 In the last few lectures we talked about what we mean by an argument and how to identify an argument that means recognizing an argument especially when what we have said was this that whenever you find some kind of indicator words for premises or indicator words for the conclusion then we are saying that there seems to be some kind of argument present in a given English language passage. So identifying or recognizing the argument is the most important thing for a logician. So once he identifies an argument then he can criticize or he can evaluate these arguments what type of argument it is etc. So in this lecture what we would be doing is simply this that once we identified the argument and then once we have distinguished it from non-arguments, non-arguments in the sense that reports, warnings, piece of advice, explanations, expositions, illustrations etc. Once you extract from these things once we have an argument then the immediate question that comes to us is what type of argument it is. So usually in logic we study two different kinds of arguments so one is inductive argument another one is deductive argument. So this lecture we will be focusing our attention on deductive arguments and then what are the characteristics of a deductive argument where do you come across these deductive arguments in what sense they are different from the other kind of argument which we are talking about that is the inductive argument. So in what sense these two are different and all. So the first and primary thing which we need to learn in any logic course is the distinction between the deduction and induction. So far we have what we have done is like this so what we have said is this that non inferential passages are non-arguments whereas inferential passages are whenever you find some kind of inferential claim in a given passage then we are saying that there is some kind of argument present in the given passage. So we will straight away move into the two different types of arguments one is inductive argument another one is deductive argument. So where do we find this inductive and deductive kinds of arguments. So what is the definition of a deductive argument any argument consist of premises and conclusion it depends upon how the premises are leading to the conclusion we have these two different kinds of arguments. So in the case of deductive arguments if the premises are true the conclusion has to be true and all. So it is by virtue of some kind of logical necessity the conclusion necessarily follows from the premises. So that means if it is a valid kind of argument which I will talk about a little bit later if you say something is a valid argument and all a deductive argument especially when if you have two premises you cannot have a false conclusion if you have a false conclusion then that is called as an invalid kind of argument. So one of the important things which you will observe in the case of deductive arguments is that the conclusion necessarily follows from the premises it is a kind of some kind of logical necessity. So if the premises are true the conclusion cannot be false enough. So the link between the premises and the conclusion in the case of deductive argument is stricter. So that means if the premises are accepted to be 100% true then the conclusion also accept accepted to be 100% true and all there is some kind of absolute certainty involved in deductive kind of arguments. So how to identify that there are deductive arguments in a English language passage that we are looking for. So again there will be some indicator words for identifying the deductive arguments especially when you look at the conclusion part and all in the given argument. So they end with these kinds of phrases necessarily certainly definitely etc and all. So there is some kind of absolute certainty involved in these kinds of arguments deductive arguments. So we find these kinds of arguments basically in mathematics accepted. So mathematics seeks some kind of certainty so usually we find these kinds of arguments in of course in some of the arguments you find it in day to day life but to what extent they will be useful and all we will talk about it little bit later. So if you want to say that a successful deductive argument these are the arguments in which the conclusion is completely guaranteed by the premises. Premises are true the conclusion cannot be false again and again I am saying the same thing. The conclusion must be contained in the premises and all. So it is in this sense that deductive arguments there is nothing new in the conclusion. So everything that is there in the conclusion is already there in the premises then what is so great about these deductive arguments and all. So whatever is there in the premises which is implicit which is made explicit in the conclusions. So there is nothing no new information which you are going to arrive at in the case of deductive arguments because the conclusion is already present in the premises which is implicit earlier it will become explicit. So this is the case of deductive arguments let us consider an example then we will talk about what are the characteristics of deductive argument. Suppose if you say that all police chiefs are honest we know that they are not all or anyhow honest and all but for time being assuming that all police chiefs chief of superintendent police etcetera and all they are all honest and all assume to be true. You have to note that in logic you need to have to be actually true and all even if you can assume some of the things to be true then based on your assumptions you will see whether the conclusion follows from that or not. So all police chiefs are honest practically speaking there is not the case anyway suppose if you say that Mr Kapoor is a police chief then it must