 In the last video, Russell was asking this question, is there any knowledge that's so certain that no reasonable person could doubt it? And he poked at a problem that we have regarding knowledge, and that's at what we, you know, at least the beginning of our knowledge, really looks like its appearances when we get through the sense data. And sense data is what we see, taste, touch, smell, the product of the five senses. But, you know, what we get from sense data is not what's found in the objects. There's a difference between sense data and reality. So, this leads to what he considers to be this main problem of philosophy. That is, you know, is there such a thing as, you know, this bench? Is this bench real at all? And if it is real, then what's its nature? What is it like? What is it, you know, what do we know about it? So, that's the two main questions that we're dealing with in philosophy. What is this object, right, or any object, frankly? What is this object and what is this nature? Well, this leads quickly to, you know, what Russell thinks is, leads quickly to the question of knowledge about physical objects, these material objects. So, you know, kind of modify the question a little bit too. What is, you know, our physical material objects real and what is our nature? And even more specifically than that is, is matter real? And if so, what is the nature of matter? So, in this second chapter that we're dealing with, the Russell, he's focusing just on the first problem there, is matter real? Does matter exist? And for Russell, everything's at stake in answering this question. If I can't know that this thing is here, I'm toast, right? I can't know anything. If I can't know something as simple as this bench is here, then there's nothing that I really can know. So, in this chapter, he's trying to figure out a way that I can know that this bench is here. But at the same time, he still has to acknowledge the problem of the difference between appearance and reality. So, Russell is dealing with this question, this first question in the problem of philosophy, and the question is, is matter real? Now, you know, one could just simply say, well, yeah, sure it is. And walk away and, oh, well, that was easy. No, no, that's not going to be that easy. Very quickly, the question of, you know, what is real? You know, trying to answer, excuse me, is matter real? And answering that question leads to the question of, well, how do you know? How do you know that matter is real? What's your proof? What's your evidence? What basis of knowledge? Well, the first approach that Russell looks at in trying to answer this question about knowledge, you know, what is going to be our standard for knowledge, is what he calls the method of systematic doubt. And he borrows this from a philosopher by the name of René Descartes. And what Descartes did is he set a very high standard of knowledge. Now, Descartes noted that, you know, doubt creeps in and tends to affect knowledge. So, you know, this, I don't know, this very little doubt that I'm standing in a park. You know, I see the trees around me and I'm standing here in a field the warmth of the sun. There's just very little doubt about that. But there are other beliefs, claims to knowledge, that have more doubt to them. So there's more, you know, so while I'm, you know, there's very little doubt that I'm standing in this park, there's more doubt that, say, you know, there's life on other planets. It's possible that there's life on other planets. And, you know, some would argue that the probability is, you know, non-negligible, that there's a pretty good probability, but there's at least some doubt. I mean, after all, we haven't heard from them, we haven't seen them, things like this. So there's no real evidence that there's life on other planets. So there's a certain amount of doubt. We may not just completely destroy the claim that, you know, that there's knowledge, that there's life on other planets, but there's at least some doubt there. Well, let's look at a belief with even more doubt. Let's say, you know, there are unicorns, right? There's a lot of doubt about whether there are unicorns. We have no evidence of unicorns, everything that we know about biology and the way species works tells us that there are no unicorns, right? And we have never seen a unicorn up to this point. We can find absolutely no evidence. And not only can't we find any evidence for the unicorns, but all the evidence seems to go to the contrary that there are unicorns. So there's a lot of doubt that there are unicorns. I mean, with that large amount of doubt, we say, well, I don't know that there are unicorns. The reason why I don't know is because I've got no reason to believe it. There's just too much doubt about the existence of unicorns. So Descartes looks at down. He notes that it tends to destroy knowledge. Now, like Russell, right? You know, Descartes, several centuries before Russell. But like Russell, you know, Descartes asks the question, what can I know with certainty? Is there something so certain, so without doubt that I can know it? And Descartes thinks that from that very certain doubt, I'm sorry, a very certain belief from which there is no doubt, then he could build the rest of his knowledge on that certain belief. So to find that belief, both Descartes and Russell, they're looking at this method of systematic doubt, and the method is