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A Rulebook for Arguments 3rd Edition
Anthony Weston -2000
ISBN 0-87220-522-5
A good argument doesn't merely repeat conclusions. Instead it offers reasons and evidence so that other people can make up their minds for themselves.
--A Rulebook for Arguments, pg xii
It is not a mistake to have strong views. The mistake is to have nothing else.
--A Rulebook for Arguments, pg xii
The first step in making an argument is to ask, what are you trying to prove? What is your conclusion?
--A Rulebook for Arguments, pg 1
Short arguments are usually written in one or two paragraphs. Put the conclusion first, followed by your reasons, or set out your premises first and draw the conclusions at the end. In any case, set out your ideas in an order that unfolds your line of thought most naturally for the reader.
--A Rulebook for Arguments, pg 3
No matter how well you argue from premises to conclusion, your conclusion will be weak if your premises are weak.
--A Rulebook for Arguments, pg 4
If you find you cannot argue adequately for your premise(s), then, of course, you need to give up entirely and start elsewhere!
--A Rulebook for Arguments, pg 5
Avoid abstract, vague, and general terms.
--A Rulebook for Arguments, pg 5
If you can't imagine how anyone could hold the view you are attacking, you just don't understand it yet.
--A Rulebook for Arguments, pg 6
In general, avoid language whose only function is to sway the emotions. This is "loaded" language.
--A Rulebook for Arguments, pg 5
When it's your turn, stick to the facts.
--A Rulebook for Arguments, pg 7
Arguments depend on clear connections between their premises and between premises and conclusion. For this reason it is vital to use a single set of terms for each idea.
--A Rulebook for Arguments, pg 7
A good way to avoid equivocation is to carefully define any key terms when you introduce them. Then be sure to use them only as you've defined them!
--A Rulebook for Arguments, pg 9
In a generalization about a small set of things, the best argument considers all, or nearly all, the examples.
--A Rulebook for Arguments, pg 10
Generalizations about larger sets of things require picking out a "sample."
--A Rulebook for Arguments, pg 10
Even a large number of examples may misrepresent the set being generalized about.
--A Rulebook for Arguments, pg 12
Look for a sample that represents the whole population being generalized about.
--A Rulebook for Arguments, pg 14
When making your own argument, do not rely only on examples that "come off the top of your head." The sorts of example you think of at a moment's notice are likely to be biased.
--A Rulebook for Arguments, pg 14
We often need background information before we can assess a set of examples.
--A Rulebook for Arguments, pg 14
To judge a set of examples then, we often need to consider background rates. Correspondingly, when an argument offers rates or percentages, the relevant background information usually must include the number of examples. Car thefts on campus may have increased 100 percent, but if this means that two cars were stolen rather than one, not much has changed.
--A Rulebook for Arguments, pg 16
Test generalizations by asking if there are counterexamples.
--A Rulebook for Arguments, pg 17
If you can think of counterexamples to a generalization that you want to defend, revise your generalization.
--A Rulebook for Arguments, pg 17
Also think of counterexamples when you are assessing others' arguments.
--A Rulebook for Arguments, pg 18
The same rules apply to anyone else's arguments as apply to yours. The only difference is that you have a chance to correct your overgeneralizations yourself.
--A Rulebook for Arguments, pg 18
Arguments by analogy, rather than multiplying examples to support a generalization, argue from one specific caseor example to another example, reasoning that because the two examples are alike in many ways they are also alike in one further specific way.
--A Rulebook for Arguments, pg 19
No one can become an expert, through direct experience, on everything there is to know. We cannot taste every wine in the world to determine which is best.
--A Rulebook for Arguments, pg 24
Factual assertions not otherwise defended may be supported by reference to the appropriate source.
--A Rulebook for Arguments, pg 25
Sources must be qualified to make the statements they make.
--A Rulebook for Arguments, pg 26
An informed source need not fit our general stereotype of "an authority" -- and a person who fits our stereotype of an authority may not even be an informed source.
--A Rulebook for Arguments, pg 26
Einstein's genius in physics does not establish him as a genius in political philosophy.
--A Rulebook for Arguments, pg 27
If you must rely on an authority with imperfect knowledge, acknowledge the problem. Let your readers or hearers decide for themselves whether imperfect authority is better than none at all.
--A Rulebook for Arguments, pg 27
Finally, beware of supposed authorities who claim to know what they could not possibly know.
--A Rulebook for Arguments, pg 28
Similarly, religious moralists often have declared that certain practices are wrong because they are contrary to the will of God. We should reply that God's will is not easy to ascertain, and when God speaks so softly it is easy to confuse that "small still voice" with our own prejudices.
--A Rulebook for Arguments, pg 28
People who have the most at stake in a dispute are usually not the best sources of information about the issues involved. Sometimes they may not even tell the truth.
--A Rulebook for Arguments, pg 28
We notice, remember, and pass on information that supports our point of view, but we are not quite so motivated when the evidence points the other way.
--A Rulebook for Arguments, pg 28
Make sure the source is genuinely independent and not just an interest group masquerading under an independent-sounding name.
--A Rulebook for Arguments, pg 29
Good arguments cite their sources [...]; look them up. Make sure the evidence is quoted correctly and not pulled out of context.
--A Rulebook for Arguments, pg 29
When experts disagree, you cannot rely on any of them alone.
--A Rulebook for Arguments, pg 30
Authorities agree chiefly on specific factual questions. [...] On many philosophical issues it is difficult to quote anyone as an uncontested expert.
--A Rulebook for Arguments, pg 30
Supposed authorities may be disqualified if they are not informed, impartial, or largely in agreement. Other sorts of attacks on authorities are not legitimate.