be the case that Kapoor has to be honest and all there is no way in which Kapoor can be dishonest based on our assumptions that all police chiefs are honest is 100% true Mr Kapoor is a police chief is certainly true that means absolutely true or 100% true then it cannot go in any other way then this that Mr Kapoor has to be honest must be honest and all. So the first premise is taken to be an absolute universal generalization without any exception and all. In the deductive arguments suppose if it begins with all police chiefs are honest and all or if you say all crores are black etcetera that is an universal generalization which is taken for granted that it is taken for granted that there are no exceptions and all. So it is in this sense the first premise is 100% true second premise is 100% true then third premise you cannot say that it is 90% true or 50% true etcetera and all there is no element of degree of truth in the conclusion if you accept the premises to be true then the conclusion must be true if the premises are true the conclusion cannot be false enough if that is the case it is not a valid kind of argument it is the invalid kind of argument which we are going to talk about little bit later so validity tells us what follows what so which we will talk about it little bit later when we talk about validity of deductive arguments etcetera. So in this example if the two premises are assumed to be absolutely true then the conclusion cannot be false enough that means you cannot come up with a single counter example in which your premises all police chiefs are honest Mr Kapoor is a police chief is true then it cannot be the case that you cannot come up with any counter example in which the Kapoor is honest you cannot come across with any instance where you can show that Mr Kapoor is dishonest and all. So premises guarantees that the conclusion is true and all there is come some kind of necessity involved in these kinds of arguments and all necessity absolute certainty these are some of the important characteristics of deductive arguments. So what we mean to say that a deductive argument is valid to say that an argument is deductively valid means that it is logically impossible for the premises to be true and the conclusion is false if you come across a situation where your premises are true and the conclusion is false then it is automatically an invalid kind of argument. So the set of three statements one of the important requirement is this that the set of three statements should be collectively consistent and all consistency in a sense that either you can show that x is the case or not x is the case and all. So if you can show both are the cases x and not x for example if you obtain if you derive something like it is raining and it is not raining simultaneously then there is something wrong with the argument. So the given premises are inconsistent if the premises taken together are inconsistent with the negation of the conclusion is another way of putting that a deductive argument is valid or invalid if the premises taken together are inconsistent with the negation of the conclusion not the conclusion and all negation of the conclusion then the then also the argument is said to be deductively valid. So this is an example which establishes this particular kind of thing all police chiefs are honest again the same example which will be taking Mr. Kapoor is a police chief therefore Mr. Kapoor is not honest suppose if you can come across with this kind of conclusion then it is considered to be an invalid kind of argument it has to be honest if it comes under the category of a police chief. So then we will talk about where do you come across deductive arguments little bit later how to identify this deductive arguments in a given language passage English language passage little bit later but we will talk about what we mean by inductive arguments. So these are the two different kinds of arguments that you come across in basically you come across in while you are reading a scientific text or reading some kind of newspaper or something like that this is commonly occurring kind of arguments which you come across even in day to day discosals. In an inductive argument on the other hand compared to the deductive arguments the link between the premises and the conclusion is not strict I mean that means conclusion can probably follow from the premises and all in the inductive arguments conclusion need not necessarily follow from the premises. So if the premises are true then the conclusion will only be probably true so probability has various connotations and all I will talk about it little bit later when I go into the details of inductive arguments but here especially to make these two arguments distinct and all on the one hand you have conclusion necessarily follows from the premises there is no way in which if premises are true the conclusion is false if you subscribe to two things and you have to you will buy two things automatically you will get the other one as free of cost you have to buy the other one else it will be given free of cost so you cannot give up the conclusion if your premises are accepted to be true the conclusion has to be must be true enough in the case of deductive arguments that is not the case in the case of inductive arguments. So the conclusion probably follows from the premises and one of the criteria is the nature of inferential link between the premises and the conclusion that is going to decide whether it is an inductive or deductive argument. So inductive arguments are based mostly based on probability and inductive arguments are based on statistical data etc and all so the support for an inductive argument is typically given by some kind of empirical evidence or direct observations etc. So here is