So now we've discussed two levels oflanguage.The linguistic level and the speech actlevel.In this lecture, we want to look at thethird level of language.Nominally the level of conversationalacts.And the basic idea is really simple.We use language to bring about a change inthe world.For example, I might turn to a friend andsay, could you loan me your car?Well, what am I doing?I'm performing a speech act of requestingorasking a favor.Something like that.But am I doing it just for its own sake?Did I ask a favor just in order to beasking a favor?Like it was fun to ask a favor?No.I was asking a favor, to bring about acertain effect.I wanted him to hand over the keys to hiscar so I could use it.And I wanted him to give me permission touse his car, so I could do it legally.So I'm trying to bring about a change, notonly in the physicallocation of the keys, but also in thelegalrights that I have with regard to his car.So I'm trying to bring about a change inthe world.Simply by uttering those words, could youplease loan me your car?It happens all the time.Here's another example.Suppose my friend is wondering whether themoon is full.And I say, the moon is full.Well am I uttering those words just toexpel hot air?No.Am I uttering those words just to expressmy own belief?No.I'm trying to inform my friend.I'm trying to bring about a change in myfriend'sbeliefs, and that's to bring about aneffect in the world.So that's a conversational act.To bring about the effect in the world ofinforming my friend.Informing is a conversational act.And almost all speechacts have particular effects that areassociated with them.When you ask a question, you're tryingto bring about someone answering thequestion.When you apologize, you're trying to bringabout forgiveness.When you promise somebody, you're tryingto bring about the person relyingon your promise in order to believe thatyou're going to do it.So speech acts are often associated withparticulareffects that the speaker intends to bringabout andthe bringing about of that effect is theconversational act.So if we want an official definition of aconversationalact we can say that the conversational actis the bringingabout of the intended effect, which is thestandard effectfor the kind of speech act that thespeaker is performing.That's what a conversational act is.Now.Since the conversationalact is the bringing about of the standardeffect.The conversational act does not occur whenthat effect does not occur.And that find seem weird that what kind ofact you perform depends on whether theeffect occurs maybe several seconds, maybeeven longer even longer in the future.But it's not that weird when you thinkabout it.Because if you pull the trigger of a gunthat's pointed at someone, then whetheryour act of pulling the trigger is anact of killing, depends on whether theperson dies.And yet the person's death is somethingindependent of it.It's an effect that occurs, maybe quite awhile in the future,but your act wasn't an act of killingunless the person died.And that's the story of conversationalacts.Your act is not this conversational actunless, the effect occurs.It has to be the intended effect, that'sthe standardeffect for the kind of speech act thatyou're performing.So, the really tricky question is, how arewe going to bring about these effects?because it's not so easy.Think about how other people bring abouteffects.Think about a baker baking a cake.Well, the baker needs to get together theright ingredients andbring them to the right place, get theright amount of ingredients.You know, if a baker fills the entirekitchenwith flour, he's not going to have anyroom left over to bake the cake.And has to bring the right ingredients.That means, if instead of bringing flourhe brings gravel, he can't bake a cake.And he has to put together thoseingredients inthe right way, in the right order forexample.You can't mix them in the wrong order, thecake won't work out.And has to bake it for the right amount oftime and so on and so on.So there're a lot of tricky rulesabout how to bring about the effect of agood cake.Well the same thing applies toconversational acts.They're going to be rules that have to befollowed, in orderto bring about the conversational act thatyou're trying to bring about.That is in order to have that intendedeffect of the speech act in thecircumstances.And the same kind of rules apply to anyrational person trying to pursue any goal.Whenever you want to bring aboutan effect, you have to follow certaingeneral rules.And so it applies to people who are tryingto bring about effectsby language, that is, to people who aretrying to perform conversational acts.If you want to inform someone, that is, tohave an effecton their beliefs, then you need to speakin a certain way.And if you want to promise someone, thatis toget them to rely on you, that's theconversational act associatedwith the speech act of promising.But you're not going to get them to relyon you unless you follow certain rules.And so what we need to try to understandare the rules oflanguage that enable us to bring aboutthese effects that are the conversationalacts.Now on this question Paul Grice helps usout alot, he's one of the great philosophers ofthe 20th century.And he laid out a series of rulesgoverning conversational acts.He called themthe conversational maxims.And we're going to look at them one byone.Grice focuses in on context where peopleare stating things andwhere they're cooperating with each otherand trying to inform each other.He's not trying to provide a generaltheoryso it's for statements in a cooperativecontext.So the first maxim is the rule of quantityand