 An analytic philosopher sits down in a bar and asks for a coffee with no cream. The waitress says, I'm sorry, but we're out of cream. How about with no milk? All right, pick a card. No, it's okay. I'm not looking. Pick a card. Just point to one on your screen. Okay, now I'm going to find the card that you picked and remove it. Are you ready? BAM! Pretty amazing, right? Only the thing is, this second set of cards is completely different from the first set that I showed you. I didn't actually find your specific card. I just told you a nice story and let you think that what I did was impressive, even though if you were paying close enough attention, you'd know that it wasn't. Logical fallacies and many of the other errors that we make in thought function on pretty much the same principle. They let us mistake something that sounds rational for something that is rational. Part of the problem is that we tend to think in language, and language is really sloppy. Like if I say the right to bear arms, you don't know if I mean the right to carry a gun or the right to carry a severed limb or the right to have the limbs of a bear. Also, unfortunately, there is absolutely nothing that prevents somebody from creating a sentence that might seem like it says something, but in actuality doesn't mean anything. I can say the bachelor went to the store for his wife, or this water doesn't have any hydrogen in it, or even this sentence is false. Those aren't even lies, they just don't mean anything and they don't sound any different from sentences that do. So how are we supposed to know if an idea actually makes sense or just sounds like it does, like in a logical fallacy? That's actually a really tough question to answer. Aristotle wrote about formal logic almost 2,300 years ago to provide some sort of a guide to interpreting the validity of certain statements, but it was still fundamentally based on interpreting language and so it was only so effective. But around the start of the 20th century, almost 2 millennia after Aristotle wrote about logic for the first time, some mathematicians decided that they'd had enough of people just wandering around and saying stuff. They began examining and defining the structure of thought under language to try and wrestle it into a format of precise analysis that was, well, more objective and mathematical. That was a huge deal, a truly momentous event in the history of human thought. Before these guys showed up, you had to depend on a sort of intuitive sense of whether or not sentences sounded like they followed logically from each other. But their work uncoupled logic and thought from language, so we could sort of step back and take a look at the shape of what was being said, independent of the contents, which made verifying whether or not a logical argument was valid as easy and mechanical as punching numbers on a calculator. Gottlieb Frege kicked this whole revolution off just by trying to put mathematics on a firmer logical footing. But in the process, he recognized that he had developed a useful way for talking about logic generally. He invented a method for writing ideas as sequences of logical symbols, including a radical new method for referencing individuals as parts of sets that was actually more specific than language could ever be. Like, you can write sentences using these logical symbols that would be vague and confusing if you tried to say them in English, and also just look at them and know whether or not they're logically valid at a glance. Something like this would have knocked Aristotle right out of his toga. Frege's work inspired philosopher-mathematicians Bertrand Russell and his pupil Ludwig Wittgenstein, who was a total genius but only has like three pictures of him and only one where he's smiling. Wittgenstein's first book of philosophy, The Tractatus Logical Philosophicus, was intended as a line in the sand, separating sense from nonsense. He basically said that if someone made a statement that was neither a testable empirical claim about the world, like, that cat is on the mat, or a relationship between word definitions, like a cat is a domesticated feline, then that person was just speaking nonsense and really shouldn't be saying anything. He also explicitly called out philosophers of the past for what he viewed as a sort of vague word masturbation, saying that they had written whole books about opaque concepts, which, if defined properly, wouldn't have been debatable at all. Ouch. That's pretty bold. But despite being confrontational, Wittgenstein's work, as well as the work of his colleagues, really changed the world. Today, analytic philosophy, the science of discovering and evaluating the structure of thought under language has become the most practiced type of academic philosophy in the world. But it's not just about logical symbols and truth tables, and it's not just for academic philosophers either. Analytic philosophy is more of an attitude than anything, and I think that it's really useful for just about anyone. We sometimes play loose with language and depend on other people to fill in the gaps in what we say for themselves. We'll sort of wave our hands and gesture broadly in the general direction of vague notions or supposed links in our chains of thought that we're either too busy or too lazy to flesh out all the way. But if we don't rigorously, mercilessly check that every single segment of that chain is impossible to disconnect from the ones that came before it, or define exactly what it is that we're talking about, it becomes really easy to skip over something important because it sounds reasonable and in the process make huge errors in reasoning. Of course free will exists. I could go back in time to this morning and choose to have something different for breakfast. Well, would you be going back in time knowing what you had for breakfast and wanting to change it? Would that prove anything? How exactly are you going back in time? Oh come on, don't be like that. You know what I meant. No, I don't. And it's entirely possible that you don't either. That's not just nitpicking. Or if it is, it's nitpicking that's absolutely essential for having a meaningful discussion instead of just throwing random words at each other. Human beings knew about logic for thousands of years before people really embraced the fact that it's only really useful if it's bound tightly to ideas, a process which requires defining those ideas rigorously, with a precision that many don't practice. But analytic philosophy and rigor have really changed the face of human thought. Of course, now that you know about it, it might be a little bit harder to appreciate dumb magic tricks. Pick a card. Look, I took it away. Not so magical now, is it? Have you ever realized that you never actually understood how to connect two links in your chain of thought when you look close enough? I certainly have. Please leave a comment below and let me know what you think. Thank you very much for watching. Don't forget to blah blah subscribe, blah share, and I'll see you next week.