an example of an inductive argument and we will see in what sense this inductive argument is different from the deductive arguments suppose if you say most fans are white I am not saying all fans are white and all basically in our observation you observe that many crores are black etc and all so you observed thousands of crores let us say it is your habit that means hobby that you are observing crores is your part of your day to day activity and all so you observed that all crores are black most of the crores are black and all. So now you got up in the morning and then you observed that the next crow that you observed is also turned out to be black and all here in this case it is a swan we are talking about swan so this bird is a swan. So therefore this bird has to be white and all most fans are white this bird is a swan then it has to be this is probably be white and all so it may happen that the bird that you come across the next bird that you are going to see the swan may be black also. So on every single morning in the human history the sun appear to rise and all so therefore we say that usually we say that sun will also appear to rise tomorrow morning in the east so based on our repeated observations and all usually we infer that we predict something and we say that let us say thousands of instances you observed where sun rose in the east and then based on that information you will say that sun will also rise in the east maybe even tomorrow morning also. So there is no such kind of absolute necessity involved in these kinds of arguments and all. So before going into the details of what kind of things are inductive and what kind of things are deductive arguments let me talk about the distinction between the deductive and inductive argument in a better way. So here is the some of the questions that we need to ask ourselves to judge whether a given argument is a deductive or inductive argument so the first question we need to ask this is the case of deduction and on the other hand we have induction so these are the two different kinds of reasoning that you come across in day to day discourse. So the first thing which you need to note is that whether the conclusion contains some information conclusion contains some information that is not in premises that is not in premises. So now the first question that you need to ask yourself is that is it the case that conclusion contains some information that is not in the premises. So depending upon the answer we can say that it is a deduction or it is an induction in the case of deductive arguments the answer is the answer is no and in the case of inductive arguments the answer is yes. So what it says is this that if you observe the argument in greater detail then what we will see is that if you ask this question whether the conclusion contains some information which is some information that is not in the premises then in the case of deductive arguments it is not the case but in the case of inductive arguments it is the case for example if you say all men are mortal socrates is man socrates is mortal there is absolutely there is no new information in the conclusion socrates is mortal for example if you say this is the common example which everyone gives all men are mortal socrates is man something like that then you say that socrates is mortal. So now observe this kind of argument is the deductive argument and now we need to ask this particular kind of question whether the conclusion contains any new information that is not there in the premises. So socrates is mortal is already hidden in all men are mortal and socrates is man socrates is mortal is made explicit in the conclusion which is already hidden in the premises and all so there are some other things which come under the category of deductive arguments which usually come across in day to day discourse also for example if you say that somebody is a liar Ram is a liar and from that you can infer that Ram always tells lies. So this is by definition that follows from this thing Ram is a liar means it tells lies one so arguments based on definition or there are some kind of analytical truths which come under I mean which we will talk about in the examples little bit later but in this case absolutely there is no new information present in the conclusion whereas in the case of inductive arguments for example you say that most of the IITK students who graduated who graduated from so most of the students just a little bit of most of the students who graduated from IITK this institute after let us say 2007 or something like that who said was graded after this thing took a course course on let us say some course which is with the name PHI 142 introduction to logic. So this is the first premise and all so we are saying that most of the students who graduated from IITK after 2007 took this course and all it so happened incidentally that you know most of the students took this particular kind of course now let us say some example now the second premise is one student with the name shaker is a student of student who graduated who graduated after let us say 2007 so the first premise is that most of the students who graduated from IITK from after 2007 so happened that they took this introduction to logic course now shaker is a student who graduated after 2007 so then you say that probably shaker took a course in logic so this is the conclusion which follows from these two premises and it appears to be the case that it is a strong argument conclusion seems to be probably following from the premises because most of the students who graduated let us say you know 90% of the students who graduated from IITK after 2007 took the course in logic and not 90% of the students in every batch so now shaker as graduated let us say in 2008 or something