Hi, welcome to our Coursera course. This is the first time we've ever taught an online course, and we're very excited about it. I'm Walter Synod Armstrong from Duke University and my co-teacher is Ron Netta from the University of North Carolina at Chapel Hill. Say hi, Ron. Hi. Thanks. This is going to be a great course. It's going to cover a lot of important practical issues, raise some fascinating theoretical questions. We'll also try to have some fun, because there are lots of wacky examples where people make silly mistakes in arguments in everyday life, and we'll try to teach you how to avoid those. The title of the course is Think Again, How to Reason and Argue, and the title pretty much tells you what the course is about. We'll try to teach you to think again about a wide range of issues that affect your life in various ways. We're not going to try to convert you to our point of view or teach you to believe what we believe. Instead, we want you to think in a new way and in a deeper way about the issues that matter to you most. The subtitle of the course, How to Reason and Argue, tells you that we're going to focus on a particular type of thinking, namely reasoning, because most people don't want to be arbitrary or have unjustified beliefs. They want to have reasons for what they think and do. But how do you get reasons? Well, we're going to approach reasons by way of arguments, because arguments are just ways to express reasons. And if you can understand arguments, you can understand reasons. And if you can formulate good arguments, you can have good reasons for the ways in which you think and behave. So that's one way in which it's important to understand arguments, namely to get better reasons for your own beliefs and actions. But another way in which it's very important to understand arguments is to avoid mistakes, because there's lots of charlatans out there who are going to try to convince you to think the way they want you to think and to behave the way they want you to behave by giving you bad arguments. So you need to spot them and avoid them. Just think about it. Use car salesmen who tries to convince you to buy a car because it looks really cool and you'll look even cooler if you're sitting in the car. Well, that might be a good reason to buy a car and it might not. And you're going to have to figure out which kinds of arguments to believe and which kinds not to believe. Consider another example. Say, a lawyer in a courtroom and you're sitting in the jury and they're going to try to convince you either to find the defendant guilty or to find the defendant not guilty. But either way, you don't want your decision to be like flipping a coin. You want to have reasons for what you're thinking and for the verdict that you reach as a member of the jury. Or an evangelist tries to convert you to their religious beliefs and gets you to give up your old religious beliefs. Well, you don't want to make that kind of decision arbitrarily either because it's so important. And then what about your personal life? You might have a friend who says, let's go for a cross country trip. It'll be great. Well, maybe it will and maybe it won't.  How are we going to study arguments? Well, in this course we'll have four parts. The first part will teach you how to analyze arguments. That might seem really simple. You just read the passage and hear what they're saying. But actually it's quite hard because some passages or some sets of words, if we're talking about spoken language, contain arguments and others don't. Here's an example. Consider a letter to the editor. Some letters to the editor don't have arguments at all. They just say, thank people for having behaved in nice ways or done nice things. On the other hand, other letters to the editor include arguments. They try to convince you to vote for a certain political candidate, for example. So you need to distinguish which passages include arguments and which passages don't include arguments. Then you need to look at those passages and figure out which of the words, which parts of those passages contain the argument. Then you need to separate out those parts, put them in a certain order, which we'll call standard form. And often these arguments will have missing parts and you'll have to supply those missing parts or suppressed premises in order to get a full picture of how the argument works. And that's what we'll do in part one. Then in part two, once we've got the argument in shape, we can start to evaluate it. But evaluations are going to depend a lot on what the purpose of the argument is. Some arguments try to be valid in a logical way. And those are deductive arguments. So we'll start first by looking at deductive arguments and the formal structure of deductive arguments. We'll look at propositional logic, then categorical logic. That'll be part two of the course. Then in part three, we'll look at a different kind of argument, inductive arguments that don't even try to be deductively valid. Here there are just a lot of different kinds. So we'll look at statistical generalizations, applying generalizations down to particular cases. We'll look at inference to the best explanation and arguments from analogy. We'll look at causal reasoning and probability and decision making. So there'll be a lot of different types of inductive arguments covered in part three. Then in part four, we'll look at fallacies. These are common but very tempting ways to make mistakes in arguments. Some of them have to do with vagueness, others have to do with ambiguity. Some of them are irrelevance, like arguments add hominem and appeals to ignorance. And we'll also look at a major fallacy called begging the question that people commit all the time. And in the end, we'll teach you a general method for spotting and avoiding these common mistakes. So that'll be part four. And at the end of each part, we'll have a short quiz with some questions to make sure you understood. So we're very glad to have you in this course and we're very honored that there's so many students in this course. But that raises one problem, namely we cannot answer emails from students. So please do not email us individually. There will be discussion forums where you can go and talk to other students about the material in the course. And I bet that if you go to those forums, not only will you get your questions answered, but if you go to those forums and help answer other people's questions, everybody will learn more. And that's what this course is all about. So thanks very much for joining us on this adventure. And we hope you stick with it because we've got a lot of fun and a lot of important things to cover. One final recommendation. We've done these lectures so that you can just watch the lectures by themselves and do the exercises and take the quizzes. However, if you're listening to a lecture and you have a little trouble understanding it, or if you're really fascinated and you want to get more detail, then there is an accompanying textbook called Understanding Arguments by myself and Robert Fogeland. Many, many, many of the best ideas in this course come from him. He's been a leader in this field of understanding arguments for many decades, and I know an awful lot to him and I really appreciate that. So I wanted to do a little shout out of thanks to Robert Fogeland before we get started on this course in the next lecture. We'll hope the first lecture convinced you that arguments really matter. Of course, they're not the only thing that matters. There's more to life than reason and arguments. But they are something that matters and they matter a lot. So we need to understand arguments. Now the first step in understanding arguments is to figure out what arguments are. And the first step in understanding what arguments are is to figure out what arguments are not because we want to distinguish arguments from all of those things that don't count as arguing. And the best source of information about what arguments are not is, of course, Monty Python. Well, that was pretty silly, wasn't it? But in the midst of all that silliness, we find some truth because after all, many members of the Monty Python troupe were philosophy majors. So each room represents a kind of thing that we need to distinguish from arguments. So let's think first about getting hit on the head lessons. Arguments are not like hitting people on the head. You hit people on the head when you wrestle. The point is that arguments are not fights. You don't win an argument by hitting somebody on the head. Sometimes little children say that their parents are arguing when they're really having a verbal fight. All this fighting reminds me of my parents. Damn it, George. I told you if you didn't quit drinking, I'd leave you.  But you cannot win an argument just by yelling at someone. That doesn't make the argument any better because that's not the point of arguing. Another room in the Monty Python skit involves abuse.  Now abuse is one of the things you do with language, but it's not the same as arguing.    That will not help you win any argument. It also won't help you win any friends. And another room in the skit has to do with complaining. But all those complaints don't amount to an argument either. They're just expressing your emotion about the situation. Arguing is something different from all of those rooms. So what is arguing? Well, at one point, one of the characters says, Well, an argument is not the same as contradiction. Can be? No, it can't. So what do they mean by a contradiction? In British English, to say a contradiction is just to deny the person or contradict what they said. But contradicting what the person said, that is denying it, is not arguing. I can say, What do you think is the best flavor of ice cream in the world? Well, I have my favorite. I know what the best flavor is. The best flavor is Ben and Jerry's coconut almond fudge chip ice cream. There's nothing better. And then you say, No, it isn't. Well, you haven't argued that it isn't, and I haven't argued that it is. We're just disagreeing with each other. We haven't given any reason for any of the positions that we've adopted yet. So, as Monty Python says later on, a different character, argument is an intellectual process. It's a process not just of asserting your views, but of giving some kind of reason for your views. So the next definition that Monty Python gives of an argument is that an argument is a connected series of statements to establish a proposition. I take it they mean intended to establish a certain proposition. So that's a pretty cool definition if you think about it, because it tells you what an argument is made of. It's a series of statements, and statements are made in language. So arguments are made of language. It also tells you what the purpose of argument it is. The purpose of argument, they say, is to establish a certain proposition. So now we have a pretty neat definition of argument. This definition gives us a nice contrast, because there are lots of other series of statements or sentences that don't count as arguments because they're not intended to establish a proposition. Consider, for example, a novel which has statements about what's going on, but it's not necessarily trying to establish any particular proposition, or a dictionary might have a series of definitions, but it's not intended to establish a certain proposition. Instead, novels and dictionaries order sentences in a different way. They order them either chronologically or alphabetically, whereas arguments are trying to put statements into a certain structure that reflects the order of reasoning in order to establish the proposition, according to Monty Python. But Monty Python, no matter how great they are, and they are great, didn't get it quite right because the purpose of an argument is not always to establish a proposition, because some propositions that are conclusions of arguments we already knew. Consider, for example, a mathematical proof. If someone tries to prove the Pythagorean theorem in geometry, people already believe the theorem. They already knew that it was true, so they weren't trying to establish the proposition, but the proof does something else. It shows you how that proposition is connected to the axioms of the system and helps you understand why the proposition is true, and we'll see that other arguments, like explanations, do the same thing. So sometimes, arguments are intended to establish a proposition, like Monty Python said, but in other cases, they're intended to help us understand the proposition and the reasons why the proposition is true. So we want to distinguish reasons to believe that the proposition is true from reasons why the proposition is true, and arguments can do both of those things. So we need a somewhat broader definition of argument to cover these different kinds of reasons. We'll think of an argument as a connected series of sentences or statements or propositions where some of these sentences or statements or propositions are premises, and one of them is the conclusion, and the ones that are premises are intended to provide some kind of reason for the one that's the conclusion. This definition is useful in many ways. First of all, it tells us what the parts of the arguments are, the premises and the conclusion. Secondly, it tells you what the argument's made of. It's made of a language, because sentences and statements and propositions are made in language. Third, it tells you the purpose of argument to give a reason for the conclusion. Fourth, a nice feature is that it's very flexible because there are lots of different kinds of reasons. We don't want our definition to be too narrow because then it won't cover all the different kinds of arguments, and the notion of reason captures the different kinds of relations between the premises and the conclusion in different kinds of arguments. So let's do a few quick exercises to make sure that you understand how this definition works. Welcome back. In the previous lecture we saw a definition of argument as a connected series of sentences, statements or propositions where some of those sentences, statements and propositions are premises and one of them is a conclusion and the premises are intended to give some kind of reason for the conclusion. In this lecture we're going to look at the purposes for which people give arguments because the purposes are crucial in determining what an object is. Take, for example, an artifact that you might find in an archaeological site. You won't be able to figure out whether it's a really big screwdriver or a really small spatula unless you know whether the people who used it intended it to screw screws or to pick up food that they were cooking. So to understand arguments we need to understand the purposes for arguments and that means why does somebody bother to give an argument instead of just asserting the conclusion without an argument? We'll just think about it. If you went to a used car lot and the salesman said you ought to buy that Mustang, would that convince you? Not a chance. But if the salesman said you ought to buy that Mustang because it looks really cool and it goes really fast or maybe it has great gas mileage or whatever and gives you a series of reasons then you might be convinced to buy the Mustang. So that's one purpose of arguments to try to convince you to do things or to believe things that you wouldn't otherwise do or believe. So this purpose is persuading or convincing. And if you think about it, what the salesman is trying to do is he's trying to change your mental states. He's trying to make you believe something that you didn't believe or do something that you didn't do. So he's trying to bring about an effect in the world. But that's just one purpose of arguments. We don't always act like salesmen. Sometimes instead of trying to change people's beliefs we're simply trying to give them a reason for their belief or for our belief and to give them a reason is not necessarily to convince them or persuade them or change their beliefs. When we're simply trying to give them a reason to believe the conclusion we're going to call that justification.   