 This first meditation or Descartes He's wondering what exactly he knows I mean the situation he's in is actually pretty familiar to us He notes that a lot of things that he learned when he was young are actually false This has happened to us time and time again we can relate to this How many of you were taught that? Oh, I don't know that Christopher Columbus discovered that the earth was round No, no that happened long before Christopher Columbus some ancient Egyptians and Other ancient civilizations thought the same or at least there were some people within those civilizations. I thought the same thing Up until what 10 years ago. We thought Pluto was a planet Not anymore. It's been declassified as a planet. It's Planetoid I think is the word that they use for it now You know we used to think that all this solid matter around us was actually solid, but you know contemporary physics tells us It's mostly empty space overwhelmingly empty space history bounds of the other examples We think that we know things from one time and we learned that they're false later That you you change your beliefs all the time. It's part of growing up You abandon and young immature beliefs and you don't older and more mature ones But if what you used to believe was false And you believe a different set of beliefs now What reason do you have to think that all of your beliefs that you have now are true? Right you I mean if history is any kind of indicator here about what happens when you grow older You abandon older beliefs and you adopt new ones that means that the beliefs that you have right now You won't have later on As you get older you're gonna abandon some beliefs and adopt new ones So how are we supposed to know anything to begin with? If any of my beliefs could be rejected by me later on Which ones are true? Descartes struggling with this question And he decided that the only way That he can know something is If he knows that there's absolutely Positively no way to doubt it absolutely positively can't be wrong There can't be a mistake With the beliefs given the evidence So he says about trying to find this foundation of beliefs this foundation this you know first set of beliefs From which all others can be derived Then you know what he what he does then he says okay I'm gonna look at the sources of my belief because you know going through each individual belief would just take way too long So it's gonna look at the sources of his beliefs is what he calls principles these sources of his beliefs And if there's some kind of flaw and the source of the beliefs Then he's gonna reject all the beliefs that come from that source well That sounds like a great project because I really want to know What I can believe I really want to know what's true what I know for certain Even if it's a very small set if it's a very small number of beliefs that I can know for certain then at least I could take those and Build up a nice body of knowledge All right, let's get started. Let's go find what we can know for certain So Descartes taking a serious look at what we can know and he reaches this inclusion that if we have any reason to Data whatsoever when we're looking at the principles of the sources of knowledge if we have any reason doubt of whatsoever We shouldn't take it as knowledge we should cast it aside until we find something we absolutely cannot doubt Well, it's a good thing that I'm out here in the world and that I can look at the world with my senses I mean after all my senses are really good, right? So I'm looking at these Trees and these flowers over here, and I'm looking at this green. Well, that's right. I'm a little colorblind so I Don't know whether that's green or it's red Come to think of it You know my eyes aren't that great all the time either you know I Sometimes I look at buildings and they seem really straight and really tall from far away And I get up close to them and they're kind of angular and the the appearance changes I you know, I think that they're smooth from far away, but I get up close. There's a lot of texture on the buildings I'm looking at these this moss here on this tree and I Thought it was growing on the tree when I was standing over there, but now Now I see it's it's kind of latched on to the branch and Is this tree even alive? I I don't know. I mean my senses told me that this was alive, but maybe now I Maybe I don't know. Oh I mean it feels like a plant But what I know the difference if it was a really good fake is that red or is that green? Well, if I have reason to doubt my senses Then according to Descartes, I can't trust my senses So all the information that I have for my senses is now gone. Well, that's just depressing I'm trying to take a little bit of a break here in this beautiful garden. I mean, I see lots of pretty colors, but you know I've lost my sin. I've lost a Reason to believe my senses so I don't even know if I see these things anymore and You know, it could just be one elaborate fake. I could be a part of a big deception Well, at least I know that I'm awake and I'm actually experiencing these things right now It's really a gorgeous garden. I remember I had a dream about a garden just like this one I was having lunch over there with some friends of mine. I had a dream about this garden and it looked just like this But but if I had a dream about this garden it looked just like this How how do I know I'm not dreaming now could I be Dreaming now I Mean the Sun was shining just like it is now and I can hear the river just just Like I hear it now And there was that building that and this tree was here just just like it is Now Am I awake? I see things around me I think I see great rock over here But my senses could be deceiving me and I see the green and the and I see the wood and the wood looks like