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Indicator word is not a reliable reason for thinking that it is not part of the expression of an argument contained in the text or speech under consideration. If a passage does not appear to have any conclusion indicators then an alternative way of trying to identify the conclusion is to try inserting conclusion indicators at appropriate places in sentences that appear to be good candidates for the conclusion. Then see if the passage or speech still reads or is heard smoothly and its meaning is...

Probably Jeremy Price opposes new laws protecting the environment

This remains inductively forceful, and it is no less inductively forceful than the previous version. But the inductive soundness of this argument is far from certain, because P2 is far from certain. This reconstruction thus makes the weakness of the original argument perfectly clear. It does so by removing the distraction created by the word 'conservative' (even if you do think that P2 is true, you have to admit that this reconstruction centres our attention on the real issue). Since many of...

Fallacies

Strictly speaking, a fallacy is a mistake in reasoning. One commits a fallacy when the reasons advanced or accepted in support of a claim fail to justify its acceptance. A fallacy can be committed either when one is deciding whether to accept a claim on the basis of a fallacious argument with which one has been presented, or when one is presenting the fallacious argument oneself. A fallacious argument or inference is one in which there is an inappropriate connection between premises and...

Truth and relativity

When we say something, claim something such as 'The kettle has boiled', we assert something we express a belief. A belief is an attitude we take towards a proposition to believe a proposition is to accept it as true. Assertion is a truth-claim, and belief is a truth-attitude. Assertion, belief, and truth are internally related in this way. From the outset we have been working with an intuitive understanding of truth such that to say that a claim is true is simply to say that things are as the...

Ambiguity

In reconstructing arguments, we have to eliminate any ambiguities in the original statement of the argument. If the original statement contains an ambiguous sentence, we have to decide which of the possible interpretations was most likely intended by the arguer, and, in our reconstruction of the argument, rewrite the sentence, choosing a form of words which conveys the intended meaning unambiguously. Let us take an example. Suppose that Jane, a Londoner, decides to invest some money in the...

Willy does not play jazz

These arguments both infer a conclusion from two premises, but there is an important difference. In argument A, each premise supports the conclusion individually. That is, PI is cited as a reason for C, and P2 is cited as another reason for C. One could argue from PI alone to C one could also argue from P2 alone to C. By contrast, in argument B, neither premise supports C by itself. Neither PI nor P2 would, by itself, be a reason to accept C. Rather, they work together to support C. Figure 6.2...

Critical Thinking

This is the best single text I have seen for addressing the level, presumptions, and interests of the non-specialist. The authors have a fine knack for articulating simply and clearly the most elementary - but also the most important - aspects of critical thinking in a way that should be clear to the novice. Attempts to persuade us - to believe something, to do something, to buy something - are everywhere. What is less clear is how to think critically about such attempts and how to distinguish...

Info

Another example is PI of the last example of the preceding section of this chapter. Conditionals can also be expressed in other ways, however. For example, the following statements express the very same proposition as the example just given they represent exactly the same connection between rain and barometric pressure It is raining only if the barometric pressure is low. Either the barometric pressure is low, or it is not raining. It is not raining unless the barometric pressure is low. If the...

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But, if you think about it, there is no point in including P2 in the reconstruction of the argument. PI alone is the basis for thinking that the restaurant will be fully booked that the arguer once dined there with Professor Gilmour is irrelevant. When a proposition stated by the arguer is irrelevant to the reasoning which delivers the conclusion, that proposition should not be included in a reconstruction of the argument. It might seem that the only reason not to include irrelevant material in...

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Valid is what we call a connecting premise. We have had to add connecting premises in many of the arguments we have so far considered. Usually, when people give arguments, the premises they give explicitly will be only those which pertain to the particular facts or sub-ject-matter they are talking about. For example, someone might say 'My cat won't have kittens she's been spayed'. The arguer explicitly sets forth the relevant fact about her particular cat, but doesn't bother to state explicitly...