Imagine that your friend is thinking about buying a car and doesn't know which one to buy. You might say, well, I think you ought to buy the Mustang because it looks really good and it goes really fast and it's actually got pretty good gas mileage and it's quite reliable or whatever. You're not necessarily trying to convince her to buy that car. It'd be fine with you if she bought any car she wanted, any car that would make her happy. You're trying to talk about the reasons for buying the car so that she can make her own decision in that sense you're trying to justify that decision or that belief that the Mustang is the best car for her to buy and not necessarily to convince her or persuade her. If she comes up with great reasons to the contrary, you're perfectly happy whereas the salesman wouldn't be. But notice that you might give exactly the same reasons that the salesman did. Exactly the same argument that the salesman did. The difference lies in the purpose because the salesman is trying to convince her to change her beliefs and actions but your goal with your friend is to discuss the reasons for her decision or action. So you're thinking about justification and the salesman was thinking about persuasion.  If you're trying to justify your friend's belief or your friend's action, then you're trying to give her good reasons. The salesman can convince her or persuade her with bad reasons. So it doesn't matter to his purposes whether the arguments that he gives are any good or bad as long as they work to affect that change in the world. Whereas you care about whether your arguments and your reasons are good reasons or arguments because you're trying to justify that belief or that action. And of course people can try to do all of these things at once. They can mix them together in various ways and that can get complicated. So when someone gives you an argument you need to ask a series of questions. The first thing you need to ask is is this person trying to change my mind or change my behavior? If so, then their goal is persuasion or to convince you. Then you need to ask are they trying to give reasons for changing my mind or for believing if I already believed it? Well if they're doing that then their goal is justification. And if you go down that series of questions you'll be able to understand what the purpose of giving the argument is at least for this range of cases. So let's do a few exercises just to make sure that you understand justification before we go on to the next purpose of argument which will be explanation. Hi again. In a previous offering of this course one student made a great point about persuasion and justification and the relation between those two. She did it in an argument that she presented for the entire class and I think we can all learn by listening to her. So here it is. Strong arguments don't always persuade everyone by Jessica Hyde from the United Kingdom. It's not enough for an argument to be strong, valid, and sound to be persuasive. You can have an argument for which every premise is genuinely true and where every conceivable flaw in the argument is negated and still not have it be persuasive. There will almost always be someone who either misunderstands the argument or blindly believes the opposite of a premise in face of facts. Human beings aren't always logical and don't always believe scientifically proven cause and effect. Religious and cultural beliefs can be too hard to overcome. So, even the best arguments can have disbelievers. Thank you, Jessica. What a great argument. I'm convinced. Remember, to persuade someone is to convince them or change their mind into believing what you wanted them to believe and what you were trying to get them to believe. Whereas justifying is giving them a reason to believe your conclusion. And those are different because, as Jessica argues very well, sometimes people make mistakes.  But still, you did give a good argument. So, you succeeded in justifying your belief. But was it a good argument if you were trying to persuade them? Well, maybe not. If your purpose was to persuade them, then it might matter to you that you didn't persuade them. Whereas if your purpose was to justify the conclusion, to give a reason to believe it, then you did succeed in that purpose. So, whether you see it as a good argument or not is going to depend a lot on what your purpose is. As Jessica points out, sometimes you're going to want to persuade and it's not always going to be easy to turn an argument that justifies and gives a good reason into one that persuades. That is going to depend on making sure that they do accept your premises and that they do understand your arguments. And that's yet another trick that we haven't discussed perhaps as much as we should have. And we learn another lesson from one of the student comments on Jessica's argument. Here it is. From Judith, I think Jessica has opened a very interesting discussion with her argument. Thank you, Jessica. I appreciate that. We do too. What I'm learning is the purpose of an argument is to state with clarity and some degree of certainty an opinion or point of view a valid strong and sound argument in and of itself may never persuade or convert anyone to adopt a different way of thinking. So what? What a strong argument does is communicate clearly what one thinks and why they think it. So I guess the benchmark of success for many arguments is not complete persuasion but is how clearly one is understood. If someone's intent is to blindly refute everything, that's not an intellectually honest engagement. I've found that in constructing better, more thoughtful arguments, people may not agree with me but they're far more considerate of what I have to say. And by using much of what we're learning, I'm listening much more intently to other views. Yes, Jessica, many things do defy logic. We just keep trying to do our best. Thank you, Judith. What a great point. Because what you've done is you've shown us that there are other goals of arguments in addition to persuasion and justification. The one you mentioned was understanding. Sometimes the point of an argument is not to bring other people over to your point of view but just to make them understand why you hold the position that you do. You're trying to show them your reasons even if you know that those reasons are not reasons that they, themselves, are going to accept. Well, why would you want to do that? As you say, because it makes them more considerate of what you believe and of you. Because if we understand each other and the reasons why we hold our positions, we'll respect each other more and be more considerate. Not always. Of course there are going to be exceptions. But as a general trend, we're going to get along with each other much better if we understand why we disagree and what reasons we have. The example where this is not working is politics. Everybody knows that politicians just yell at each other and don't really listen to each other. They just scream out what's going to appeal to their base without thinking about what the real reasons are for the positions they're holding. I think they'd be a lot better off and we'd be a lot better off if they were to take Judith's lesson and say give us the reasons so that we can understand why you're adopting that position. We'll give you our reasons so you can understand why we're adopting our position and then we can seek a compromise by satisfying the values that we both are most concerned about. And arguments can play a role then in helping us cooperate with each other and live with each other and compromise on the very important issues that we all face. Another lesson that Jessica and Judith have taught us is don't set your sights too high. If your goal is to persuade everybody, you're going to be constantly frustrated because there are always going to be people out there who don't understand your argument or who understand it but are obstinate to accept your premise no matter how well you argue for it. So if you try to convince everybody you're not going to succeed. So give it up. You can't convince or persuade everyone. Still you can accomplish a lot. You can help them understand you you can come to understand them and you can give them good reasons to believe your conclusion. Well, that's a lot and that can be very important even if they're not persuaded. And you if you're justified in believing your conclusion can have reason to believe that the fault lies with them not with you when they don't accept your conclusion. Of course you probably can't convince that. You can't convince them that the fault lies with them not with you but still you might have accomplished your goals if your goals are reasonable namely to increase understanding to find the reasons for your belief and to present those reasons in ways that people ought to understand and accept. That's what justification is and that's what understanding is and those can be extremely valuable in arguments even if there's still some people out there who aren't persuaded. As I said in the first lecture arguments are used for many purposes and in the lecture just before this one we saw that it can be used for persuasion and also for justification of various sorts but persuasion and justification are not the only purposes for which arguments are given arguments are also given in order to explain things so we're going to spend this lecture talking about explanation indeed what we're going to try to do is to explain explanation we explain things all the time and I'm going to give an example that will probably really take off my co-teacher Ron because he's from Chapel Hill but my example is somebody might ask why did the Duke basketball team win the national championship in 2010 the answer might be that they had great players and a great coach because they got lucky you have to have some luck to win a national championship but in any case an explanation of that event is a reason why it happened so to explain something is to give a reason why it happened or to answer a question about why it happened notice that when you explain something you assume that it's true it wouldn't make any sense to ask why did Duke win the national championship in 2011 because they didn't you can only ask why this thing happened if it happened so we've already got one difference between explanation and justification and persuasion when you try to persuade someone to believe something that thing doesn't have to be true and they don't have to have believed it in advance when you justify something you can justify belief in something that they don't already believe but when you explain something both the arguer and the audience are assuming that that thing happened that the conclusion is true and they're looking for the reasons why it happened so if the goal of explanation is not to persuade or to justify and the arguer and the audience both already believe the conclusion then what's the point what's the goal of explanation the goal of explanation is to increase understanding not to it is true but to help us understand why it's true and we can do that in a number of different ways they're actually according to Aristotle four different types of causes he would call them but we would probably call them explanations the first he called efficient causation we'll just call it causal explanation and that tells you why something happened why did the bridge collapse because there was an earthquake and the bridge collapsed the second type of explanation he called teleological or purposeful explanation because it's looking at the purpose or the telos or the goal why did Joe go to the grocery store to buy milk his goal of buying milk is what explains why he went to the grocery store third type of explanation is formal why does this peg not fit into this hole and the answer is because the peg is square and the hole is round that's why it doesn't fit in the hole and that explains it that helps you understand why it didn't fit the fourth kind of explanation is material why is this golf club so light why is it way so little the answer might be because it's made out of graphite that helps you understand why the weight is so low on this golf club it would be a lot heavier if it were made out of steel so we can have four different types of explanation we can have causal we can have teleological we can have formal and we can have material and all of those different types of explanation are aimed at helping us to understand why something happened so did you hear that train whistle we want to ask why does the train emit such a loud noise well one answer might be that what causes it to make that noise is that the conductor pull lever on the train which creates that noise that would be a causal explanation another explanation might be the teleological explanation the train was crossing an intersection with cars and wanted the cars to know that they're coming another explanation might be a formal explanation because the whistle on the top of the train has a certain shape that makes the air come out with a certain vibration and a final explanation might be a material explanation because air has a certain density and a certain material that makes it create that kind of sound so we can give all four types of explanations for the same event here's another example we can apply all four types of explanation to a single event Joe jumped out of an airplane that's what caused him to fall but then why did he jump out of the airplane to get excitement why did he fall so fast because of his shape it was aerodynamic and because of the material that he was made out of heavy flesh which was a lot denser than the surrounding air so all four of those factors go into an explanation of why Joe fell when he jumped out of the airplane so next we need to talk about the forms of explanation you can actually give explanations in several different forms for example if somebody said why did you move to Duke I might tell a story about things that happened before I moved to Duke that led me to want to move to Duke and I could talk about moving to Duke and all the nice people here and so on you can give explanations in the form of narratives like that that's not going to imply that everybody in similar circumstances is going to behave in exactly the same way so you're not going to get general principles out of those types of narrative explanations but other explanations are given in the form of arguments and that's the kind that we're going to be interested in here the form in which explanations occur in arguments is really pretty simple one premise usually states some kind of general principle that can apply to a lot of different situations the second premise talks about the current situation and says that those types of features that the principal mentions are instantiated in this case and then the conclusion says that explains why it happened this way in this case for example if we want to know why objects fall right so there's a book and it falls we want to explain that we need to cite a general principle but notice that not all objects fall some objects actually rise helium balloons rise so we need a principle that's going to explain why some objects fall and other objects rise then we'll understand why helium balloons rise just to stick with that example and the answer is that when an object is suspended freely in a medium where the medium is more dense than the object then it rises and when an object is suspended freely in a medium where the object is more dense than the medium then it