Logical Fallacies by Todangst

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Latest revision as of 09:47, 22 February 2012

Contents 1 See Also 2 Nature of Informal Fallacies 3 Types of informal fallacies 3.1 Internal Contradiction: Fallacies of Self Refutation 3.1.1 Stolen Concept Fallacy 4 Fallacies of Relevance - Rhetoric 4.1 Appeal to Force: Ad Baculum 4.2 Appeal to Faith 4.3 Appeal to Ridicule 4.4 Appeal to Pity 4.5 Appeal to Superiority 4.6 Appeal to the People 4.7 Argumentum ad Numerum 4.8 Argumentum ad Nauseum 4.9 Appeal to Wonder 4.10 Appeal to Incredulity 4.11 Appeal to Beliefs - "Everybody Knows That!" 4.12 Appeal to Normality 4.13 Appeal to Tradition 4.14 Appeal to Antiquity 4.15 Argumentum ad Novitatem 4.16 Appeal to Wealth 4.17 Appeal to Poverty 4.18 Appeal to Adverse Consequences 4.19 Against the Person 4.19.1 Ad homninem abusive 4.19.2 Ad Hominem Circumstantial 4.19.3 Ad Fidentia 4.19.4 Genetic Fallacy 4.19.5 Poisoning the Well 4.19.6 Guilt by Association 4.19.7 Ad Feminam 4.19.8 Tu Quoque 4.19.9 Valid Ad Hominem 4.20 Appeal to False Authority 4.21 Appeal to Anonymous Authority 5 Fallacies of False Presumption 5.1 Fallacy of Magical Thinking 5.2 Special Plead 5.3 False Criteria 5.4 Extension 5.5 Emotional Reasoning 5.6 Universal Skepticism 5.7 Naked Assertions and Related Fallacies 5.7.1 Fallacy of Belief as Proof 5.7.2 Shifting the Burden of Proof 5.8 Arguments from Ignorance 5.8.1 God of the Gaps 5.8.2 The Centipede Fallacy 5.8.3 The Platonic Fallacy 5.9 Complex Proposition 5.10 Argument from Uncertainty 5.11 Fallacy of the Golden Mean 5.12 Fallacy of the Law of Averages 5.13 Gambler's Fallacy 5.14 The Conjunction Fallacy 5.15 Reification 5.16 Category Error 5.17 Circular Logic 5.18 Begging the Question 5.18.1 Complex Question 5.19 Meaningless Question 5.20 Category Error 5.21 False Dichotomy 5.22 Natural Law 5.23 Appeal to Nature 5.24 The "Fallacy" Fallacy 6 Fallacies of Weak Induction 6.1 Sweeping Generalization 6.2 Hasty Generalization 6.2.1 Anecdotal Evidence 6.3 Fallacy of the Undistributed Middle 6.4 Argument from Ignorance 6.5 Argument from Silence 6.6 No True Scotsman Fallacy 6.7 Ad Hoc 6.8 Saliency 6.9 Weak Analogy 6.10 Overextended Analogy 6.11 False Analogy 6.12 False Continuum 7 Causal Fallacies 7.1 False Cause 7.2 Post Hoc Ergo Propter Hoc 7.2.1 Cum hoc ergo prompter hoc 7.2.2 Complex Cause 7.2.3 Insignificance 7.2.4 Fallacy of Regression 7.2.5 Necessary vs. Sufficient conditions 7.3 Transductive Reasoning 7.4 Slippery Slope 7.5 Fallacy of the Pre-Determined Outcome 8 Semantic Fallacies 8.1 Vagueness 8.2 Equivocation 8.3 Euphemism 8.4 Fallacy of Composition 8.5 Fallacy of Division 8.6 Amphiboly 8.7 Accent 9 Suspect Debate Tactics 9.1 Rhetoric of Imperatives 9.2 Question Begging Epithets 9.3 Catastrophizing 9.4 Inconsistency 9.5 Red Herring 9.6 Black Holing 9.7 Strawman Fallacy 9.8 Preponderance of Garbage Defense 9.9 Intellectual Dishonesty 9.10 Suppressed Evidence 9.11 Disadvantageous Comparison Error 9.12 Postdiction 9.13 Insertionism 9.14 Stacking the Deck 9.15 Misuse of Statistics 9.15.1 Misusing statistics out of ignorance 10 References