Solid, but you know, maybe I don't see the rot that's in there And it could all fall in my head in any moment And you know this could all be an elaborate deception to begin with and I don't even know if I'm awake Lee, there's there's possible deception possible false beliefs and and and fallible sources of information all over the place Man, I just Glad at least I have my two hands I mean it's not as if I could be fooled about that right I I see what I see I mean at least I see something there and you'll at least I have my hands. I could feel my hands But you know aren't they Don't don't hearing aids Let people hear things And and don't they make cameras now that they can hook up to people's brains and they could they can see now With the brains and and the cameras And Wait What if the technology for that's actually a lot better than I think it is What what if what if I'm lying in a hospital bed and I've got a bunch of electrodes being fed into my brain and I'm maybe I'm in a coma. I could be in a coma But they're trying to let me live out a normal life By by putting electrodes in my brain and just kind of have me run through an elaborate computer program What if there was a horrible accident and my body was destroyed? But all my brain was left and maybe they just put my my brain in a vat with the electrodes in there and I'm living out a life in a computer program and you know the electrodes are feeding sensory information to me So I I think and I feel and I I sense I have since sensory information and I and then that way I could feel my hands This could be an illusion. I mean I'd have hands at all, you know Come to think of it You know that there are greater and more powerful beings and that there are less powerful beings and You know, I know I have a mind and I know I have an imagination But what if there's a being That's much more powerful than I am Right when I when I have a figment of imagination, you know, I imagine I imagine, you know, like a I have this hallway here right now and I can imagine somebody walking down this way, right? So Yeah, I just imagine somebody walking from over here to over there. I Know I can do that. What if I'm a Figment of somebody's imagination what what if It's it's a being so powerful that it's that the figments of its imagination are conscious and He's this this being is just imagining me talking to a camera right now. I Wouldn't even have hands. I wouldn't even have a brain. I Wouldn't have a body at all. I would just be an image and And What if What if this this thing that's imagining me just imagine me and All the memories and and experiences that I have were we're already given to me at the moment that that it Imagine me walking around that corner. I Wouldn't even have been around as long as I think I have I have reason to doubt my senses. I Have reason to doubt that this world is genuine that it's not an elaborate deception I have reason to doubt that I'm awake I have reason to doubt that that I have a body I have reason to doubt that I have a brain I have a reason to doubt that I have any kind of physicality. I have reason to doubt I've existed more than five seconds Wow, well for Descartes standards Right now for me to know something I Have to have absolutely no reason to think that What I know could be wrong That means that any kind of scenario I can imagine That's consistent with the evidence that I have That's somehow an illusion or false or deception or Imagination That means that any scenario that I that I have Sorry any evidence I had this consistent with any one of those scenarios. I now lose any reason to believe I Mean this is the high demand, right? This is the high demand for knowledge. You have to be absolutely certain There's just no possible way You can be wrong well, I might disappear From the from this being's imagination the minute I go off camera You don't kind of think of it. I Might just be existing on this image on this screen, you know That's not funny I'm I'm stuck. Please don't turn the video off. Please don't turn the now before you panic. Yes, you exist Yes, you've existed through your whole life. Yes, your senses can you know might have some error in there? But you can trust them. Yes, you are actually living in a world There is no massive deception where you're somehow on a movie set You know, you do exist beyond the scope of this video Don't panic Like I said in a philosophy class is perfectly appropriate to question What exactly you know and how you know now once you stop watching the video once you know You know go about living your life The world exists around you, okay? The world exists around you if you see a car coming towards you get out of the way Don't doubt that the car is it may be a figment of imagination. Just get out of the way. All right But what Descartes has given us here are some really interesting things to think about when we're talking about our knowledge I mean if our standard for knowledge is absolute certainty well We might have a real problem here Because there are lots of scenarios that are because that are consistent with the evidence that we have Which would not? Which would be contrary to you know what we think is the real world and we wouldn't have one reason to go with the Skeptical high skeptical hypothesis or go with the view that this world really is real So it raises a real problem for our knowledge, but please believe that you are in the real world. You are So You know I want you to think about the standard of knowledge that that Descartes has given us this absolute certainty with anything we know and Think about you know, how it actually applies to your life. How much of what you believe is Absolutely certain how much of what you believe Could be a deception and ask yourself What impact does this have on my knowledge?