falls so you can explain why helium balloons rise by having as your first premise whenever an object is freely suspended in a medium like a gas or a liquid and the medium is more dense than the object then the object rises in circumstances in this particular case the helium balloon is less dense than the air that surrounds it therefore the helium balloon rises and that explains why the helium balloon rises and you can see how you give another argument to explain why the book fell now this form of argument gives some people the impression that any generalization can be used for explanation but that's not quite right one example is Bode's law Bode's law says that .4 plus .3 times 2 to the n can be used to predict all the distances between planets and the sun where n is the number of the planet so if n is Venus then n is 0, Earth is 1, Mars is 2 and so on this law was actually used to predict both the largest asteroid belt series and also Uranus so this law is a generalization that held for all the planets that they knew in Bode's day and also used to predict new observations of planets, pretty cool it actually turns out to fail when you get to other planets including Neptune and Pluto but still it worked pretty well for the data that they had but nobody thought that this law explained why the planets were that far from the sun they happened to fall in that pattern it could be used to predict but it didn't explain why they were the distance that they actually were from the sun so Bode's law is an example where you can get a prediction without explanation now let's look at the reverse an example where you have explanation without prediction you should just imagine that a woman is HIV positive and she gets pregnant and has a baby and the baby is also HIV positive how did the kid become HIV positive well the explanation is that the mother was HIV positive and they were sharing blood but notice that you cannot predict whether the mother is HIV positive that the child will be HIV positive because less than half of the children born to mothers who are HIV positive are themselves HIV positive you also cannot use the fact that the mother is HIV positive to justify the claim that the child is HIV positive if you want to know whether the child is HIV positive you need to check its blood so in this example we have an explanation of why the child is HIV positive when it is but we don't get any prediction that it will be HIV positive and we don't justify the belief that the child is HIV positive so you can have explanation without prediction and without justification so then more positively what is the goal of explanation well the goal of explanation is a particular phenomenon into a general pattern and that's what all these explanations do why do you want to fit them into a general pattern is simply to increase your understanding of why they came about they came about because they fit into this particular type of pattern and this kind of understanding of fitting them into a well-known pattern is useful because most of the things that we want to explain are kind of weird, unusual bewildering, surprising phenomenon that's when you need an explanation because fitting into the pattern makes it a little less bewildering a little less surprising because it shows that it's kind of like other things that have happened before and that's what Bode's law does not do because Bode's law although it holds for all the planets that have been observed in the day of Bode it doesn't explain anything else it doesn't fit into a larger pattern of the planets around other solar systems and now that we've discovered planets we found many planets around other stars that don't seem to follow Bode's law at all so it doesn't fit our solar system into a general pattern and that's why even though it's a generalization and was used to predict other planets it does not provide an explanation of why the planets are certain distances from the sun so now we've learned a little bit about what explanation is and what explanation is not explanation is an attempt to fit a particular phenomenon into a general pattern in order to increase our understanding of why it happened and to remove bewilderment or surprise explanation is not persuasion or justification or generalization or prediction those are other uses of argument a variety of different uses of argument but we've only scratched the surface there can be lots more and lots more to say about each of these so if you want to learn more about these purposes of argument a good place to start would be chapter one of the accompanying text understanding arguments but we're going to leave this topic for now and turn to a separate topic in order to understand something you want to know not just its purpose but the material which it's made so the next few lectures will be about the material out of which arguments are made namely language last time we discussed what arguments are for their purposes we saw that arguments have at least three purposes namely persuasion justification and explanation we also saw that one way to explain something is to cite its purpose so we can understand why Joe went to the store by seeing that he went to the store because he wanted some milk so his purpose was to get milk similarly we can understand arguments by looking at their purposes and that's what we did last time but this time we're looking at a different kind of explanation as we saw one way to explain things is to look at the material so you want to understand why a MacBook Air is so light the answer is it's made out of aluminum similarly if we want to understand arguments we're going to gain understanding by looking carefully at the material that they're made out of and we saw that arguments are sets of sentences statements and propositions so that means they're made out of language so in this lecture and the next few we're going to look at the nature of language in order to better understand arguments so if we know that arguments are made out of language we know that the only creatures who can give arguments are ones that can use language now some people think that other animals can use language and there's a minimum kind of language that other animals can use but other animals cannot use language that's complex enough to make arguments it might seem that there's some exceptions here's one possibility but no matter what it sounds like this goat is not really arguing maybe he's fighting maybe he's fending off what he takes to be an enemy but he's not arguing so if other animals can use language we can't define humans as the animal that talks but we can define humans as the animal that argues or as Aristotle said the rational animal the animal that reasons because other animals don't do that humans are the only one that argues and reasons in this sense so we can understand humans and arguments better if we understand language better now I can't tell you everything that needs to be said about language you'd need to take a linguistics course for that and I recommend that you try one but here I'm only going to be able to make four basic points about language first of all, language is important second, it's conventional third, it's representational and fourth, it's social that should at least get us going in understanding what arguments are made of first, language is important it would be extremely difficult to live life without language just try to imagine what it would be like it's really hard to imagine but think about someone like Helen Keller who was born able to see and hear but very shortly thereafter lost her ability to see and hear and it was only much later in life that she gained the ability to use language because she never had that in her early years and when she gained that ability she was amazed it has a name W-A-T when Helen Keller gained the ability to use language and to communicate she didn't become able to see or hear she still couldn't see or hear but she could do amazing things she went around the country giving presentations she graduated from Radcliffe College all of that was made available to her simply by adding language and communication to her life so language is extremely useful and that explains why it's all around us just imagine walking down the streets of a city and all the signs that you'd see you just see words here there and everywhere and now we have a mystery if we're not paying attention to language then how can we use it so well to achieve so many purposes the answer to that lies in the second general feature of language that I want to talk about language is conventional what's a convention remember that in the United States people drive on the right hand side of the road that's our convention but what does that mean it means that there's a general pattern of behavior that most people throughout society obey on a regular basis and they criticize people who deviate from that pattern and the same applies to language we have certain patterns of using words in certain ways and when people deviate from those patterns we criticize them we say they're misspeaking or it's ungrammatical of course conventions can vary everybody knows that there are many countries around the world where people don't drive on the right hand side of the road they drive on the left hand side of the road the United Kingdom is one of them but there are lots more and the same applies to language you can have the same word that's used to mean very different things in different languages the most notorious example is football in the United States it's used to refer to American football whereas in the rest of the world it's used to refer to what Americans call soccer and people in the rest of the world think that America is kind of silly because you don't use your feet on the ball except for punting and place kicking in football but whether it makes sense or not the point here is simply that the conventions can vary from part of the world to the other and of course you can do that with any word you could in English use the word money to refer to socks at least the English language could have done that it didn't but it could have so in this way conventions seem to be kind of arbitrary they could have been very different but language is far from completely arbitrary because the conventions of language have limits and two of these limits that I want to emphasize come from the fact that language is also representational and social so first language is representational when we use language we're often trying to refer to objects in the world and describe facts in the world and you can't change those objects or those facts merely by changing your language one good story to illustrate this is about the young Lincoln when he was a lawyer he supposedly examined a witness during a trial and he said okay how many legs does a horse have and the witness said four and then Lincoln said well if we call a tail a leg then how many legs does a horse have and the witness said well then I suppose the horse would have five legs and Lincoln said absolutely not that's wrong calling a tail a leg doesn't make it a leg and the point of the story whether it's true historically or not is that language cannot change the facts of the world it can't make horses have five legs if you merely change your language here's another example suppose that you don't have much money but you happen to have a lot of socks in your drawer well you could say I'm going to use the word money to refer to socks and now all of a sudden I've got lots of money I'm not poor anymore it ain't going to work and that's because language again can't change your financial situation because that's the fact about the world not about how you're using the word socks or the word money and the other limit on the conventions of language comes from the fact that language is social sure sometimes we talk to ourselves and use language to write things down notes to ourselves for example without other people around but basically language evolved because of its social function and what that means is that there's a point in following the conventions of the language as shared by the rest of the society that speaks that language you know I've always thought that it was kind of silly that grapefruits are called grapefruits sure they're fruits but they don't look like grapes at all they look more like lemons they're like really big lemons and that's why I think they ought to be called mega lemons but if I went to a restaurant and I wanted to order grapefruit juice so I turned to the the service person and said I'd like some mega lemon juice I probably wouldn't get what I wanted and so even if I think the language is not using the right conventions there's a point in following the conventions of the language in order to be able to communicate with other people and get what I want and again the great philosophers Monty Python saw this very well when they produced their little clip called the man who speaks only in anagrams our first guest in the studio tonight is a man who talks entirely in anagrams Tassi Kriacht do you enjoy this? I storm certainly odd, Revy Chumso and what's your name? Hamrag, Hamrag Yattlerot so the point is obvious, namely language is shared and once it's shared then it makes sense to actually follow the conventions of society even if you don't like them overall then language is important and it's conventional in ways that might seem arbitrary but actually it's limited in important ways by the fact that language is so representational and social but it's kind of cheap to say language is conventional which are the conventions which are the rules that language follows and this is actually extremely complex because language follows rules or conventions at many different levels just take a real simple example you walk into a pizza shop and you say gimme pepperoni well the person then fixes a pepperoni pizza but how did that work that you said gimme pepperoni well first of all notice that you had to use words that were meaningful to the person you were speaking to gimme wasn't a word in English a long time ago but this person understands gimme as a word and therefore they can understand but in addition to those semantic constraints you also have to have physical production constraints you have to say it loud enough if the pizza shop is really noisy then you have to speak pretty loudly to get the person behind the counter to understand what you're saying you also have to put the words in the right order if instead of saying gimme a pepperoni pizza you said pizza a gimme pepperoni they might not understand at all what you're saying so there's structural combination rules that you have to follow as well and there are also etiquette rules in some pizza places if you just said gimme pepperoni the waiter might say well forget it sir I don't serve such impolite people I certainly would say that to my son if my son said gimme pepperoni I wouldn't get him a pizza I'd say you need to ask me properly so rules of etiquette can also get in the way of communication and cooperation so language operates at all of these levels physical production syntax or the rules of grammar and etiquette now all this might seem obvious to you it probably should be obvious to you but the rules of language are not always obvious and that's what we're going to be learning throughout this course I'll start with a simple example what's this well that is a finger but what's this that is a singer this is not a finger that's not a singer why do we pronounce the word finger with a hard G and the word singer with a soft G that's a rule that we all follow but very few people know the rule behind that pronunciation so do you know the rule take a little while and think about it have you got it yet okay I'll tell you the answer when a word ends in NGER and it's derived from a verb that ends in NG then you get a soft G like