“How do we combine concepts to form thoughts? How can the same thought be represented in terms of words versus things that you can see or hear in your mind’s eyes and ears? How does your brain distinguish what it’s thinking about from what it actually believes? If I tell you a made up story, yesterday I played basketball with LeBron James, maybe you’d believe me, and then I say, oh I was just kidding, didn’t really happen. You still have the idea in your head, but in one case you’re representing it as something true, in another case you’re representing it as something false, or maybe you’re representing it as something that might be true and you’re not sure. For most animals, the ideas that get into its head come in through perception, and the default is just that they are beliefs. But humans have the ability to entertain all kinds of ideas without believing them. You can believe that they’re false or you could just be agnostic, and that’s essential not just for idle speculation, but it’s essential for planning. You have to be able to imagine possibilities that aren’t yet actual. So these are all things we’re trying to understand. And then I think the project of understanding how humans do it is really quite parallel to the project of trying to build artificial general intelligence.” -Joshua Greene

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