--A Rulebook for Arguments, pg 30
The evidence for a claim about causes is usually a correlation between two events or kinds of events.
--A Rulebook for Arguments, pg 32
Sometimes, additional evidence is necessary before any explanation can be accepted with much confidence.
--A Rulebook for Arguments, pg 35
Some correlations are just coincidental.
--A Rulebook for Arguments, pg 36
Some correlations are not relations between cause and effect but represent two effects of some other cause.
--A Rulebook for Arguments, pg 36
Correlation also does not establish the direction of causality. If A is correlated with B, A may cause B -- but B may cause A.
--A Rulebook for Arguments, pg 38
Seldom do we fasten onto the one and only cause.
--A Rulebook for Arguments, pg 39
Causal arguments are important because even finding a cause is often useful.
--A Rulebook for Arguments, pg 39
In nondeductive arguments, the conclusion unavoidably goes beyond the premises -- that's the very point of arguing by example, authority, and so on -- whereas the conclusion of a valid deductive argument only makes explicit what is already contained in the premises.
--A Rulebook for Arguments, pg 41
End without prejudice.
--A Rulebook for Arguments, pg 69
One of our most common temptations is to draw conclusions from too little evidence. [...] This is the fallacy of generalization from incomplete information.
--A Rulebook for Arguments, pg 72
A second common fallacy is overlooking alternatives.
--A Rulebook for Arguments, pg 72
Try to increase the number of options you consider, not narrow them!
--A Rulebook for Arguments, pg 73
When a term is contested, you can distinguish three relevant sets of things. One set includes those things to which the term clearly applies. Second are those things to which the term clearly does not apply. In the middle will be those things whose status is unclear -- including the things being argued over. Your job is to formulate a defininion that
Definitions help us to organize our thoughts, to group like things with like, and to pick out key similarities and differences. Sometimes, after words are clearly defined, people may even discover that they do not really disagree about an issue at all. By themselves, though, definitions seldom settle difficult questions.
--A Rulebook for Arguments, pg 84
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While we should assume until we learn otherwise that political leaders are acting in good faith, unless rewards for truth and sanctions for dishonesty are in place, the temptation to distort the facts will prove too great for at least some.
[...]
The custodianship of fact should be the bedrock underlying all the functions jounalists perform. The principle we suggest center fact in political reporting and campaigning, tie campaigning more clearly to governance, and reduce audience confusion:
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There are pillars of good journalism: thoroughness, accuracy, fairness, transparency and independence.
The lines separating them are not always clear. They are open to wide interpretation, and are therefore loaded with nuance in themselves. But I think they are a useful way to approach ethical journalism, and they are notably easier to achieve in an online setting. [...]
Thoroughness
When I was a reporter and, later, a columnist, my first goal was to learn as much as I could. After all, gathering facts and opinions is the foundation of reporting. I liked it best when I felt I had left 95 percent of what I’d learned out of the final piece. The best reporters I know always want to make one more call, check with one more source. (The last question I ask at all interviews is, "Who else should I talk with about this?")
Today, thoroughness means more than asking questions of the people in our address books, real or virtual. It means, whenever possible, asking our readers for their input, as I did when I wrote a book on grassroots journalism in 2004 (and as other authors are beginning to do in theirs). Competitive pressures tend to make this a rare request, but I’m convinced that more journalists will adopt it.
Accuracy
Be factual. Say what you don’t know, not just what you do. (If the reader/listener/viewer does know what you don’t, you’ve just invited him/her to fill you in.)
Accuracy means correcting what you get wrong, and doing it promptly. This is much easier online, where we can mitigate or at least limit the damage from our errors for new readers.
Fairness
This one is as difficult, in practice, as accuracy is simple. Fairness is often in the eye of the beholder. But even here I think a few principles may universally apply.
Fairness means, among other things, listening to different viewpoints, and incorporating them into the journalism. It does not mean parroting lies or distortions to achieve that lazy equivalence that leads some journalists to get opposing quotes when the facts overwhelmingly support one side. Fairness is also about letting people respond when they believe you are wrong, even if you do not agree. Again, this is much easier online than in a print publication, much less a broadcast.
Ultimately, fairness emerges from a state of mind. We should be aware of what drives us, and always be willing to listen to those who disagree. The first rule of having a conversation is to listen - and I know I learn more from people who think I’m wrong than from those who agree with me.
Transparency
Disclosure is gaining currency as an addition to journalism. It’s easier said than done, of course. No one can plausibly argue with the idea that journalists need to disclose certain things, such as financial conflicts of interest. But to what extent? Should journalists of all kinds be expected to make their lives open books? How open?
Personal biases, even unconscious ones, affect the journalism as well. I’m an American, brought up in [sic] with certain beliefs that many folks in other lands (and some in the United States) flatly reject. I need to be aware of the things I take for granted, and periodically challenge some of them, as I do my work.
Another way to be transparent is how we present a story. We should link to source material as much as possible, bolstering what we tell people with close-to-the-ground facts and data. [...]
Independence
Honorable journalism means following the story where it leads. When media are consolidated into a few big companies or are under the thumb of governments, this cannot happen. It is simple to be independent online. Just start a blog. But no one should imagine that the same pressures from businesses and governments will not apply when a blogger tries to make a living at his or her new trade.
Jeff Jarvis, a prominent American blogger (buzzmachine.com), adds several other ideals. Bloggers must value the ethic of the conversation. He notes what for me is a bottom line of this new world : that conversation leads to understanding.
In a conversation, the first rule is to listen. Ethics requires listening, because it is how we learn.
Dan Gillmor
Dan Gillmor is founder of Grassroots Media Inc., a company aimed at enabling grassroots journalism and expanding its reach. Its first site is Bayosphere.com in the San Francisco Bay Area. He is author of "We the Media : Grassroots Journalism by the People, for the People" (O’Reilly Media, 2004).