singer but when the word that ends in NGER is not derived from a verb that ends in NG then you get either a hard G like finger or a kind of medium G like plunger or danger now when do you get that medium G or that hard G that's a trickier question I don't know the answer to that one we use language according to rules without knowing what the rules are we don't have to be conscious of the rules at all and a lot of what we're going to be doing in this course is looking behind our language to try to figure out the rules that govern the way we use language especially when we're making arguments in order to better understand what we're doing some of the answers we give will be obvious once you mention them but I bet you hadn't thought of them before the rules that we've looked at so far apply to every use of language but we want to focus on those rules that are important specifically to arguments at least normally misspelling or mispronouncing a word doesn't affect an argument of course if you pronounce one word so that it sounds like another word it can be very confusing and people won't understand you or if you misspell it so badly they don't know what word you wanted the argument's not going to work but normally misspelling and mispronunciation don't make the argument bad instead what affects the argument is what's going to affect the proposition that's getting expressed the meaning of the sentence because that's going to affect whether the premises justify the conclusion or whether they explain the conclusion and so we need to focus on those rules of language that in particular deal with the meanings of words and of sentences so what's meaning well, one thing I can tell you is we're not going to be talking about the meaning of life in this course the meaning of life is a totally different topic we're also not going to be talking about whether clouds mean rain in the sense of giving some indication or evidence that there's going to be rain we're concerned with the meanings of words and sentences in language we're concerned with linguistic meaning in particular so how are we going to understand linguistic meaning well one way to think about the meanings of words and sentences is to ask how you would explain them to someone who doesn't understand them like a small child or someone who doesn't speak this language well if somebody said what's the meaning of the word chair you might go well when I use the word chair I'm referring to these things something like this when I say I'm sitting on the chair what I mean is my body is above the chair and so that approach to teaching language suggests to many people that what words mean is the same as what they refer to and what sentences mean are the facts that they try to describe now that view of language is often called the referential or descriptive view of language so is this referential or inadequate no no no no absolutely not that theory does not cover a lot of language that's extremely important just think about greeting someone in the morning hello are you referring to an object when you say hello or think about the word not in a sentence and the word not is going to be crucial to arguments but does the word not refer to something well if it did then there would be more objects in the room when I'm not sitting on the chair than when I am sitting on the chair so you cannot understand the meanings of many words like hello or not or for that matter am or sitting many words don't fit this referential or descriptive theory of meaning so if meaning is not reference or description what is it so here we are going to take our cue from Ludwig Wittgenstein the great 20th century Austrian philosopher who argued that meaning is use if you want to understand the meaning of the word hello you don't look for some object that it refers to you ask how is it used and the answer is obvious it's used to greet people if you want to understand the meaning of the question where is the library the answer is well that question is used to inquire about the library to ask where the library is if you want to understand the meaning of an imperative like give me a pizza then that is a way of ordering a pizza you are using that phrase to order a pizza so the meaning of the phrase is given by the way those words are used in normal situations by competent speakers of the language this point about meaning being used is very important to the language of argument as we saw the word not does not refer to an additional object the same goes for the word and when you say I am sitting in the chair and I am in the office the word and doesn't refer to an object either so if you want to understand what the word and is used to do then we have to think about what people do with it and what they do is they conjoin different sentences they don't add an extra object or an extra fact they just conjoin sentences and form a whole sentence out of two parts each of which was a sentence to begin with of course the word and is not always used to conjoin sentences we can say things like Roberto and Olivia went to Sao Paulo together and Roberto is not a sentence Olivia is not a sentence there are people not sentences and there weren't three things that went to Sao Paulo together Roberto, Olivia and this third thing and whatever that is still the word and is used to conjoin in this case it's used to conjoin things or people in the previous examples it was used to conjoin sentences but if we want to know what the word and means we shouldn't be looking for some object that it refers to instead we should be describing how it's used and what it's used to do namely it's used to conjoin and when we look more closely at the uses of language we see that language is used in a lot of different ways use is diverse just take a simple example I'd like to give you a little piece of personal advice you want to floss your teeth every day so what did I just do I made a bunch of words I made physical motion in the air but in addition those words were meaningful you ought to floss your teeth every day each of those words is meaningful in the language and I put them together in an order that was grammatical so the whole thing makes sense when you make a meaningful utterance like that we're going to say you perform a linguistic act and there's a linguistic level of the use of language that we will study in one lecture the next lecture but in addition when I said you ought to floss your teeth every day I also gave you a piece of friendly advice I advised you and notice that even if you don't follow my advice I still advised you and if you don't follow my advice and your teeth rot out then I can say look you should have listened to me you ought to floss your teeth every day so the speech act level occurs even when it doesn't affect your actions at all that's the second level of use of language the speech act level and we'll talk about that in more detail two lectures from now the third level of language has to do with the production of certain effects maybe when I say you ought to floss your teeth every day I persuade you and what that means is I bring about a certain effect in your behavior or your thought or your attitudes well that's what we're going to call the conversational level and conversational acts are the acts of bringing about those effects and persuasion is one example so now we have three levels of language we have the linguistic level which is the meaningful utterance producing a meaningful utterance we have the speech act level advising is a nice paradigm that which can be accomplished even if you're not persuaded and we have persuading you which is the conversational level so there's the linguistic level the speech act level and the conversational level and each of these levels will be explored in more detail in one of the next three lectures but here's a little warning and you have a choice the material in the next three lectures is a little bit more abstract but it's fascinating and we're going to try to make it fun and it's really important to understand how your language works but it's not absolutely essential to the things that we're going to cover in the rest of this course so it's up to you you can listen to these three lectures if you want and there will be some exercises throughout those lectures that will test your understanding but none of that material is going to be on the quiz so you can listen to the next three lectures in order to be able to go through the rest of the course and do well on the quiz at the end of this part so as we saw last time there are three distinct levels of language linguistic level, the speech level and the conversational level and all of these levels of meaning affect arguments so in the next three lectures we want to work through these levels one by one and this lecture is going to deal in particular with the linguistic level of language and the production of a meaningful utterance so in order to perform a linguistic act all you have to do is utter a set of words that are meaningful that fit together according to the semantics that is the meanings of particular words and the syntax or the grammar of the language in general for example, it's easy it's easy in a linguistic act because it's as a contraction it's allowed to contract it and is according to the rules of English and easy as a word so it's easy follows the semantics and the syntax of the language of English that's all there is to it although linguistic acts are really simple they do require some special components that are worth separating out for example they require meaningful words when you simply hum a tune like mm-hmm then you're not performing a linguistic act because there are no meaningful words in it but when you sing a song I love Miranda and Nicholas too then you are performing a linguistic act because you uttered words that were meaningful when they were put together in that way and I've been taking this for granted but of course the words you utter have to be meaningful it's not going to be a linguistic act if you utter what looks like a sentence namely a set of sounds that look like words if they're not really words so if you say twas brilig in the sly thee toes did gyron gimbal in the wave and so on from Lewis Carroll's famous Jabberwocky poem then it's not going to be a linguistic act if those words are not meaningful words in any language and you can also get nonsense when you take words that have meanings and put them together in an order that doesn't make any sense my dog has fleas makes sense but dog fleas my has doesn't make any sense so meaningful words with the wrong grammatical structure won't work and Noam Chomsky from MIT taught us that you can also get nonsense if you take words that make sense and you put them together with the right grammatical structure but they still don't fit together because of the relation between the meanings his example here was colorless green ideas sleep furiously what does that mean colorless green ideas sleep furiously well colorless makes sense green that's a word ideas sleep furiously each of those words make sense and they're each in their appropriate grammatical role but altogether it doesn't make any sense so there are lots of ways you can get nonsense in language and when you do you're not performing a linguistic act now there's some really fun examples where it's not clear whether or not the utterance is meaningful some of these examples among my favorites are garden path sentences here's one the man who whistles tunes pianos wait a minute what does that mean if you think of it as the man who whistles tunes is one unit then you don't understand what the word pianos is doing because the man who whistles tunes sounds like a reference to a particular man and pianos is not a verb but if you think of it as the man who whistles is one unit and the second unit is tunes pianos so it's the man who whistles tunes pianos then it makes sense because it's the man who's whistling also tunes pianos so you have to be able to carve the set of words up into the right units and see what grammatical structure they have in order to understand the sentence because tunes can either be a verb which tells you what the man is doing to the pianos or it can be a noun which refers to the thing that the man is whistling and you have to get those grammatical categories straight and the garden path sentences lead you astray and make you think of it in the wrong way and there will be some more examples of that in the exercises but my favorite example of all is buffalo, buffalo, buffalo what does that mean well buffalo are American bison okay but buffalo the word buffalo in English that is can also be used as a verb to refer to tricking or fooling someone so you can have buffalo, American bison buffaloing that is tricking or fooling buffalo, American bison buffalo, buffalo, buffalo but you can go even further because there's a city in New York named Buffalo and of course there can be buffalo that is American bison from the city of Buffalo, New York and when they trick or fool other by American bison from Buffalo, New York then you have buffalo, buffalo buffalo, buffalo, buffalo or buffalo, buffalo, buffalo, buffalo buffalo which doesn't sound like a meaningful utterance but it is and you can go even further you can actually build it out to 11 straight utterances of the word buffalo buffalo, buffalo, buffalo, buffalo, buffalo buffalo, buffalo, buffalo and tell me what that means I'm not going to explain it to you because it takes a while to explain it but if you think about it you might be able to figure it out and even if you can't figure out 11 buffaloes in a row the point still holds because the point is just that sometimes what doesn't seem meaningful turns out to be meaningful and if you're careful and charitable and do your best to interpret what it really means there are other utterances that don't seem to make sense at first and when you can make sense out of them then they're linguistic acts for now I don't have time to go into any detail on semantics or syntax although we will discuss some details when we discuss vagueness and ambiguity in the discussion of fallacies later in this course but I hope that the linguistic level is pretty simple and understandable so we can go on and look in more detail at the speech act level the second level of language that we want to discuss is speech acts we already saw one instance in the example of advising when I advised you to floss your teeth every day but the clearest examples probably occur in games and in ceremonies one famous incident that occurred I believe in a Yankees game was when a batter had two strikes and three balls and the pitcher threw the ball near the strike zone and the batter didn't swing so the umpire didn't say anything and the batter turned to the umpire and said well ump, am I out or was that a walk and the umpire said you ain't nothing till I say so and that's the lesson of speech acts with a speech act the saying so that makes you so and the rules of baseball mean that you're out and it was a strike if the umpire says so now maybe the umpire should have called a ball when he called a strike or should have called a strike when he called a ball but it doesn't matter because if he makes a mistake and calls it a strike then you're out so the next kind of example involves ceremonies imagine that you're at a traditional marriage ceremony the bride and the groom show up with an officiant in an appropriate location and the officiant says to the man do you take this woman to be your lawfully wedded wife and he says I do then the officiant turns to the bride and says you take this man to be your lawfully wedded husband and she says I do then the officiant says I now pronounce you husband and wife that's pretty cool by uttering those words he made them husband and wife the words change their relationship in a legal way in a