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Lesson 1.5: Reason and the Senses
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If our senses can deceive us and our reasoning can outrun experience, which should we trust as the true foundation of knowledge: reason alone, or the evidence of the world?
Topics discussed:- How radical skepticism (including modern versions like simulations) motivates Descartes’ turn inward
- A reconstruction of René Descartes’ Cogito argument as a proposed foundation of certainty
- The difficulty of moving from Descartes’ foundational truths to knowledge of the external world
- Philosophical objections to Descartes’ inference from thinking occurs to a unified self exists, including Nagasena’s chariot analogy
- The role of innate ideas and God in Descartes’ attempt to bridge the epistemic gap
- John Locke’s rejection of innate ideas and the blank slate hypothesis
- Locke’s empiricism, including simple vs. complex ideas and indirect realism
- The tension between reason and the senses as competing sources of knowledge
- The emerging dilemma between rationalism and empiricism as rival epistemic frameworks
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Transcript
Descartes' Quest for Certainty
00:00:01
Speaker
When we last left off, we had looked at Descartes' negative project, his destructive phase, as I called it. Basically, he was tearing down beliefs with a machete, right? He was trying to knock down beliefs as quickly as possible because what he wanted to know is what he knew with certainty and that required that he got rid of every belief that he didn't know with a certainty and it was pretty brutal right it was uh quite violent and it was the evil demon argument that took us to that possibility hey maybe we don't know anything at all
00:00:48
Speaker
What I would like to do in this lesson is rehash that argument in perhaps a more modern fashion.
Introduction to Nick Bostrom and AI
00:00:57
Speaker
So let me introduce you to Nick Bostrom.
00:01:03
Speaker
Mr. Bostrom is a very prolific philosopher. and quite famous as far as modern philosophers go.
00:01:14
Speaker
He is the head of the Future of Humanity Institute, at least as of this recording end. He is known primarily for his views on artificial intelligence. He believes that in a nutshell, that we are on track for creating a super intelligent form of artificial intelligence and that this poses an existential risk to us humans.
00:01:47
Speaker
It's a bad idea, in a nutshell, is what he's trying to say. And heck, you know, sometimes, depending on how much caffeine I've had, I agree with him. So,
00:01:59
Speaker
That's not the view we're going to cover right now.
The Simulation Argument
00:02:02
Speaker
We're going to look at another famous argument from him called the simulation argument. So let me explain an important concept so that we can get to the simulation argument.
00:02:15
Speaker
It is the post-human stage. Now, what is the post-human stage? That is a stage of technological maturity required to create ancestor simulations.
00:02:30
Speaker
And these ancestor simulations would be sufficiently detailed detailed I suppose fine-grained, to include conscious beings.
00:02:42
Speaker
In other words, they are little simulations of human history. And they are so detailed, so granular, that the little people inside are actually conscious.
00:03:00
Speaker
Let me mention something real quick about this before we leave this slide. Why would anyone want this? I can tell you with considerable certainty that a lot of different categories of people would probably want these.
Purpose of Ancestor Simulations
00:03:22
Speaker
First and foremost, probably historians. There's actually already historians who use computer simulations to explore different possibilities and test their hypotheses.
00:03:36
Speaker
One such person is named Peter Turchin. But actually, come to think about it, a lot of different disciplines, different scholars in different disciplines use computer simulations. right I think every single one of these people or almost every single one, would want one of these ancestor simulations, right? they would It would be the most accurate model you can possibly use.
00:04:05
Speaker
So that sounds likely. I'm guessing if you are in the world of business and you are thinking, hey, should we make this product? Should we fund this movie? Should we whatever, right?
Assumptions of Post-human Stage
00:04:20
Speaker
ah Well, one where one place where you can test those ideas, products before you actually launch them, movies before you make them, whatever, that would be an ancestor simulation, right? It's almost basically...
00:04:36
Speaker
a dry run, right? you're You're trying things out, but not in the real world, in a simulation. The point I'm trying to make here is that if it ever is the case that humans get to this post-human stage where we do have the technology to make these simulations where the the people inside are actually conscious, well, we're probably going to do it.
00:05:05
Speaker
That's my guess, at least. One other thing that I can mention here is that this is quite a big assumption that is being made here, that consciousness is realizable in a computational fashion.
Possibilities of Simulation Reality
00:05:21
Speaker
What does that mean?
00:05:22
Speaker
Basically, you can make conscious beings in a computer. That's a very big assumption that assumes that something like machine functionalism is true, that you know, mental states, they're just computational processes. that's ah That's a big if, right? So we will discuss that in a lesson a long time from now.
00:05:46
Speaker
But that is an assumption that is being made here. just wanted to flag that so that maybe one day we'll talk about it. Okay. Nick Bostrom asks us to think about the following three possibilities.
00:06:04
Speaker
He just basically says, imagine that, you know, ancestor simulations are a thing. What could be the case with regard to these simulations?
00:06:17
Speaker
Well, think of the whole universe and think about all the intelligent civilizations they're Here's basically the three kinds of possibilities that might be the case.
00:06:33
Speaker
It might be the case that zero intelligent civilizations ever reach the post-human stage. That is, no intelligent beings anywhere in the universe ever get the technological sophistication to make these little simulations where the people inside are conscious.
00:06:55
Speaker
That's possible. Why might that be the case? Well, maybe every single intelligent civilization destroys itself eventually. It might be the case, and you know if our intelligent civilization is any ah indicator of this, that we just don't know how to play with our toys well,
00:07:18
Speaker
our weapons are too powerful and we just can't agree on not using them and so we destroy ourselves it might be the case that there's a great filter such that no intelligent civilization ever acquires these ancestor simulations okay well that's one depressing thought maybe here's another one maybe some intelligent civilizations do reach the post-human stage, but they don't run the simulations. They say to themselves, well, that's ah it's kind of messed up, right? All the little people inside these simulations, that is real suffering.
