 So let's give this a shot. What question is Locke trying to answer? And what is his answer? Now we've changed tactics, okay? So from the pre-Socratics, we were dealing with the question, what does it mean to exist? The Sophists, at least they're Semicas, excuse me, at least they're our protagonists are Gorgias. We're asking this question about the nature of truth. What does it mean to be true? We switch very briefly over then to Descartes and Russell when we deal with skepticism. And they were trying to deal with knowledge, at least in a very limited extent. When we get back to Plato and Aristotle, they're both dealing primarily with metaphysics. What does it mean to exist? Now the answers up to this point have been very unsatisfying for us involved and pretty much for everybody at large. You have the pre-Socratics with all their disagreement. You have Plato talking about being, but then you can't define being. You just have to know being by contemplating being. That's not very helpful. You have Aristotle who says what it means to exist is to be a composite of form and matter. But then by the way, since neither form nor matter are substance, they don't actually exist. So you have what's real being composed of what's not real. It has some very unsatisfying approaches up to this point and people get really, really tired of this. Now what Locke is doing is saying he's kind of had enough of this. Enough of this trying to give an account of existence by appealing to some kind of weird knowledge. So he's going to take a step back or at least he at least tries to question, well, then how do we know about what's real? So he switched questions. He switched from what does it mean to exist to what's knowledge? What is knowledge? Now his answer to this question is what is knowledge are ideas. Ideas are the only thing that we know. If it's not an idea, then we don't know it. Then we can very quickly ask, well, then what's an idea? Or at least what's the source of all ideas? All the ideas are happening up here, but where do they come from? What's the source of all ideas? And according to Locke, the source of ideas is experience. So the problem that Locke has with everything that Plato and Aristotle have done, and we haven't even looked at these other folks, is how they are trying to account for their knowledge. Where does the source of their knowledge? For both Plato and Aristotle, they both have some kind of non-empirical account of knowledge. At least some of the sources of their knowledge is not empirical. For Plato, it's this recollection of the forms that you had prior to your physical birth. For Aristotle, it's this recognition, but it doesn't really go into what that is. Somehow the form of the object is transmitted to your brain. It's never a very satisfactory account of knowledge, because it's always non-empirical. Instead, Locke says, forget about these non-empirical accounts of knowledge. Forget rationalism, because that's only going to lead you down a crazy train. Forget rationalism. Instead, we're going to say, all knowledge is empirical. All knowledge comes from experience. So the source of all ideas for Locke is experience. Is experience. And there's two kinds. He's got two kinds of experiences, sensation and reflection. Sensation, this is what you get from your five senses. For your eyes, your ears, your skin, your nose, what you see, what you smell, what you taste, what you hear, what you touch. That's the source. That's sensation. This is the raw data that you're dealing with. If it doesn't at least start, when you acknowledge that the outside world doesn't at least start with sensation, you've got a big problem. That's one kind of experience of sensation. The other kind is reflection. Sensation is what you experience from the outside. Reflection is what you experience on the inside, inside your head. So it's how you think and how you react and how you deal with this sensation, with all these sensations. What do you cognize with these sensations? So here's what Locke's trying to do. He's trying to answer the question, what's knowledge? How do I know? He's not really dealing with metaphysics deals with just a little tiny bit. He gives a little tiny bit of an account of what it means to exist, but not very much. He's dealing primarily with knowledge. All knowledge is an idea or ideas. The source of all ideas is experience. The two kinds of experiences we have are sensation and reflection. Sensation is what we experience from the outside, reflection is what we experience from the inside. And he's rejecting rationalism. Rationalism is the claim that there's some kind of non-empirical, non-experiential knowledge.