religious way and in a personal way and just by uttering words and notice also that you can use a special little word to explain this you can say that he thereby pronounced them husband and wife by uttering the words I now pronounce you husband and wife he thereby pronounced them husband and wife because it was right then and there in those words by means of those words that he made them husband and wife provide us with a nice general test called the thereby test here's a certain pattern of words if I say I blank then I thereby blank I blank by means of saying I blank now sometimes filling in that blank with some words will make sense but it won't make sense with other words and that'll provide a test because when you can fill in that blank with a verb it makes sense then that verb names a speech act so for example if I say I now pronounce you man and wife then I thereby pronounce you man and wife my speech act is pronouncing you and if I say I apologize I thereby apologize notice that what the formula does is it takes you from the words which are in quotation marks of the thereby test to the world because when it's not inside quotation marks on the right side of the thereby test it refers to the world so when it's in quotation marks it's about the words when it's not in quotation marks on the right side it refers to the world and the formula takes you from the words to the world and that's what's tricky about it it's amazing that you can actually use your words to change but only in the special case of speech acts of course all of this works only in the right circumstances you can't just randomly walk up to any couple on the street and say I now pronounce you husband and wife just try it excuse me I wanted to say something I now pronounce you husband and wife thank you whoa, I'm lucky they didn't hit me you obviously cannot pronounce people husband and wife if you're not an efficient they're not a bride and a groom who have said I do it has to occur in the right circumstances and sometimes which circumstances are the right circumstances will be very controversial people argue about whether a man can marry a man or a woman can marry a woman the ones who think that you can't think that marriage has as part of its appropriate circumstances that only people of different genders can get married a man can marry a woman but can't marry another man whereas other people think that a man can marry a man and a woman can marry a woman so it's going to be controversial which circumstances are appropriate for a marriage ceremony but everybody agrees that you can't just do it randomly to any old couple on the street so everybody agrees that there are going to be limits and that the speech act works only in the appropriate circumstances and we can build that into the thereby test in the appropriate words if I say I blank in the appropriate circumstances then I thereby blank but it's only in the appropriate circumstances that you can perform the speech act by uttering the words now we can use the thereby test to pick out speech acts because it works for a lot of different examples if I say I promise to meet you for lunch tomorrow in the appropriate circumstances then I thereby promise to meet you for lunch tomorrow so promising is the speech act if I say I thank you for inviting me to your party and throwing such a great party by the way then I do thereby thank you for inviting me to your party and for throwing such a good party by the way so thanking is the speech act if I say I apologize for tripping over your legs then I thereby apologize for tripping over your legs notice the circumstances matter in all these cases if I say I apologize then I did apologize but it was an insincere apology because the circumstances weren't right since I didn't have the appropriate feelings but I still did apologize now in contrast whether I promise you or threaten you depends on whether the thing that I promise or threaten to do is something that you want to do it then I'm promising but if you don't want me to do it then I might be threatening so your attitudes towards the thing that I'm going to do determines whether my speech act is a promise or a threat in all of these cases the circumstances are going to matter so in that example the circumstances affect which speech act I perform but in other cases the circumstances affect whether I really perform any speech act at all or fail to perform the speech act that I was trying to here's an example of that if I say to you, I bet you that Duke will win the next national championship and I think Ram Netta might be foolish enough to take that bet then what if he responds by saying no, I won't bet you now, have I performed a speech act of betting no, have I performed another speech act not really what have I performed sometimes when the circumstances aren't right you perform a different speech act and sometimes when the circumstances aren't right you don't perform any speech act at all it really is very sensitive to the particular circumstances in which you're speaking but why do we care about speech acts here when we're supposed to be studying arguments, well that's because arguing is a speech act you argue with language it's one of those things that you do in using language in a certain way you're intending to provide reasons and you're providing what you take to be a reason to justify or explain the conclusion and justifying and explaining are other things that you do with language those are speech acts too so when we're studying arguments we're studying a particular kind of speech acts and that's why it makes it important to understand speech acts because we need to view arguing in the context of these other speech acts that I've just discussed now there's an awful lot more to say about speech acts and I can't say it here in these lectures I just want to give the idea in a very basic and simple way if you want more detail we have a more extended discussion of speech acts in the accompanying book understanding arguments but just to make sure you understand the basics let's do a few exercises first and then in the next lecture we'll go on to talk about conversational acts so now we've discussed two levels of language the linguistic level the speech act level in this lecture we want to look at the third level of language not only the level of conversational acts the basic idea is really simple we use language to bring about a change in the world for example I might turn to a friend and say could you loan me your car well what am I doing I'm performing a speech act of requesting or asking a favor something like that but am I doing it just for its own sake ask a favor just in order to be asking a favor like it was fun to ask a favor no I was asking a favor to bring about a certain effect I wanted him to hand over the keys to his car so I could use it and I wanted him to give me permission to use his car so I could do it legally so I'm trying to bring about a change not only the physical location of the keys but also in the legal rights that I have with regard to his car so I'm trying to bring about a change in the world simply by uttering those words could you please loan me your car it happens all the time here's another example suppose my friend is wondering whether the moon is full and I say the moon is full am I uttering those words just to expel hot air no am I uttering those words just to express my own belief no I'm trying to inform my friend I'm trying to bring about a change in my friend's beliefs and that's to bring about an effect in the world so that's a conversational act to bring about the effect in the world of informing my friend informing is a conversational act and almost all speech acts have particular effects that are associated with them when you ask a question you're trying to bring about someone answering the question when you apologize you're trying to bring about forgiveness to somebody you're trying to bring about the person relying on your promise in order to believe that you're going to do it so speech acts are often associated with particular effects that the speaker intends to bring about and the bringing about of that effect is the conversational act so if we want an official definition of a conversational act we can say that the conversational act is the bringing about of the intended effect which is the standard effect for the kind of speech act that the speaker is performing that's what a conversational act is now since the conversational act is the bringing about of the standard effect the conversational act does not occur when that effect does not occur and that might seem weird that what kind of act you perform depends on whether the effect occurs maybe several seconds maybe even longer in the future but it's not that weird when you think about it because if you pull the trigger of a gun that's pointed at someone then whether your act of pulling the trigger is an act of killing depends on whether the person dies and yet the person's death is something independent of it it's an effect that occurs maybe quite a while in the future but your act wasn't an act of killing unless the person died and that's the story of conversational acts your act is not this conversational act the fact occurs it has to be the intended effect that's the standard effect for the kind of speech act that you're performing so the really tricky question is how are we going to bring about these effects because it's not so easy think about how other people bring about effects think about a baker baking a cake well the baker needs to get together the right ingredients and bring them to the right place and get the right amount of ingredients the baker fills the entire kitchen with flour he's not going to have any room left over to bake the cake and he has to bring the right ingredients that means if instead of bringing flour he brings gravel he can't bake a cake and he has to put together those ingredients in the right way in the right order for example you can't mix them in the wrong order the cake won't work out it has to bake it for the right amount of time and so on and so on the effect of a good cake well the same thing applies to conversational acts there are going to be rules that have to be followed in order to bring about the conversational act that you're trying to bring about that is in order to have that intended effect of the speech act in the circumstances and the same kind of rules apply to any rational person trying to pursue any goal whenever you want to bring about an effect you have to follow certain general rules and so it applies to people who are trying to bring about effects by language that is to people who are trying to perform conversational acts if you want to inform someone that is to have an effect on their beliefs then you need to speak in a certain way and if you want to promise someone that is to get them to rely on you that's the conversational act associated with the speech act of promising but you're not going to get them to rely on you unless you follow certain rules that you're going to understand are the rules of language that enable us to bring about these effects that are the conversational acts now in this question Paul Grice helps us out a lot he's one of the great philosophers of the 20th century and he laid out a series of rules governing conversational acts he called them the conversational maxims and we're going to look at them one by one Grice focuses in on context where people are stating things cooperating with each other and trying to inform each other he's not trying to provide a general theory so it's for statements in a cooperative context so the first maxim is the rule of quantity and it basically says don't say more than is required for the purpose that you're trying to achieve if you say too many words the point gets lost in the words so you shouldn't say more than you need for the purpose at hand the second part of the rule of quantity you shouldn't say too little because if you say too little then that's going to be misleading and it's not going to fulfill your purpose because the person that you're talking to won't have all the information that they need second rule is the rule of quality the rule of quality says don't say what you don't believe to be true don't lie, don't mislead, don't deceive but also this is the second part of the rule of quality don't say something that you lack adequate justification for because you shouldn't just be talking off the top of your head with no reason to believe what you're saying these are all pretty common sense rules but they weren't apparent to people until Grice formulated them the third rule is the rule of relevance and it's the toughest of all the rule of relevance says be relevant look, it's short I'll grant you that but it really is kind of tricky to apply the rule because you have to figure out what's relevant and we'll see some problems with that but for now just remember that it should be obvious when you're talking about a subject and you want to achieve a certain purpose and the person you're talking to is cooperating with you as Grice is assuming then you ought to be talking about things that are relevant and if you change the subject you're just leading and the fourth conversational maxim is the rule of manner it says be brief, be orderly avoid obscurity and avoid ambiguity pretty simple, it's all about style because if you're not brief enough people won't pay attention to you if it's not orderly people will get confused by that and if you're ambiguous or obscure then people won't understand what you're saying so these four rules are followed by speakers they're cooperating with each other when people aren't cooperating they're trying to trick or deceive each other they might violate these rules and mislead people by abusing these rules but when they're cooperating these are the rules they follow and that makes them able to deceive people by violating them and also notice that these rules might not be completely clear to you you might not have ever thought of them before but now that you mention them they probably seem pretty obvious but that's another rule that we saw before regarding pronunciation that's a rule that you hadn't thought of before but once it's pointed out it seems kind of obvious well that's what Grice has done but he's shown us the rules governing conversational acts that enable us to bring about certain effects by language now we can use these rules to understand what's going on in a lot of conversations imagine you're in a restaurant and the waiter walks up to your table and says well for dessert what is that ice cream? well what has that waiter suggested? he's suggested that that's all you can have cake, ice cream, well he didn't mention pie so you can't have pie because if he's a good waiter and he knows that they have pie back there and you could order it then you ought to be telling you about the pie he would be violating the rule of quantity that is not providing you all the relevant information if he said you can have cake or ice cream you also have pie but he didn't mention pie so because you assume that he's cooperating with you and trying to get you what you want to eat since he is your waiter after all there must not be pie available so you say I'll take ice cream even though you would have preferred pie what's happening here is called conversational implication when the waiter said you can have cake or ice cream he was conversationaly implying that you can't have pie and the reason that he conversationaly implied that is because if he were cooperating and following the conversational rules or maxims then he would have mentioned pie so you assume that since he said only cake or ice cream that you can't have pie he in effect conversationaly implied that you cannot have pie and the way you figure that out you took what he said a little