Indian Institute of Technology Kanpur. NP-TEL National Programme On Technology Enhanced Learning. Course Title Introduction to Logic

Transcription

1 Indian Institute of Technology Kanpur NP-TEL National Programme On Technology Enhanced Learning Course Title Introduction to Logic Lecture-09 Informal Fallacies: Fallacies of relevance and fallacies of Weak Introduction by Prof. A.V. Ravishankar Sarma Dept. of Humanities and Social Sciences Welcome back in the last lecture we discussed various kinds of informal fallacies informal fallacies which arise out of fallacy of relevance if the premises are not relevant to the conclusion then these kinds of fallacies arises and informal fallacies can only be deducted by analyzing the content of the argument so where as the formal fallacies which we have fallacies we struggled earlier. So these those fallacies can be deducted only by the form of the argumentation so formal fallacies usually arises in the case of deductive arguments where as informal fallacies might arise in the case of other kinds of arguments that we use in day to day discourse mostly inductive kind of arguments so in the last class we studied different kinds of informal fallacies which come under the category of fallacies of relevance and you should note that this is not a final kind of classification. This is classification is only we are using it for our convenience to classify these this fallacies into some kind of group and all they are grouping into some kind of thing and all so under informal fallacies we are studying fallacies of relevance under which we studied different kinds of fallacies such as fallacies by applying to force fallacies by invoking pity in the mind of a reader or listener or fallacies such as add homonymous kind of fallacy of accident and missing the point kind of fallacy extra and all.

2 So today we will be studying to more fallacies which are under the category of a fallacies of relevance they red herring and straw man and arguments. (Refer Slide Time: 01:58) So these 2 are extremely important kind of fallacies usually we find these kinds of fallacies in day to day argumentation etc so in all the fallacies that we have discussed we have an arguer and we have a reader or listener or sometimes may be an opponent or sometimes there is a different arguer and all so an arguer present some kind of a. Today we will be discussing 2 important kinds of fallacies they are red herring and straw man and fallacy so what is a red herring kind of fallacy. (Refer Slide Time: 02:36)

3 So in the red herring kind of fallacy it is an arguer A so here is your reader or listener R stands for reader in a sense that you will be reading some bodies arguments and all are listener and you will be listening to some bodies arguments and all so A the arguer draws off-track the reader or listener and he poses some kind of conclusion and all so this is what he wants to persuade the reader or listener to accept. So what he does is he draws of track the reader or listener and he poses some kind of conclusion in all so what he does here is changes a subject matter of the argument may be that subject matter might be of interest to the reader or listener so we will show interest to that subject matters so A knows that reader or listener is interested in such kind of subject matter so A easily draws off track the reader or listener and poses some kind of conclusion and all. So he starts with some particular kind of things but he changes a subject matter and his conclusion will be based on whatever he has changed it and all whatever the subject matter which he has changed it in the due course so the one of the important things he should note is note here is that the reader or listener may not be in a position to point out that you know A is drawing of track the argument and all. So reader or listener may not be in position to notice it now so we A cleverly draws off-track the reader or listener and then we will post some kind of conclusion in that case it is called as red herring kind of argument. So in the red herring kind of arguments the structure of the arguments will be like this.

4 (Refer Slide Time: 04:37) Your premises will be something like something relevant to the topic red hand is described then he changes the subject matter of that particular kind of thing and then in a conclusion what happens is a distracting but often unnoticed change of subject occurs that is a thing which he achieves in the premises and then different kind of compulsion follows and all let us consider one simple example to see where the arguer is trying to of track the reader or listener. So it is an example there is a good deal of talk these days about the need to eliminate pesticides from our fruits and vegetables so is talking something relevant to the topic the topic at hand is the pesticides and all so now he draws off track reader or listener in this way now he goes on talks about this particular kind of thing but many of this foods are essential to our health carrots are an excellent source of vitamin A broccoli is rich in iron oranges and grapes etc fruits or which are in high vitamin c and all. He started with there are subject matter pesticides that is eliminating pesticides in all then he change the subject matter to the importance of vitamins in the diet etc and all so this all though it seems to be the case that is talking about the fruits but he is talking about something else so he change the subject matter from pesticides to there is a subtotal change in the subject matter and all so then so he as to the conclusion here is that we somehow wants to establish that we need to eliminate the pesticides from our fruits and vegetables in all.