See Also

• Logical fallacy summary

Nature of Informal Fallacies

There are two general types of fallacies in logic: formal and informal. Formal fallacies are errors in logic that are due entirely to the structure of the argument, it is an error in the process of building an argument - not the content of the premises, meaning that even if the premises are true, the argument cannot support its conclusion. Aristotle held that the basis for all formal fallacies was the non sequitur, which is why the term is known in Latin as Ignoratio elench - or an ignorance of logic. For more on formal fallacies, see the Formal Fallacies section.

Informal fallacies have to do with the content of the premises. They occur when the "reasoning" or rationale behind the specific premise is illogical - i.e. the support for the argument relies on rhetoric (appeals to emotion) or another form of faulty logic. While these arguments also possess a particular form, one cannot tell from the form alone that the argument is fallacious.

Below is a list of some common fallacies. The list isn't exhaustive; however, the hope is that if you learn to recognize some of the more common fallacies, you'll be able to avoid being fooled by them. This is not only of help in combating arguments, it's good for your psychological well being. According to Rational emotive behavioral therapy (REBT), the root cause of psychopathology is irrational beliefs. In other words, learning logic won't only help you win some arguments, but it may help you to live a healthier life in general! Cognitive and REBT therapists present their clients with a brief list of irrational thoughts. I present here a much more detailed list.

Types of informal fallacies

Other than the Self Refuting statement, there are six main types of informal fallacies. They are:

Fallacies of Relevance Fallacies of Presumption Fallacies of Weak Induction Causal Fallacies and... Fallacies of Ambiguity and Grammatical Analogy.

Internal Contradiction: Fallacies of Self Refutation

If you have read the section on the axioms of classic logic , you learned that classic Aristotelian logic is based on the law of non contradiction ¬ (P + ¬ P) , which in turn is defended through retortion - according to defenders of classical logic, denials of the law of non contradiction rely on the LNC. In the words of Aristotle, the law of non contradiction declares: "One cannot say of something that it is and that it is not in the same respect and at the same time (without falling to a contradiction)" And it follows from Aristotle's view of logic that all contradictions are false.

Therefore, the Self Refuting fallacy is the simplest fallacy to understand - it is a statement that renders itself false by containing within itself a(n) (internal) contradiction. Because these argument trip over themselves, they are usually humorous in nature. Here is my all time favorite, from the biblical book of Numbers, supposedly written by Moses. I will let Thomas Paine explain it for you:

"But granting the grammatical right, that Moses might speak of himself in the third person, because any man might speak of himself in that manner, it cannot be admitted as a fact in those books, that it is Moses who speaks, without rendering Moses truly ridiculous and absurd: -- for example, Numbers xii. 3: "Now the man Moses was very MEEK, above all the men which were on the face of the earth." If Moses said this of himself, instead of being the meekest of men, he was one of the most vain and arrogant coxcombs; and the advocates for those books may now take which side they please, for both sides are against them: if Moses was not the author, the books are without authority; and if he was the author, the author is without credit, because to boast of meekness is the reverse of meekness, and is a lie in sentiment

Here is another favorite self refutation. This is from the creationist "scientist" Henry Morris:

Thus there was no death before sin entered the world. The finished creation was "very good" (Genesis 1:31), with an abundance of food and all other provisions for man and animals. There was certainly no struggle for existence, or survival of the fittest, for every creature was created fit for its own environment. When Adam sinned, God brought the curse of decay and death not only upon Adam, but also upon his dominion (Genesis 3:17-20, 1 Corinthians 15:21-22, Romans 8:20-22).