background knowledge about him being a waiter and having certain goals and what happens in restaurants performed a little mini calculation using the maxim of quantity and inferred that he must believe that you can't have pie and of course since he's a waiter he ought to know whether you can have something else or not and therefore you can't have pie but what if he was a customer at another table and he knew there was only one slice of pie back there and he didn't want you to order it and he said you can have cake or ice cream and didn't mention the pie so you wouldn't order it and his favorite customer would get it instead of you well he still conversationaly implied that you can't have pie but he misled you he misled you because he was trying to get the pie for somebody else he was not cooperating with you so the tricky thing about these conversational maxims is they work perfectly fine when you're cooperating with the person and trying to give them all of the information that they need for your common purpose with that other person but if you're not cooperating then you can use them to mislead the other person and that's the double edged sword of conversational implication but one of the features of conversational implication is really important to arguments and that's that you can cancel conversational implications the waiter can say you can have cake or ice cream oh yeah and you can also have pie and when he said and also you can have pie he did not take back you can have cake or ice cream because you can still have cake or ice cream it's just that you can also have pie so he can cancel the conversational implication that you cannot have pie by saying oh yeah so with a conversational implication if a certain sentence p conversational implies another sentence q then you can deny q and p still might be true and that's an important fact because it distinguishes conversational implications from logical entailments or logical implications if I say Alice is my sister then that implies Alice is female and I can't go Alice is my sister oh yeah and she's not female that doesn't make any sense because she's not female she can't be my sister because that's a logical implication or entailment but with a conversational implication instead you can deny what is conversational implied and the original sentence is still true so if the waiter says you can have cake or ice cream and then I find out that he's been saving the table then I can come up to him and say wait a minute you lied to me he didn't really lie to me because what he said was still true I could have cake or ice cream it's still true I can have cake or ice cream he didn't say anything false to me he simply didn't mention the pie that I could also have so that's very different in the case of conversational implication than in the case of logical entailment and that'll be important to us especially when we get to formal logic in a later part of this course so let me give you another example that's more important as a politician says I've got a policy that's going to reduce crime by getting criminals off the streets and the policy is lock them all up when people are suspected of crimes you lock them all up that's going to get criminals off the street well that might convince people if they don't notice that he's left out another fact he's not just going to get people off the street who are criminals he's going to get lots of other people off the street too he didn't give you all the relevant information like the waiter who misled you with the pie he suggested that his policy will solve the problem of crime by putting people in prison who would commit crimes and just left out the other relevant fact there's lots of other people in prison too so he has adversely implied that there's no other relevant facts to consider by only mentioning that it's going to reduce the crime rate and you have to be good at looking through that implication and asking yes, but is there something he's leaving out and that's often what you need to do in order to avoid being misled by sleazy politicians and other people who leave out the relevant information for the issue that you're talking about now of course the politician might not care that he misled you that might be the goal he wants to persuade you and he doesn't care whether he misleads you because it's persuasion not justification that he's interested in in addition he's got his defense ready he can say I didn't say anything false what I said was true if we put all those potential criminals in jail we're going to reduce the crime rate maybe it's also true that we're going to put some innocent people in jail but we will reduce the crime rate and that's what I said this is maximum of quantity does is it tells us exactly why we have a criticism of him now we can say he's not cooperating because he's not following the conversational maximum of quantity he's not giving us all the relevant information that we need in order to achieve our purpose if we have a common purpose and this politician is pretending to have a common purpose with us the good of the country when actually he doesn't have a common purpose with us he just wants to get elected and so Gries gives us an insight into what's going on when we get misled in those contexts and also what we need to do to respond through those types of bad arguments now this distinction between conversational implication and logical entailment is crucial to arguments because it tells us something about how to refute arguments when you don't like the premise of an argument because it's misleading because it conversationaly implies something false that's not a way to show that the premise is false in order to show it's false you have to show that it actually logically entails something that's false then you can infer that the premise itself is false this will become important later when we look at the role of conversational implication and logical entailment in arguments but for now the important thing is to understand the distinction between conversational implication and logical entailment the speakers usually follow these conversational maxims that Gries enunciated when they speak and when they're cooperating but they don't always follow these maxims sometimes they violate them and of course as always there's a lot more to be said about conversational acts if you want to learn more about conversational acts you should look at the chapter in understanding arguments and the text that accompanies this course but I think we've learned enough about conversational acts to move on because so far we've looked at language in general at the linguistic level, at the speech act level and at the conversational act level now we want to take these lessons and apply them more specifically to the language of argument that is the particular kind of language that gets used in arguments and that's what will be the topic for the next few lectures welcome to week two in week one we talked about language in general this week we want to talk about how language is used in one particular context namely the context of arguments we need to understand the language of argument in order to be able to spot an argument that is to determine when a passage contains an argument and what part of the passage is that argument so how can we tell when an argument is being given well recall the definition of an argument as a series of sentences statements or propositions where some of them are premises and one of them is a conclusion and the premises are intended to give a reason for the conclusion so the real question of when an argument is being given comes down to the question of when certain sentences are intended as reasons for other sentences now the answer is that we can tell a person's intentions speaking by which words they choose so there are going to be certain words that indicate that some sentences are reasons for others just compare these two sentences I am tall and I am good at sports and compare that to I am tall so I am good at sports now notice that you can take the first sentence I am tall and I am good at sports and switch it around and I am tall switching doesn't make any difference but it's very different if you say I am tall so I am good at sports that's very different from I am good at sports so I am tall so we know from the fact that you can switch around the and sentence and you cannot switch around the so sentence the word so introduces something very different from just conjoining the two claims but then what's the difference is that when you use the word and you're simply stating the two facts I am tall I am good at sports and the and says that they're both true but when you use the word so you're indicating that one of them is a reason for the other if you say I am tall so I am good at sports then you're suggesting that the reason why you're good at sports is that you're tall but if you say I am good at sports so I am tall then you're indicating that the fact that you're good at sports is some kind of evidence that you must be tall maybe because you can only be good at sports if you're tall which isn't true that just shows it's a bad argument but it is an argument because by using the word so you're indicating that one of the sentences is a reason for the other of course the word so is not the only word that plays this role in arguments or has this function you can also say I am tall therefore I am good at sports or I am tall thus I am good at sports or I am tall hence I am good at sports or I am tall accordingly I am good at sports all of these different pairs of sentences play the same role they indicate that there's an argument there namely the fact that I'm tall is a reason for the conclusion that I am good at sports so we're going to call all of these words argument markers because they indicate the presence of an argument next we want to distinguish two different kinds of argument markers so far we've looked at so and therefore and thus and accordingly each of those indicates that the sentence right after it is a conclusion and the other sentence in the pair is a premise so we're going to call these conclusion markers because they indicate that the sentence right after them is a conclusion but there are other argument markers that also indicate arguments in the same way but what they indicate is that the sentence after them is a reason or a premise not a conclusion for example I could say I'm good at sports because I am tall now the word because indicates that the fact that I'm tall is a reason for the conclusion that I'm good at sports it doesn't mean that the sentence after the word because is a conclusion instead it means that the sentence after the word because is a reason or a premise so we're going to call it a reason marker or a premise marker and there are other reason markers as well you could say I am good at sports for I am tall I am good at sports as I am tall I am good at sports for the reason that I am tall I am good at sports and the reason why is that I am tall there are lots of different ways to indicate that the fact that I am tall is a reason for the conclusion that I'm good at sports all of these words both the conclusion markers and the reason markers indicate that there's an argument present but only in some cases you can't just look at the word and figure out whether it's an argument marker or not you have to think about the role that it's playing a perfect example of that is another reason marker since you can say I'm good at sports since I am tall and then it looks like you're presenting the fact that you're tall as a reason why you're good at sports but the word since doesn't always play that role after all you can say the sun has been up since 7 o'clock this morning and that doesn't mean that somehow the sun has an alarm clock that causes it to come up right at 7 o'clock all it's saying is that the sun has been up after the time of 7 o'clock and all times since then it doesn't indicate any kind of rational relation such as the fact that it's 7 o'clock being a reason why the sun came up oh what about this one it's been raining since my vacation began very disappointing but you're not saying that it's raining because your vacation began as if there's some kind of plot against you in the nature of weather that would be very paranoid all you're saying is that it has been raining every day since the time when your vacation began or every day after your vacation began so the since there indicates just a temporal relation not some kind of rational relation and what this shows us is that you can't just look for the word since you always mark it as an argument marker you have to think about what the word sense is doing in that context and that'll be true for a lot of other reason markers and conclusion markers as well here's another example of the same point but with a conclusion marker the word so sometimes indicates that the sentence after it's a conclusion and the sentence before it's a reason but it can also indicate something entirely different you don't need to eat so much so there doesn't indicate that much is a reason for anything the word so is getting used in an entirely different way that should be obvious but the point again is that you can't just look for the word so and label it as an argument marker you have to think about the function that is playing in the particular context but then how can we tell what role a word is playing in a particular context here's a little trick try substituting another word that's clearly an argument marker that is it's clearly a reason marker or a conclusion marker for the original word that you weren't so sure about here's an example he's so cool does that mean he's because cool no if you substitute because for so the meaning changes entirely not even clear what it means or how about he's therefore cool that doesn't make much sense either so in this case you can't substitute another argument marker because or therefore for the original word so without changing the meaning of the sentence entirely and that shows you that in the original sentence the word so was not being used as an argument marker or reason marker or conclusion marker here's another example well since he left college he's been unemployed well are you saying that because he left college he's unemployed maybe if that's what you're saying then you can substitute the word because without changing the meaning of the sentence and then the word since was being used as a reason marker in that case but probably not simply that since the time when he left college he's been unemployed and then if that's what you mean then when you substitute because for since it changes the meaning and that would show that in that context the word is not playing the role of an argument marker or a reason marker because it changes the meaning to substitute something like because that's clearly an argument marker on the other hand you might have a similar claim where you can substitute it since he failed out of college he's unemployed now somebody says that they don't just mean since the time when he failed out of college he's unemployed probably the meaning has not changed if you simply said because he failed out of college he's unemployed so since you can substitute because for since in that sentence in that sentence the word since is probably being used as an argument marker that's the role it's playing that's its function that's how it's being used and notice also that you can tell that the word since in that sentence is a reason marker instead of a conclusion marker because you can substitute because and you cannot substitute therefore therefore he failed out of college he's been unemployed that doesn't make a lot of sense so if you can substitute because without changing the meaning then the original word since in this case was being used as a reason marker you cannot substitute