5 But he is saying that in a that should not be the case and all so by invoking some kind of importance of this fruits dilatory consequences etc in all what kind of vitamins are present in that particular kind of fruit etc is focusing on some other topic and then he poses some kind of conclusion in all actually what the arguer is trying to show here is this that we need not have eliminate pesticides from fruits and vegetables and all. So why in what way what sense he is arguing he is arguing that all these things consist of vitamins etc and all so that is why we should not eliminate pesticides from our fruits and vegetables in all so the subject matter as been changed from pesticides to the importance of vitamins in the fruits etc and all so with that he poses some kind of conclusion whatever he wants to convince the reader or listener and all. On that case the arguments A is said to have committed the fallacy which is called as red herring fallacy this red herring fallacy as I mean got his name in a sense that usually some kind of hunting dogs they are usually trained to follow some kind of scent so whenever I mean they it if they if it is a good hunting dog and it will be able to chase the scent and then it will not be off track and all so it will be able to chance the scent in particular in sense etc. So this red herring as come from that particular kind of idea and all so here the reader in general off tracks reader or listener and poses some kind of conclusion and all and hence he seems to be committing this particular kind of fallacy. (Refer Slide Time: 08:25)

6 Another kind of fallacy which you commonly see is his that it is called as straw man argument in the straw man argument you have an arguer and you have an opponent and then what the arguer does is the arguer attacks this misrepresentation of the opponents view and all so the idea here is to describe something that sounds like you now opponents view but it is easier to knockdown and to refute in all so usually these straw man arguments will have this particular kind of structure premise will be like this a misrepresentation of the view is usually false. (Refer Slide Time: 09:38)

7 You shows that it is falls in all and the conclusion is where actually that we use is false, so in this case what happens is this thing instead of A drawing of track the reader are listener instead of reader or listener and opponent may be your enemy or may be something else who you do not like and all so what he does here is instead of changing the subject matter sultry or minimally etc. And all here what he does is it distorts the original argument so he knows that the opponents arguments cannot be suppose if you take opponents arguments actual argument into consideration there is no way when which you can conclude you can come up with some kind of misrepresentation and then he cannot show that the opponents arguments are falls are un so, so what he does is he distorts the opponents arguments and then he opposes some kind of conclusion in that process A is said to be committing this Straw men kind of fallacy. So how this name as come into existence so this is what is the actual man let us say actual person or something like that and then this is what is straw men etc. Which he is trying to construct so actual man person will be having actual arguments which the argument knows it is very difficult to attack and all, so this is a actual argument presented by his opponent all but what he does is corresponding to the actual man he constructs a straw, and then this straw men are straw person as corresponding to some kind of straw. Kind of argument these are not actual arguments and all so now what he does here is he knocks down the straw man it is straw is the straw men in a sense that he is destroying straw men s

8 argument and all, so that means he attacking the arguments of a straw men rather than the actual person actual person he knows that he cannot attack those arguments so what he does he is distorts the arguments but constructing some kind of straw person and attaches from kind of straw arguments to him. And then he knocks down this is straw person and he thinks that actually he has attack the actual argument, but what he has done that argue has done is he distracted the argument and then he has given some kind of misrepresentation of what the actual misrepresentation of an actual argument are the actual argue might be arguing something else here in this case opponent, see knock down the straw and thinks that he is knock down the argument of a an actual person but actually that is not the case so he knock down the straw men and then he knock down only the misrepresentation of what we see in the actual argument of an opponent. So if that happens when this is called as some kind of straw men kind of argument actually he knocking down the straw men rather than the actual person corresponding to actual person is corresponding to the actual argument straw men is having straw argument. (Refer Slide Time: 12:49)

9 So the structure of this argument has this particular kind of thing a misrepresentation of the view he shows that you know already distorted the argument you know and then he has come up with some kind of the misrepresentation of an argument, he could come up with some kind of misrepresentation of opponents argument then he can clearly show that that is falls you know but actually the argument is not the arguer in question is not presenting this particular kind of argumentum. It is the opponent who has misrepresented the view of an actual argument or actual argue whatever it actual arguer is trying to say, so since he distorted the argument and then he showed that it is a misrepresentation it is constructed to be a misrepresentation obviously you can show that if it is discharge the argument in the and misrepresent it and then that view may be turn out to be falls, so straw men consist of making your own position appears strong by making the opposing opponents position appear. Weaker than actually it is so an opponent has presented some kind of augmented, so that may be very string you know if we know which the arguer is not able to attack, so what he does now he misrepresents his original argument all and then he distorts the argument and he comes up with different kind of argument which is called as misrepresentation of the actual argument, so the intension of an arguer is that he wants to make the opponents position weaker he can only do it by distorting the argument we have note here that the arguer is not trying to change the subject matter.