In this passage, Morris tells us that there was no death in the world - but that people still ate food which is in this case would presumably be plant life, a living substance that died when it was consumed. One cannot deny that there was 'death' if one maintains that there was 'food', unless of course, one redefines what the term 'death' means. (See the ad hoc fallacy)

Stolen Concept Fallacy

The fallacy consists of the act of using a concept while ignoring, contradicting or denying the validity of the fundamental characteristics or axioms on which it logically and/or genetically depends.

Example written by Nathaniel Branden:

One of the most grotesque instances of the 'stolen concept fallacy' may be observed in the prevalent claim-made by neo-mystics and old-fashioned mystics alike-that the acceptance of reason rests ultimately on "an act of faith." Reason is the faculty that identifies and integrates the material provided by the senses. Faith is the acceptance of ideas or allegations without sensory evidence or rational demonstration. "Faith in reason" is a contradiction in terms. "Faith" is a concept that possesses meaning only in contradistinction to reason. The concept of "faith" cannot antecede reason, it cannot provide the grounds for the acceptance of reason-it is the revolt against reason. One will search in vain for a single instance of an attack on reason, on the senses, on the ontological status of the laws of logic, on the cognitive efficacy of man's mind, that does not rest on the fallacy of the stolen concept. This fallacy must be recognized and repudiated by all thinkers, if truth and reality are their goal. In the absence of such recognition and repudiation, the gates are left open to the most lethal form of mysticism-the mysticism that postures as "science." Who are the neo-mystics' victims? Any college student who enrolls in philosophy courses, eagerly seeking a rational, comprehensive view of man and existence-and who is led to surrender the conviction that his mind can have any efficacy whatever; or who, at best, gives up philosophy in disgust and contempt, concludes that it is a con game for pretentious intellectual role-players, and thus accepts the tragically mistaken belief that philosophy is of no practical importance to man's life on earth.

Fallacies of Relevance - Rhetoric

Rhetorical appeals are logical fallacies when one presents them as reasons to accept an assertion. Rhetorical appeals are logically irrelevant because they don't attempt to state premises that prove or disprove a conclusion, instead, rhetoric is an attempt to appeal to one's emotions rather than one's reason. For this reason, we can refer to all rhetorical appeals in logical arguments as False Signs.

Appeal to Force: Ad Baculum

We can call this the Sledgehammer Fallacy - Argument through intimidation. Threat or harm is promised or implied to the listener if the conclusion is not accepted. The crudest of crude fallacies and the "logic" of that oafish overvalued officer, Major West...

Smith! Concede that Platonic Reals have an existence external from the mind!

Never, you ninny!

Example: All those who refuse to accept the truth of the bible will burn in Hell.

What to look for: In an appeal to force, you are never given any reason for believing - you are given a reason to comply.

Appeal to Faith

This is the claim that you can possess truth or knowledge with faith. Theistic, or non contingent faith, is a claim that one does not need justification to hold a belief. It is not an epistemological position, it is a rejection of epistemology itself. Therefore faith cannot stand in as a premise in a logical argument.

See also: the argument to uncertainty and the universal skepticism fallacy.

The "appeal to faith" is often used in a different way by theists - who claim that all forms of thought rest upon faith. This claim, which was created to undermine logic itself, is false. Classical logic rests on axioms, not faith. Other forms of logic, such as natural or propositional logic, rely on self declared definitions.

The axioms of classical logic are not merely beliefs without justification, they are self evident, implied in all propositions (indeed, classic logic relies on them), and defended through retortion (see above). As Ayn Rand notes concerning the axioms of her metaphysics, axioms are supported by the fact that we cannot know anything, or make any claims, without illustrating their veracity.

Faith, by definition, relies on a belief that does not rest on logic or evidence. Faith depends on irrational thought (i.e., a desire) and produces intransigence. Faith has never been shown to be anything more than believing what you want to believe no matter the reality. Historically, people "of faith" have used the very next appeal that follows "to alter the opinions" of their opponents.