the word therefore that shows it's not being used as a conclusion marker so you can use this substitution test to determine whether the words being used as a reason marker or as a conclusion marker or as no indicator whatsoever of an argument but in some entirely different way one last word that we have to talk about is that little word if sometimes it's linked with the word then in an if then clause which is also called a conditional we'll talk a lot about conditionals later in this course but for now I just want to make one point the word if might seem like an argument marker because it's often used in arguments for example I might say if I'm rich enough I can buy a baseball team I am rich enough so I can buy a baseball team that would be an argument but if all I say is if I'm rich enough I can buy a baseball team when I know I'm not rich enough so I would never assert the if clause that says I'm rich enough then that little if sentence is not being used to indicate an argument at all it's just saying if I am rich enough then I can buy a baseball team it's not saying that I am rich enough and it's not saying that I can buy a baseball team so the word if by itself does not indicate an argument it sets a pattern for argument if one thing then another well the one thing therefore the other but the if one thing then another doesn't by itself indicate any argument at all because it doesn't assert that if clause which is also called the antecedent of the conditional so we are not going to count the word if as an argument marker to identify an argument pretty simple huh but just to make sure you've got it straight let's do a few exercises now that we've identified arguments and we've also identified premises and conclusions we need to put them in order the actual word order doesn't always tell us the order of argument compare these two sentences because I am a professor I teach classes I teach classes in those two examples the words I am a professor in one instance occur at the beginning and at the other instance occur at the end but they actually express exactly the same argument namely the fact that I am a professor is a reason why I teach classes but contrast both of those with this example I teach classes so I must be a professor the point there must be something like nobody but professors can teach classes and whether or not that's true the point here is that's a different argument from the first one and we need to represent the difference between these two arguments very carefully in order to show what is shared by the first two examples that's different from the third example we put the arguments in what's called standard form and it's really easy basically you put the premise down and if there's another premise you put that down then you draw a line then you put what I call a dot pyramid it's basically three little dots with two at the bottom and one at the top and then you put the conclusion after that it's also useful we'll see why later but it's useful to number the premises and to number the conclusion so that we can refer back to the premise and conclusion with the number instead of having to repeat it all the time and that's all there is to standard form you just put down the premises on different lines then you draw a line put the little dot pyramid and then write down the conclusion and then number them all that's it and this standard form accomplishes what we wanted to namely it helps to show what's common so the first two examples at the beginning of this lecture that distinguishes them from the third example so the first two examples were I teach classes because I'm a professor and because I'm a professor I teach classes there the senate says the premise that goes above the line is I'm a professor and the conclusion that goes below the line and next to the dot pyramid is I teach classes but the next example the third example at the beginning of the lecture was I teach classes so I must be a professor now that means that I am a professor is the conclusion that goes below the line next to the dot pyramid and the premise is I teach classes so when you put these two in standard form right next to each other it makes it absolutely clear what the difference is and what's in common to the first two that distinguishes them from the third one no matter how easy I think it's still worthwhile to do a few exercises just to make sure we've got it straight because this notion of standard form will become important later now we've learned how to identify an argument and put it in standard form we've also learned from the definition of argument that the premises are intended to be reasons great intended to be a reason for the conclusion well intentions are nice but success is better what we need to figure out is when the person succeeds in giving premises that really are reasons for the conclusion for simplicity let's focus on arguments whose purpose is justification then the question is do the premises justify you in believing the conclusion well, imagine that you don't know whether there's any life on Mars you have no evidence one way or the other then you ask a friend and the friend says I know there's life on Mars I can prove it to you here this argument will show you that there's life on Mars there is at least one bacterium on Mars therefore there is life on Mars now notice that if the premise is true the conclusion has got to be true and if you and your friend are justifying and believing the premise then you and your friend are also justifying and believing the conclusion so this argument looks pretty good so far but of course you have to ask your friend how do you know that there's at least one bacterium on Mars and suppose your friend says well, I'm just guessing then the argument is clearly no good if there's no reason to believe the premise because your friend is just guessing then you're not justifying and believing that premise and if you're not justifying and believing the premise then how can that premise make you justified in believing the conclusion more generally an argument cannot justify you in believing the conclusion thus you're justified in accepting the premises of that argument now suppose your friend says but I do have a reason for the premise I do then we have to ask what kind of reason is it and at that point your friend needs to express that reason and how do we express reasons in arguments so your friend has to give another argument for the premise where the premise of the first argument is the conclusion of the second argument but wait a minute now we've got a problem because that second argument is itself going to have premises and you have to be justified in believing those so the premises of the second argument have to be the conclusion of a third argument and so on and so on because the third argument needs premises that have to be justified so they have to be the conclusion of another argument that have premises and those have to be the conclusion of another argument and so on and so on it looks like we've got a real problem here in order for the premises to be justified they have to be backed up by an argument but the argument has premises of its own that have to be backed up by another argument and so on and so on this problem is called the problem of the skeptical regress because you regress back to one argument after another after another after another after another and it's hard to see how that regress is ever going to come to an end there seem to be only three ways to get around the skeptical regress the first is to start with a premise that's unjustified if it's unjustified then it doesn't need an argument to back it up and that means that you're not going to have this chain of arguments going back and back and back and back and back and back the second possibility is to have a structure where the arguments move in a circle one claim is justified by another which is justified by another which is justified by another which is justified by the first claim and they just move in a circle the third possibility is that the chain of arguments goes back infinitely it never stops every claim has an argument to back it up and there's no end so you never have a premise which doesn't have an argument to back it up because it's infinite those seem to be the three main options here to avoid the skeptical regress the first possibility then is to start with a premise that's unjustified and that seems pretty neat if you can get away with it but we already saw why that won't work we saw your friend arguing that there's life on Mars because there's at least one bacterium on Mars and he was just guessing if you just guess at your premises you have no reason to believe them then an argument that uses those premises cannot justify you in believing the conclusion but in addition just think about it this way you could prove anything if we let you start with unjustified premises if you can just make up your premises for no reason then there's no stopping you from believing whatever including things that are obviously false so it seems to be a real problem to start with premises that are unjustified next the second way to respond to the skeptical regress is to use a circular structure and it's kind of neat if you think about it because if you want to prove one claim you prove it on the basis of another claim and then you prove that second claim on the basis of a third and that third on the basis of fourth and the fourth on the basis of fifth and the fifth on the basis of the first and now you've got this circle and the argument's going a circle but that means that every premise has an argument to back it up because you can keep going around the circle forever but if you think about it a little bit it'll be obvious that that's no good and that can be shown by looking at the smallest circle there is so suppose your friend says I can prove there's life on Mars here's my argument there's life on Mars clearly that's no good and the reason why it's no good is that if you didn't know whether there's life on Mars to begin with you wouldn't know whether the premise was true because if you don't know the conclusion you can't know the premise since the premise is the conclusion so if you're not justified in believing the conclusion to begin with you're not justified in believing the premise and that means that the argument didn't really get you anywhere it just ends up where it started and in addition it has the same problem we saw in the first approach involving unjustified premises because you can use circular arguments to prove anything you can prove there's life on Mars there's life on Mars therefore there's life on Mars you can prove there's no life on Mars there's no life on Mars therefore there's no life on Mars you can do it either way and the fact that an argument can be used either way to prove either conclusion suggests there's a big problem of argument so now we're down to the third and final way to get around the skeptical regress and that's to use an infinite chain of arguments but if you think about it in a concrete case you'll see why that's a problem as well suppose your friend says there's life on Mars and I can prove it and you say fine give me your reason well there's at least one bacterium on Mars therefore there's life on Mars and you go okay fine but how do you know there's at least one bacterium on Mars I've got another argument he says there are at least two bacteria on Mars therefore there's at least one bacterium on Mars but how do you know there's at least two well there are at least three bacteria on Mars therefore there are at least two bacteria on Mars but how do you know there are at least three well there are at least four so there are at least three well there are at least five so there are at least four literally six or at least five, and so on and so on and so on. You could go on infinitely. So an infinite chain of arguments would allow you to prove that there's life on Mars, even if you have no evidence whatsoever of any bacteria, because you're going to have an argument. But if the premise that you're arguing from doesn't have an independent justification, then the infinite chain is going to be no good at all in justifying the conclusion of that argument. So many people see this skeptical regress as a deep and serious philosophical issue. If the unjustified premise approach doesn't work and the circular argument structure doesn't work and the infinite chain of arguments doesn't work, then it's hard to see how we can get around the problem, which is to say, it's hard to see how any kind of argument could ever justify us in believing anything. Philosophers really scratch their heads about that for a long time and worry about it. It keeps them up at night. But we're going to have to look at how practical people solve a similar problem in everyday life. So how do we solve the skeptical regress problem in everyday life? Well, there are various tricks that you can use. For example, one way is to just start from assumptions that everybody shares.  You don't like to have to take it into the mechanic all the time. You don't want it to break down on the road. And if you want reliability and I want reliability, then we can start from the assumption that reliability is a good thing and that that's a reason to buy a car that is reliable. But of course, you might say, well, but our Honda is reliable. And then I might appeal to an authority. Well, it's obvious that they are. Or Consumer Reports has done a study that shows that they're reliable. And I can appeal to an authority. And if you accept that authority, go, ah, Consumer Reports, we can trust them, then my argument's going to work. You're going to have a reason to believe the conclusion, and it might persuade you and make you come to believe the conclusion. But suppose that someone is going to raise an objection. They say, well, Consumer Reports has been wrong before. They might be wrong this time. Well, then I need to discount that objection. I need to respond to it and say, well, maybe they have been wrong sometimes. But this time they've got a good study and it was careful or whatever. And the but means I'm discounting the objection that you have raised. And I might even discount it in advance. Or I might just guard my claim. I might say, well, they might be right in this case. Or they're probably right without claiming that they definitely are right. So I can assure you by citing some kind of authority, I can discount objections. And I can guard my premises by saying, well, it's probably right. Instead of saying it's definitely right. And those are three ways of solving the skeptical regress problem in everyday life that we're going to look at in much more detail in the next three lectures. But the point of this lecture has been more general. In order to solve the skeptical regress problem, you have to find some assumptions that you and your audience share. They might be assumptions about the premises of your arguments. They might be assumptions about authorities that supposedly support your premises and that they accept as authorities or whatever. But there have to be some assumptions that you share with your audience in order to get the argument going. And that's kind of tricky because it's going to depend on the context. If you're dealing with an audience that shares a lot of your assumptions, then argument's going to be relatively easy. But if you're dealing with an audience that doesn't share any of your assumptions, it's going to be impossible. And in areas where there's lots of disagreement, it's going to be hard to get your arguments going because your premises are going to be questioned and denied or rejected by the people in the audience. So what these tricks do is they give you ways to get the argument going, but they're not going to work in every case. And we'll have to look at that as we're looking at these three different ways to solve the skeptical regress problem in the next three lectures. In the previous lecture, we looked at the skeptical regress problem and I kind of introduced three different ways of solving that problem in practical life, namely assuring, guarding, and discounting. Those are three ways to solve the skeptical regress problem in practical life. And in the next three lectures, what we're going to do is look at each of these in much more detail and more carefully so as to understand how they work. Let's begin with assuring. Here's an example. I assure you that smoking is bad for your health. If I say I assure you that I'm trying to get you to accept that claim on my authority. Now, I might have some reason for saying that smoking is bad for your health, namely, I've read the US Surgeon General's report which cites the scientific evidence to show the smoking is bad for your health. But notice that I don't actually say it. When I say, well, it's obvious that smoking is bad for your health or everybody knows that smoking is bad for your health or I assure you, certainly, clearly smoking is bad for your health. Then what I'm doing is I am trying to get you to accept that premise without actually citing the Surgeon General or anybody. I haven't cited the evidence. I simply have indicated to you, I do have evidence. I do have a reason to believe that smoking is bad for your health, but I haven't given you what the reason is. So what good is that? It's a lot of good because what it means is that if I don't give the reason, you can't question the reason. If I simply say everybody believes it, it's certainly true, then you can't ask whether those people who believe it have any reason to believe it or whether I have any reason to be so certain about it.  