[This material is copyrighted Dan Gillmor and Reporters Sans Frontieres; it is reprinted here with permission from Mr. Gillmor, but without permission from RSF. Editorial changes have been made to HTML formatting so the material will conform to formatting for this site, and it might have been edited down to conform to fair use, but the text remains unchanged. See the source article for more background. Also see Mr. Gillmor's Center for Citizen Media site. --MN]
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Logic is the study of argument. As used in this sense, the word means not a quarrel [...] but a piece of reasoning in which one or more statements are offered as support for some other statement. The statement being supported is the conclusion of the argument. The reasons given in support of the conclusion are called premises.
--With Good Reason, by S. Morris Engel, pg 6
The act of passing from premises to conclusion is know as inference. Here too we must distinguish the use of this term in logic from its common usage. As ordinarily used, an inference is a guess -- something doubtful or speculative [...]. In logic, infrences are never merely guesses. Thye are instances of reasoning and as such may be either good or bad reasoning.
--With Good Reason, by S. Morris Engel, pg 6
. . . logic defines truth rigorously and separates it from two other concepts -- validity and soundness -- with which it is sometimes confused in ordinary speech. Together, these three concepts provide a basis for evaluating any argument.
--With Good Reason, by S. Morris Engel, pg 7
Validity refers to the correctness with which a conclusion has been inferred from its premises. Turth, on the other hand, refers to whether those premises and conclusion accord with the facts.
--With Good Reason, by S. Morris Engel, pg 7
We can summarize the points covered in this analysis of truth, validity, and soundness in argument as follows:
1. Truth and falsity are descriptive of the properties of statements alone.
2. Validity and invalidity refer to inference and are determined independently of the truh or falsity of the premises or conclusion of the argument.
3. If an argument is valid and its premises are true, the conclusion will be true.
4. If in addition to being valid an argument contains true premises, the argument must be considered sound. Otherwise, it must be considered unsound. All sound arguments therefore are valid, but valid arguments can be either sound or unsound.
--With Good Reason, by S. Morris Engel, pg 9-10
Arguments in which the conclusion follows with necessity from the premises are called deductive arguments. Those in which the conclusion is derivable from the premises only with probability are called inductive arguments.
--With Good Reason, by S. Morris Engel, pg 11
Common sense is always an asset, but unfortunately it does not always suffice. Common sense may enable us to untangle this or that particular case, but, lacking a broad familiarity with the general principals which such particular cases exhibit, we may find ourselves powerless when the same errors appear in more complicated and subtle forms. Practice in the study of argument provided by logic increases our ability to detect poor reasoning skills even in complex cases where common sense could
not lead us to the heart of the error, in either our own or other people's reasoning.
--With Good Reason, by S. Morris Engel, pg 13
Logic increases our sensitivity not only to structures that may mask poor reasoning but to the very language in which arguments are expressed. Words can conceal or distort as well as clarify. And argument can try to persuade not by appeals to reason but by appeals to emotion and prejudice. By heightening our awareness of ways in which words can obscure and distort, logic helps to free us both from confusion and from the designss such arguments have upon us.
--With Good Reason, by S.
Morris Engel, pg 13
The relationshiop between language and thout is an age-old question. In the past, two views were dominant: one holding that language is merelyl the vehicle or outergarment of thought; the other maintaining that the stream of language and the sgtream of thought are one, that thtought is merely soundless speech.
More recently, research has tended to confirm the view that language and thought are intimately connected, that language is not merely sound but a union of sound and sense in which each is highly dependent upon the other. Modern theories hold that words without thoughts are indistinguishable from other sounds to be found in nature. Such theories maintain that, although we may have "vague thoughts" or ideas which we are unable to put into words, we cannot have a clear thought without
being able to express it in language.
--With Good Reason, by S. Morris Engel, pg 18
The art of renaming in order to hide unpleasant connotation produces euphemisms. A euphemism is any agreeable expression that we substitute for one we find offensive.
--With Good Reason, by S. Morris Engel, pg 25
Good style is a matter of saying clearly, simply, appropriately, and concisely what it is we wish to say. If a thing can be put simply, why put it otherwise? Even if a subject is complex, we should strive to express it at least clearly -- with as much precision as we can command.
--With Good Reason, by S. Morris Engel, pg 27
To achieve good style is to exercise restraint; one must avoid using many words where fewer will do, big words where smaller ones will do. One must curb the desire for elegance or picturesqueness and cultivate the desire to speak plainly.
--With Good Reason, by S. Morris Engel, pg 27
Ambiguity and vaugeness are alike in that they are both characters of imprecise language. The distinction between them is instructive, however. A word or expression is ambiguous if its meaning is unclear. Ambiguous language confronts us with several meanings, of which the correct one is diffitult to determine, while vagueness confronts us with the task of hunting for any meaning at all.
--With Good Reason, by S. Morris Engel, pg 29
While the meaning of vague words is doubtful, that of ambiguous words is double (or even triple and beyond). In many cases, the context in which the ambiguous language occurs will determine which of its meanings is intended. This importance of context is not necessarily a defect of language but rather an indication of its flexibility. Until put to work in a specific context, some perfectly serviceable words ncessarily remain indeterminate. If they remain indeterminate once placed in a
context, however, such words must be considered ambiguous.
--With Good Reason, by S. Morris Engel, pg 29
The case with vagueness is different. Some words are always vague, regardless of context, for their meanings are not merely indeterminate but indefinite.