What to look out for: Faith is not a means to gain knowledge. Faith is simply an assertion that one can accept a belief without justification. It's an end to rational thought, not a beginning.

By Nathaniel Branden: One of the most grotesque instances of the stolen concept fallacy may be observed in the prevalent claim—made by neo-mystics and old-fashioned mystics alike—that the acceptance of reason rests ultimately on "an act of faith." Reason is the faculty that identifies and integrates the material provided by the senses. Faith is the acceptance of ideas or allegations without sensory evidence or rational demonstration. "Faith in reason" is a contradiction in terms. "Faith" is a concept that possesses meaning only in contradistinction to reason. The concept of "faith" cannot antecede reason, it cannot provide the grounds for the acceptance of reason—it is the revolt against reason. One will search in vain for a single instance of an attack on reason, on the senses, on the ontological status of the laws of logic, on the cognitive efficacy of man's mind, that does not rest on the fallacy of the stolen concept. The fallacy consists of the act of using a concept while ignoring, contradicting or denying the validity of the concepts on which it logically and genetically depends. This fallacy must be recognized and repudiated by all thinkers, if truth and reality are their goal. In the absence of such recognition and repudiation, the gates are left open to the most lethal form of mysticism—the mysticism that postures as "science." Who are the neo-mystics' victims? Any college student who enrolls in philosophy courses, eagerly seeking a rational, comprehensive view of man and existence—and who is led to surrender the conviction that his mind can have any efficacy whatever; or who, at best, gives up philosophy in disgust and contempt, concludes that it is a con game for pretentious intellectual role-players, and thus accepts the tragically mistaken belief that philosophy is of no practical importance to man's life on earth.

Appeal to Ridicule

The Appeal to Ridicule is a fallacy in which ridicule or mockery is substituted for argument.

Appeal to Pity

In Latin, Ad Misericordiam. Here, a blatant attempt to invoke sympathy is offered. The protypical example is the downtrodden employee who implores his boss to give him a raise so that he can take better care for his starving children. He has not given his boss a reason why he deserves an increase of salary, only a reason why he needs more money. Note well the difference.

Warning catchphrase Simple - Ad Misericordiam arguments usually focus on the happenstance or misfortune of a person or people and draw upon feelings of guilt.

Appeal to Superiority

Akin to the appeal of snobbery, this is an appeal that claims that one's proposition must be true, since it is is not shared by the common man - but only held within intellectual circles. See the next fallacy.

Appeal to the People

Ad Populum. Here, the listener's desire to be loved, accepted or respected is played to... Advertising makes heavy use of this appeal. The appeal to vanity, and the appeal to snobbery/superiority are two common types used by advertisers. However, the most common approach would be the the bandwagon appeal which implies that some claim must be true, because everyone of any note or importance believes it. But in an argument, it doesn't matter who believes in a claim or how many people believe in a claim, what matters are the reasons why they believe in the claim.

Warning, Warning!: Ad populum arguments prey upon our lesser side our pride, our fears, and our petty hatreds.

Note: Ad Populum is often equated with Ad Numerum, which follows. Some hold the two to be identical and therefore, interchangeable, others hold that a true Bandwagon appeal makes an appeal only to others in the immediate vicinity (those around the bandwagon) whereas the appeal to numbers cites overall numbers of people who hold to a belief. Feel free to use the terms as you wish.

Argumentum ad Numerum

This fallacy is closely related to the ad populum fallacy. It consists of asserting that the more people who support or believe a proposition, the more likely it is that that proposition is correct. There is at least a weak correlation between the number of people who accept a proposition and its validity - but correlation is not causality.

Argumentum ad Nauseum

A fallacious argument is more likely to be accepted as true if it is repeated over and over. We can also refer to this process as Propaganda. Joseph Goebbels discovered that if something is repeated enough times, people will eventually come to accept it as true, even unquestionable.

Here is a nice example of this fallacy. It appeared on a web site of a "martial arts master" who argued over the existence of something called "Qi". The page is a good example of logical fallacies, so check it out here.