10 Of an argument like in the case of red harry he is not drawing after the arguer reader or listener or you know where he change the subject matter very certainly you know which you know the reader or leader may not leader or listener may not be able to identify that particular kind of change and change in the subject matter, but here arguer clearly distorts the argument of an opponent and, so if that happens whatever explained here if the arguer distorts the argument of an opponent. And puts his position such a way that his arguments are very weak then obviously can attack an opponent argument and all, if that is the case then A is set we have committed this particular kind of fallacy which is called as straw men fallacy, so some examples might help us in. (Refer Slide Time: 15:31) Understanding this concept in a better way so an arguer is argue Mr. Goldberg whatever he is considering this argument is usually constructed in the opponent of an arguer, so he is arguing the arguer is arguing like this Mr. Goldberg has argued against prior in the public schools so that is what is the actual thing which Goldberg is trying to say may be he is argued for against the public schools to maintain some secularism all kinds of things. May be it might be a very strong augment etc you know it is very difficult to find flaws with that particular kind of argument, so now the arguer is saying here the Goldberg is opponent for this arguer so now the arguer is goes on and says that Mr. Goldberg advocates atheism is position in which you not believe the existence of god, but atheism is what they sued to have in Russia and

11 the past atheism reaches suppression of all religions and the replacement of god by an omnipotent state. So we are distorting the actual argument is argument against the prayer in the public schools for some reason he might or provided these kinds of reasons one can be an ethics but still he can argue for the against a theist and still we can argue against the prayer you know he if he has some secular values etc and all he can still, argue for argument against prayer in all in the public schools, so he goes on and says that he said what we want for this country etc and hardly think so, so clearly Mr. Goldberg argument is nonsense. So ultimately is wants to show that Goldberg s argument is nonsense but if he takes Goldberg s actual arguments into consideration he may not be able to do that particular kind of now he is distorted the argument and then he is bring in all the relevant factors such as atheism he is an atheist and what happen in Russia all these things and then atheism reaches suppression of all religions etc, and all these may not be the case are replacement of god by some kind of omnipotent state as marks for pointing. Out all these things may not be relevant to what actually a Goldberg is time to argue so here what happen was is that Goldberg who is constructed to be an opponent of an arguer yes put his position in such a way that his arguments look very weak and all, so he distorted the argument and then he destroyed the distorted argument and all. So ultimately his intention is to show that Goldberg s argument is nonsense here, if we take an actual argument he cannot say that particular kind of thing so he distorts the argument according to his convenience and then he shows that whatever follows from the distorted argument he will show that is obviously false and all. He constructs in a very nice way in a clever way you know in which you know obviously it will look like a weak argument and all, that is what he does distorts argument and then he posses the conclusion based on the distorted argument and all. So in that case the arguer is seems to persuaded the reader or listener and then he posses this particular kind of conclusion, then the opponent should be in a positions to say that you are the arguer is distorted the argument and all. So one should be clever enough to identify whether the arguers intention and all is he trying to distort the argument or he is trying to changes a subject matter, as in the case of red herring

12 fallacy. So there are other examples which we take in to consideration suppose if arguer is arguing in this way for example we disparately somebody argues like this we desperately need a Nationalized Health Care program or it looks well and good and all. So those who opposite think that there are many people who seems to be opposing at the moment for example, so is taking the opponent whosever is opposing is particular kind of Nationalized Health Care program. So now those who opposite think that private sector will take care of the need of the poor, but this is not being the case in the past and obviously will not be in the future etc and all. That may not be directly relevant to the need for a Nationalized Health Care program again he is seems to be distorting the argument and then he is talking about something else and all. So if an arguer distorts the argument of an opponent then the arguer is set to you how committed this particular kind of fallacy, which is called as fallacies of relevant, and that is called as Straw men kind of fallacy. So in simple terms what actually he is doing is actual person is corresponding to some kind of actual arguments straw person he construct another straw men which is a imaginary kind of thing which he thinks at easily he can knock down the straw person and all. And then he attributes some kind of argument to the straw person and he knock down the straw and then he thinks that he is actually destroyed the original argument. Original argument stands as it is but what he has knock down is the straw person and corresponding the distorted kind of argument and all, from that some kind of conclusion follows from that. So this is what is consider to be a straw men kind of argument sometimes these argument may also be very persuasive and sometimes he may not any fallacy involved in these particular kind of examples now. Suppose if one argues that empiricism is the view that nothing should be believed in unless unread can be directly observed, so no one can see here taste, smell, touch, touch protons, electrons, co- ox etc and all, you can see the effects of this things. (Refer Slide Time: 21:39)

13 (Refer Slide Time: 21:45) So I will impress pretend to be advocates of science their views in fact rule out most of the advances physical science of our times, most of the advance physical science of our time involves the presence of electrons, protons etc and all which we can only see the effects of this things but you cannot directly see the things and all, so that seems to be good and well crafted kind of argument for this particular kind of view.