Causal generalisation A causal generalisation is a generalisation to

The effect that things of one kind tend to cause things of another kind. Such a generalisation is true if the presence of a thing of the first kind raises the probability of things of the second kind, even when other possible causes are absent. Conclusion An argument's conclusion is the proposition that its premises are intended to support. The distinctive aim of giving an argument is rationally to persuade an audience that the conclusion is true. Conclusion indicators These are words such as...

Knowledge and rational persuasiveness

Rational persuasiveness requires that you be justified in accepting the premises of an argument. If the argument is deductively valid, then if you are justified in accepting the premises, you are equally justified in accepting the conclusion. If the premises of such an argument are actually true, then since you know the premises to be true, you know the conclusion to be true.8 However, there are two complications. First, a rationally persuasive argument can be unsound rational persuasiveness...

Supposing the conclusion false

Another way to assess the validity of an argument is to suppose the premises are true but the conclusion false. If we can see that this is impossible, then, according to the definition of validity, the argument is valid if we can see that this is possible, then we know that the argument is invalid. So consider the first argument about the Italian footballers. To suppose the conclusion false is to suppose that there is at least one Italian striker who does not tackle well. If he does not, then...

The world was created by an omnipotent and omniscient being

Some people, let's call them 'theists', believe the proposition expressed here. Others, atheists, disbelieve it. Others, agnostics, are not sure whether or not to believe it so they have suspended judgement until such time as they acquire sufficient evidence (or faith) to support a belief either way. These three positions probably cover most adults in our society. But consider the position of most pre-school children. They do not believe that a deity made the world. They do not believe that a...

Some strategies for logical assessment

Once we have an argument represented in standard form, we have to pronounce whether or not the argument is valid, and if not, whether or not it is inductively forceful. To do this, the basic technique is simple ask yourself, can I imagine or conceive of a situation in which the premises are true, but the conclusion false If under no conceivable situation could that be, then the argument is valid. If you can think of ways in which the premises would be true but the conclusion false, then you...

Practical reasoning

The conclusion of the above argument about the automobile is one that has a practical conclusion rather than saying that some proposition is true, it enjoins or commends a particular action. What the argument says, roughly, is that doing one thing (finding alternatives to the petrol-driven automobile) is necessary if a certain desirable outcome or end (finding alternatives to vehicles that emit carbon monoxide) is to be achieved. Other arguments with practical conclusions are those that say...

[Vo1xPo1l[Vo2xPo2l

The value of each outcome must be assigned a number, but the purpose of the numbers is only to indicate the comparative values of the possible outcomes. For example if one outcome is judged to be twice as good as a second, we could assign them any two numbers so long as the first is assigned a number that is twice that assigned to the second. Expected value is the central concept of cost benefit analysis. The idea is that, given a range of possible actions, one should perform the action with...

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Truth-value Sometimes it is convenient to speak of the truth-value of a proposition (see for example speaker-relativity) The truth-value of a true proposition such as 'snow is white' is truth, and that of a false proposition such as 'snow is green' is falsity. Vagueness An expression is vague if (i) its extension is indefinitely bounded, e.g. 'bald', 'tall' or (ii) in a given context it is unclear what is meant by it. In the first case the meaning of the term may be clear, but the extension is...

It is true that Venus Williams was the Wimbledon Womens Singles Champion in 2000

Must have the same truth-value if one of them is true, then so is the other. This necessary equivalence is the fundamental fact about the ordinary meaning of the word 'true'. Suppose, then, that Julie says that Venus Williams was the Wimbledon Women's Singles Champion in 2000. To say that Julie's claim is true, at bottom, is just to say that Venus Williams did win the Women's Singles at Wimbledon in 2000. Thus, although truth is a feature of claims that people make (of some claims, of course,...