If Qi were just a concept, why would there be such a plethora of information regarding it's 
importance and use? 

Appeal to Wonder

This is the fallacy that declares that any statement which appears too novel, too wonderful or astounding, must be false, simply because of this sensation of wonder or amazement. There is nothing wrong with this sense of wonder causing us to take pause, and express doubt, but to rely solely on this sensation as a proof is a logical fallacy. As Carl Sagan stated in Candle In The Dark, science (i.e. rational thinking) is a blend of wonder and skepticism.

A nearly identical fallacy is the the Appeal to Incredulity

Appeal to Incredulity

This fallacy occurs when we assert an argument is false because the conclusion seems too incredible to us. A very famous example would be Einstein's denial of quantum theory - "god does not play dice with the universe!" The fact that a conclusion appears incredible to us is not a fit refutation for an argument. What matters is whether the evidence justifies the premises of an argument, and whether the argument form is sound. If the argument is valid and sound, it's conclusion is true, no matter how perturbing the conclusion is...

The fact that a conclusion appears incredible to us is meaningless. What matters is whether the evidence justifies the premises of an argument, and whether the argument form is sound. If both of the facts are true, then the argument is valid and sound, no matter how perturbing the conclusion is.

Let me speak for the theistic side, for a change. There have been times - when I've studied brain anatomy and have had the thought "This is just a bit too much to have come about by natural processes"

So I can appreciate how others get this sense too. A sense of wonderment.

But seeing as a sense of wonder only speaks to being overwhelmed by the limits of our understanding, we can't allow this sense of wonderment put a stop to our striving to understand. Yes I can appreciate how the "complexity" of the world can lead a theist to say "goddidit". But we would only be reifying our ignorance if we were to stop here. It would be a sign of of intellectual laziness to stop at this sensation, and to call it a discovery - or an answer.

So while I can see how both the uneducated and the informed can wonder at complexity, but to say things are "too complex" is only to say that we we find it marvelous and wondrous.

Appeal to Beliefs - "Everybody Knows That!"

This is the fallacy of simply asserting that a claim ought to be well known or obvious, and that therefore, it should simply be accepted. This is a particularly insidious rhetorical appeal because it is often an attempt to use people's vanity against them: since most people are unwilling to appear ignorant of such claims, they tend to accept them to avoid appearing ignorant.

An excellent example of a television character strongly influenced by this appeal would be 'Barney Fife' from The Andy Griffith Show.

Appeal to Normality

This is the fallacy of believing that any behavior that becomes a common practice must be a valid behavior. We often make culturally based assumptions on just what is normal. And they rely on limited knowledge. But many commonly accepted practices are reevaluated and found morally wanting. It was once normal to own slaves and beat your children, for example. But not many today would argue that those once normal practices were correct. See the next fallacy, as well as the Appeal to Natural Law fallacy.

Appeal to Tradition

This is the fallacy of asserting that something must be right or good because "that's the way it's always been." It is a form of an appeal to Antiquity.

Appeal to Antiquity

Argumentum ad antiquitatem. This is the fallacy of asserting that something is right or good simply because it's old. This mindset was directly responsible for the error of the scholastics, who held that Aristotle and Plato had to be correct in their views on science and nature, because they were venerable philosophers from a golden age. In fact, this very fallacious mindset is behind the entire concept of a 'golden age'. The reality is that the past was a brutal, primitive and ignorant world to live in.

The opposite of Argumentum ad Novitatem.

Example: "For thousands of years Christians have believed in Jesus Christ. Christianity must be true, to have persisted so long even in the face of persecution."

Response: It is not the antiquity of a tale that is an evidence of its truth; on the contrary, it is a symptom of its being fabulous. - Thomas Paine, Age of Reason

Argumentum ad Novitatem

This is the opposite of the Argumentum ad Antiquitatem; it's the fallacy of asserting that something is better or more correct simply because it is new, or newer than something else. Yes, it's true that our distant ancestors were brutes, but not every new idea is automatically better than what they came up with.