basically this. That, you know, Descartes says, you know, he will believe only what he sees clearly and distinctly. And what he means by that is beliefs that have no doubt. It's just not possible to doubt the belief at all. Now, last time we saw that there's, you know, more than a few problems with the belief that there are real objects around, that there are these physical objects around me, right? All that knowledge that there are physical objects around me is based upon appearances. But appearances don't tell us about the physical objects. There's a difference between the material objects and what we see in appearances. Well, that's kind of a problem, right? But the problem could be even worse, right? I mean, you might say, yeah, well, maybe I don't know about the material objects, but at least I know that they're there. And after all, that's the first question of philosophy to begin with, is matter or material objects real? Well, what are some of the possibilities? You know, I said that there's very little doubt that I'm standing in this park, but hey, I could be dreaming. I've had dreams about walking in parks before. I could be dreaming right now. So I may not actually be in the park. Well, so there's a further disconnect between appearances and the objects. I can have the appearances and the objects need not be here at all. You know, it can get even worse. I could be in the matrix, right? If, you know, I could be a body suspended in a vat of liquid with electrodes in my brain that are feeding all this information into my brain, making it seem like I am experiencing a warm sun and green trees and a humid air and all that could be fed into my brain. I may not be in this park at all. All the evidence I have that there's a park around me is consistent with the claim that I'm in the matrix and I'm suspended in a very elaborate computer program. For all I know, I could be, you know, in the delusion of some insane super-beam, right? I could be trapped in some super-beam's dream. For all I know, right? For all the appearances that I have, that could happen. So, you know, granted, I think the probabilities of that are really, really small. There's just that much doubt that the objects that I perceive around me are actually there. But for the method of systematic doubt, that's enough. So, if there's a smallest amount of doubt that I am around these material objects that matter itself is real, then with the method of systematic doubt, that's not knowledge. So, this poses a real problem. If we're going to take the method of systematic doubt as our standard of knowledge, it doesn't look like we know that there's matter around us. And so, we're in trouble, right? Because remember what Russell said. The belief that there's matter, that knowledge that there's matter around us, that's foundationally. You've got to have at least that to have anything else. Well, you know, systematic doubt doesn't remove everything. You know, so I sit here and I am experiencing sense data. I am experiencing green and blue and white. Well, green from the trees, blue from the sky, white, I hear the plane above me right now. I feel the warmth from the sun. I am actually experiencing all those things. It's really impossible for me to be mistaken that I'm experiencing green and blue and white. I might be mistaken about what's causing it. Okay, right. I could be mistaken that there are trees out there. But I can't be mistaken about the fact that I'm having these sensations. These sensations are occurring. So that bit of knowledge, that is beyond doubt. There's no way to doubt that from the very fact that I'm experiencing these things. Well, you know, since I... since it's impossible to doubt that I'm experiencing these things, it's also impossible to doubt that I exist. I am experiencing these things. That's impossible to doubt. Since I am experiencing these things since it's possible to doubt, that implies that I exist. Even if I'm being massively deceived, if I'm in the Matrix, if I'm in some elaborate computer program, I exist. If I am deceived, then I exist. You all suppose I am in the delusion of some mad super being. I exist, right? Because I am the one that's in this delusion. So, you know, it doesn't matter what scenario put together with trying to cook up some kind of scenario in which I'm deceived or these things around me don't exist, there's still the I there that does exist. Now, you know, that gets me to at least that I exist. It doesn't get very much beyond that. So for instance, I don't get to have something like I have existed for over 20 years. Because all that's based upon memories. And memories are even less reliable than since data. We've all experienced faulty memories. So, you know, there's that room of doubt, room for doubt on the belief that I've existed for 20 years because that's based upon memory. For all the memories that I have, for all the since data that I'm experiencing right now, I could have popped into existence five seconds ago. So, I don't really get the claim that I've existed for a long period of time, but I do get the claim using the method of systematic doubt that I exist and that I'm experiencing since data. And, well, that's a start. So, systematic doubt is causing us a lot of problems. So, if we're going to have any kind of knowledge about whether the matter is real, right, whether material objects are real, it's not going to be by the method