True for me true for you

Often, people who have succumbed to the myth that 'the truth is always relative' respond to a disagreement about the facts by saying something like, 'Well, that may be true for you, but it's not true for me.' In doing so, they use a common ploy to avoid proper engagement with the argument. Unless the matter under discussion is one that is actually implicitly speaker-relative, as it is in the ice cream example, this is not a legitimate move to make within an attempt to persuade rationally. It is...

195

The goal of argument reconstruction is to produce a clear and completely explicit statement of the argument the arguer had in mind. The desired clarity and explicitness is achieved by putting all the argument, and nothing but the argument, into standard form this displays the argument's premises and conclusion, and indicates the inferences between them. The strength of the argument is understood in terms of the concepts discussed in Chapters 2 and 3 - validity, inductive force, deductive and...

Milk drinkers tend to become heroin addicts

Obviously this argument would not give us a reason to outlaw the drinking of milk. Yet it has a true premise, just as the first argument, and more importantly, it embodies exactly the same reasoning as the first argument. In particular, both arguments assume that if almost everyone who does X did Y beforehand, then having done Y makes them more likely to do X (or, those who do Y tend to become people who do X). As the second argument above illustrates, that is clearly wrong. If you were given...

La Paz is the capital of Bolivia

He says 'La Paz is not the capital of Bolivia' (perhaps he thinks it's the capital of Colombia). In this case, there is exactly one proposition - that La Paz is the capital of Bolivia - such that Julie asserts it and John denies it. That is what genuine factual disagreement is genuine disagreement is when there is one proposition that is asserted by one person but denied by another. If Julie and John value the truth, they will want to know whose claim is true. But suppose...

91

But this argument, though valid, is probably not sound, since P2 is probably false. Yet the original argument is surely a good argument, in some sense. The truth of the premise would be a good reason for expecting the conclusion to be true one would be surprised to find it was false. Certainly if you had to bet on whether or not the conclusion is true, then, given no relevant information except for PI, you would bet that it is true, not that it was false. You would reasonably infer the truth of...

The cause of this plants not growing well is that it has not got enough fertiliser

Or, as we might more naturally put it, this plant is not growing well because it has not got enough fertiliser - that would be the causal use of 'because' that was discussed in the first section of this chapter. Note that in order to obtain the desired conclusion, it was necessary to include the word 'cause' (or the word 'because') in PI. If we had left PI as it is in the first version, then the inference to the conclusion in the second version would have been invalid. For it is certainly not...

Consequent See antecedent and conditional

Context The context of an argument is the set of circumstances in which an argument is actually advanced by an arguer. Context is significant because in order to reconstruct an argument we often have to fill in premises that are only implicitly assumed by the arguer. To determine what an arguer is likely to have assumed, we usually need to know the circumstances in which the argument is advanced. Cost benefit Potential actions are evaluated as justified or not in terms of their costs and...

How representative is the sample

Suppose you live near the North Pole, and every bear you've ever seen is white. So you argue Formally, this argument is just like the one about the guppies. But, whereas the guppy-inference seemed to be correct, this one seems not to be. Only a small minority of bears are white (Polar Bears, and perhaps the occasional albino). The difference is that, whereas the guppy-arguer can reasonably assume that the sample of observed guppies was representative of the total population of guppies, the...

To say that an argument is valid is to say If the premises are or were true the conclusion would also have to be true

If the condition specified by the definition does not hold, then the argument is invalid. A consequence of these definitions is that the following cases of valid arguments are all possible 1 The premises are all (actually) true, and the conclusion is (actually) true. 2 The premises are all (actually) false, and the conclusion is (actually) false. 3 The premises are all (actually) false, and the conclusion is (actually) true. 4 Some of the premises are (actually) true, some (actually) false, and...

6Julie believes that Scorpios tend to be luckier than Libras

So according to this version of the relativity-myth, Julie's utterance of (4) is equivalent to (6). But (6) is certainly not equivalent to (3). (3) makes no reference to Julie it would be possible for (3) to be true but (6) false, or the other way round (in fact, if (6) were true, then since presumably (3) is false, they would differ in truth-value). Thus, according to this version of the myth, we would have to say that (4) is not equivalent to (3). But that cannot be right, for that is simply...

