of my favorite things in all the world this thing here um and um i i say that um despite the fact that i have serious philosophical issues with rene descartes but i just love the exercise of reading and thinking with with descartes and sort of going through the exercise that he he walks us the readers through i also love it as a teacher i feel like um especially meditation one is is so profoundly effective at what it does um it's it's kind of awe-inspiring like like like he's a very powerful thinker and a powerful writer okay and so what i want us to do with the majority of our time is to kind of is to think with renee descartes okay i want us to think with it rene descartes and it requires the like the the like biggest philosophical skill which is something like being game to play along okay it's really like if if i were to say what is the most important characteristic of a good philosopher it is that quality all right being being game to play being willing to play the game all right and so so there is a particular kind of mindset again so let's travel in our imagination sort of back to renee descartes room okay um in the evening time by himself um i used to give descartes a cat but i i think he has to be alone he has to be alone for this imaginative exercise all right we might want to put some like fuzzy bunny slippers on or something just to to cheer the place up a little bit but but absolutely alone okay you've got this fire going he's seated at his riding desk he's wearing his heavy pajamas his winter dressing gown taken his deep breaths freed his mind of all cares freed his mind of all prejudices he says okay and begins his philosophical demolition of everything he once believed to be true okay all right so we're there with descartes um in his room seated next to the fire at his writing desk um and he begins to write his text which has a very funny title to me the full title is meditations on first philosophy in which the existence of god and the distinction between the soul and the body are demonstrated okay it's a mouthful um and it's also um quite ambitious especially since this is like the size of a pamphlet right but but we'll see we'll we'll see if he's successful um in demonstrating these two things the distinction of the soul from the body and proving the existence of god all right so meditation one concerning those things that can be called into doubt he says several years have now passed since i first realized how numerous were the false opinions that in my youth i had taken to be true and thus how doubtful were all those that i had subsequently built upon them and thus i realized that once in my life i had to raise with a z everything to the ground and begin again from the original foundations if i wanted to establish anything firm and lasting in the sciences but the tasks seemed enormous and i was waiting until i reached a point in my life that was so timely that no more suitable time for undertaking these plans of action would come to pass for this reason i procrastinated for so long that i would henceforth be at fault where i to waste the time that remains for carrying out the project by brooding over it okay let me give you all a little bit of context for for what he's talking about the project that he says he's like put off for too long um i can give you a little bit of context because he has a whole series of uh correspondences where he talks about um the meditations and what he's doing in the meditations um and um and descartes is um we should mention sort of first off a very devout christian okay a very devout christian um one of my favorite experiences and memories in life is wandering around the beautiful city of paris and i go into the oldest cathedral in paris there are some old cathedrals i go into the oldest cathedral in paris and in that cathedral is the grave marker for renee descartes okay like like that committed a dude right they're like he gets the special spot um but very very devout christian um in particular so remember sort of the time period post protestant reformation and so he is a particular um roman catholic christian devotee okay so this is the tradition the christian tradition that he's a part of um and so he's a very devout christian um and he also has like this very i don't know it still feels a little medieval like very fire and brimstoney sort of notion um of sort of what happens if you if you cross the lord's will and he has a very vivid dream in which he comes to realize that if he keeps wasting his life applying his huge intellect which no one can deny he has a huge intellect to sort of pure mathematical questions then he is neglecting his obligation to god and he needs to apply his intellect to more significant questions like questions of the human condition the existence of the world the distinction of the soul from the body and proof for the existence of god okay and so so he needs to apply his intellect to these things because god wants him to right and so he has the sense that if he fails at this task he will literally be punished okay so this is like serious thing and he's like i have put this off for too long so that's what he's talking about here in this beginning paragraph i've procrastinated for for too long and i'm going to be held to account if i don't get started okay all right so here that um as that kind of context that sort of background and so this is what he says accordingly i have today suitably freed my mind of all cares secured for myself a period of leisurely tranquility and am withdrawing into solitude at last i will apply myself earnestly and unreservedly to this general demolition of my opinions yet to bring this about i will not need to show that all my opinions are false which is perhaps something i could never accomplish but reason now persuades me that i should withhold my ascent no less carefully from opinions that are not completely certain and indubitable than i would from those that are patently false okay let me talk about that for a second um when i'm thinking about the meditations and thinking about descartes um i tend to think of sort of what's happening in the meditations as like a kind of marine condoing of one's mind okay and so he's kind of like going through all of his opinions sort of like am i going to donate this or keep it right and so on the one hand you have sort of the pile of like thank you for your service uh i'm getting rid of you kind of an idea the pile of those things which can be called into doubt right those things that can be doubted um those go in one pile and the things that are certain and indubitable go in the other pile all right so we're kind of like two stacks as we're going through all of our opinions so he's like anything that admits of the least possibility of doubters in this pile and then everything certain can go over here okay but then he says if i were to go through each and every one of my opinions i would never get out of this room right like if i went through every single opinion like um i am wearing earrings today something like that that's an opinion um i'd have to like go through a whole process of sort of is there such a thing as an earring