it basically says, don't say morethan is required for the purpose thatyou're trying to achieve.If you say too many words the point getslost in the wordsso you shouldn't say more than you needfor the purpose at hand.The second part of the rule of quantity isyou shouldn't say too little.Right?Because if you say too little then that'sgoing to be misleading and it's not goingto fulfillyour purpose because the person thatyou're talkingto won't have all the information thatthey need.Second rule is the rule of quality.The rule of quality says, don't say whatyou don't believe to be true.Don't lie.Don't mislead.Don't deceive.Right?But also this is the second part of therule of quality.Don't say something that you lack adequatejustification for.Because you shouldn't just be talking offthe top of your head.With no reason to believe what you'resaying.These are all pretty common sense rules,butthey weren't apparent to people untilGrice formulated them.The third rule is the rule of relevanceand it's the toughest of all.The rule of relevance says, be relevant.Look, it's short, I'll grant you that.It's going to be easy to remember, I'llgrant you that.But it really is kind of tricky to applythe rule,because you have to figure out what'srelevant and we'll seesome problems with that, but for now justremember that it should be obvious.When you're talking about a subject andyou wantto achieve a certain purpose and theperson you're talkingto is cooperating with you, as Grice isassuming, thenyou ought to be talking about things thatare relevant.And if you change the subject, that'sgoing to be very misleading.And the fourth conversational maxim is therule of manner.It says be brief,be orderly.Avoid obscurity, and avoid ambiguity.Pretty simple, it's all about stylebecause if you'renot brief enough, people won't payattention to you.If it's not orderly people will getconfused by that, andif you're ambiguous or obscure then peoplewon't understand what you're saying.So these four rules are followed byspeakers when they're cooperating witheach other.When people aren'tcooperating, they're trying to trick ordeceive each other, theymight violate these rules, and misleadpeople by abusing these rules.But when they're cooperating, these arethe rules they followand that makes them able to deceive peopleby violating them.And also notice that these rules might notbe completely clear to you.You might not have ever thought of thembefore, butnow that you mention them they probablyseem pretty obvious.It's kind of like the finger and singerrule that we saw before regardingpronunciation.That's a rule that you hadn't thought ofbeforebut once it's pointed out it seems kind ofobvious.Well that's what Grice has done.But he's shown us the rules governingconversational actsthat enable us to bring about certaineffects by language.Now we can use these rules to understandwhat's going on in a lot of conversations.Imagine you're at a restaurant and thewaiter walks up to your table and says,well for dessert you can have cake or icecream.Well.What has that waiter suggested?He's suggested that that's all you canhave cake, ice cream.Well he didn't mention pie so you can'thave pie.Because if he's a good waiter and he knowsthat they have pie back thereand you can order it, then he ought to betelling you about the pie.He would be violating the rule ofquantity, that is not providingyou all the relevant information, if hesaid you can have cake orice cream and you can also have pie but hedidn't mention pie.So because you assume that he'scooperating withyou and trying to get you what youwant to eat, since he is your waiter,after all, there must not be pieavailable.So you say, I'll take ice cream, eventhough you would have preferred pie.What's happeninghere is called conversational implication.When the waiter said you could have cakeor icecream, he was conversationally implyingthat you can't have pie.And the reason that he conversationallyimplied that is because, if he werecooperating and following theconversational rules, ormaxims, then he would have mentioned pie.So you assumed that since he said onlycake and I, cakeor ice cream, that you can't have pie.He, in effect, conversationally impliedthat you cannot have pie.And the way you figured that out was youtook what he said, a littlebackground knowledge about him being awaiter andhaving certain goals and what happens inrestaurants.Performed a little mini calculation usingthe maxim of quantity.And inferredthat he must believe that you can't havepie.And of course since he's a waiter, heought to know whetheryou can have something else or not, andtherefore you can't have pie.But what if he had a favorite customer atanother table and he knew therewas only one slice of pie back there andhe didn't want you to order it?And he said, you can have cake or icecream.And didn't mention the pie so you wouldn'torder it and his favoritecustomer would get it instead of you.Well, he still conversationally impliedthat you can't have pie.But he misled you.He misled you because he was trying to getthe pie for somebody else.He was not cooperating with you.So the tricky thing about theseconversational maximsis they work perfectly fine when you'recooperating withthe person and trying to give them allof the information that they need for yourcommonpurpose with that other person.But if you're not cooperating then you canuse them to mislead the other person.And that's the double edged sword ofconversational implication.But one of the features of conversationalimplication is reallyimportant to arguments, and that'sthat you can cancel conversationalimplications.The waiter can