14 So now what is the difference between the straw men and red herring kind of fallacy both are fallacies of relevant so the premises are irrelevant to the conclusion because in the one case in the case of red herring the arguer changes the subject matter whereas in the case of straw men the arguer distorts the argument and all. There is the difference between change of subject matter and totally distorting the argument and all. (Refer Slide Time: 22:45) So in the case of straw men, the first thing which we need to note is the arguer distorts the opponent s argument, so how he does it? He constructs a straw man and he knocks downs the straw men shoppers and says that actually he knocks down the original argument which is attached to the original arguer s arguments. In the case of red herring the arguer either changes the topic or subject matter. So he knows the reader or listener is interested or paginate about some kind of subject matter and all, he knows when to change the subject matter often argument and all, so he slightly changes the subject matter and then he posses conclusion based on the changed kind of subject matter and all. So in that case it is called as red herring, so in the case of straw men opponents position is

15 mischaracterize or misrepresented in such a way that it is easier to represent and dismiss and all, if he has correctly represented it is very difficult to argue against his position and all. So he knows that he has to missive present is position somewhere rather, so he construct a straw men and corresponding to that a straw argument and all which he imagines to be the actual argument but actually that is not the case. So in the case of red herring a distraction is introduce in to the discourse in order to lead and opponent are audients away from the issue at hand, so clearly he knows when to introduce his distraction and all. Since that case in arguer may not be in a position to notice the change in the subject matter and all, so he cleverly does it when to change the subject matter etc and all the arguer is smart enough to know that particular kind of thing. So a distraction is introduce in to the discourse in order to lead and opponent are an audients away from the issue at hand, that is what happens in the case of red herring. Third one in the straw men an arguer attributes the position to someone, that actually he did not take in to consideration he is not having that particular kind of view he is not responsible for that particular kind of argument and all. But you know he misrepresents him and then he attribute some kind of position which is actually not accepted by that actual arguers arguments and all which you will not find it in the actual arguers argument. So in the case of red herring usually what happens is ignoring the actual subject matter and all, so he draws soft from the original topic and then he moves some other topic which is closely relevant to the initial topic and all, so ignorance is what is consider in important here. So in the case of straw man forth point is that it always involves two arguers, so that is for distorting an argument you need to have a your opponent and all. And then you will be distorting your opponents position And all, so that means at least two arguers are important in the case of straw man but in the case of red herring one arguer who is arguing a particular kind of thing he is sufficient and all, he is drawing half rag reader or listener who may not be involved in the particular kind of argument and all, so he may not be directly involved in that particular kind of thing. So one arguer is enough for this particular kind of fallacy in the case of red herring, so another for example he find it in the text books for example you are the reader or the listener you are not

16 directly engaged in the argument and all, but in the case of straw man two people are actually involved in the argument one is usually the arguer who wants to misrepresent is opponents position and other one is opponent is also another kind of argument. Just in the case of a adhominom argument also two arguers are important now, because adhominom arguments are always directly towards other arguers and all, so it is in response to what other argue and then a1 will be responding to a2 argument and all. This is one of the important differences between straw men and red herring although it looks like that change of subject matter is same as distorting the argument but actually that is not the case. So the fifth one is this that in the straw man he tries to justifies the rejection of a position by an attack on different and usually a weaker kind of position and all, so actual person has an actual argument which is strong argument and all for example, then he changes are misrepresent it in such a way that will look very weak kind of argument he changes a distortion argument and all, he looks like a premises maybe weak enough to support the conclusion and all. He is totally distorted the argument and all, and then he shows that the conclusion is false and all conclusion dies not follow from the premises, so fallacies one of the important difference of fallacies is that one does not follow from something non sequent that is the one phrase that we have used earlier. So in the case of red herring fallacy what happens is that it tries to justifies the conclusion. (Refer Slide Time: 28:04)