what do we define an earring as the earring attaches to what oh there's such a thing as an ear do you in fact have an ear it's made of certain kind of material and not other kinds of material does that material actually exist this earring appears to be emerald green but is there something wrong with my perception or the lighting that would allow me to reach that conclusion it seems to have a particular kind of texture etcetera you all understand like if i were to go through each and every opinion separately and distinctly it would take much too long and i would accomplish nothing of the kind of significance that i feel obligated to accomplish okay so he says i'm going to go after the foundations of those things okay i'm going to go after the foundations and so let's turn on to page 14 and skip a little bit um down to that tiny paragraph that's at the top of the page on on page 14. um it's it's not even a proper paragraph it's composed of two sentences one is just kind of the the introduction the sort of um laying the groundwork for the like real punch that comes in the second sentence which is extremely important um but also um surprisingly not unusual in the history of philosophy we hear this kind of critique a bunch he says surely whatever i had admitted until now is most true i received either from the senses or through the senses okay he's thinking about like most almost all of my opinions right things that i think to be true are things that i think are true because i'm like looking at something i'm smelling something tasting feeling it right like i believe this table to be solid there's a table in front of me i believe this table to be solid because i feel it right something like that right most of my opinions almost every single one of them i arrive at the conclusion that it is true that my shirt is black because i'm looking at it right and so so there's that most of my opinions come from my senses here's what he says however i have noticed that the senses are sometimes deceptive and it is a mark of prudence never to place our complete trust in those who have deceived us even once okay with that with that little sentence there he has annihilated the vast majority of his opinions okay almost every single thing that he has believed because and this is i think helpful descartes thinks about these kinds of modes of inquiry ways of accessing things that we've called true kind of like um scientific instruments if you will okay um and so maybe hearken back to like um um a sort of fellow renaissance dude galileo right in his famous telescope so thinking about the sort of scientific instrument um also sort of a note about modernity this is also one of the very significant sort of markers of modernity is the rise of instrumentality right the rise of the instrument um in particular to science but also in other disciplines um so you have you have galileo's telescope the sort of understood to be the first proper scientific instrument invented purely for the sake of scientific examination not for some other purpose but for the sake of science so say you've got a telescope and that telescope is kind of messed up you're not quite sure how but it's very unreliable sometimes it gives you good data sometimes it gives you bad data and there's not a real clear way to tell the difference between the two and so you got a bunch of garbage basically um from this this faulty instrument right someone maybe the lenses are off of the mirror is messed up right and you've got a faulty instrument and so that's how he's thinking about the senses okay the senses are unreliable they yield good stuff sometimes bad stuff other times okay and so any conclusion that's based upon this shaky foundation has to be thrown into the garbage right like bad data acquired through a messed up instrument a messed up instrument that's messed up only sometimes but you don't know when you understand does that make sense okay so thinking about sensation like this this next paragraph here is pretty important um and i want us to hear it here so page 14 again but perhaps even though the senses do sometimes deceive us when it is a question of very small and distant things okay the other night we were actually looking at a telescope up at mars right now it's so bright you guys should if you have a telescope you should you should point it up at mars you can see it really really well right now but we're looking at mars and even through the telescope it looks like like a tiny little bead like a little tiny thing right and so mars is very distant far away um and it has the appearance uh to me to be you know this size okay i know that it is not that size i know it is massively huge okay but to to to me my perception it appears to be very small and so describes like maybe i can't rely on my senses for things that are really really far away but what about things that are really really close okay seems like we shouldn't doubt those things still there are many other matters concerning which one simply cannot doubt even though they are derived from the very same senses for example that i'm sitting here next to the fire wearing my winter dressing gown that i'm holding the sheet of paper in my hands and the like but on what grounds could one deny that these hands and this entire body are mine unless perhaps i would have likened myself to the insane whose brains are impaired by such an unrelenting vapor of black bile that they steadfastly insist that they are kings when they are utter poppers or that they are arrayed in purple robes when they are naked or that they have heads made of clay or that they are gourds or that they are made of glass but such people are mad and i would appear no less mad were i to take their behavior as an example for myself okay now i hope you notice this move he begins the paragraph as though he's talking about sensation right but he moves very quickly away from the sensation right the senses are unreliable any conclusion i reach based upon them go in the garbage heap he says well is there there any way for me to doubt something so obviously true like i'm sitting where i'm sitting next to the fire wearing my winter dressing gown with my fancy tassels right is there any way to doubt that that seems evidently the case how could i possibly call that into question and this is what he says i can call it into question if my mind is also a broken instrument you understand that's why he goes into sort of absurd kind of medieval speculations um about these poor folks perceptions that they are gourds or made of glass okay right it's not a problem of like bad lighting or something that someone believes that they're made of glass right if only we can sort of get get some sunlight in here they would absolutely realize no this is not a problem of sense this is a problem of mind and descartes like um do i have the same issue right is my mind unreliable in this kind of way right and here we go probably one of the most famous paragraphs in all of the history of philosophy he's like am i am i able to perceive something with my mind or is my mind broken like the broken telescope of sensation he says but such people are mad