like that and probably shaker also would have taken this particular kind of course in logic you need to note that the conclusion only probably follows from the premises it might be the case that shaker might not have taken this particular kind of course he might not have fallen under the category of most of the students so suppose if you convert this argument reinterpret this argument in a different way for example if you say that all the students who graduated in IITK after 2007 took a course graduated took a course in PHA 142 and it so happened that PHA 142 is compulsory or something like that every student must do and all then this argument may turn out to be the case that you know shaker also took a course in logic and all but in this case the way this argument is interpreted the conclusion only probably follows from the premises and all so now again coming back to this or from initial question that whether the conclusion contains some information that is not in the premises definitely it is not a certain kind of information which is not present in the premises and then what we are trying to do is that the conclusion probably shaker also took course in logic seems to be going beyond what is stated in the premises and all. So the idea here is this that whether or not the conclusion contains some information which is not there in the premises if the answer is no then it is a deductive argument because there is no absolutely there is no new information in the conclusion in the case of inductive arguments the conclusion contains some information which is not there in the premises and all. So one example another example of an inductive argument could be is that all of us travel in commercial flights and all Indigo, Air India etc all these things two different places and it so happened that in a 99.99% it is not 100% and all 99.99% of commercial airline flights completed have completed without any incident and all it so happened that they landed safely and all. Also based on that kind of premise you can infer that the next plane that you are going to take from Lucknow airport or something like that will all most certainly arrive safely and all. So there is no guarantee that it 100% it will land safely and all though our information or we have trust in our safety of our public safety etc of flights etc and all even then you cannot say with 100% certainty that the next flight that you are going to take will also land safely and all it might be the case that you know some technical problem or something might wrong might happen in the engine etc so many things might happen and all. So in that case also the conclusion goes beyond what is stated in the premises and all there is no absolute certainty involved in these kinds of argument. So the other important feature that distinguishes inductive and deductive argument is the next question that you need to ask is and based on whether your answer is yes or no and that is going to decide whether it is a deduction or induction so now the next question that you need to ask is it truth preserving is your argument truth preserving. So deductive arguments preserves a truth one of the definitions of value deductive argument is that if the premises are true the conclusion cannot be false and all that means it is preserving the truth and all so if the premises are true the conclusion must be true and all that means the truth is preserved throughout the argument and all. So one example is all men are mortal socrates is man socrates is mortal and all you will be bored by this example but in the classic textbooks this is the example which everyone gives so in that particular kind of example all men are mortal if is assumed to be true socrates is man is true then socrates must be true and all that is what is called as truth preserving kind of argument so the answer for this question is yes then it is a deductive argument if it is not truth preserving then it is called as inductive argument what does it mean if the in the case of inductive arguments the conclusion only probably follow from the premises that means you can come up with an instance where your premises are true but your conclusion can be probably false in most of the cases it might happen your observations etc tells us that the next thing that you are going to predict is also true and all but there is no absolute guarantee that you know conclusion is true and all but that is not the case in the case of arguments that you commonly come across in the case of in the field of mathematics etc if something is true then it has to be absolutely true and all in mathematics we did not say that the premises are 90 percent true 70 percent true except I know once you accept that something is true and that is absolutely true certainly true except I know so this is the reason why you know if mathematics does not strive for some kind of certainty then other fields I mean we do not have anything to say about other fields so mathematics definitely seek some kind of certainty and all so this is the kind of ideal kind of situation the ideals which we want to achieve so the question is whether do we come across these kinds of argument in day-to-day discourse are not little bit patient they will come to know about these things a little bit later so truth preserving then the answer is yes in the case of induction the answer is no now the third one is is the argument is having some kind of variable strength so these are the questions and all answer will be like this in the case of deductive arguments it is no and in the case of inductive argument is yes that means conclusion is accepted with some degree of truth so since in the case of inductive arguments conclusion need not necessarily follow from the premises conclusion only probably follow from the premises