of systematic doubt. So, it's at least an uncomfortable consequence that knowledge is going to have to allow for at least some doubt. Now, the question is, in other words, if I know something, well, that means that I'm going to have to have at least a little bit of doubt available to it, to that belief. At least interesting questions about how much doubt is acceptable. A little, a lot, what counts as doubt, this sort of thing. Well, the next approach that Russell considers is what he calls, you know, kind of like, you know, when he talks about sense data, right? Now, the thing about sense data is sense data is private evidence. But that he means that only I have access to my sense data. Nobody else has access to my sense data. I see green and I see blue and I see white, right? But nobody can see me seeing green and nobody can see me seeing blue when nobody can see me seeing white or anything like that. You are hearing my voice right now, but nobody else can hear you hearing my voice, right? The closest that we get to something like that is, you know, reporting to other people what we in fact see. So you can't have my perceptions of green and blue and white, but you can listen to me say, hey, I'm seeing green and blue and white. Okay, so from that, right, the idea is, well, you know, sure seems, I mean, sure seems like I can tell other people, hey, I see material objects too. And then from that group consensus, right, we can then say, hey, that material objects are real. After all, we are all seeing material objects. Well, as noted before, you know, there's going to be problems here about systematic doubt. After all, you know, we could all be a leader program and we could all be listening to each other and we could all have the same experiences. So, you know, systematic doubt still affects this kind of argument. Even, you know, reporting to everybody else what we see, the systematic doubt is still going to whittle away this argument. But, you know, if we leave aside systematic doubt, just what do we get from this? Well, Russell says not a whole lot. After all, you know, what's happening when we say, I'm here and I'm reporting that I see material objects and you're there and you're reporting that you're seeing material objects. Well, Russell says, well, if you suppose that somebody else is there and that they're reporting that there's material objects, then you're supposing that there are other objects out in the world, namely other people. And if you're already assuming that there are other people, you haven't proven the conclusion, you've assumed the conclusion. This is an informal fallacy called begging the question. You'll find this in pretty much any logic textbook, actually. Begging the question is an informal fallacy. That means it's not a fallacy of form. It means that, you know, you've made some kind of error in ways other than by the form of the argument. You know, I'm sure you've heard the phrase begging the question and people use this phrase to mean that leads to the question. Unfortunately, that usage has creeped in, but the original notion of begging the question is that we've assumed the answer to the question and trying to answer the question. So in saying, hey, other people are reporting that they see these trees around us with their sense data and reporting this and taking that evidence to be true, we've already assumed that there are other objects out there. So that's not going to do it. We can't prove the conclusion by assuming it's true. So where does this leave us? Well, this means that, you know, whatever evidence we take, whatever argument we use to prove that there are material objects that matter is real, we can't rely upon other people to prove it. All that's going to have available to me are the appearances that I'm experiencing, the sense data that I'm experiencing. But we still have all the problems about sense data, right? Sense data is not reality. So what are we going to do? The question is, using just my sense data, which doesn't accurately report reality, how am I going to show that matter is real? Well, we're not left with many options. Certainty isn't going to help us. The method of systematic doubt shows us that lots of beliefs that we have about the world around us, about material objects are open to it, and even the smallest measure of doubt. So that's not going to work. So we've got to allow some doubt to creep into our beliefs. And we're trying to prove that material objects exist. Well, we can't do that by assuming other people can prove it with us because that's assuming that there are other material objects. So we have only our own sense data to prove to us that there are material objects. Well, taking a look at the world around me, I'm seeing lots of trees right now. But I'm also hearing lots of things, too. And I hear cars off of the distance. Now, I can't see those cars. The trees are blocking the view. So here's what Russell notes. He's like, look, objects go through changes whether we see them or not. They appear to continue to exist even though we don't perceive them. So I'm not perceiving the cars right now other than hearing them. I don't see them, but I hear them. Well, the question is, well, what's causing those sounds? I can hear the cars driving by the highway so they make that eeww sound, right? It's a Doppler effect. That means that the car is running, the engine is running before I hear it, and