--With Good Reason, by S. Morris Engel, pg 29
. . . it is important that we make a distinction between two types of disputes, real disputes and verbal disputes [...]. A dispute is said to be real when one party believes that a certain statement is true while the other party believes the statement is false. Real disputes arise when genuine differences of opinion exist regarding matters of fact.
Verbal disputes, on the other hand, occur when one party believes that a certain statement is true, while another party believes another statement is false. Rather than a difference of opinion over a single statement, there is a different view of what is at issue. In such a case the parties argue at cross purposes because neither party realizes that the argument is not over the same statement.
--With Good Reason, by S. Morris Engel, pg 30
The assumption that readers "will know what I mean," even if I don't express it clearly, is more dangerous the more complex my subject is.
--With Good Reason, by S. Morris Engel, pg 53
Two statements are said to be contraries when it is impossible for both to be true but possible for both to be false. [...] Two statements are said to be contradictories, on the other hand, when it is impossible for both to be true, and also impossible for both to be false. Either that man is alive or he is dead. Either today is your birthday or it isn't. If one contradictory is true, the other must be false, and vice versa.
--With Good Reason, by S. Morris Engel, pg 72
The fallacy of question begging epithets is so widespread that it has come to be known by a variety of labels: mud slinging, name calling, use of loaded words and controversial phrases, verbal suggestion, and emotive language. Question-begging epithets are objectionable because their object is to arouse our passions and prejudices through the use of emotionally charged language. By overstatement, ridicule, flattery, abuse, and the like, they seek to evade the
facts.
--With Good Reason, by S. Morris Engel, pg 80
We can observe, also, that one may beg the question not only with dyslogistic (uncomplimentary) epithets but with eulogistic (complementary) ones as well.
--With Good Reason, by S. Morris Engel, pg 81
It is told of King Charles II of England that he once asked members of the Royal Society to determine for him why it is that if you place a dead fish in a bowl of water it makes the water overflow, while a live one does not. Some of the members thought about this a very long time and offered ingenious but unconvincing explanations. Finally, one of them decided to test the question. He discovered, of course, that it did not make a bit of difference whether one placed a dead fish or a live one in the bowl of water.
Whether the story is true or not, it holds an important lesson. Before rushing to answer a question, it is best to question the question.
--With Good Reason, by S. Morris Engel, pg 82
Distorting the adversary's position in this way [misrepresenting it as extremist] makes it appear ridiculous and thus easily overthrown. If the adversary is tricked into defending a position that is more extreme than his original one, he is in all likelihood destined to fail. Although this is a popular trick in debating, it is a dishonest one.
--With Good Reason, by S. Morris Engel, pg 98
Not all fallacies of irrelevant theses stem from a conscious effort to distort, however. Pressed for time, or lacking distance, we may regard certain facts as relevant that we would otherwise recognize as beside the point.
--With Good Reason, by S. Morris Engel, pg 98
Closely related to the abusive form of the fallacy of personal attack is the form known as poisoning the well. In such arguments, an attempt is made to place the opponent in a position from which he is unable to reply. This form of the fallacy received its name from John Henry Cardinal Newman, a nineteenth-century British churchman, in of of his frequent controversies with the clergyman and Novelist Charles Kingsley. During the course of their dispute, Kingley suggested that Newman, as
a Roman Catholic priest, did not place the highest value on truth. Newman protested that such an accusation made it impossible for him, or for any other Catholic, to state his case. For how could he prove to Kingsley that he had more regard for truth than for anything else if Kingsley presupposed that he did not? Kinglsey had automatically ruled out anything that Newman might offer in defence. Kingsley, in other words, had poisoned the well of discourse, making it impossible to partake of it.
--With Good Reason, by S. Morris Engel, pg 109-110
A further variant of the personal attack fallacy is the genetic fallacy. It is an attempt to prove a conclusion false by condemning its source -- its genesis. Such argument are fallacious because how an idea originated is irrelevant to its viability. Thus it would be fallacious to argue that, since chemical elements are involved in all life processes, life is therefore nothing more than a chemical process; or that, since the early forms for religion were matters of magic, religion is nothing but magic.
Genetic accounts of an issue may be true, and they may be illuminating as to why the issue has assumed its present form, but they are irrelevant to its merits.
--With Good Reason, by S. Morris Engel, pg 111
Through an unfavorable psychological account of how or why the advocate of a certain view came to hold it, one might claim to undermine any argument whatsoever. But although it may be true that one's motives may weaken one's crediblity, motives are irrelevant to the credibility of an argument itself. Arguments are sound not because of who proposes them but by virtue of their internal merit. If the premises of an argument prove its conclusion, they do so no matter who happens to forumlate the
argument. If they do not, the greatest logician cannot make them sound.
--With Good Reason, by S. Morris Engel, pg 112
Another form in which the fallacy of personal attack commonly occurs is the form known as tu quoque, in which the person advocating a position is charged with acting in a manner that contradicts his own position. The thrust of the tu quoque fallacy is that an opponent has failed to follow his own advice.
[...]
We have a natural tendency to want others to "practice what they preach." But practice is irrelevant to the merits of an argument. [...]
Those who resort to this kind of attack often draw courage from another cliché: that people who live in glass houses should not throw stones. There is no reason, however, why a stone thrown from a glass house cannot find its mark.
--With Good Reason, by S. Morris Engel, pg 112-113
We make an appeal to authority whenever we try to justify an idea by citing some of expertise as a reason for holding that idea. Appeals to authority are often valid, as when we tell someone to use a medicine because a doctor has prescribed it. But appeals to authority can be fallacious, as when we cite those who have no special competence regarding the matter at hand. The fallacy of appeal to authority, therefore, is an argument that attempts to overawe an opponent into accepting a
conclusion by playing on his reluctance to challenge famous people, time-honored customs, or widely held beliefs. The fallacy appeals at base to our feelings of modesty, to our sense that others know better than we do.