then it is having some kind of variable strength and all so this is not permitted in the case of deductive arguments conclusion necessarily follows from the premises there is no kind of variable strength which you will come across in the case of deductive arguments the answer here is no the answer here is yes is the argument is having some kind of variable strength if you ask yourself this question if your answer is no then that is a deductive argument if your answer is yes then it is an inductive argument and one of the another final thing which you need to notice this thing is it an open ended argument or not open ended argument or not so if your answer is that means additional premises can weaken or strengthen the argument open in the sense that you know if the argument is closed then additional premises will not invalidate the conclusions that you have drawn earlier if it is an open ended argument then then addition of new premises will weaken or strengthen the argument so in the case of deductive arguments the answer is no suppose if you ask yourself this is the case that your argument is an open ended argument that means addition of new premises or new information we can strengthen the conclusion that you have drawn earlier then the answer clear cut answer in the case of deductive argument is no in the case of inductive arguments answer is yes so that means inductive arguments are open ended kind of arguments so this is the main distinction between the deductive and inductive arguments so in a nutshell it is like this that in the case of deductive arguments the conclusion necessarily follows from the premises there is no new information in the conclusion which is not stated in the premises suppose if it is something some new information is present in the conclusion then that means the whatever is stated in the conclusion goes beyond whatever stated in the premises that means it is not a deductive kind of argument and then the conclusion necessarily follows from the premises that means your premises are true the conclusion cannot be false and then it is not an open ended kind of argument is logically closed that means even if you add thousands of premises etc and all suppose if you have derived some kind of conclusion that is not going to violate the conclusion that you have derived earlier and all so usually you will find these kinds of arguments in a specific form of reasoning and all that is mathematical kind of reasoning we employ this deductive arguments you might ask suppose if the conclusion nothing is new nothing new is stated in the conclusion what is so great about this deductive arguments and all now one of the strengths of a deductive argument is that you know you will achieve some kind of certainty and then deductive arguments does not have any variable strength once you accept it you accept it as 100% true even the conclusion is also 100% true and absolutely true etc there is no way in which you can say that the conclusion is 90% true or 70% true etc and all so in the case of inductive arguments the conclusion probably follows from the premises and no there is a new new new information in the premises that means you know especially when in the case of when you are predicting something you will go beyond what is stated in the premises and all so based on today's whether you can infer some of the other things and all so predictions whether predictions etc there all arguments which come under the category of inductive arguments I will talk about a little bit later. So inductive arguments are open ended arguments in a sense that you keep on adding new information then it will weaken a strength in the argument and all for example if you say that let us say 75% of the commercial airlines lane fries completed without incident and all the next plane you will take almost certainly arrive safely and all if this percentage of safety increases and all then you are strengthening this particular kind of argument and all let us say you went from 75 to 99.99% and all means you are increasing the strength of the argument and all. So now we spoke about the distinction between inductive and deductive arguments and then we need to look into this aspect that where do we come across this inductive arguments just like in the case of arguments where you know first you need to identify premises and for identifying the premises you need to have premise indicators in the case of conclusion indicator in the case of identifying the conclusion you need to have conclusion indicators suppose if these two are missing then you need to find out whether there is any inferential claim present in the passage it can be factual or inferential claim if one of these things are present then you say that is an argument present in the English language passage and all. So our English language passage is crowded with all these kinds of things and all arguments non-arguments etc. So now once you identify that this is an argument then the next question arises is what kind of argument it is let us say you have identified that it is an inductive argument usually inductive arguments you have to look for the indicator words so in the argument in an argument you will find these kinds of phrases then you can say that seems to be some kind of inductive argument present in a English language passage probably less likely or more likely reasonable plausible all these things are the phrases which you commonly see in inductive arguments and other kinds of arguments that you commonly come across in the everyday discourse are these things statistical data once you are trying to come up with once you come up with the statistical data you will interpret it and you will say with some kind of certainty some kind of degree you will make some kind of claims etc and