17 That is the one the face that we have used earlier so in the case of red Herring fallacies what happens is that it tries to justify the conclusion irrelevant to the issue because you have an exchange the subject matter of the sentences subject matter of the argument and all so that is totally different and all form that he poses some kind of conclusion. Actually it could have denied form the actual subject matter and all then it will not created problem here it cleverly changes the subject matter it clause after the reader or the listener and then he posing some kind of conclusion and will so that later this too red herring kind of fallacies this is how the important differences between straw man and red herring and then so usually in the case of red herring argument arguer ignores opponents arguments. If there is any certain kind of conclusions which is presenting this argument and certainly subject change the subject matter it does not changes the subject matter completely and all but it is changes very sub clear in the case of straw man he discharges and opponents argument and concludes by knocking down the distorter it presents some distorter argument and not down the distorter arguments. So it just like the knocking down the stop and the actual so this is what happens in the case of straw man so there are some examples which we can taken into consideration little bit later but so these examples will considerate it later for example so far we have studies about various kinds of fallacies. (Refer Slide Time: 29:35)

18 Let us consider it is some three examples and all and we will see what kind of fallacies it is, it is somewhat some fallacies of relevance of fallacies may be form fallacies etc and all let us consider the first example all the really hot new thinkers are using principles form sociobiology and now it is a new wave in ethics so you should accept the principle of sociobiology so this fallacies seems to be like a fallacies by appealing to people it is also called as band wagon kind of argument. A 99 people does something when then you do not want to be single doubt form the particular kind of thing and you also start believing that particular kind of thing since it is a popular new wave in ethics it does not mean that you should accept the principles of sociobiology and all even if 99 people accept it but still you can critically exanimate and then you can consider all the weak points of it and then you will you need not accept the principles of sociobiology so this is appealed to people kind of fallacies. So it is like you know 99 peoples jumped into fringe into a well consider the second argument Kapoor this paper merits at least B this is what the student is arguing with a professor I stayed up all night working on it and if I do not get B then I will put on academic probation nd my grades will suffer and so on and so forth ill happen.

19 My entire family is dependent on me and I am coming from poor family all these things we know it tries to see so ultimately the conclusion is that stayed up merits at least that means I should get always B so getting B is dependent on so my other factors and all. It is not what the arguer is trying to do here is the invokes pretty in the mind of professor Kapoor and then he is posing this particular kind of conclusion a conclusion is this that we should get B and all so this clearly an argument from pretty third one smoking cigarettes can harm one s health so it is best to avoid smoking does not mean one wants to be healthy. So it seems that any particular kind of fallacy because smoking cause harm to one s health and all so this seems to be no fallacy in thus particular kind of argument there is no making this argument so these examples will consider little bit later. (Refer Slide Time: 32:11)

20 Now we will move on to inductive arguments, inductive arguments can also be fallacies so what are the inductive arguments when inductive arguments are fallacies and it is called as fallacies of weak induction so far we how studies fallacies of relevant were the premises are irrelevant to the conclusion most of the cases in this case what happens here is this the premises are not sufficient enough to provide evidence to belief the conclusion to be true if they are usually consider the weak arguments. The weak arguments are automatically consider to be fallacies kind of arguments so all the inductive arguments can be fallacies and all so inductive arguments are defined as arguments that are intended to be usually strong or weak and all but an inductive argument can never be valid or invalid if I use this concepts validity and invalidity or if we tribute validity and invalidity inductive arguments there is some mistake which will be there. We can only talk about strength of the inductive arguments so these are some of the examples which we have already discussed in greater detail a deductive argument is like this all crows re black therefore if there is crow on the top of the Charminar then it has be black and all. All crows are black it is kind of general without any exception if you believe that particular kind of thing to be true then if you find some other kind of crow on the top of the Charminar then it has to be black it cannot be white and all provided you take into consideration all crows are black is absolutely true and all. There is no exception for that particular kind of thing but actually later disclosures that is not the case better best thing to represent this argument is most of the crows are black so inductive arguments is this that in all crows that we are observed so far are black it is based on your observation etc. And then based on your observations you are moving beyond whatever you are observed and you are predicting that probably all crows are black and all so the conclusion always goes bayou what is stated the premises conclusion need not have to follow necessarily form the premises and then it is always some kind of new information. And these arguments are all is visible kind of arguments that means addition of new information led to withdrawal of your conclusions at your derived earlier so this is some of the inductive arguments basically you will find inductive generalizations.