--With Good Reason, by S. Morris Engel, pg 123-124
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The following is from a series of messages originally crossposted to Interuser Echo by Don Alt. It has been slightly edited and reformatted for HTML, but is otherwise unchanged. I offer it here as material for those who seek to improve their ability to think critically.
Although there is much argument on Usenet, the general quality of argument found is poor. This article attempts to provide a gentle introduction to logic, in the hope of improving the general level of debate.
Logic is the science of reasoning, proof, thinking, or inference [Concise OED]. Logic allows us to analyze a piece of reasoning and determine whether it is correct or not (valid or invalid). Of course, one does not need to study logic in order to reason correctly; nevertheless, a little basic knowledge of logic is often helpful when constructing or analyzing an argument.
Note that no claim is being made here about whether logic is universally applicable. The matter is very much open for debate. This document merely explains how to use logic, given that you have already decided that logic is the right tool for the job.
Propositions (or statements) are the building blocks of a logical argument. A proposition is a statement which is either true or false; for example, "It is raining" or "Today is Tuesday." Propositions may be either asserted (said to be true) or denied (said to be false). Note that this is a technical meaning of "deny", not the everyday meaning.
The proposition is the meaning of the statement, not the particular arrangement of words used to express it. So "God exists" and "There exists a God" both express the same proposition.
An argument is, to quote the Monty Python sketch, "a connected series of statements to establish a definite proposition." An argument consists of three stages.
First of all, the propositions which are necessary for the argument to continue are stated. These are called the premises of the argument. They are the evidence or reasons for accepting the argument and its conclusions.
Premises (or assertions) are often indicated by phrases such as "because", "since", "obviously" and so on. (The phrase "obviously" is often viewed with suspicion, as it can be used to intimidate others into accepting suspicious premises. If something doesn't seem obvious to you, don't be afraid to question it. You can always say "Oh, yes, you're right, it is obvious" when you've heard the explanation.)
Next, the premises are used to derive further propositions by a process known as inference. In inference, one proposition is arrived at on the basis of one or more other propositions already accepted. There are various forms of valid inference.
The propositions arrived at by inference may then be used in further inference. Inference is often denoted by phrases such as "implies that" or "therefore."
Finally, we arrive at the conclusion of the argument -- the proposition which is affirmed on the basis of the premises and inference. Conclusions are often indicated by phrases such as "therefore", "it follows that", "we conclude" and so on. The conclusion is often stated as the final stage of inference.
For example:
Every event has a cause (premise) The universe has a beginning (premise) All beginnings involve an event (premise) This implies that the beginning of the universe involved an event (inference) Therefore the universe has a cause (inference and conclusion)
Note that the conclusion of one argument might be a premise in another argument. A proposition can only be called a premise or a conclusion with respect to a particular argument; the terms do not make sense in isolation.
Sometimes an argument will not follow the order given above; for example, the conclusions might be stated first and the premises stated afterwards in support of the conclusion. This is perfectly valid, if sometimes a little confusing.
Recognizing an argument is much harder than recognizing premises or conclusions. Many people shower their writing with assertions without ever producing anything which one might reasonably describe as an argument. Some statements look like arguments, but are not.
For example:
"If the Bible is accurate, Jesus must either have been insane, an evil liar, or the Son of God."
This is not an argument, it is a conditional statement. It does not assert the premises which are necessary to support what appears to be its conclusion. (It also suffers from a number of other logical flaws, but we'll come to those later.)
Another example:
"God created you; therefore do your duty to God."
The phrase "do your duty to God" is not a proposition, since it is neither true nor false. Therefore it is not a conclusion, and the sentence is not an argument.
Finally, causality is important. Consider a statement of the form "A because B." If we're interested in establishing A and B is offered as evidence, the statement is an argument. If we're trying to establish the truth of B, then it is not an argument, it is an explanation.
For example:
"There must be something wrong with the engine of my car, because it will not start." -- This is an argument.
"My car will not start because there is something wrong with the engine." -- This is an explanation.
There are two traditional types of argument, deductive and inductive. A deductive argument is one which provides conclusive proof of its conclusions -- that is, an argument where if the premises are true, the conclusion must also be true. A deductive argument is either valid or invalid. A valid argument is defined as one where if the premises are true, then the conclusion is true.
An inductive argument is one where the premises provide some evidence for the truth of the conclusion. Inductive arguments are not valid or invalid; however, we can talk about whether they are better or worse than other arguments, and about how probable their premises are.
There are forms of argument in ordinary language which are neither deductive nor inductive. However, we will concentrate for the moment on deductive arguments, as they are often viewed as the most rigorous and convincing.
It is important to note that the fact that a deductive argument is valid does not imply that its conclusion holds. This is because of the slightly counter-intuitive nature of implication, which we must now consider more carefully.
Obviously a valid argument can consist of true propositions. However, an argument may be entirely valid even if it contains only false propositions.
For example:
All insects have wings (premise) Woodlice are insects (premise) Therefore woodlice have wings (conclusion)
Here, the conclusion is not true because the argument's premises are false. If the argument's premises were true, however, the conclusion would be true. The argument is thus entirely valid.
More subtly, we can reach a true conclusion from one or more false premises, as in:
All fish live in the sea (premise) Dolphins are fish (premise) Therefore dolphins live in the sea (conclusion)
However, the one thing we cannot do is reach a false conclusion through valid inference from true premises. We can therefore draw up a "truth table" for implication.
The symbol "=>" denotes implication; "A" is the premise, "B" the conclusion. "T" and "F" represent true and false respectively.
A B A=>B
..................