00:08:05
Speaker
Why multiply suffering needlessly? so that's another possibility. For the record, i think that if humans ever achieve ah the capacity for ancestor simulations, we're probably going to use them.
Implications of Living in a Simulation
00:08:23
Speaker
Maybe that's, ah maybe maybe I just haven't had enough caffeine today. I'm ah being a little negative. Okay, the third possibility is that, of course, some intelligent civilization, maybe us, reaches a post-human stage, and of course, we run these simulations.
00:08:43
Speaker
If I, well, you know, what Bostrom says is that, you know, knowing nothing else, you might want to label these three equal probabilities, right? They're just as possible.
00:08:55
Speaker
i don't know. You can go ahead and disagree about that. That's not really the point of the argument. The argument really is asking you really focus on the third scenario. Imagine that humans, for example, really do reach the post-human stage.
00:09:17
Speaker
Well, then that means that you are very likely in a simulation. Why? Well, that's because... There would be more, way more simulations than actual realities. How many actual realities are there?
00:09:37
Speaker
One. How many simulations would there be? Well, maybe not everyone would have a simulation, but a lot of people would have a simulation.
00:09:48
Speaker
How about half of the population? Okay, well, that's already 4 billion simulations. So what are the odds then that you're in the real reality as opposed to the simulation or one of the
Connecting Bostrom and Descartes
00:10:06
Speaker
simulations?
00:10:07
Speaker
Well, that's about one in four billion. Those are not good odds, right? And that's just assuming that, you know, half of the population has one simulation, right?
00:10:21
Speaker
Maybe they don't have one. Maybe they have more than one, right? Two, three, whatever. And we haven't even gotten to the issue of a simulation within a simulation. Well, that multiplies things exponentially.
00:10:35
Speaker
Basically, your odds are really, really bad. If one day you see on the news, hey, we have finally made simulations where the people inside are actually conscious, you should automatically say to yourself, oh,
00:10:55
Speaker
ah that means I'm in a simulation or I'm very likely in a simulation or it's more likely that I'm in a simulation than not. That's at least what Nick Bostrom wants you to think. Scary, right?
00:11:12
Speaker
Well, when I present this argument to students, there's, i mean, you know, they're at least paying attention. That's kind of nice.
Descartes' Foundational Beliefs
00:11:20
Speaker
um A couple of things we can say here.
00:11:23
Speaker
First of all, Nick Bostrom and Rene Descartes have nothing in common. The only reason why I used this example is because it helps you really sort of you know, almost visualize, maybe seem to visualize a scenario where you really can question everything. Because if you are in a simulation, then it's even the case that, you know,
00:11:51
Speaker
maybe math is all messed up in your simulation. Like they they're having you believe that two plus three equals five, but you know that's just because the simulation was programmed that way. In reality, it's ah six or whatever. you know And so if you live in a simulation, it really is a case that you probably or can be at least wrong about everything.
00:12:16
Speaker
Math, logic, your body. You think you have a body, but you're just, i don't know, binary code ones and zeros. So if you're in a simulation, literally everything is questionable.
00:12:31
Speaker
And that means that you no foundational beliefs, right? Right. So that's why I invoked Mr. Bostrom's simulation argument.
00:12:42
Speaker
I'll give you one other comment here that I just want to make sure is clear. Bostrom, ah he had no epistemic aims with this particular simulation argument. Again, he is not trying to get you to, you know, conclude to the same thing that Descartes does, right? So these are completely separate. I just kind of borrowed it very briefly to make that point. And I hope you enjoy that point.
00:13:12
Speaker
So what are we left with? Do we know nothing with absolute certainty? Well, now we get to Descartes' absolute most famous argument. i'm actually I'm actually guessing you've heard of it before, even if you don't recognize here my my Latin title, the cogito argument.
00:13:40
Speaker
Cogito being Latin, as I mentioned. So Descartes would say something like, no, I know at least one thing. I know that I exist because I have convinced myself that I can doubt everything, including my own existence.
00:14:02
Speaker
But i can only doubt that I exist if I actually exist. Now that's kind of the wordy way of making this argument.
00:14:15
Speaker
Sometimes it gets truncated, it just you know gets abbreviated to just the following statement. Something to the effect of, I think, therefore I am.
00:14:31
Speaker
Well, that's wonderful, Descartes. That is what that means. i i bet you've heard of it before. and and now you know what the point of it is.
00:14:43
Speaker
He has found his first foundational belief, but it's not the only one. So let's kind of fast forward a little bit because it just it's just easier. I'm sorry.
00:14:58
Speaker
go check out Descartes' Meditations if you want to get the full story. But he, you know, sits there and continues to think. And he realizes, well, there's actually a couple of things that I know. So here are the four foundational beliefs that he arrives at.
00:15:16
Speaker
We've already named the first one. He, at the moment he is thinking he is thinking, must exist, right? So I think therefore I am. Another one is each phenomenon must have a cause.
00:15:33
Speaker
C, an effect can be greater, sorry, an effect cannot be greater than the cause. And D, the mind has within it the ideas of perfection, space, time, and motion. He says, we come out of the package already understanding space and time and motion and perfection. And he says, yeah, this idea of perfection, it's in there already.
00:16:02
Speaker
so from these foundational views, Descartes is going to try to, well, he's going to work his way all the way to science.
Simulation Compatibility with Certainty
00:16:13
Speaker
He's going to say, yeah, everything that we see, the way that we inquire with science, all of that is justified, and it is all based on these four foundational truths.
00:16:25
Speaker
Now, to be honest, you can question any one of these um and probably find a gap or something.