21 (Refer Slide Time: 34:50) For example if we say I have lots of friends most of them think that I would make get president of Gymkhana IITK so most of the IITK students probably agree with it so we not be case that most of the IITK cases students would not probably agree with this particular kind of thing and all just because you have lots of friends does not mean that you will be elected as a some kind of Gymkhana president and all or everywhere wants him to be some kind of president of Gymkhana of IITK and all. Or suppose we know we make this kind of inductive generalizations all the time suppose if I mess worker in the hostel stole my bicycle and all so I will come to some kind of sweeping generalization I will say that all mess workers are thieves so it is kind of some kind of sweeping generalization and all.

22 So when the generalizations are not used in the proper sense if we use some kind of sweeping generalization then that is considered to be a mistaken in the argumentation and all so when we talk about slippery inductive generalizations then will discuss all this things in later detail inductive generalizations can be also be fallacies and all. So some questions we need to ask for this particular kind of thing that is the premises are acceptable? Is the sample too small? Is the sample biased? Are the results affected by other sources of bias? All these things we need to ask to come off with some kind of good inductive generalizations. (Refer Slide Time: 36:27) Other ways it will lead to some kind of fallacies so why this I am talking more about this inductive generalizations here is the it is an argument presented by a famous philosopher Hume s David Hume is argument is called as Hume s Skeptical argument of believing this justification of inductive general edition is under what basis an inductive generalization can be justified an inductive generalization can be like this. For example if you say metal one starts expands upon heating metal two starts upon expands upon heating and then you generalize it and say that all metals expands upon heating and all so this is this how some kind of inductive generalization and then gradually you elevated to some

23 kind of law statement nd all that so now under what condition this kind of inductive generalizations can be justified. So Hume s has presented some kind of Skeptical argument he says that it cannot be justified either by means of principles of logic or by means of inductive itself or by experience so he says that our inductive generalization seems to rest on the assumptions that unobserved cases will follow from the patterns that we discovered so far. From the observed cases and all so from observed cases unobserved kind of things follows and all most of the crows that you re observed so far are black in color the next crows that you have going to see which is not there in the premises and all so that is unobserved kind of things so we are predicting that next crows that we are going to see is also going to be black and all. (Refer Slide Time: 38:06) So from we are moving from observed to unobserved kind of cases and all, so that is our inductive generalization seem to suppose that nature operates uniformly and all. So what is the guarantee that this will lead to the next and all, the next crow is going to be black and all 99% of cases tells us this is going to be black and all, usually a predictor gut feeling says that the next bird that you are going to see is also going to be black in color. So how do we know that it is going to be case in all in the next case also that is going to be true, then we are relying on the principle of uniformity of nature, inverse does not behave in a random

24 way and all, it behaves in a uniform way etc and all. So because of that obviously the next bird that you are going to see is also turn out being black in color. So the way the things are observed to behave here and now are accurate indicators of, how things behave anywhere and at anytime but what right that we can assume that the nature is uniform. How do we know that the universe is governed by the principle of uniformity of nature? So he goes on and says that because this claim itself as a contingent matter of fact it could only be established by inductive reasoning. So the idea here is very simple that is under what basis you can say that sun raises in the east tomorrow and all, so it arose in the east all the time you got up from the bed you saw the sun rise in the east and on what basis you can justify that the unobserved case that is about the tomorrow thing under what condition it is going to arise in the east only. So you are saying that since universe behaves in a certain way and then it behaved in a certain orderly way yesterday and day before yesterday etc and all. Universe also behaves in the same way maybe day after tomorrow also, so under what basis you can justify this particular kind of inductive generalization and all, you are relying on the principle of uniformity of nature. What is principle of uniformity of nature? Again it is some kind form of induction and all, so that means induction is justified by induction itself, like sun always rises in east etc. Then we are relying on principle of uniformity of nature, universe always behave in a certain way and we do not have any exceptions etc and all and we assume that universe also behaves in a same way may be tomorrow, or may be day after tomorrow also it behaves in a same way etc. that makes this uniformity of nature and all. So Humes says that if inductive generation are justified by the principle of uniformity of nature which self is some kind of induction then it leads to some kind of circularity and all. So the principle of uniformity of nature that is the claim that itself asserts some contingent matter of fact it could only be established by some kind of inductive reasoning and all. So that means instead of uniformity of nature worked yesterday principle of uniformity of nature day before yesterday etc. But because all inductive reasoning pre suppose that the principle of nature is uniform that means any inductive justification of this principle would always seem to be circular because if