The murderer has size 10 feet

He can do this because A logically entails B the inference from A to B is deductively valid. However, belief A is false because despite all the evidence to the contrary, Billy did not commit the crime in question. Perhaps he was actually at the scene around the time and his fingerprints were found there, because he was in the process of a burglary. The actual murderer, however, is Wild Willie Williams, who does indeed have size 10 feet. So while belief A may be false, belief B is true, the...

The speed limit should be reduced to 5 mph

Since PI is true and C false, and the argument is valid, P2 must be false. So the original argument, since its P2 is the same, is unsound. Of course, this does not mean that nothing should be done to reduce road fatalities. It means only that the fact that a given remedy would reduce them is not sufficient for carrying it out. As explained in the Chapter 5 section on practical arguments, we must, in such cases, show that the envisaged remedy would not cause worse problems, and also that no...

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Streets should not be allowed to live on the street. On the other hand, the intended proposition might be that we should not tolerate the fact that there are homeless people living on our streets. That is to say, the view expressed might be critical of a society in which people are forced to live on the streets rather than critical of such people themselves. Vagueness is a property of words and phrases. It is not the same as ambiguity, but it is often mistaken for it. For instance, when former...

We must find alternatives to the petroldriven automobile

Assuming the truth of PI, this is a deductively sound argument. Even if you doubt PI, this is, at any rate, a much better argument than the earlier version since the new P2 is a narrower generalisation than the old P2, its premises have a better chance of being true. Furthermore, by narrowing the generalisation, the issue is defined more exactly. We now have it explicitly before us that the point at issue is the use of petrol-driven automobiles, not automobiles in general. Thus, when...

The woman who will get the part has a surgically enhanced body

Suppose that Glossie sees that if she's justified in believing C, she is also justified in believing D and thereby forms the belief D. However, unknown to Glossie, Barbie will be given the part. Also unknown to Glossie is the fact that Barbie has also had her body surgically enhanced to meet Hollywood's exacting standards. Thus D is true, but C from which, following rules of entailment, she inferred D, is false. Once again, all the conditions for knowledge according to the tripartite account...

P3 No marathon runner who eats and sleeps well is not healthy

If we do it this way, then the three premises work together to support the conclusion an instance of this generalisation would be 'If PI and P2, then Susan is healthy'. So the argument would be represented as shown in Figure 6.5. Figure 6.5 Three premises supporting a conclusion jointly A deductively valid argument is rationally persuasive for you if you have good reason to accept its premises. An inductively forceful argument is rationally persuasive for you provided that you have good reason...

Argument trees

An argument tree is a device that can be used for representing arguments in the form of a diagram. They are helpful when we are reconstructing arguments, particularly complex ones, because they provide a means of showing the ways in which the different parts of an argument are related to each other. They show how the premises support the conclusion. It is great discipline to construct argument trees and you will find it helpful to use argument trees in your own analyses of complex real-world...

Explanations as conclusions

In the first chapter, we took care to distinguish arguments from explanations. An argument supplies reasons why we should believe a certain proposition whose truth-value is in question. By contrast, an explanation tells us why it is that a certain proposition is the case, when the truth-value of that proposition is not in question. It is especially important to observe this distinction when dealing with arguments whose conclusions are themselves explanations. The aim of this sort of argument is...

A programme for assessment

We are now in a position to outline a basic procedure for the assessment of arguments represented in standard form. We first consider arguments that have only one inference. When you represent an argument in standard form, do not include the word 'probably', or any similar word, in the conclusion - not yet. Put such words in the premises only. Once you have reconstructed the argument in this way, you should proceed as follows (and you should, looking back at the definitions given in this...