00:16:38
Speaker
And indeed, we will question two of them in this very lesson. A and d to be precise. But let's just start by taking Descartes at face value. just saying You know, OK, let's take these four beliefs.
00:16:55
Speaker
Take us all the way to science, Descartes. Take us all the way to the view that that this cup of coffee that I'm looking at is actually real. It's not some kind of figment of my my my imagination.
00:17:11
Speaker
get me to the view that I know with a hundred percent certainty that the mug of coffee in front of me is real. It is the way I think it is. Right? So, okay.
00:17:24
Speaker
We'll give Descartes the benefit of the doubt. No pun intended. We'll accept these four beliefs. Even if you accept those four foundational views,
00:17:37
Speaker
It's not clear ah this might work out, right? ah okay let me give you the ah the rationale here, or at least the the objection.
00:17:50
Speaker
It is not all clear, not at all clear how one would go from these four foundational beliefs to the rest of our beliefs about ourselves, other people and reality itself.
00:18:06
Speaker
For example, these foundational beliefs seem to be compatible with our existing in a simulation right so what do we got i i think therefore i am well you could be in a simulation uh each phenomenon must have a cause with the sure that's the way the source code is written an effect cannot be greater than the cause, says the simulation, and the mind has within it certain ideas.
00:18:38
Speaker
Sure. um That's because the programmer put those ideas in your head. Why not? So, you know, it's not the case that Descartes can get us from these four beliefs. At least it's not obvious.
00:18:55
Speaker
how he takes us from those four beliefs to the belief in the world, the way we think that it is, right?
Descartes' Argument for God's Existence
00:19:02
Speaker
So Descartes does consider this to his credit.
00:19:08
Speaker
And he said, no, I can bridge this gap. I gotcha. He said he could argue and prove that God exists.
00:19:18
Speaker
And because God exists, well, such a being wouldn't let us be deceived about those things of which we have a clear and distinct perception.
00:19:31
Speaker
So I see the you know cup of water in front of me. I have a clear and distinct perception about that. Actually, in my case, it's a cup of coffee. And what I can say is,
00:19:43
Speaker
Well, it seems like it's there. And Descartes wants to say, well, then you know it's there. And how is that? Well, you got to your four foundational beliefs and then you have to establish that God exists and God wouldn't let you be deceived about there being a cup of water or a mug of coffee in front of you.
00:20:03
Speaker
And so that's why you can trust that what you're seeing right now is as it is. So that's the general strategy.
00:20:17
Speaker
His argument. let me give it to you in an unacceptably small nutshell, was that he has an innate idea of a perfect God, right? he he says, even if I so doubt everything else, I do have this idea of perfection in my mind and of this perfect being, God.
00:20:40
Speaker
And well, you know, it seems to be the case that that idea was in there before I was born, it was is there already. Well, how did that idea get into the mind?
00:20:54
Speaker
It must be the case that it was provided for or implanted is maybe a better word by a perfect being. The idea of perfection can only be implanted into you by a perfect being, which of course is God.
00:21:14
Speaker
Therefore, God exists. I hope that made sense to you. If I could run through the whole thing one more time real quick, here we go. i know I exist.
00:21:26
Speaker
I have, even if I doubt everything else, by the way. Additionally, I have this idea of perfection and a perfect being, and we call that God. And the only way that idea could be in my mind is if that perfect being put it there.
Challenges to the Ontological Argument
00:21:43
Speaker
And so that perfect being must exist. All Well,
00:21:53
Speaker
we should give this a label. This is called an ontological argument because it basically relies on reason and definition, the definition of a perfect being alone to establish God's existence. There are many ontological arguments in the history of Western western and non-Western philosophy. It's all over the place.
00:22:18
Speaker
And historically, at least, Descartes' ontological argument is... not a winner, not really well regarded.
00:22:29
Speaker
in fact, even in his own lifetime, Descartes views were challenged. There was a princess named Elizabeth who was in a you know long exchange of letters between herself and Descartes. And you know it starts off like, hey help me understand your philosophy.
00:22:52
Speaker
And then it got more like, hey, this part still it doesn't make any sense. What about this problem? And it's really nice, though. they're They're very polite to each other. I wish our letters were this polite. In any case, Elizabeth basically demonstrates that, um you know, I'm not sure you got us there, Mr.
Eastern Philosophy on Self and Identity
00:23:12
Speaker
Descartes.
00:23:13
Speaker
So that is one very unsatisfactory aspect of Descartes' views. Basically, he needs God for his foundational project and his argument for God's existence is not fabulous. It is not the best thing in the world.
00:23:35
Speaker
So that's one problem. um When we accept those four views, it's still not the case that Descartes gets us out of skepticism. He needs God as a ladder and we're not sure he actually is entitled to that ladder.
00:23:51
Speaker
There are other problems. As I mentioned, i wanted to maybe question some of those foundational beliefs. So let's do that, you know.
00:24:03
Speaker
Here's a philosophical argument or perspective that runs counter to this idea from Descartes, this claim that he knows that he or i guess his self, his soul exists as a distinct thing.
00:24:24
Speaker
This is none other than that I think therefore I am inference. And so let's break it down here. Descartes is basically saying thinking occurs, therefore I know that a self exists.
00:24:39
Speaker
Okay, well, the question that we might pose here, the philosophical puzzle that we're going to cover next, is this. Does the existence of a thinking thing, sorry, does the existence of thinking require the existence of a unified self, a thinking thing?
00:25:02
Speaker
Hmm, well, this might be easier to understand if I first tell you a little bit of a story.
00:25:14
Speaker
So we are moving into the east and there is a king named Melinda. And by the way, ah this is an Indo-Greek king ah because if you don't know the details, Alexander the Great conquered a ton of stuff, like a lot of territory.