25 you are ask to justify inductive generalization like heating or sun always rises in east etc and all you are following back on principle of uniformity of nature which is self is nothing but a kind of inductive. So induction is justified by induction so it leads to some kind of circularity, so it seems that we all have no ultimate justification for inductive reasoning at all. So that is what is the skeptical argument of Hume even till to date, there was no appropriate solution for this particular kind of argument how to justify induction and all. But we heavily rely on induction in natural sciences in particular that whenever the scientist is coming out with some kind of law statement. And inductive generalization based on some principle of uniformity of nature etc and all he always take it for granted that principle universe behaves in a certain way in order etc and all. Suppose what happens if the universe does not behave in the same order that we are trying to expect and all, so then the principle of uniformity of nature might or not be false and then inductive generalization rested on principle of uniformity of nature can be questioned and all. So this is the skeptical argument presented by Hume and ultimately concluded that inductive generalization cannot be justified and all, if it is justified it as to be based on either deduction which cannot be the case because inductive arguments cannot be justified by invoking some kind of deduction and all. In the case of deduction it is obvious that the conclusion necessary follows from the premises. But clearly in this case inductive generalization is always being the case that conclusion goes beyond what is stated in the premises, so induction cannot be justified deduction that is ruled out. But whether on what condition induction can be justified and all, so then you are saying that principle of uniformity of nature that is making you to believe that sun always rises in the east is going to be true today tomorrow. So induction what is the principle of uniformity of nature? That is gain induction cannot be justified by induction so in the either cases there seems to be a problem so that is why Hume posses some kind of skeptical kind of conclusion that means doubtful kind of conclusion that you know induction cannot be inductive generalization cannot be justified and all. So we look into this aspect may be late but this is a reference in which you know you will find this particular kind of argument.

26 (Refer Slide Time: 44:51) The skeptical kind of argument and all, so forget about this negative aspect of inductive kind of arguments and all, but inductive arguments are useful for us and there are inductive generalization are important in coming with some law statements etc and all. So then you know once you propose law statements you can elevate it to some kind of formal theory and etc and all. (Refer Slide Time: 45:22)

27 So I have said in the beginning that even inductive arguments can also be fallacies, when all the weak inductive arguments are obviously fallacies arguments in the essence that premises will not be sufficient enough there are not providing adequate support to believe the conclusion to be true and all. So all the inductive arguments which we spoke about in the basic concepts they lead to this particular kind of fallacies and all. So these are some of the important fallacies of weak induction, 1 appeal to unqualified authority, the Latin name of that one is Argumentum ad Verecundiam and 2 nd one appeal to ignorance because you know all these arguments comes under the category of inductive arguments, if the premises are not providing sufficient evidence to believe the conclusion to be true then it will leads to weak argument. All weak argument are fallacies arguments and the hasty generalization false cause, slippery slope, weak analogy all these comes under they are inductive arguments if they are weak enough then they are called as fallacies of weak induction, as fallacies of weak induction arises especially when your premises are not able to provide sufficient evidence to believe your conclusion to be true, in that case it leads to fallacy of weak induction. Let us consider one example the 1st one that is. (Refer Slide Time: 46:50) Fallacy of weak induction arises because of appealing to unqualified authority, so this arise in this particular way the diagram for this one is like this so what happens here is that arguer sight

28 some kind of unqualified authority and then he imposes some kind of conclusion so this is what it happens here. (Refer Slide Time: 47:26) So you have a arguer A so what he does is sized some kind of authority unqualified authority so here means unqualified authority and then he pose a conclusion that means this conclusion is based on falling back on some kind of unqualified authority if it is based on qualified authority and all then it seems to be mistaken that argumentation so it is not consider as fantasy weak because strong argument. So defiantly it is not a fallacy of weak indication so now the question that comes towards this qualified authority and what constitutes an qualified authority here are some feeds in which it is very difficult to say that the person has any authority one is region politics ethics extra and all this values etc and all somebody who is studying about values it is very difficult to become expertise in this particular kind of area.

29 So somebody is arguing something related to political kind of thing and all it is very difficult to have authority on this particular kind of subject so we can question the authority of a person especially when he is talking when he is making some claims about values judgments etc so what is consider as appeal to what is argument looks like this. (Refer Slide Time: 49:18) It is an argument in which the conclusion is based on the judgment of someone who is not actually the authority issue at hand so it gives to unqualified authority and he imposes some kind of conclusion or it is an argument which is based on the judgment of a genuine authority on the issue at hand. But concerns a issue about which there is no disagreement among experts in the field then also it is called as an unqualified authority the problem here is that although he refers to some kind of genuine authority and all but the problem here is that this disagreement amount experts in the field so then that is also consider to be some kind of unqualified authority.