F F T If the premises are false and the
F T T inference valid, the conclusion can be
true or false.T F F If the premises are true and the
conclusion false, the inference must
be invalid.T T T If the premises are true and the
inference valid, the conclusion must
be true.
A sound argument is a valid argument whose premises are true. A sound argument therefore arrives at a true conclusion. Be careful not to confuse valid arguments with sound arguments.
To delve further into the structure of logical arguments would require lengthy discussion of linguistics and philosophy. It is simpler and probably more useful to summarize the major pitfalls to be avoided when constructing an argument. These pitfalls are known as fallacies.
In everyday English the term "fallacy" is used to refer to mistaken beliefs as well as to the faulty reasoning that leads to those beliefs. This is fair enough, but in logic the term is generally used to refer to a form of technically incorrect argument, especially if the argument appears valid or convincing.
So for the purposes of this discussion, we define a fallacy as a logical argument which appears to be correct, but which can be seen to be incorrect when examined more closely. By studying fallacies we aim to avoid being misled by them.
Below is a list of some common fallacies, and also some rhetorical devices often used in debate. The list is not intended to be exhaustive.
ARGUMENTUM AD BACULUM (APPEAL TO FORCE)
The Appeal to Force is committed when the arguer resorts to force or the threat of force in order to try and push the acceptance of a conclusion. It is often used by politicians, and can be summarized as "might makes right." The force threatened need not be a direct threat from the arguer.
For example:
"... Thus there is ample proof of the truth of the Bible. All those who refuse to accept that truth will burn in Hell."
Argumentum ad hominem is literally "argument directed at the man."
The Abusive variety of Argumentum ad Hominem occurs when, instead of trying to disprove the truth of an assertion, the arguer attacks the person or people making the assertion. This is invalid because the truth of an assertion does not depend upon the goodness of those asserting it.
For example:
"Atheism is an evil philosophy. It is practised by Communists and murderers."
Sometimes in a court of law doubt is cast upon the testimony of a witness by showing, for example, that he is a known perjurer. This is a valid way of reducing the credibility of the testimony given by the witness, and not argumentum ad hominem; however, it does not demonstrate that the witness's testimony is false. To conclude otherwise is to fall victim of the Argumentum ad Ignorantiam (see elsewhere in this list).
The circumstantial form of Argumentum ad Hominem is committed when a person argues that his opponent ought to accept the truth of an assertion because of the opponent's particular circumstances.
For example:
"It is perfectly acceptable to kill animals for food. How can you argue otherwise when you're quite happy to wear leather shoes?"
This is an abusive charge of inconsistency, used as an excuse for dismissing the opponent's argument.
This fallacy can also be used as a means of rejecting a conclusion.
For example:
"Of course you would argue that positive discrimination is a bad thing. You're white."
This particular form of Argumentum ad Hominem, when one alleges that one's adversary is rationalizing a conclusion formed from selfish interests, is also known as "poisoning the well."
Argumentum ad ignorantiam means "argument from ignorance." This fallacy occurs whenever it is argued that something must be true simply because it has not been proved false. Or, equivalently, when it is argued that something must be false because it has not been proved true. (Note that this is not the same as assuming that something is false until it has been proved true, a basic scientific principle).
Examples:
"Of course the Bible is true. Nobody can prove otherwise."
"Of course telepathy and other psychic phenomena do not exist. Nobody has shown any proof that they are real."
Note that this fallacy does not apply in a court of law, where one is generally assumed innocent until proven guilty.
Also, in scientific investigation if it is known that an event would produce certain evidence of its having occurred, the absence of such evidence can validly be used to infer that the event did not occur.
For example:
"A flood as described in the Bible would require an enormous volume of water to be present on the earth. The earth does not have a tenth as much water, even if we count that which is frozen into ice at the poles. Therefore no such flood occurred."
In science, we can validly assume from lack of evidence that something has not occurred. We cannot conclude with certainty that it has not occurred, however.
This is the Appeal to Pity, also known as Special Pleading. The fallacy is committed when the arguer appeals to pity for the sake of getting a conclusion accepted.
For example:
"I did not murder my mother and father with an axe. Please don't find me guilty; I'm suffering enough through being an orphan."
This is known as Appealing to the Gallery, or Appealing to the People. To commit this fallacy is to attempt to win acceptance of an assertion by appealing to a large group of people. This form of fallacy is often characterized by emotive language.
Examples:
"Pornography must be banned. It is violence against women."
"The Bible must be true. Millions of people know that it is. Are you trying to tell them that they are all mistaken fools?"
This fallacy is closely related to the argumentum ad populum. It consists of asserting that the more people who support or believe a proposition, the more likely it is that that proposition is correct.
The Appeal to Authority uses the admiration of the famous to try and win support for an assertion.
For example:
"Isaac Newton was a genius and he believed in God."
This line of argument is not always completely bogus; for example, reference to an admitted authority in a particular field may be relevant to a discussion of that subject.
For example, we can distinguish quite clearly between:
"Stephen Hawking has concluded that black holes give off radiation" and "John Searle has concluded that it is impossible to build an intelligent computer"
Hawking is a physicist, and so we can reasonably expect his opinions on black hole radiation to be informed. Searle is a linguist, so it is questionable whether he is well-qualified to speak on the subject of machine intelligence.
The Fallacy of Accident is committed when a general rule is applied to a particular case whose "accidental" circumstances mean that the rule is inapplicable. It is the error made when one goes from the general to the specific.
For example:
"Christians generally dislike atheists. You are a Christian, so you must dislike atheists."
This fallacy is often committed by moralists and legalists who try to decide every moral and legal question by mechanically applying general rules.