00:25:35
Speaker
And then he died. And members of his entourage, basically, they couldn't keep the empire together. So it just fragmented and a bunch of Greeks were running, were in charge of territories, basically all over the place. You know, really vast distances were run by Greeks.
00:25:58
Speaker
And this is called the Hellenistic Age, by the way. These are usually called Hellenistic hellenistic Kingdoms. And yeah, I mean, very famous example is Cleopatra about a century after the century we're talking about right now.
00:26:14
Speaker
And we're in the second century BC, right? So k Cleopatra, a little bit after this point, ah she, you know, she runs Egypt, but she's Greek, right? So ah it's it's a mess, but it did happen. So whatever.
00:26:30
Speaker
Okay, there is a king of this Indo-Greek world because it's really far east. And he is known for his sharp intellect and love of philosophical debate.
00:26:43
Speaker
And one day he welcomes the Buddhist monk Nagasena. And he questions him, hoping to you know catch him in an inconsistency. So going to kind of give you this little dialogue.
00:26:55
Speaker
King Melinda says to Nagasena, tell me, monk, what is your name? Nagasena says, I am called Nagasena, your majesty.
00:27:07
Speaker
The king says, and this Nagasena... Is this truly you? Is your body Nagasena? What is this Nagasena exactly?
00:27:18
Speaker
And Nagasena says, no, your majesty, it's not my body. And the king says, well then are your sensations Nagasena? Or your feelings, your perceptions, your thoughts?
00:27:30
Speaker
Nagasena says, no, your majesty. Okay, the king says, is your consciousness Nagasena? And Nagasena says, no. The king, now getting frustrated, then is Nagasena the collection of all these things?
00:27:47
Speaker
Nagasena says, no, your majesty. Then i must ask plainly, where is Nagasena? I see a man sitting before me. I hear you speak.
00:27:59
Speaker
Yet you deny that any part of you is Nagasena. Are you lying to me? Nagasenna, the monk, says very calmly, you know, they're all Zen and stuff.
00:28:11
Speaker
Your Majesty, how did you arrive here today? The king says, in my chariot, of course. Nagasena says, then please tell me, what is the chariot?
00:28:24
Speaker
Is it the wheels? No. Is it the axle? King says, no. Is it the frame? The king says no again. is it the collection of wheels, axle, and frame?
00:28:39
Speaker
The king says, that's not quite right either. Nagasenna says, then your majesty, where is the chariot?
00:28:50
Speaker
The king says, chariot is only a name, a convenient way of speaking. It refers to the arrangement of its parts.
00:29:01
Speaker
And so Nagasena says, just so, your majesty. And in the same way, Nagasena is only a name, a way of speaking about the body, sensations, perceptions, thoughts, and consciousness taken together.
00:29:18
Speaker
There is no separate self behind them.
00:29:23
Speaker
Okay, I don't know if that was sufficiently cryptic for you, I hope it was, but what is that exactly is being said here? What is being questioned is whether or not the coagito argument actually proves the existence of a persistent, independent self that carries Descartes' personal identity.
00:29:50
Speaker
What Nagasena is basically saying, except not, never actually says it, just as motion does not require a separate chariot substance, thinking may not require a separate thinking substance.
00:30:10
Speaker
It is, according to this way of thinking, a conceit that we all have that there is an eye behind our thoughts.
00:30:24
Speaker
Now, this is incredibly Eastern. Let me be be very clear as to what's being said. First of all, This does not deny experience.
00:30:36
Speaker
You, as you're sitting there right now, I'm positive that you are seeing images. I'm positive that you are hearing my voice.
00:30:47
Speaker
i am positive that you are aware that you are seeing images and hearing my voice. What Nagasena is saying though, is he's saying having an experience, a conscious experience, does not prove the existence of a self, of a thing like self.
00:31:13
Speaker
So, According to Nagasenna, Descartes shows us that thinking itself cannot be doubted. That part's true. If there is, you know, doubting going on, there is thinking going on.
00:31:30
Speaker
What Nagasenna is getting at is, a you know, involves a different question. Does thinking require a thinker or just thinking? it Can thinking be done just without a thinker?
00:31:50
Speaker
So, of course, we are not explaining this thoroughly ah because we would have to get into Buddhism for all this. But a very central tenet of Buddhism has to do with the way that um we construe the self.
00:32:13
Speaker
And they have some, you know, Pali words for this. But here are the basics, basic gists of ah of this tenet. There is no eternal self. And by the way, Descartes believes that his soul is eternal.
00:32:28
Speaker
There is no stable perceiver or haver of thoughts. You might have heard that saying that you never step into the same river twice because you are not the same and the river is not the same.
00:32:41
Speaker
That's the same idea here. you change over time. Your likes, your dislikes, your thoughts. There is nothing having the thoughts. The thoughts are just there.
00:32:55
Speaker
And awareness of the thoughts makes you believe there is an I there. But Buddhists deny this, right? They say, well, it seems that way, but it's not.
00:33:06
Speaker
There is no essential self, right? Tied to a notion of personal identity. Your awareness of a thought, of a perception of whatever, it doesn't mean that you have a persistent personal identity.
00:33:24
Speaker
Descartes, by realizing that he's you know he's thinking when he's doubting, he doesn't establish that Descartes' personal identity is real.
00:33:37
Speaker
How could he? It's just a moment when he realizes where he's thinking. It doesn't connect to some identity where he likes these things and he doesn't like those things. and you know's There's no connection there.
00:33:53
Speaker
And there is no self as a thing that originates or causes anything. You don't need a self to have thoughts. You don't need a self to cause thoughts to arise.