Gary Kemp

11 New Fetter Lane, London EC4P 4EE Simultaneously published in the USA and Canada by Routledge 29 West 35th Street, New York, NY 10001 Routledge is an imprint of the Taylor & Francis Group This edition published in the Taylor & Francis e-Library, 2001. 2002 Tracy Bowell and Gary Kemp All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and...

The number of doctors should be increased

This argument is valid.4 Strictly speaking, PI and P2 are now redundant, since they can be inferred from P3 and P4 but it is harmless, and it makes it clearer, to leave them in. Of course, the argument is a bit vague it does not say to what extent the NHS should be improved, nor by how many the number of doctors should be increased. Someone actually advancing this argument would want to fill in these details. In considering this issue we focused on an argument of type (1), but the weighing of...

4It is true that Scorpios tend to be luckier than Libras

According to what we said about the word 'true' at the beginning of this chapter, (3) and (4) are necessarily equivalent it is impossible for one of them to be true and the other false. That is why we can always register our agreement with a claim simply by saying, 'that's true'. And that, we might say, is the point of having the word 'true' that is how the word is used. However, according to the version of the myth we are considering, if Julie asserts (4), then she would be speaking more...

259

Explain why simply having a true belief that P, is insufficient for knowledge that P. 3 Suppose you are justified in believing a proposition that is in fact false. Could there be an argument for that proposition which is rationally persuasive for you Would the situation change if the proposition were actually true rather than false Explain your answer, using examples - your own examples - if you find it useful. 4 Consider the following case and then answer the questions that follow. Julia,...

We must find alternatives to the automobile

Note that in writing PI, we added the quantifier 'all' this makes for a somewhat awkward sentence, but such awkwardness is a price we sometimes have to pay for the sake of explicitness. Now assume you really do believe PI. This argument is deductively valid. However, you must admit that it has a weak point. For P2, as written, is clearly untrue. Some automobiles, for example, are electric, and run on batteries. Since they do not burn petrol (or any other petroleum product), they do not emit...

Insufficiency

Consider Mrs Green, the greengrocer, who discovers that a customer has left their shopping behind. She has served five customers so far that day - Mr Red, Mrs Pink, Mr Orange, Mr Yellow and Mrs Blue. She has no reason to suppose that any one of them is any more forgetful than any of the others. None of them is in the habit of forgetting their shopping, for instance. Mrs Green concludes that one of the men left the shopping behind. She does have some justification for forming this belief of the...

Engaging with the argument avoiding the Who is to say criticism

Sometimes an argument will contain a premise which no one would say can be known with certainty. Sometimes these will have to do with what a particular person was thinking, or with what motives people in certain circumstances are likely to have, or with the future, such as whether unemployment will increase or the Labour Party will win the next election. Consider this argument If they close down the factory - making over 500 workers redundant - then unemployment in our town will immediately...

Chapter Summary

The aim of argument reconstruction is to clarify, and make fully explicit, the argument intended by an arguer. We do this by putting the argument into standard form. If our main concern is whether or not the conclusion of the argument is true, then our reconstruction should be guided by the Principle of Charity we should aim for the best possible reconstruction of the argument. In order to do this, we need precise concepts in terms of which to assess arguments. We need, to begin with, the...

Belief justification and truth

It is not the case that for any given proposition, we either believe it to be true (believe it), or believe it to be false (disbelieve it). We may simply have no attitude towards it, either because it has never come to our attention, or because we choose not to consider the question. Or we may have an attitude that is midway between belief and disbelief we may suspend judgement, because we find upon reflection that we lack sufficient evidence to make the judgement. This happens when we lack an...

Probably next years Cabernet Sauvignon harvest will be good

With suitable connecting premises added (for example 'If next summer's weather is good for Cabernet Sauvignon grapes, then, probably, next year's Cabernet Sauvignon harvest will be good'), this becomes an inductively forceful argument, and P2 is true. Now suppose Jane knows that P2 is true. She also thinks that PI is true, but her reason is that she has the superstitious belief that whenever it rains on Winter solstice, the following summer will be hot (assume it really is unreasonable for her...