CONVERSE ACCIDENT / HASTY GENERALIZATION
This fallacy is the reverse of the fallacy of accident. It occurs when one forms a general rule by examining only a few specific cases which are not representative of all possible cases.
For example:
"Jim Bakker was an insincere Christian. Therefore all Christians are insincere."
SWEEPING GENERALIZATION / DICTO SIMPLICITER
A sweeping generalization occurs when a general rule is applied to a particular situation in which the features of that particular situation render the rule inapplicable. A sweeping generalization is the opposite of a hasty generalization.
NON CAUSA PRO CAUSA / POST HOC ERGO PROPTER HOC
These are known as False Cause fallacies.
The fallacy of Non Causa Pro Causa occurs when one identifies something as the cause of an event but it has not actually been shown to be the cause.
For example:
"I took an aspirin and prayed to God, and my headache disappeared. So God cured me of the headache."
The fallacy of Post Hoc Ergo Propter Hoc occurs when something is assumed to be the cause of an event merely because it happened before the event.
For example:
"The Soviet Union collapsed after taking up atheism. Therefore we must avoid atheism for the same reasons."
This fallacy is similar to post hoc ergo propter hoc. It asserts that because two events occur together, they must be causally related, and leaves no room for other factors that may be the cause(s) of the events.
PETITIO PRINCIPII / BEGGING THE QUESTION
This fallacy occurs when the premises are at least as questionable as the conclusion reached.
This fallacy occurs when one assumes as a premise the conclusion which one wishes to reach. Often, the proposition will be rephrased so that the fallacy appears to be a valid argument.
For example:
"Homosexuals must not be allowed to hold government office. Hence any government official who is revealed to be a homosexual will lose his job. Therefore homosexuals will do anything to hide their secret, and will be open to blackmail. Therefore homosexuals cannot be allowed to hold government office."
Note that the argument is entirely circular; the premise is the same as the conclusion. An argument like the above has actually been cited as the reason for the British Secret Services' official ban on homosexual employees.
Another example is the classic:
"We know that God exists because the Bible tells us so. And we know that the Bible is true because it is the word of God."
COMPLEX QUESTION / FALLACY OF INTERROGATION
This is the Fallacy of Presupposition.
One example is the classic loaded question: "Have you stopped beating your wife?"
The question presupposes a definite answer to another question which has not even been asked. This trick is often used by lawyers in cross-examination, when they ask questions like:
"Where did you hide the money you stole?"
Similarly, politicians often ask loaded questions such as:
"How long will this EC interference in our affairs be allowed to continue?" or "Does the Chancellor plan two more years of ruinous privatization?"
The fallacy of Irrelevant Conclusion consists of claiming that an argument supports a particular conclusion when it is actually logically nothing to do with that conclusion.
For example:
A Christian may begin by saying that he will argue that the teachings of Christianity are undoubtably true. If he then argues at length that Christianity is of great help to many people, no matter how well he argues he will not have shown that Christian teachings are true.
Sadly, such fallacious arguments are often successful because they arouse emotions which cause others to view the supposed conclusion in a more favourable light.
Equivocation occurs when a key word is used with two or more different meanings in the same argument.
For example:
"What could be more affordable than free software? But to make sure that it remains free, that users can do what they like with it, we must place a license on it to make sure that will always be freely redistributable."
Amphiboly occurs when the premises used in an argument are ambiguous because of careless or ungrammatical phrasing.
Accent is another form of fallacy through shifting meaning. In this case, the meaning is changed by altering which parts of a statement are emphasized.
For example, consider:
"We should not speak ILL of our friends" and "We should not speak ill of our FRIENDS."
One fallacy of composition is to conclude that a property shared by the parts of something must apply to the whole.
For example:
"The bicycle is made entirely of low mass components, and is therefore very lightweight."
The other fallacy of composition is to conclude that a property of a number of individual items is shared by a collection of those items.
For example:
"A car uses less petrol and causes less pollution than a bus. Therefore cars are less environmentally damaging than buses."
The fallacy of division is the opposite of the fallacy of composition. Like its opposite, it exists in two varieties. The first is to assume that a property of some thing must apply to its parts.
For example:
"You are studying at a rich college. Therefore you must be rich."
The other is to assume that a property of a collection of items is shared by each item.
For example:
"Ants can destroy a tree. Therefore this ant can destroy a tree."
This argument states that should one event occur, so will other harmful events. There is no proof made that the harmful events are caused by the first event.
For example:
"If we legalize marijuana, then we would have to legalize crack and heroin and we'll have a nation full of drug-addicts on welfare. Therefore we cannot legalize marijuana."
"A IS BASED ON B" FALLACIES / "IS A TYPE OF" FALLACIES
These fallacies occur when one attempts to argue that things are in some way similar without actually specifying in what way they are similar.
Examples:
"Isn't history based upon faith? If so, then isn't the Bible also a form of history?"
"Islam is based on faith, Christianity is based on faith, so isn't Islam a form of Christianity?"
"Cats are a form of animal based on carbon chemistry, dogs are a form of animal based on carbon chemistry, so aren't dogs a form of cat?"
This fallacy is an argument of the form "A implies B, B is true, therefore A is true." To understand why it is a fallacy, examine the truth table for implication given earlier.
This fallacy is an argument of the form "A implies B, A is false, therefore B is false." Again, the truth table for implication makes it clear why this is a fallacy.
Note that this fallacy is different from Non Causa Pro Causa; the latter has the form "A implies B, A is false, therefore B is false", where A does NOT in fact imply B at all. Here, the problem is not that the implication is invalid; rather it is that the falseness of A does not allow us to deduce anything about B.
This fallacy is an argument of the form "If A then B, therefore if B then A."
This is the fallacy of asserting that something is right or good simply because it is old, or because "that's the way it's always been."