John Locke's Empiricism
00:34:04
Speaker
The self is itself a thought that arises and goes away. Now, we will eventually dive deeper into Buddhism But initially here, all we want to do is make that challenge to Descartes.
00:34:22
Speaker
Does awareness that you're thinking really establish the existence of the self that Descartes wants to establish, his soul, as a thinking substance,
00:34:36
Speaker
The Buddhists would say no, right? So maybe this is not quite a knockdown argument. Maybe I'm just presenting two alternatives to get you to at least see that, well,
00:34:49
Speaker
Maybe this whole, I think, therefore I am is not indubitable, right? mean you Maybe you can question it. So there you go. And unfortunately, this changes, um if you take the Buddhist perspective, it changes the argument. I think, therefore I am becomes something with a little bit less of a ring, right? It's something like, doubting is thinking, therefore there is a thought when doubting is occurring.
00:35:18
Speaker
That's not, doesn't kind of roll off the tongue, you know. Not only that though, this eliminates ah the interference from thinking to a thinking thing, which is one of Descartes' foundational beliefs. And so there you go.
00:35:37
Speaker
Maybe a little difficult to grasp, but there is a challenge there to Descartes' cogito argument. Now, there is another view that we can challenge, that that fourth view, D, which I mentioned earlier, this idea that you are born with ideas inside your head.
00:36:00
Speaker
And to understand that, we're going to look at um a division of thinkers that has been very... um I guess I should say important in the history of philosophy.
00:36:18
Speaker
There's two camps of thinkers that retrospectively historians of philosophy have kind of lumped together. On the right hand side here we have Descartes and Spinoza and Leibniz. We will talk about them later.
00:36:36
Speaker
But these are known as the rationalists. And on the left, we have in the center, John Locke, and that's the person we will be covering, but also David Hume, bottom left, and George Barclay,
00:36:53
Speaker
top left. So these two camp, or they're called the empiricists, by the way. And so I guess one thing I should say real quick is that if you were to ask them whether they're a camp, they would probably say no.
00:37:08
Speaker
They would say, no, I argue against these other people all the time, right? Everyone here argues against everyone else. So it's not that, you know, they would have thought of themselves as being in the same camp.
00:37:20
Speaker
But for our purposes, we will realize that lumping them together helps us understand the basic distinction between their approaches to knowledge. And so, well, I guess we should ah get to that right now.
00:38:14
Speaker
So we've been looking at Descartes' four foundational truths. Purportedly, he can get us from these four truths all the way to the knowledge of everything that we have a clear and distinct perception of.
00:38:32
Speaker
And that, among other things, allows him to do science and all kinds of things that he wants to do without getting in trouble. This is maybe where I can mention that, you know, it was the case that he was talking about an evil demon causing us to be able to doubt everything. So now you can see his overall project as really having that, you know, ah you know being um driven by this desire to reconcile faith and reason.
00:39:05
Speaker
If demons are associated with doubt, well then pray tell, what does God give you?
00:39:17
Speaker
God is the one that gives you knowledge, right? So he is trying to, mean, he's selling it, right? he's He's definitely giving us what he believes is a strong philosophical foundation for understanding reality. And he's emphasizing that this need not be in any way counter to faith.
00:39:38
Speaker
the christian faith he was a catholic by the way so that is where we were and we went ahead and saw that taken as a group it's not clear it's not obvious that they can take us all the way to the promised land of you know absolute certainty in everything that we see And in fact, even if we you know don't take them as a group, but we start questioning each of them individually, we see that there might be some holes in these, right? So we took some time to take a look at the Buddhist perspective and how that might cause us to doubt the truth of this first proposition here. He, at the moment he is existing, must exist.
00:40:27
Speaker
I'm going to go in a different direction now and let's look at this idea here, proposition, the fourth one, d The mind has within it the ideas of perfection, space, time, and motion. This is known, are these built-in ideas, they're known as innate ideas, ideas that you're born with.
00:40:53
Speaker
And some philosophers of the era didn't find that view terribly attractive. So now we move into the views of John Locke.
00:41:06
Speaker
John Locke has an interesting history. He was a physician and also a philosopher, also a political philosopher in particular. But today we will be looking at his views on epistemology coming from his an essay concerning human understanding 1689.
00:41:29
Speaker
He does not think we have innate ideas and he gives us a nice, neat argument to convince us of that. Premise one, if humans really had innate ideas, for example, our idea of self, of perfection, of God, of logical principles, whatever, then young children would understand them, right?
00:41:54
Speaker
If they, you know, if we come out of the box with these ideas, well then those creatures that literally just came out of the box should have those ideas in them, right? Young children should have an idea of perfection, of God or whatever, right?
00:42:15
Speaker
But children don't show any or much comprehension of these particular ideas. They have to be taught.
00:42:28
Speaker
Therefore, humans aren't born with innate ideas. As you can tell, all of the whole force of the argument hinges on that premise too. And we can think about this for a second. I mean, it really is a case that kids are not terribly...
00:42:46
Speaker
ah well-informed about a lot of things that um we might say are the kind of ideas that Descartes was getting at with the idea of perfection. Kids would do anything until you teach them to not do that. They will draw on your walls. They will eat things they're not supposed to eat.
00:43:07
Speaker
play with things that are dangerous. They will put their hand on a hot stove and whatever. Of course, when it comes to things like an idea of a perfect God, i have, I'm actually sure that a lot of you can, if you grew up in a religious household,
00:43:29
Speaker
The theology of very young children is sometimes a little askew. it's It's kind of hilarious, actually. I remember personally that I would ask if God could handle a lot of spicy food because I, at the time,
00:43:49
Speaker
Everyone that I thought was awesome in my life when I was a kid apparently liked spicy food. And so I figured, well, God um is even better, right? So he must be able to handle a lot of spicy food. That question doesn't even make any sense, right? It's not a physical being. It doesn't have a mouth. God doesn't have a mouth. So, yeah you know, the whole idea that children come out of the box knowing ideas of ah of a perfect being like God, that Doesn't really pass the smell test. Do they have an idea of self?