Every striker on the Italian national side tackles well

Here, as before, we begin by supposing the premises true. But in this case the conclusion is a generalisation. Now recall from Chapter 5 that generalisations can typically be regarded as generalised conditionals. So the conclusion C can (somewhat awkwardly) be reworded as 'If someone is a striker on the Italian national side, then that person tackles well'. Thus suppose that PI and P2 are true. What we do in this case is to suppose that someone is a striker on the Italian national side that is,...

Glossary

Words written in bold indicate references to relevant further glossary Ambiguity A sentence is ambiguous in a given context if there is more than one possible way to interpret it in that context. A word is ambiguous in a given context if there is more than one possible way to interpret it in that context. See also lexical ambiguity, syntactic ambiguity. Compare vagueness. Antecedent A conditional statement asserts a relation between two propositions, the antecedent and the consequent. When the...

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To compassion, pity or guilt, appeal to cuteness, appeal to sexiness, appeals to wealth, status, power, hipness, coolness, etc., appeal to fear (also known as scare tactics), the direct attack and hard sell, buzzwords, scare quotes, trading on an equivocation, smokescreen (changing the subject). Rhetorical question An interrogative sentence that is not really intended as a question, but as a statement, usually of a proposition with which the speaker or writer assumes the audience will agree....

C1 The tuna population will vanish unless the tuna industry is regulated more stringently

This is easier to read, and it saves you having to write things out unnecessarily. Henceforth, whenever an argument draws an inference from a conditional premise, feel free to abbreviate in this way. CHAPTER This chapter was concerned to address some of the main logical SUMMARY problems encountered in the reconstruction of arguments. In many cases, one or more premises upon which a conclusion depends is left implicit by the arguer. A necessary part of reconstruction is to make such premises...

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Once we put the two steps of the argument together to form a complex argument, we see that it begs the question of who should get the biggest share P1) I'm getting the biggest share of the haul. P2) Whoever receives the biggest share of the haul is the leader. C1) I must be the leader of the gang. P3) Gang leaders always receive the biggest share of their gang's haul. C2) I'm getting the biggest share of the haul. Thief number one is guilty of begging the question (in addition to armed robbery)...

133

Those days, people didn't succumb to anorexia or bulimia and the incidence of obesity was much lower. Seems the 'experts' have got it wrong again. This argument seems to conclude not only that eating traditional British cooking protects people from anorexia, bulimia and obesity, but that not eating it causes those things. To expose the fallacies, we can reconstruct the entire argument as an extended argument P1) When we ate traditional foods (X) there was a significantly lower incidence of...

Why Are Rhetorican Ploys Not An Argument

Rhetoric - Any verbal or written attempt to persuade someone to believe, desire or do something that does not attempt to give good reasons for the belief, desire or action, but attempts to motivate that belief, desire or action solely through the power of the words used. The difference between fallacies and rhetorical ploys is understood most easily as a difference in the function of the language being employed. As we saw in Chapter 1, politicians, advertisers and newspaper columnists tend to...

Probability

We express the probability that a given proposition is true (or that a given event has occurred or will occur) on a numerical scale between 0 and 1, expressed either as a decimal or as a fraction. For example the probability that a tossed coin will land heads-up is 0.5 or 1 2. Perhaps surprisingly, there are different ways in which to explain probability. We'll briefly consider three proportion, frequency, and rational expectation.1 First, proportion. Many arguments contain a premise that says...

Radiant Thinking For A Single Person

Of decriminalisation can use it in support of their cause their opponents can use it to back up their anti-decriminalisation stance (the latter might say, 'Only some members of parliament support. . .'). 3 Often people simply omit quantifiers. For instance, someone might protest Lecturers don't give students a chance to complain. At face value this might appear to convey the proposition that No lecturer (ever) gives a student a chance to complain. Yet it is likely that what the speaker really...