So assuring is kind of tricky. I say I assure you and if you can trust me, that's fine, but if you can't trust me, then you should be asking, well, what kind of reason does he really have? Now, there are many ways to assure people. There are three kinds that we're gonna look at. Authoritative, reflexive, and abusive. Let's start with authoritative. Authority is just what it says, it cites an authority. So I might say, I assure you the smoking is bad for your health. The surgeon general has shown that smoking is bad for your health and I cite an authority, the surgeon general. Okay, fine, but have you seen the studies? Have I cited the numbers? If I told you when the studies were done, how many subjects, under what circumstances, which statistical tests were used, how do you know it's causation of correlation and so on and so on? No, I just say the surgeon general has shown this and you're supposed to take my word for it that those are good studies unless of course you share my assumption that the surgeon general is trustworthy. So that's the way an authoritative assurance works. It cites an authority that the audience shares as an authority with the other person. They share the assumption that that authority is trustworthy. Now sometimes it's the surgeon general and the surgeon general is pretty reliable but you also get this kind of thing from reporters. They say an unimpeachable source close to the president has assured me that the president's plans are such and such and they cite an unimpeachable source but they won't tell you what the source is and they won't tell you how the source knew it was true. So they're citing an authority but they're not telling you what the authority is or what reason the authority has or what the authority claims. Now if you trust that authority then that's fine and if the authority's reliable then you might be safe but if you don't know who the authority is or where they got their information there can be problems. And here's my favorite, here's my favorite. I sometimes hear students say but Professor Sinan Armstrong, my teacher in the other course said that blah, blah, blah, blah. Well, why do you trust your professors? I mean, why do you trust me? You shouldn't be trusting me or your other professors any more than you're trusting an unimpeachable source close to the president. So you have to trust somebody sometime and you have to decide who you're gonna trust and then it's gonna be okay to cite an authority in this kind of assurance but you have to watch out for tricks when people start citing authorities that aren't really authorities because even the best authorities sometimes do studies that aren't very careful and might even be wrong.  Reflexive because it's talking about yourself. I believe that, I know that, I am certain that, I feel sure that. And you're citing something about your own mental state. You feel sure, great, you feel sure but why do you feel sure? Notice however that this assurance works because people don't wanna question what other people feel sure about. If I say, well, I feel sure that this is gonna happen. In many societies it's gonna be implied to go, well, I don't feel sure, matter of fact, I think you're wrong or why do you feel sure? Because then you're questioning the person and if that's impolite then using this type of phrase, I am certain that will get people to shut up and not say anything. So here's an example from Monty Python. Now let's get one thing quite clear. I most definitely told you. But my favorite is when people say, I've held this opinion for years I've thought about it year after year. It's really bothered me and you know, after careful consideration, I've come to the conclusion that blah, blah, blah, whatever. And you're supposed to say, well, since you've thought about it so much, I'll save myself a lot of trouble thinking about it and trust you and go along with what you say. Well, if you let other people do your thinking for you then that's up to you. But you're gonna be misled in some cases because they've thought about it for years and years and gotten themselves in a tizzy and ended up with the wrong conclusion. So the fact that somebody's thought about it for years doesn't necessarily mean it's right. But somehow in conversation, when you say I've thought about it for a long time and checked all the sources I could, then people take the fact that you've reached a certain conclusion to be okay for them to reach the same conclusion. And that's how this reflexive type of assurance works. But the most fun of all is the abuse of assurance. Here's another example from Monty Python. No, no, nonsense. Maybe he's right. Maybe it is nonsense. But the point is that he gets you to accept what he believes by abusing you and calling it nonsense. And the same thing happens to him sometimes. Nobody but a fool would think that. Everybody knows this.  And so they're abusing you in order to get you to agree with them by making a conditional abuse that applies to you only if you don't agree with them.  You don't wanna speak nonsense.   Then that's going to incline you to agree with them. Some of these abusive assurances are a little bit more subtle. So it's worth mentioning one that's used all the time. And this is what might be called appeal to common sense. So it says it's just common sense that such and such. And it doesn't matter what the such and such is. The point here is simply that if you deny that, then you're telling that person you lack common sense. And nobody wants to lack common sense. So by saying it's just common sense that it's just plain common sense. People say it all the time, but what they're doing is they're abusing their opponents by saying that their opponents lack common sense. So it's a little bit more subtle, but it shows that abusive assurances occur either subtly or openly all the time. So we've seen three different types of assurances, okay? The first is authoritative, the second is reflexive, and the third is abusive. And they're all used in common speech to stop the skeptical regress problem. So why do we need any of these assurances in the first place? And the answer is we've got limited time. You know, you can't go out and check every study. You can't go out and look into every issue. You've just got to accept authorities and listen to other people and learn from them, or you'll never be able to figure out the issues that matter to you in life. So assuring can be a perfectly good thing. If you trust the surgeon general of the United States instead of going out and starting your own laboratory and doing your own statistical studies, there's absolutely nothing wrong with that. But when you start trusting authorities that are not worthwhile or not trustworthy, then you can get yourself into trouble. And we'll talk later in the course about ways to tell which authorities are reliable or trustworthy and which ones are not. That tells you why assurances are needed in general. But what about particular cases? Well, when you're talking to a certain audience, if they share your trust of a certain authority, or if they trust you when you give a reflexive assurance, or if what you're saying really is something that everybody with common sense believes in, then again, it can be perfectly fine to use an assurance. It saves you the time of having to go check out every issue, and it helps you avoid the skeptical regress problem in a very practical way. So assuring can be a really useful tool in argument, but you have to be careful, because assurances are also subject to a lot of tricks that you have to learn to watch out for. We've already seen that you can cite authorities that aren't trustworthy, and that's kind of obvious. But something that's maybe a little less obvious is that people use assurances at points in their argument in order to distract you. If something really is questionable, they often say, well, that's obvious in order to get you to not pay attention to it. So when someone says, that's obvious, it's certain, I'm sure, it's worth looking carefully at what they're so sure about and asking yourself whether you agree with them, because people try to paper over the cracks in their arguments with these assurances, at least in some cases, and you have to learn to watch out for that. Another trick is when assurances get dropped, people will start off saying, he believes this, I believe that, and then they drop in and start talking as if it's true. My favorite example of this was a case a few years ago when there was a person caught in Germany for cannibalism, and it started off with the reporters saying, well, he, the person accused of cannibalism, says that there are lots of other cannibals in Germany. And then it becomes, it is reported that there are lots of cannibals in Germany. And then it became sources have said that as if the sources are reliable. And pretty soon they were saying, there are lots of cannibals in Germany. And it moved from he believes it to there are lots of them. And that's the trick of dropping the assurance in a way that can be illegitimate. So assurances can be useful, and they can also be misleading. And that's gonna be true of all the different ways of stopping the skeptical regress. There can be uses and abuses of all of these tricks. For assurances, we wanna have an assurance when, first of all, somebody might question it, second, that audience accepts the authority that is being referred to, and third, it would be too much trouble to actually cite the study and all the numbers and the evidence in the particular people. But assurances are not appropriate when nobody would question the claim anyway, then why are you wasting your time assuring people? When the authority that you're basing your assurance on is not really trustworthy, because then why should they believe your assurances? And third, when you've got plenty of time and it would be really easy to give the reason straightforwardly instead of simply assuring them. So you've got good and bad uses of assurances, and I hope we understand what they are and how to distinguish them. But let's do a few exercises just to make sure that we've got the general idea. The second common move in arguments that's supposed to solve the skeptical regress problem is guarding. The basic idea of guarding is very simple. It's just making the premises of your argument weaker so that there'll be fewer ways in which your opponents can raise trouble for them or show that they're false. So here's an example. So someone says, we ought not to build any new nuclear power plants, because they'll explode. Now wait a minute, how do you know that any of them really will explode? How can you tell that in the future? You don't even know what kinds of standards they're gonna be built to. So someone can object to that argument by saying you're not justified in asserting that premise that these new nuclear power plants will explode. So how do you stop that problem? Well, you simply say, well we ought not to build any new nuclear power plants because some of them might explode or even weaker because I believe that some of them might explode. Now we've got a premise. I believe that some of the new nuclear power plants might explode. That's gonna be hard to deny. What's an opponent gonna do? Show that you don't really believe it? Show that it's not true that they might explode, that there's no possibility that they'll explode or that any of them will explode. You're not claiming all of them will, just some of them. So by guarding the premise in this way, you make it more likely to be true and less subject to objection. And that's what guarding does. It enables you to start an argument with that premise if other people agree that it's true because it's so weak. And get them to agree to share your assumption by weakening your premises. Now of course, what happens now is someone says, wait a minute, they might explode. Sure, and the sun might not come up tomorrow. All kinds of things might not happen or might happen. Might's too weak to establish that we shouldn't have new nuclear power plants. So what you're suggesting is not just that it might happen but that it's likely to happen. And if the chance of it happening really is so slight as to be negligible, then you weaken the premise too much and it's not gonna follow that we shouldn't have nuclear power plants. So the issue's gonna come down to is the risk of them exploding or some of them exploding enough to justify the conclusion that we ought not to have them. And that's gonna depend on exactly how much risk there is and by looking at the guarding term, at the might term and questioning it and saying, can we replace might with probably or something like that? Then we're gonna have a better handle on how to assess the argument. So when you see someone using guarding like this, you need to ask why did they put in the guard and have they put in too much guarding? That is weakened it so much that the conclusion no longer follows. So the general trick of guarding is to weaken the premise so it's gonna be harder to deny. And that's how your argument gets going. But there are at least three different ways to do this. One is the extent, the other is probability and the other is mental. First, guarding by extent. We need a new alcohol officer on our campus because all students drink too much. Well, that's clearly false. Not all students drink too much. Most students drink too much. Well, not most, maybe not most. Many students drink too much. Okay, too many because it's too much. Some students drink too much. Notice that you can guard or weaken the claim, the premise from all students drink too much to most students drink too much to many students drink too much to some students drink too much. And as you move down that scale, the premise gets harder and harder to deny. So whether this counts as guarding depends on the expectation. If you expect the claim that most or all students drink too much, then it's guarding to say many or certainly to say some. But if you don't expect that many or most or all, then to say some is s