all probably 90% of ITK students are bright or something like that some data you will infer some of the things or generalizations from past experience in the past sun always risen in the east so now you will say with this thing with confidence that sun also rises in the east even today also or you observed all the close to be most of the close to be black and all the next row that you are going to observe is also turned out to be black appeals appeal to science evidence based on evidence otherity most of the cases you know causal relationships come under the category of inductive argument causal inferences in particular that means the reasoning from cause to effect so these are the things which you commonly come across in the today discourse sun now once you identify that it is an inductive argument the next question that arises is whether it is strong or weak a strong inductive argument is a one in which it is probable but definitely it is not necessary that the premises are true the conclusion is probably true enough a weak inductive argument is a one in which it is not probable that if the premises are true the conclusion is true conclusion may probably be false enough we will talk about these particular kind of distinction little bit later and once you identify that it is a weak or strong inductive argument a strong inductive argument can be a cogent argument for it so happened that all the premises are probably true and it is called as a pro cogent argument it so happens that one of the premises is probably false then it is called as an uncogent argument this is the main there is the main differences which you came across while distinguishing deductive and inductive arguments the main difference lies in the sort of relationship the other or expositor of the argument takes there to be between the premises and the conclusion the relationship between the conclusion and premises if it is necessary that is a deductive argument it is probable then it is the inductive argument if the other are other of the argument believes that the truth of the premises definitely establishes the truth of the conclusion due to some kind of definition logical entailment or mathematical necessity and so on and so forth then it is called as a deductive argument so we will talk about where do we come across this deductive arguments in a while from now and even inductive arguments also the third distinction is this that if the other of the argument does not think that the truth of the premises definitely establishes the truth of the conclusion that means the conclusion only probably follows premises but nonetheless believes that the truth provides good reason to believe that the conclusion is true then the argument is inductive so an inductive argument the fourth distinction is this that an inductive argument expresses an inference in which the conclusion goes beyond what is implicit in the premises there is a new information in the conclusion this is what we already talked about in the last few slides a valid deductive argument is a one in which the conclusion can be inferred merely by unpacking what is already stated in the premises whatever is already implicit in the premises you are trying to make it explicit so here is a very interesting story which is formulated by Bertrand Russell the great philosopher in mathematician on he shows an instance of his inductivist Turkey this is an example so the story goes like this imagine a situation where your turkey is a kind of looks like hen and all so the turkey found that on his first morning at the turkey form he was fed at 9 am and all so the turkey is experiencing that you know his master is every day is feeding this turkey at 9 am and all is giving breakfast something or other however being a good inductivist the turkey did not jump to the conclusion if he is a good inductivist there is no guarantee that the next day also you will give the give this you food at 9 am and all he waited until he had collected large number of observations of the fact that he has that he was fed at 9 am and all. So if you want to make your inductive argument little bit strong and all then your sample size etc should be a large enough and all so you have repeatedly observed for so many cases and all then you know your argument will become strong and all suppose with two instances you cannot say that something is good or bad and all but you know you have to repeatedly observe some of the instances and all but it is very difficult to come up with what constitutes sound argument etc and all is it 90% is enough 50% is enough 40% is enough all depends upon very subjective kind of things. So here in this case in this story the turkey was fed at 9 am every day and he has collected large number of observations every day was fed at 9 am only and he made this observations under a wide variety of circumstances etc it is not enough that you know under various circumstances his master fed him at 9 am only despite the fact that you know he is busy or maybe training all kinds of situations circumstances and all his food he did not miss his food and all turkey and he made those observations under wide variety of circumstances these are the important things for a good inductive argument and all on Wednesdays Thursdays and warm days and even cold days etc and all and in fact even in the rainy days and even the dry days also it so happened that he was fed at 9 am only sharp master was so good that he fed him at 9 am only each day he added another observation statement to his list and all his strengthening his argument based on his observations and all. So finally his inductive his conscience was satisfied and then he carried out an inductive inference to conclude that I am always fed at 9 am only so this is what you know even the most