Christianity is just the thought of the ancients. Modern science is latest way of thinking, and therefore the best.

Appeal to Wealth

Argumentum ad crumenam. The fallacy of believing that money is a criterion of correctness; that those with more money are more likely to be right. The opposite is known as Argumentum ad Lazarum. Example: "Microsoft software is undoubtedly superior; why else would Bill Gates have got so rich?"

Appeal to Poverty

Argumentum ad lazarum. This is the fallacy of assuming that someone poor is more virtuous than someone who is wealthier. This fallacy is the opposite of the Argumentum ad Crumenam. For example:

Monks are more likely to possess insight into the meaning of life, as they have given up the distractions of wealth.

Poor people can be stupid too, and often are. This fallacy stems from a psychological phenomena: we tend to find that our own characteristics and strong points are the most important characteristics and strong points for everyone. If you are poor, you're likely to find wealthy people to be inferior to you in some way.

Appeal to Adverse Consequences

This argument is based on holding that what a person "wishes" to be true, must be true, because the alternative is too undesirable to consider.

Ninny!

Example: A God offering us eternal life must exist; because if He didn't, where will I end up after I die?

Let's examine the illogic of this claim. A useful tool for uncovering the fallacious nature of an argument is through substituting new premises into the form of the argument:

A parachute offering me an escape from the horrible fall I am now experiencing after being tossed from the empire state building must exist; because if it doesn't, what will happen to me when I hit the ground?

Clearly, our own hopes and desires for a thing does not make it so.

Here is a classic example of this fallacy:

If there is no resurrection of the dead, then not even Christ has been raised. And if Christ has not been raised, our preaching is useless and so is your faith. More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead. But he did not raise him if in fact the dead are not raised. For if the dead are not raised, then Christ has not been raised either. And if Christ has not been raised, your faith is futile; you are still in your sins. Then those also who have fallen asleep in Christ are lost. If only for this life we have hope in Christ, then we are to be pitied more than all men." (1 Corinthians 15:13-19, NIV)

In other words, if you don't believe Christ was raised from the dead, then we must face the painful reality that the dead are merely dead.

Warning signals Watch out for an opponent who confuses what he desires to be true for what is true. When this occurs, disengage from the conversation, as you are wasting your time... and his.

Against the Person

One of the few fallacies known better by its Latin nomenclature than its English equivalent, the Ad hominem fallacy occurs when one makes an issue of the arguer himself, rather than his argument. The intent is more than just to hurl an insult, it's the act of insulting with the intent of undermining the credibility or competence of the arguer, so that one simply ignores the argument altogether. So the intent is to get people to simply dismiss the argument without ever considering it.

There are valid forms of ad hominem - in the case of testimony, the character of testifier is the source of credibility for the claim. However, to doubt or reject a valid deduction based on the source, is an ad hominem fallacy. For more on legitimate forms of ad hominem, see below.

Types of Ad Hominem fallacies

Ad homninem abusive

Ad homninem abusive is the most crude form of ad hominem. It is a direct assault upon a person's intellect or moral character in order to undermine the argument.

The fool sayeth in his heart that there is no god.

Simply being insulted by your opponent is NOT ad hominem. It's an INSULT. To refer to an insult as ad hominem is to misapply this fallacy. To put it briefly, If I were to call, say, this robot:

a clinking, clanking collection of corroded cathodes, this would merely be an insult, and a well deserved one at that. If I were to reject one of his emotionally driven arguments because he's a clinking, clanking, collection of corroded cathodes, I would be committing an ad hominem fallacy.

Ad Hominem Circumstantial

is the questioning of an arguer's motives. Freud's famous attack on the motives of Christians, in: Civilization and its Discontents, can be taken as an ad hominem circumstantial attack - if one refuses to acknowledge Freud's comments that the question of the validity of Christianity has been settled elsewhere.