00:44:25
Speaker
um Maybe, but you know, isn't, doesn't it take a long time to discover who you are, what you're really about? That doesn't seem to be the case that we also come out of the box knowing. ah how about of logical principles?
00:44:42
Speaker
I teach symbolic logic. I can tell you with a considerable degree of confidence that most people don't come out of the box knowing how to do logic or how to apply logical principles.
00:44:58
Speaker
You have to be taught to do it. And so, well, all all that counts against this idea that these concepts come embedded in us.
00:45:11
Speaker
It must be the case, John Locke would say about Mr. Descartes, that Descartes learned these things at some point. And that's why they're they're intuitive to him. they're they're They're very well integrated, but he didn't come out of the box knowing them.
00:45:29
Speaker
Okay, well, if you're beginning to like some of Locke's ideas, let's have a little checklist here. See if by the end of the lesson you are Lockean. First of all, he rejects this notion of innate ideas. if That sounds good to you. We'll check that off. Let's keep going here.
00:45:49
Speaker
According to Locke, we are born with a blank slate. What this hypothesis amounts to is that human are born with the Latin phrase a tabula rasa or blank slate. In other words, we are born not knowing anything.
00:46:09
Speaker
So, no, the mind doesn't have any innate ideas within it. Everything that we know is acquired through sensory experience and of course reflection on that sensory experience.
00:46:28
Speaker
John Locke is incredibly clear about this, right? I have a direct quote from the man. Let us then suppose the mind to be, as we say, white paper, void of all characters, without any ideas.
00:46:46
Speaker
How comes it to be furnished? Whence has it all the materials of reason and knowledge? To this I answer in one word, from experience.
00:46:57
Speaker
In that, all our knowledge is founded and from that, it ultimately derives itself. So there you go, the senses, your eyes, your ears, when you touch things, when you smell things, when you taste things, that's how you come to know everything.
00:47:16
Speaker
You are born with zero knowledge and then you go and passably experience things through your senses and that's how you get your ideas of everything and that goes from you know what watermelon tastes like what the sound of birds is to you know eventually mathematical principles and of course theology all of that is acquired over time This view that everything we know comes from sensory experience is known as empiricism.
00:47:54
Speaker
Now, the key aspect that I want to stress right now is that it is... it right sensory experience alone nothing else um helps you acquire the basic building blocks of knowledge anything that enters your your mind is either a product of sensory experience or a product of your ideas of sensory experience things that you already have in your mind that you put together in your mind
00:48:28
Speaker
There is therefore no possibility of separating knowledge from the subjective condition of the knower. We build up our personal knowledge structures on our own, in our minds, right? Through the information that we get from the senses.
00:48:50
Speaker
So
00:48:53
Speaker
Let's go back here to this slide where we have, on the one hand, the rationalists who are, let's just say that Descartes is our poster child for them at the moment.
00:49:03
Speaker
And John Locke will be the representative for empiricism. Now you can kind of tell the difference. The the rationalists, they basically believe that you can get a sort of a bird's eye view of reality. You can come to know everything, ah typically through mathematics. They are very much fans of mathematics and
Simple vs. Complex Ideas
00:49:29
Speaker
logic. And through this, ah they they think, you know, we can discover mathematics from pure reason.
00:49:36
Speaker
And from that, we discover the nature of reality sort of ah from above, right? It's very top down kind of approach. um Or maybe another way to put it is it's an inside out kind of approach. Essentially, you begin with the foundational truths in your mind that you come to discover on your own. And then from that, you but build a belief structure that helps you understand all of reality.
00:50:05
Speaker
Well, Mr. John Locke is not quite of that camp. He is an empiricist. And that means that it's actually more so outside in.
00:50:15
Speaker
We are born with nothing in the brain. And all we can do is, you know, go look at stuff, go taste things, go feel things.
00:50:26
Speaker
And so the outside world imprints itself inside of our mind, outside in. And that's how we build our model, our map of reality.
00:50:38
Speaker
But it's not perfect. So you can't get that deductive certainty that Descartes is trying to get. The best you can do is, let's use a little bit of jargon here, is inductive, you know, knowledge, right?
00:50:54
Speaker
It's probabilistic knowledge. So when you distinguish induction from deduction, deduction is about certainty. It's an all or nothing kind of thing, right? Either you're sure about everything or you're not.
00:51:07
Speaker
But induction is, you know, more so in it comes in degrees, right? So I have a 95% confidence that my map of reality is accurate.
00:51:19
Speaker
it leaves a little bit of room for for error, right? You cannot create a perfect map of reality in your mind. So if I had to break these break down these two views into a nutshell, empiricism, knowledge comes from the senses and it ends up not being quite very perfect And for rationalism, at least Descartes' rationalism, knowledge is rooted in reason. And you have to begin with things that you know from, you know, pure reason alone. And of course, in the case of Descartes, it is those four foundational truths that we talked about. And then from there, he builds up his model of reality.
00:52:00
Speaker
And there you go. That is the rationalist approach. Maybe one last thing I can highlight here is that whereas Descartes had all kinds of arguments, you know, for why it is that perception, the senses are not reliable.
00:52:18
Speaker
He instead relied on reason. He says, well, reasons for you really want to, you know, put all your eggs in that basket of reason. ah Locke says, yeah, obviously, you know, the senses aren't perfect, but they're pretty darn reliable. And so that might be another Lockean point that you subscribe to most people.