30 (Refer Slide Time: 50:07) So these are some of examples which we take into consideration but we did not answer what constitutes qualified authority what constitutes a unqualified authority so for example if a person who has expertise in politics etc he may not be able to he may not be having expertise in medicine or what kind of drugs one should take etc in or a person may be having authority ion one or more fields as person is good in mathematics may be good in physics as well. So he has different kinds of expertise in more than one filed and in the same way for example in mathematician all of us start claiming that everyone should take some drug prescribe some kind of drug etc and all then you know we will usually question this expertise so if somebody pose some kind of conclusion based even though he is a great mathematician and all but still you know we will be doubtful about this particular kind of argametics Because he is not having expertise in the medicine so let us consider a simple example and then we will this lecture so tom Jones a respected actor who plays the brilliant cardiologist Dr john smith in the film emergency recommends some kind of drug in improving the overall health of the heart so therefore it would be wise to take this particular kind of drug I might be a fan of tom Jones etc and all I admire him a lot etc and all he acted brilliantly as cardiologist etc and all. But it does not mean that if he starts describing some kind of drug then he start a leaving he is taking its statement seriously that means you should use it would be wise to take drug X than if you conclude that it will be wise to take drug X then arguer is sighting some kind of unqualified

31 authority unqualified authority means in the sense he is referring to an actor who is not having any expertise in the medicine. And he is posing this particular kind conclusion that it would be wise to take drug X so in this lecture what we have seen is you have discussed fallacies of formal fallacies especially fallacies are the informal fallacies in the sense that fallacies of relevant under which we discussed tom and red hating arguments we discuss in detail the distinction between the red hearing fallacy and tom and his arguments. And in one hand we have change of subject matter is the one which you seen in the place of tome and argument where the arguer cross after reader and listener and in the case of strong the arguer distorts the argument in miserable the original position of an argument and he poses some kind of and he shows that arguer argument is weak enough this presentation out of it representation he conclude something. And which shows that the argument are weaken a then we moved on to in the new generations and then we discussed about whether this inductive generation be justified etc and then we have presented cube argument and then we showed that inductive generation cannot be justified either by reduction or by induction if you justify based on the reduction then inductive arguments cannot be justified by deduction and inductive arguments are justified by induction. Then it leads to some kind of circularity so despite having these problems with induction generations we moved on to some of the mistakes that we commonly make with respect to inductive argument so when we make mistakes with respect to inductive arguments they are called as fallacies of weak induction. So one particular kind of fallacy we discussed that is fallacy might appealing to unqualified authority so when arguer is sighting a qualified authority is not having expertise in that particular area and then he pose some particular kind of conclusion zed we have said to committed this fallacy of unqualified authority so in this next lecture we will be covering some other interesting and existing kind of fallacies which come under the category of fallacies of weak induction. So they are fallacies which arises of causal effect or you know the kind of some slippery slope and some other very interesting kind of fallacies which we will discuss in the next lecture in all

32 these fallacies one of the most important thing is to note is that premises are not an arguer especially the premises are not enough to provide sufficient evidence to believe. The conclusion to be true and then these kind of fallacies arises so the arguments are to be weak so that is why they are called as a weak induction so in the next class we will continue with slippery slope and some other very interesting kind of fallacies weak analysis etc we study in later detail in the next class. Acknowledgement Ministry of Human Resource & Development Prof. Phalguni Gupta Co-ordinator, NPTEL IIT Kanpur Prof. Satyaki Roy Co Co-ordinator, NPTEL IIT Kanpur Camera Ram Chandra Dilip Tripathi Padam Shukla Manoj Shrivastava Sanjay Mishra Editing Ashish Singh Badal Pradhan Tapobrata Das Shubham Rawat Shikha Gupta Pradeep Kumar K. K Mishra Jai Singh Sweety Kanaujia Aradhana Singh Sweta Preeti Sachan Ashutosh Gairola Dilip Katiyar Ashutosh Kumar Light & Sound Sharwan Hari Ram

33 Production Crew Bhadra Rao Puneet Kumar Bajpai Priyanka Singh Office Lalty Dutta Ajay Kanaujia Shivendra Kumar Tiwari Saurabh Shukla Direction Sanjay Pal Production Manager Bharat Lal an IIT Kanpur reserved