身邊的邏輯學：常見邏輯謬誤的破解之道（附英文原稿）

10. Semantic vs. Syntactic Ambiguity In the last lecture we learned what ambiguity was and we saw some examples that helped you to understand why it's important for us to have ambiguity in our language [00:00:17] today, before turning to the topic of fallacies of equivocation, the fallacies that ambiguity gives rise to. I want to talk briefly about a difference between two kinds of ambiguity. We call them semantic ambiguity and syntactic ambiguity. Semantic ambiguity is where you have a single word or maybe a phrase that has two different meanings. [00:00:46] In the last lecture I gave the example of the phrase, the third member of the series, what you're talking about. When you refer to the third member of the series is going to depend on which particular series you have in mind, you're going to have different series in mind, in different situations. And so the phrase, the third member of the series is going to refer to different things in different situations. [00:01:14] T...

9. Ambiguity In the last few lectures, we've talked about the phenomenon of vagueness and the slippery slope fallacies to which vagueness gives rise today. I want to start talking about a different phenomenon from that vagueness. I'm going to be talking about ambiguity, and then I'll talk about fallacies of equivocation, which are fallacies to which ambiguity gives rise. [00:00:28] But before I talk about fallacies of equivocation, let's first discuss the phenomenon of ambiguity itself. What is ambiguity and how does it differ from vagueness? [00:00:43] Ambiguity is when an expression has two or more different meanings. Now an expression can be ambiguous, even if every meaning that that expression has is perfectly precise in that case, the expression would be ambiguous, but it wouldn't be vague. Let me give you an example, consider the expression, the third member of the series, that expression is ambiguous, but it's not vague. [00:01:19] Why is it ambiguous? Well, because w...

8. Causal Slippery Slopes In the last two lectures, we saw how the vagueness of some of the terms that we ordinarily use to describe a relation between two things. The vagueness of those terms can make it easy for us to engage in fellowships. Reasoning makes it easy for us to engage in fallacious reasoning precisely by making it hard for us to notice that the reasoning is. [00:00:29] Fallacious, [00:00:33] both cases, both in the case of a conceptual slippery slope fallacy. And in the case of the fairness, slippery slope fallacy, what happens is we're reasoning about some relation that we're treating as transitive. Right. We think if one thing bears that relation to a second thing, and then a second thing bears that same relation to a third thing. [00:00:58] Then the first thing must bear that relation to the third thing. That's transitivity and for many relations, well, they are transitive, right? So for instance, consider the relation of being greater than. If the first th...

7. Fairness Slippery Slopes In the last lecture, we talked about conceptual slippery slope, fallacies. Those are fallacies that we can easily make when we neglect the fact that the phrase a significant difference is a matter of degree. So if we treat the phrase a significant difference as a yes or no matter, either a difference, a significant, or it isn't, then we'll be tempted into a conceptual slippery slope fallacy. [00:00:30] Today. I want to talk about another kind of slippery slope fallacy that we'll call a fairness, slippery slope fallacy. And let me explain what a fairness, slippery slope fallacy is. Once again, by giving an example. Suppose I'm teaching a course with a bunch of students. I'm grading their work in the course. [00:00:51] Now it's obvious that if a student gets 100% on all the assigned work in the course, then that student deserves an a plus in the course, they deserve the highest grade. Okay. But now suppose another student does. Almost exactly as well ...

6. Conceptual Slippery Slopes So far in our course, you've learned what paradoxes are and why it's important to study them. You've also learned what vagueness is, why vagueness is crucial for us to use in our thought and language, but how vagueness can give rise to paradoxes today? I want to start explaining how big this can give rise to fallacies as well. [00:00:22] And we're going to do that by spending today, studying a particular kind of fallacy that we call the conceptual slippery slope fallacy. [00:00:34] Let me explain what conceptual slippery slope fallacies are by giving an example, and then generalizing from that example. So here's a fact that we've learned from physics electromagnet, medic radiation with a wavelength of 620 nanometer is red light. We all, I also know from physics that electromagnetic radiation with a wavelength of 495 nanometers is Greenlight, but now a difference of one nanometer in wavelength. [00:01:10] Is not a significant difference. One nano...

5. Paradoxes In the last lecture, I explained why it was crucial for us to be able to use vagueness both in our language and in our thought. But today I want to describe some of the difficulties that vagueness can lead us into. I'll start not by talking about slippery slope fallacies, which are the fallacies that result from the use of vagueness rather. [00:00:28] I want to talk about another phenomenon that can be easily confused with slippery slope fallacies. I want to talk about the paradoxes of vagueness. [00:00:42] Paradoxes are not the same as fallacies fallacies, as I've explained are errors in reasoning. Paradoxes in contrast are sets of statements. Each one of which appears to be obviously true. But they can't all be true together. Let me explain by giving an example of a paradox of vagueness, let's take a term that doesn't have a precise definition. [00:01:13] It's only vaguely defined. Consider the term crowd. Now, I assume we can all agree that one person is not ...