00:52:42
Speaker
When I kind of, you know, ask them which one of these ah is more reasonable to you, they usually go with luck. they They do like this idea that, yeah, obviously we can use our senses for something, but maybe not. Hey, maybe you like that reason approach. I'm going to let you make up your mind about that later.
00:53:03
Speaker
Let's move into simple and complex ideas. Simple ideas are passably received by the mind and have no other ideas as parts.
00:53:14
Speaker
These ideas perfectly represent the external world. So simple ideas are, you know, that you you go around the world and the world imprints itself in your mind. And it's kind of like a typewriter. I think Locke uses that metaphor where you, you know, go look at something and it's like, you know, the characters are being written in the brain and you don't have to do anything. It happens just naturally.
00:53:44
Speaker
Let me give you some examples of some simple ideas. I will use one of my very favorite topics is coffee. I am a fan of coffee, maybe caffeine in general. I am not an addict though, for the record.
00:53:59
Speaker
My wife though, maybe. Okay. So coffee has several different, if you have good coffee, by the way, do yourself a favor, grind your own coffee beans, preheat the vessel. You got to warm up your cup before you just pour stuff in there like that. Anyway, once you kind of ah build a um you know, a sense for these things, you can actually pick up quite a few beautiful notes of flavor in your coffee.
00:54:31
Speaker
And I'll give you some ideas here. So especially if you get a medium roast, you know, a nice Arabica, you might get ah a little bit of a caramel flavor or sometimes maybe a very subtle butterscotch flavor.
00:54:45
Speaker
a spiced rum flavor. I've had some barrel aged coffee beans because why not? Sometimes you will get a a light mouthfeel with coffee. Mouthfeel, it depends on what you're drinking, right? If you're drinking wine, some wines feel kind of heavy in the mouth. Sometimes they feel light.
00:55:03
Speaker
ah The feel of velvet. I love a good, maybe a light roast might be a little softer and belvety. There's no way you can further break down these ideas. If you go up to someone and you're like, oh, this coffee has a little bit of a caramel flavor.
00:55:21
Speaker
And they ask you, oh what's what's caramel flavor composed of? It's, that i don't know, it's caramel. You know, there's really, you can't break it down any further. And so that's a good example of a simple idea. It's just like the basic atomic building block of of a flavor. Now you might put all these flavors together,
00:55:44
Speaker
And then, you know, you can say, well, this is this all together is the experience of drinking this particular coffee. And that might be the case, right? now You might have a very complex coffee where you can actually, if you think about it, pick up all these things.
00:56:01
Speaker
And so in that case, if you're thinking about drinking this coffee, that is a complex idea. It is composed of lots of simple ideas. So let me give you here the definition of complex ideas.
00:56:14
Speaker
Basically, they're just ideas produced by the mind operating on ideas that are already in the mind. So if in your mind's eye you put a bunch of simple ideas together, like I just told you about one of my favorite cups of coffee that I brew for myself, well then yeah, i have a if I'm thinking about that coffee, that is a complex idea composed of lots of other simple ideas like spiced rum and the light mouthfeel and whatever else I said, right? So
00:56:46
Speaker
These are not as accurate as simple ideas in representing the external world. And that is very important. So in other words, it's kind of easy in my mind's eye to sort of invoke or think of the flavor of
Locke's Indirect Realism
00:57:05
Speaker
what's a good one? Butterscotch. I think I have it in my head. I can literally kind of not taste but, you know recreate it in my mind. I don't know how.
00:57:15
Speaker
But to recreate something more complex, like a very complex coffee, that's a little difficult, right? I'll give you another example. how about this? It's easy to think about maybe the color red or different shades of red.
00:57:33
Speaker
But now i try to imagine a painting that has lots of different shades of red in it. it's hard to visualize it perfectly. You're really kind of getting a blobby creation, you know?
00:57:49
Speaker
And it's only when you are looking at the painting that you can really kind of, okay this kind of red, this kind of red. So complex ideas are just a little less, what's the word I'm looking for?
00:58:02
Speaker
there's a little bit less fidelity, right? So simple ideas are closer to the actual thing out in the world and a complex idea that, you know, our map of them is just a little bit fuzzier than of simple ideas.
00:58:17
Speaker
Okay. So, To sum up, out of simple ideas, you can make complex ideas and you can also reflect upon them. So let me give you an example that. um I don't know, maybe you think the color blue, that's a simple idea. And the color blue makes you feel calm.
00:58:38
Speaker
Yeah, well, that would be reflecting on sort of the effect of the color blue on you. or you might also say what's another simple idea that you might reflect on maybe the you know spiced rum flavor that i mentioned earlier that reminds me of christmas i don't know why that reminds me of christmas i'm not even sure why i said that but the general idea here is that simple idea might invoke some other memory you might make some other association with it in your mind and that would be reflection
00:59:13
Speaker
Out of complex ideas, you form more and more complex ideas. So an example of that might be you can take the concept of a car and take the concept of a plane and put them together in your mind. And now you have a flying car.
00:59:35
Speaker
And there you go. Two complex ideas fused together based off of ah prior complex ideas already existing in your mind. And there's also categories of ideas that can help you sort of organize your your map of reality. So the category of horse or hoarseness, if you want to say it like that.
00:59:59
Speaker
Basically, you're thinking of a mammal. That's a complex idea. And you're thinking of a... four-legged creature and that's a complex idea and you're thinking of a domesticated animal too and that's its whole category and so you're putting all these things together with a ton of biological information that I don't know I don't know that much about horses but you put all these ah complex ideas together and that's how you get your idea of hoarseness or the category of a horse maybe a visual would be ah good for you here
01:00:32
Speaker
So let's start with simple ideas being put together. You take the simple idea of red and simple idea of sweetness and all kinds of other simple ideas to be honest. And then eventually you produce the complex idea of an apple. Okay, there is one example.