and i would appear no less mad where i to take their behavior as an example from myself this would all be well and good were i not a man who is accustomed to sleeping at night and two experiencing in my dreams the very same things or now and then even less plausible ones as these insane people do when they are awake how often does my evening slumber persuade me of such ordinary things as these that i am here clothed in my dressing gown seated next to the fireplace when in fact i am lying undressed in bed right now my eyes are certainly wide awake when i gaze upon this sheet of paper this head which i am shaking is not heavy with sleep i extend this hand consciously and deliberately and i feel it such things would not be so distinct for someone who is asleep as if i did not recall having been deceived on other occasions even by similar thoughts in my dreams as i consider these matters more carefully i see so plainly that there are no definitive signs by which to distinguish being awake from being asleep as a result i am becoming quite dizzy and this dizziness nearly convinces me that i am asleep okay i love it so much okay all right so descartes obviously anything i've concluded with my senses like a broken scientific instrument unreliable gotta throw that data out okay but do i have any other instrument available to me to assessing if something is true or not well hey my mind my mind right he's a descarte he loves the mind okay he's a rationalist okay what about my mind is my mind a reliable instrument and he says like shoot dang it i go to sleep sometimes right and when i sleep i have dreams and very often when i am dreaming as i am dreaming i do not know that i am dreaming right i do not know as i am dreaming in fact this is the norm in my dreams every once in a while i'm aware that i'm dreaming while i'm dreaming but most of the time i do not know that i am dreaming while i am dreaming it is only later after the fact that i realized i was dreaming but while i was in the dream i did not know it and so then he says what about right now is there any way i can know definitively right now that i am awake do i know for certain that i am awake right now okay and he says and he's right there's no way to tell right there's no way to tell right now that i am currently awake okay right so it seems like the obvious solution is to not do philosophy while you're asleep okay just like wait for the time that you're awake but the problem is you can never know if you're awake or not and let me tell you sort of the implications of that that means everything that i am experiencing and believing to be the case right now right that i am heather ross daughter to craig and alicia mother to ian and zebby right that i am 48 years old that i grew up in nashville tennessee right that this is my body that i am in this room that i am in southern california that i'm in north america that i inhabit planet earth etc right all of those things are could absolutely be a function of my unconscious mind right i could be a 90 year old man in a coma circling mars right now having this dream okay so every aspect of my experience my my encounter with the world that there even is a world is called into question with this tiny little paragraph right i could be asleep and dreaming right now i cannot know for certain that i'm awake so anything that i am concluding to be true based upon the assumption that i am conscious okay is now called into question right which is terrifying it's terrifying so descartes he moves into his next question right and he's he's playing a game okay because realize y'all descartes does not think he is asleep and dreaming right he thinks he's awake you all understand okay he just doesn't know for sure so then he speculates if in fact i am asleep and dreaming is there anything i could know even if i'm asleep okay because if i can find something that i know even if i'm asleep then how secure will that thing be right how reliable will that certainty be right it's true even if i'm unconscious okay and he goes through all kinds of possibilities he walks through all kinds of possibilities sort of dismantling every aspect of possibility um all the way down to um dismantling any science that is based upon the assumption that there exists bodies and a world okay all thrown into the garbage heap and then he comes to the basis of arithmetic and geometry okay it's known as the principle of identity right it's also the foundation of logic and he says what about these very simple things two plus three equals five and a square cannot have more than four sides how could i possibly doubt those things even if i'm asleep and dreaming a square has to have four sides if there's something in my dream that has more than four sides it's not a square okay how could i possibly call those things into question and it is here that he introduces the sort of final nail in the coffin of all of his world okay he introduces the possibility of what's known as the evil deceiver okay sort of an all-powerful um brilliant um deceptive being okay in order to get to the evil deceiver um he starts with this assertion right um is it possible that there exists an all-powerful being right we mentioned before he is a devout christian he's like yeah it's possible right not only possible i go to mass to celebrate this being every day okay so he asked this question is there is it possible there exists an all-powerful being and is it possible that that being created me he's like high five to that yes i think that is possible and again mass celebration right right now is it possible that say an all-powerful god would create me in such a way that i'd be deceived when i count the size of a square or i think some simpler thought even if that's possible okay is it possible that there exists such a being and he says yes i would be confused right like is it outside the bounds of the nature of a good god that god would never deceive me like that and descartes says well it seems like if this were so important a part to the nature of god right then god would never allow me to be deceived and that's false i'm deceived all the time i'm finite this is the whole idea of the meditations as i'm deceived all the time so god is obviously letting me be deceived right does god do stuff that i don't understand absolutely right i might not understand why god would create me this way but it is possible right and then he says maybe it's too upsetting to say that this is god doing this thing is it possible there's some other kind of malicious being that created me to be deceived right like some kind of trickster deceiver okay and descartes like yes it's absolutely possible again he doesn't think he's asleep and dreaming and he doesn't think he is being uh controlled by an evil genius deceiver god right is it possible he says yes okay and it's with the possibility of the evil deceiver for descartes that even the assertion a square has four sides um and two plus three equal five are called into question because he can't rely upon that even even something so simple as that because he might be created to be deceived every time he thinks a thought okay all right um