of the scientists will also do and all when they are trying to come up with some kind of inferring conclusions and all then they will base their experiments thousands of experiments they will do and then once they are convinced and satisfied with so many experiments etc and all they will infer some other things they conclude something. So in this case the turkey concluded that repeated observations he was fed at 9 am Thursdays warm day cold day all days he was fed up at 9 am so at last this so now he came to the conclusion that I am always fed at 9 am so based on the repeated observations is a story is a story and all so turkey came to this conclusion that I am going to be fed at 9 am even tomorrow also so this conclusion was shown to be false in no uncertain manner when let us say in one fine Christmas Eve and all instead of being fed at 9 am and all it is he had his throne cut and all so they I mean several days etc and all he was fed at 9 am and all that does not give us guarantee that he is going to be fed the next day also it so happened that in a fine Christmas Eve and all his master took him for this thing he had cut his throat and all. So poor inductive is turkey what is he has to do is the question despite is repeated observations and then you need to see that under wide variety of circumstances etc based on all this information etc and all he came to this particular kind of there is nothing wrong with the inductive is turkey but this argument shows that argument that the turkey has come up with I am going to be fed at 9 am based on all the repeated observations etc this conclusion is shown to be false and inductive is inference with two premises and led to false kind of conclusion this is what is stated in David Chalmers book what is what is this thing called science so what does it this story tells us is simply this that despite you know you have various I mean you have evidence and your gut feeling says that it is going to be the case and all in the case of inductive arguments there is no guarantee that your conclusion necessarily follows from the premises this is different in the case of deductive arguments if the conclusions are true premises are true the conclusion cannot be false so this is the story tells us that in the case of induction the conclusion probably follows from the premises and then despite all the evidence etc and all we cannot justify that this inductive argument is justified and all so we will talk about this particular kind of story little bit later but in this particular kind of course will be mainly focusing our attention on the deduction part so basically you know we will not talk much about the induction so basically we are trying to capture some kind of mathematical reasoning which can be done with the help of deduction so where do we come across deductive arguments so deductive arguments usually you will come across in mathematics etc and all and whenever you come across some kind of valid forms which I talked about in the last class a valid form is considered to be a valid kind of argument if the argument is having a valid form then that particular kind of argument is valid if it is having invalid form then it is called as an invalid kind of argument so in this lecture what I spoke about is like this first we identified the once we recognizing recognize the arguments and all the next question that comes to us is what type of argument it is then we asked some set of questions with which they are depending upon whether our answer is yes or no we classified the argument into deductive or inductive argument so there is one thing which is which I missed it out usually this is the mistake which we commonly traditionally speaking this is the case deductive argument is a one in which you know move from particulars to general whereas in the case of inductive arguments we move from general to particular and all but that definition will not serve us well and all because we can have particular arguments but you can still have a general kind of conclusion now so there are some kind of deductive arguments we move from particulars to general also where there are some there may be some inductive arguments to move from the particular general to particular also so these are some of the problems which we commonly encounter so this is not a appropriate definition and all what is important here is that is it true preserving whether the conclusion necessarily follows from the premises or is there any argument is having variable strength these are some of the important questions that we need to ask to judge whether it is an inductive argument or deductive argument usually inductive arguments which you come across in the arguments of science predictions etc and all which will talk about it in detail little bit later and deductive arguments are the ones which you will find it in the arguments of mathematics etc sometimes you come across some kind of valid forms which I am going to talk about in the next lecture so these are some of the important distinctions between the deductive and inductive arguments and in the next lecture what we are going to talk about is where do we come across this deductive and inductive arguments what is the significance of this deductive and inductive arguments and then we also talk about whether a deductive argument is when do you say that a deductive argument is valid when do you say that deductive argument is invalid is there any method with which you can judge whether the argument is valid or invalid in the case of inductive arguments if the argument is whether the argument is strong or weak how do we judge these things and once it is strong or weak whether it is a cogent argument or uncogent argument These are the questions that we are going to answer in the next lecture.