01:00:51
Speaker
And of course, you can also lump together complex ideas. So as I mentioned earlier, you take your simple ideas that constitute the idea that eventually, sorry, the simple ideas that eventually constitute the complex idea of a horse, like this horse right here, and take some other complex idea that you have in your mind, maybe like ah like a shark.
01:01:15
Speaker
and now combine them in your mind and you get a hark or a source i don't know what you want to call that thing but it is horrifying so the point is you can put together complex ideas and those are the workings of the mind If you like those, let's go ahead and check those off. Maybe you're a Lockean. I don't know.
01:01:42
Speaker
Let's check off the last item here so that in the very least, maybe you don't agree with Locke, but you understand the man. This view, it actually goes by a lot of names. I don't like some of the names that it goes by. We're going to call this indirect realism.
01:02:01
Speaker
That's the view that all we ever perceive is our own ideas, not the external world. Our ideas, however, are similar to the external world.
01:02:15
Speaker
What does that mean? Well, the world imprint itself on us as we experience it. But all we really you know have access to is our ideas of the world, not the world itself.
01:02:34
Speaker
Our senses are like a mediator for us. They're the ones that are you know taking input from the world. But what it produces in us, what we have conscious access to, that's all been interpreted by our eyes and ears and mouths and whatever, right? So it's not direct contact with reality.
01:02:57
Speaker
It is indirect contact with reality. If you want to visual a visual representation here, you got Homer and he's sitting there drinking a beer And I don't know why when he's drunk, he likes to look at people's foods. So he points his eyes in the direction of some carrot cake.
01:03:16
Speaker
Now, this carrot cake is not being directly seen by him. His senses are, you know, light goes into the eyeball and it's upside down or whatever. And so eventually his visual cortex produces an image of this carrot cake.
01:03:35
Speaker
And it is, you know, there isn't perfect fidelity. It is his senses interpreting what is outside in the world and producing an image in his mind, in Homer's mind.
01:03:49
Speaker
And in fact, there is no way that you can ever come into direct contact with the world itself.
Empiricism vs. Rationalism
01:03:58
Speaker
It is always the case that it will be mediated by your sensory organs.
01:04:05
Speaker
So indirect realism. What you're looking at is a world. Your senses are reliable, but it is indirectly and it is an approximation. It is not perfect. So there, once again, we see that basic difference between the rationalist Descartes, who believes we have deductive certainty in you know what we see,
01:04:32
Speaker
And Locke who says, well, i don't know about certainty. It's a pretty good approximation. You can have a you know considerable degree of confidence, but it is not perfect.
01:04:45
Speaker
In a nutshell, perfect knowledge of the world is not possible. There's at least two reasons for this, right? No one person can interact with all the things in the universe to produce an idea of those things. That's sort of the li the less important reason. The more important reason is that by our very nature, knowledge of complex ideas is not perfect.
01:05:12
Speaker
We have to put them together based on our experience of simple ideas. But as we put these simple ideas together into complex ideas, the degree of accuracy goes lower and lower and lower. And of course, the world is very complex. The world is hard, right? And so, yeah, our map of the world is not at 100% accurate. It's just an approximation.
01:05:42
Speaker
and as such, well, we should attenuate our confidence. We cannot say that we know with 100% certainty
01:05:54
Speaker
what is going on, right? there There is no, you shouldn't know things, you shouldn't claim to know things with a moral certainty.
01:06:05
Speaker
And that actually brings this full circle to how we began these lessons on Descartes and we snuck in some Locke in there. Remember, these thinkers were considering how it is that they can help mitigate some of the harm being done by overly dogmatic religious convictions.
01:06:30
Speaker
Right. Some people were believing that they knew what was right and wrong to such a high degree of confidence that they were literally torturing and killing other Christians because they didn't believe the exact same thing that they believed.
01:06:48
Speaker
Each person in their own way, Locke and Descartes, they're trying to get the people of their age to tone it down a little bit, right? Descartes was saying, okay, first of all, science and um faith and religion, They are compatible. In fact, the work of demons, that's what causes doubt. It is the case that it is God who can help us achieve knowledge of reality.
01:07:21
Speaker
And so that's you know Descartes' way of of trying to you know simmer things down a little bit. Locke, for his part, was saying, look, we're trying to build our maps of reality, each and every single one of us.
01:07:37
Speaker
And you know we're humans. The way that our minds work, it's not going to be perfect. You shouldn't think that you have a perfect map of reality, that you know everything perfectly.
01:07:49
Speaker
You probably don't. And so if there's a little bit of a, you know, tension here or there with someone else about their beliefs, hey, take a step back and say, well,
01:08:02
Speaker
Let's see what we do agree on and let's see if we can figure out why we disagree what we disagree on So both of these thinkers in their own way are addressing the concerns of their age.
01:08:16
Speaker
But now the question is, who do we go with? Who do we side with? These are literally... incompatible views.
01:08:27
Speaker
rational Rationalism begins with reason, empiricism begins with the senses, and they build up entirely different belief structures.
01:08:37
Speaker
So They each have problems and maybe it'll be easier to see this when we look at some problems with Locke's view in the next lesson.
01:08:48
Speaker
But for now, I just want you to think about what is the intuitive appeal of each? Which one would you side with?
Evaluating Epistemological Approaches
01:08:57
Speaker
If you're living in the late 1600s and you've been exposed to both the views of Descartes and of John Locke, who are you siding with?
01:09:10
Speaker
Well, don't make up your mind yet. We still have to look at some issues with Mr. John Locke, and then we'll consider them in tandem, right? We'll even add there Francis Bacon.
01:09:23
Speaker
What is the right approach to knowledge? All that and more the next lesson.