say you can have cake orice cream,oh yeah, and you can also have pie.And when he said, and also you can havepie, he did not take backyou can have cake or ice cream, becauseyou can still have cake or ice cream.It's just that, you can also have pie.So, we can cancel the conversationalimplication that you cannot havepie by saying, oh, yeah, and you can alsohave pie.So with a conversational implication,if a certain sentence, P, conversationallyimplies another sentence, Q,then you can deny Q and P still might betrue.And that's an important fact because itdistinguishesconversational implications from logicalentailments or logical implications.If I say Alice is my sister, then thatimplies Alice is female, and I can't go,Alice is my sister, oh yeah, and she's notfemale.That doesn't make any sense because ifshe's not female, shecan't be my sister because that's alogical implication or entailment.But with a conversational implicationinstead,you can deny what is conversationallyimplied.And the original sentence is still true.So if the waiter says you can have cake,or ice cream, and then, I find outthat he's been saving the last piece ofpie for this other table, thenI can come up to him and say wait aminute, you lied to me.He didn't really lie to me, because whathe said was still true.I could have cake or ice cream.It's still true, I can have cake orice-cream.He didn't say anything false to me.He simply didn't mention the pie that Icould also have.So that's very different in the case ofconversationalimplication, than in the case of logicalentailment.And that'll be important to us, especiallywhen we getto formal logic, in a later part of thiscourse.So let me give you another example that'smore important.Imagine a politician says I've got apolicy that'sgoing to reduce crime by getting criminalsoff the streets.And the policy is lock them all up.When people are suspectedof crimes, you'll lock them all up.That's going to get criminals off thestreet.Well that might convince people if theydon't notice that he's left out anotherfact.He's not just going to get people off thestreet who arecriminals, he's going to get lots of otherpeople off the street too.He didn't give you all the relevantinformation,like the waiter who mislead you with thepie.He suggested that his policy will solvethe problem ofcrime by putting people in prison whowould commit crimes.And just left out the other relevant fact,thatit's going to put lots of other people inprison too.So he has conversationally implied thatthere's no other relevant factsto consider by only mentioning that it'sgoing to reduce the crime rate.And you have to be good at looking throughthat implication and asking, yes, but isthere something he'sleaving out?And that's often what you need to do inorder to avoid being misled by sleazypoliticians and other people who leave outtherelevant information for the issue thatyou're talking about.Now, of course, the politician might notcarethat he misled you, that might be thegoal.He wants to persuade you and he doesn'tcare whether hemisleads you because it's persuasion notjustification that he's interested in.In addition,he's got his defense ready.He can say, but I didn't say anythingfalse, what I said was true.If we put all those potential criminals injail we're going to reduce the crime rate.Maybe it's also true that we're going toput some innocent people injail, but we will reduce the crime rateand that's what I said.What Grice's maxim of quantity does is ittellsus exactly why we have a criticism of himnow.We can say he's notcooperating because he's not following theconversational maxim of quantity.He's not giving us all the relevantinformation that we needin order to achieve our purpose if we havea common purpose.And this politician is pretending to havea common purpose with us, the good of thecountry, when actually he doesn't have acommonpurpose with us, he just wants to getelected.And so Grice gives us an insight intowhat's going on when we get misled inthose contexts, and alsowhat we need to do to respond to thosetypes of bad arguments.Now this distinction betweenconversationalimplication and logical entailment iscrucialto arguments, because it tells ussomething about how to refute arguments.When you don't like the premise of anargument,because it's misleading, because itconversationally implies something false.That's not a way to show that the premiseis false.In order to show it's false you have toshow that it actually logicallyentails something that's false then youcaninfer that the premise itself is false.This will become important later when welook atthe role of conversational implication andlogical entailment in arguments.But for now, the important thing is tounderstand the distinction betweenconversational implication and logicalentailment.Speakers usually follow theseconversational maxims that Griceenunciated, when they speak, and whenthey're cooperating.But they don't always follow these maxims,sometimes they violate them.And of course, as always, there's a lotmore to be said about conversational acts.If you want to learn more aboutconversational acts you should lookat the chapter in understanding argumentsin the text that accompanies this course.But Ithink we've learned enough aboutconversational acts to move on.Because so far we've looked at language ingeneral at the linguisticlevel, at the speech act level, and at theconversational act level.Now we want to take these lessons.And apply them more specifically to thelanguage of argument.That is the particular kind of languagethat gets used in arguments.And that's what will be the topic for thenext few lectures.