77

Is clearly not an inductively forceful argument. If the only propositions you knew relevant to the conclusion were PI and P2, then you would be wrong to think that C is probably true. To say that all rodents have tails is the same as saying 'Every rodent has a tail', or 'Any rodent has a tail', or 'No rodent has no tail'. To say that most rodents have tails is to say that more than half of all rodents have tails, or that there are more rodents with tails than there are without them. But what...

Covering generalisations

In the politician case, the connecting premise was a generalisation (review the discussion of generalisations in Chapter 1 if you are not clear about what a generalisation is). Connecting premises are usually generalisations. But in the inflation case the connecting premise we used was a conditional (see Chapter 2). This is also common. However, there is an important relationship between conditionals and generalisations that must be appreciated. Consider the following propositions (a) If Betty...

Scorpios tend to be luckier than Libras

John does not believe in astrology, and therefore does not believe that one's fortune depends on the part of the year during which one is born. So he thinks this proposition is false. But John, wishing to avoid a painful disagreement, expresses himself by saying, 'Well, that may be true for you, but it isn't true for me'. As we have just seen, where implicit speaker-relativity is involved, the use of such phrases as 'true for you' is perfectly legitimate. But in the astrology case, the use of...

Abortion is immoral

According to the relativist view, when anti-abortionists say abortion is morally unacceptable and their opponents contradict them and say that it is morally acceptable, there is no real disagreement rather the two sides do not share the same moral preferences. Thus, for the relativist, value-statements are always speaker-relative, whether implicitly or explicitly. An apparent disagreement over a value is in this respect like that between Julie and John concerning chocolate versus vanilla ice...

Argument commentary

We have now completed our survey of our basic concepts and procedures of argument analysis. By 'argument analysis' we mean a two-stage process comprising first the reconstruction, then the assessment of the argument. At this point, we need to say a bit more about the final product of this process. When the analysis of an argument is undertaken, you may sometimes want to produce a piece of written work which summarises the analysis you have made. This should consist of three parts 1 The argument...

The scope of a generalisation

Consider the following hard generalisations 2 All black cows are herbivores. The subjects of these generalisations - what the generalisations are about - are cows and black cows, respectively. Both generalisations are true, and they stand in a special relationship. There are two aspects of this relationship. First, they attribute the same feature to their subjects (that of being herbivores). Second, the subject of the second is a subset of the first (all black cows are cows). Thus we say that...

Chocolate ice cream tastes better than vanilla

The implicit speaker-relativity of a sentence like this might be described by saying that the sentence is true for Julie, and not true for John. Upon hearing Julie assert this sentence, John might say, 'Well, that may be true for you, but it isn't true for me'. John might, in this case, simply be making the point about implicit speaker-relativity. If so, then that is all right he is quite right to do so. However, phrases such as 'true for me' are sometimes used in what appear to be factual...

2Vanilla ice cream tastes better than chocolate to John

These are two different propositions. There is certainly no logical conflict between them they could both be true. But in that case, Julie and John 2 There is one slight complication, however statements of this kind may mean that something is preferred or liked by most people. For example, this is plausibly what someone means who says 'Soured milk does not taste good'. Nevertheless, these statements are still implicitly relative, because they still depend for their truth on reference to...

More on generalisations

As we noted in Chapter 1, only hard generalisations can rightly be conveyed by using a quantifier-word like 'all', 'no', or 'every'. Indeed, that is the usual function of those words - to make it perfectly explicit that a hard generalisation is what is intended. For example someone at a meeting of Parliament might say, 'Every single MP in this chamber takes bribes', rather than 'The MPs in this chamber take bribes'. Soft generalisations, indeed, are very often expressed without any quantifier...

C1

In this case the argument whose conclusion is CI is a sub-argument for an extended argument whose conclusion is C2. You would first assess the argument from PI and P2 to CI you would then assess the argument from CI and P3 to C2. Finally, you would use these results to assess the total argument from PI, P2 and P3 to C2. Assessment is to be distinguished from reconstruction, which is discussed in more detail in the next chapter. Broadly speaking, assessment may be said to fall into two...