the engine continues to run after I hear it. Well, that means that this engine exists. I don't see the engine. I don't see the car right now. But it exists before I hear it and exists after I hear it. And there's no other sensory information I have about it. So that means that there's some sense in which that object continues to exist even though I don't perceive it. And there's lots of objects. I mean, this happens all the time. I leave my room, I leave my computer in my room and when I come back, lo and behold, it's still there and there's nobody around to see it. Nobody else is around to see it. So what accounts for that continued existence? Now, what Russell mostly has in mind here is he's contrasting the common sense view that matter is real to what's called idealism. And idealism is the view that matter, that all objects are really just ideas. It's just mental phenomenon. So actual physical stuff doesn't exist. The phenomena exists. So right now I'm clapping and I feel the texture of my skin and I hear the sound and my hands are warm. The warmth, the sound, the texture, that's what's real. That's what exists but not flesh and blood. Not stuff. So Russell's contrasting this common sense view versus the idealist view. We at least have idealism with the method of systematic doubt. Because remember what we said earlier, we at least have sense data. That's beyond a doubt and I at least have my own existence but we want to go one step further. Not only do I exist and my ideas exist but there's matter out there, there are material objects out there. Well, idealism has a difficult time accounting for the continued existence of objects when we don't perceive them. So when I leave the room and I come back my computer is still there. But I didn't perceive it anyway. Well if I didn't perceive it, if there was no mental phenomena on the computer then what explains this continued existence? Well Russell points out that if you have, if you're considering idealism versus the common sense view that there's material objects, this is actual stuff, the common sense view has an easier time dealing with the continued existence of things. Because when we say that matter is out there we're saying that matter exists whether we perceive it or not. Matter exists, material objects exist, whether we perceive it or not. So we have this evidence, we have this claim that objects appear to continue to exist even when we don't perceive them. Now if we're just going idealism then we have to say that when I leave the room and I leave my computer, my computer ceases to exist for a period of time but then when I perceive it again it pops right back into existence. Well that's pretty complicated. You've got things coming in and out of existence all the time and no account for why they come in and out of existence. But if you're dealing with material objects well it's easy to say that the thing continues to exist because it's material. Matter, physical stuff, doesn't require us to perceive it in order for it to exist. So when we're comparing the two the common sense view that there's material objects is a simpler view than idealism. Now in a sense it's a simpler view than idealism so we've already got that we exist and we got that sense data exists. So what we have left is trying to prove that there's material objects. Well the view that there are material objects is simpler than simply saying that there's only us and only our sense data. There's got to be something more to account for all of our evidence and that's something more is the existence of matter. So this is how Russell answers this question. This question is is matter real and Russell says yes, matter is real and how do I know? Well the view that matter is real accounts for our evidence better is a better explanation than saying that only we in our sense data exist. It's far cry from certainty. We left certainty behind some time ago. I mean this is an argument that's called an argument form called inference to the best explanation and you know we use it all the time but inference to the best explanation is pretty susceptible to error because you've got a couple of really big questions that you now have to answer. What makes one view better than another? And on top of that what makes one view more simple than another? The second approach to that is to say that what makes one view more simpler than another is the number of objects that are or number of kinds of objects that are presupposed to exist. So that's one part of it. There's another really big part of it though that Russell really doesn't go into and you know inference to the best explanation you might have also heard it called Occam's razor. Inference to the best explanation we use it a lot and you know there are problems with it but it's also really useful. But you know the full view the full claim about inference to the best explanation is not that the simplest explanation is the true one that's not it. It's the full claim about it is given equal explanatory worth given the fact that two theories explain equally well the simplest view is the true one or the simpler view is the true one. Okay. Or when I say you know the better view is the true one. Okay. Again what makes one better? So Russell claims that idealism can't account for the continued existence of objects but material objects do but the common sense view that there's matter does. Okay. Well, does it work?