This is the opposite of the argumentum ad antiquitatem; it is the fallacy of asserting that something is more correct simply because it is new or newer than something else.
The fallacy of believing that money is a criterion of correctness; that those with more money are more likely to be right.
The fallacy of assuming that because someone is poor he or she is sounder or more virtuous than one who is wealthier. This fallacy is the opposite of the argumentum ad crumenam.
This is the incorrect belief that an assertion is more likely to be true the more often it is heard. An "argumentum ad nauseam" is one that employs constant repetition in asserting something.
Also referred to as the "black and white" fallacy, bifurcation occurs when one presents a situation as having only two alternatives, where in fact other alternatives exist or can exist.
PLURIUM INTERROGATIONUM / MANY QUESTIONS
This fallacy occurs when a questioner demands a simple answer to a complex question.
A non-sequitur is an argument where the conclusion is drawn from premises which are not logically connected with it.
This fallacy is committed when irrelevant material is introduced to the issue being discussed, so that everyone's attention is diverted away from the points being made, towards a different conclusion.
Reification occurs when an abstract concept is treated as a concrete thing.
The burden of proof is always on the person making an assertion or proposition. Shifting the burden of proof, a special case of argumentum ad ignorantiam, is the fallacy of putting the burden of proof on the person who denies or questions the assertion being made. The source of the fallacy is the assumption that something is true unless proven otherwise.
The straw man fallacy is to misrepresent someone else's position so that it can be attacked more easily, then to knock down that misrepresented position, then to conclude that the original position has been demolished. It is a fallacy because it fails to deal with the actual arguments that have been made.
The fallacy of the Extended Analogy often occurs when some suggested general rule is being argued over. The fallacy is to assume that mentioning two different situations, in an argument about a general rule, constitutes a claim that those situations are analogous to each other.
This fallacy is best explained using a real example from a debate about anti-cryptography legislation:
"I believe it is always wrong to oppose the law by breaking it."
"Such a position is odious: it implies that you would not have supported Martin Luther King."
"Are you saying that cryptography legislation is as important as the struggle for Black liberation? How dare you!"
This is the famous "you too" fallacy. It occurs when an action is argued to be acceptable because the other party has performed it.
For instance: "You're just being randomly abusive." "So? You've been abusive too."
Often, people will argue from assumptions which they do not bother to state. The principle of Audiatur et Altera Pars is that all of the premises of an argument should be stated explicitly. It is not strictly a fallacy to fail to state all of one's assumptions; however, it is often viewed with suspicion.
As was stated earlier, if we're interested in establishing A, and B is offered as evidence, the statement "A because B" is an argument. If we're trying to establish the truth of B, then "A because B" is not an argument, it is an explanation.
The Ad Hoc fallacy is to give an after-the-fact explanation which does not apply to other situations. Often this ad hoc explanation will be dressed up to look like an argument.
For example, this conversation:
"I was healed from cancer." "Praise the Lord, then. He is your healer." "So, will He heal others who have cancer?" "Er... The ways of God are mysterious."
This is the "fallacy fallacy" of arguing that a proposition is false merely on the grounds that it has been presented as the conclusion of a fallacious argument. Remember always that fallacious arguments can arrive at true conclusions.
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ARGUMENT FROM PERSONAL INCREDULITY
If it seems impossible to me, then it must be impossible.
--Richard Dawkins
An assertion without supporting proof. From Latin, literally: he himself said it. The term is the Latin equivalent of the Greek autos epha, referring to Pythagoras, as in, The master (Pythagoras) said it so it must be true and no proof is needed. In our modern world, this has many forms:
Child: Why do I have to go to bed at eight every day?
Parent: Because I said so.
This fallacy occurs when one argues that by observing what "is the case" (for example, by seeing the rules that do exist in a given society) one can know what "should, or ought to be, the case" (in regard to the rules of a society). In other words, the world we live in provides us with what is the character of our existence. In turn, our morality, or ethics, provides us with belief about what ought to be the character of our lives. Just
because certain laws, social relationships, and customs exist in a given society does not make them just; their mere existence does not mean they ought to exist.
--Richard Lerner, Final Solutions, pg 24
[In essence: Since this is right because we are this way, then naturally this is the way the world ought to be. --MN]
[What] John Stuart Mill called a pseudo rebuttal [is] a move that pretends to engage the facts of an opposing argument but instead puts in place alternative evidence that fails to directly take on the offered data. The evidence itself need not be bad--it may in fact be accurate--but the relevance of the supposed rebuttal to the opposing claim is not established. Instead, the pseudo rebuttal is a tacit confession framed as a rejection.
But juxtaposing unengaged fact is only the first part of pseudo rebuttal. If one set of facts simply follows another, a discerning viewer might surmise that one candidate either didn't hear or didn't understand the point being made by the other. Alternatively, those who fail to ascertain that both claims may indeed be true may instead assume that both are false. Or they may conclude that there is not a clear factual basis for understanding this issue. But in 2000 Bush added another
problematic element to such exchanges by rejecting accurate claims by Gore as "fuzzy math," indicating that there was a computational error in Gore's analysis that could be corrected. After doing so, he then offered data that failed to address Gore's evidence. In other words, he signaled that he was going to rebut the false claim or expose the fuzzy math and then failed to do so.
--Kathleen Jamieson & Paul Waldman, The Press Effect, pg 188
[On the face of it, the pseudo rebuttal appears to be more of a straw man argument than a red herring, but it also seems to have elements of the red herring fallacy. Personally, I'd say that it fills a niche halfway between the two. --MN]
This is not a fallacy, but a method of testing the integrity of an argument. My dictionary defines it as: a method of proving the falsity of a premise by showing the logical consequence is absurd.