Implicit and explicit

Not only do actual statements of arguments typically include a lot of material that is inessential to the argument, they often exclude some of what is essential to the argument some essential propositions are left implicit, when our task in reconstruction is to make the argument fully explicit. To say that a proposition is implicit in an argument is to say that it is part of the argument intended by the arguer - either as a premise or as the conclusion - but that it has not actually been stated...

Extraneous material

The first step in analysing and reconstructing an argument is to identify its conclusion, then its premises. But much of what people say or write, when advancing an argument, plays no argumentative role. Much is there for emphasis, or is rhetorical, or plays some other role than that of expressing the propositions that properly constitute the argument. When reconstructing arguments, then, we have to hive off this extraneous material. Here's an example we've given each sentence a number in order...

Example

P1 Every Roman emperor before Constantine was a pagan. Invalid. P2 says that Julian was a Roman emperor, but not that he ruled before Constantine. It would be possible for the premises to be true but the conclusion false, then, if Julian were a non-pagan Roman emperor after Constantine. a P1 Constantine ruled Rome before Constantius. P2 Constantius ruled Rome before Julian. C Constantine ruled Rome before Julian. b P1 The only just political systems are democracies. P2 Rome's political system...

Gettier cases

We have said that knowledge is justified true belief. However, as you're no doubt aware by now, philosophers like to get to the bottom of things, and this can often mean throwing the spanner in the works of an apparently satisfactory theory. We are going to end this chapter by discussing some cases that cast some doubt on the plausibility of the intuitive theory that knowledge is justified true belief. These sorts of cases, in which we have a true belief for which we have adequate rational...

Whenever The Cherry Trees Blossom The Weather Begins To Get Warmer

Democracy is the best system of government. Most people in the world believe in the superiority of democratic systems. Fallacy of majority belief P1 Most people believe in democratic systems. P2 Any belief held by the majority is true. C Democracy is the best system of government. a Our lecturers are always extolling the virtues of critical thinking, but they would say that wouldn't they They only keep their jobs if they've got students to teach. b It's not illegal for me to exaggerate my...

Iiiit is not an inductively forceful argument that is defeated for that person

It can even happen that an argument is rationally persuasive for you at one time, but not at a later time, because you have acquired new evidence which defeats the argument by suggesting that the conclusion is false, more strongly than the argument suggests its truth . To be strictly accurate, then, we should speak of rational persuasiveness for a person at a particular time. For the sake of simplicity, however, we have omitted this complication from what is already a rather complex definition....

Counterexample i A counterexample to a generalisation is a

Particular statement - a statement that is not a generalisation - that is the negation of an instance of the generalisation. For example 'Darcy Bussell is a great ballerina who is tall' is a counter-example to 'No great ballerinas are tall', ii A counter-example to an argument is an argument of the same form or pattern as the first argument that is clearly invalid or inductively non-forceful. It is used as an illustration to make it clear that the first argument is invalid or inductively...

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And so on, they invite pop stars to their parties and comport themselves as if they too were pop stars, just out to sell themselves really. In this example the speaker gets side-tracked into commenting upon the prime minister's suits and party guest-lists, and fails, beyond the vague charge that the government's policies are 'poll-driven nonsense', to offer a substantive criticism. Most of what is said is at best only obliquely relevant to the issue. 4 As with conclusions, there are certain...

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The focus of this book is written and spoken ways of persuading us to do things and to believe things. Every day we are bombarded with messages apparently telling us what to do or not to do, what to believe or not to believe buy this soft drink eat that breakfast cereal vote for Mrs Bloggs practise safe sex don't drink and drive don't use drugs boycott goods from a particular country abortion is murder meat is murder aliens have visited the earth the economy is sound capitalism is just...