Ad Fidentia

(Against Self-Confidence) occurs when a a debater attacks his opponent's confidence instead of the argument. Ad Fidentia is a fallacy, because however unconfident a person may be in their assertions, their ideas may still be correct. We must challenge facts and logic, and not people.

Genetic Fallacy

occurs when it is held that a claim must be false because it originates from a certain person or institution. The classic example is "Hitler/Mussolini/Bin Laden says 2+2=4, but it must be untrue, because he was a Nazi/tyrant/terrorist."

Poisoning the Well

is a form of ad hominem similar to the genetic fallacy, wherein your opponent attempts to weaken your argument with points that are true, but which are extraneous to the current argument. A great example can be heard by listening to Sean Hannity, an ABC political pundit, who can't help but throw in every supposed Clinton scandal (proven or unproven) into every discussion about Clinton.

Guilt by Association

is used in two general forms: one, the crude form, directly links the arguer to some unsavory individual, such as pointing out that your opponent is one of "Newt Gingrich's boys". In the less crude, more indirect form, your opponent links you to another who might not necessary be in disfavor, but might also support views that are more extreme as yours. For example: "My opponent frequently sides with Governor Ventura, who is on record for legalized marijuana." Unless the opponent also explicitly agrees with the legalization of marijuana, this argument is the logical fallacy of guilt by association.

Ad Feminam

is the fallacy of appealing to irrelevant personal considerations concerning women,especially prejudices against them. - Always in touch with my feminine side...

Tu Quoque

or "You too" fallacies, concern arguments that are used to justify or defend one's wrong-doing by claiming that an opponent has committed a similar crime. This is more commonly known as "two wrongs don't make a right."

Valid Ad Hominem

There are legitimate forms of ad hominem. This second, valid form of the ad hominem is discussed in John Locke's 'An Essay Concerning Human Understanding'

(It is legitimate) to press a (testifier) with (the) consequences drawn from his own principles or concessions and to show that these claims are mutually exclusive.

Another form of a valid argument ad hominem, would be an examination of the credibility of a witness providing testimony. Premises discrediting the person can exist in valid arguments, when the person being criticized is the sole source for a piece of evidence used in one of his arguments.

Person 'A' committed perjury when he said 'Q' We should not accept testimony for which perjury was committed Therefore, A 's testimony for Q should be rejected

Appeal to False Authority

Ad verecundiam occurs when an arguer cites an authority who is not an expert at the subject at hand. This fallacy does not occur if the authority is legitimately an expert in the field of discussion. Even citing a reliable authority, on its own, does not make a deductive argument valid, however.

Appeal to Anonymous Authority

Closely related to the above fallacy. This fallacy occurs whenever anyone cites an anonymous source as evidence for their claims. We cannot allow anonymous sources to be used as evidence because there is no way to verify the veracity of the source. You'll most likely hear this fallacy stated thusly: "Scientists say.... or "leading experts agree that...". Oddly enough, those citing the bible commit this fallacy, unless they are citing one of Paul's works, because every other book of the bible is written anonymously.

Fallacies of False Presumption

In fallacies of presumption, the arguer has made an epistemological, or ideological assumption that is in error. An epistemological error concerns beliefs towards how one learns about the world. For example, some people believe we can learn things "emotionally." There is no such thing as an "emotional truth" only things we cognitively hold as true concordant with strong emotional feeling.

An ideological assumption concerns beliefs towards how logic and reason work, and their value. For example, some theologians and mystics claim that science or logic or even reason itself is only illusion. This is simply incorrect. I repeat here the words of Ethan Allen, the revolutionary war hero, who states why:

Those who invalidate reason ought seriously to consider whether they argue against reason with or without reason; if with reason then they establish the principle that they are laboring to dethrone: but if they argue without reason (which, in order to be consistent with themselves they must do), they are out of reach of rational conviction, nor do they deserve a rational argument.

With this renewed acceptance of the validity of reason, and thereby logic, we proceed to the following section.

Fallacy of Magical Thinking

Also known as the Labeling Fallacy, and similar to reification, the fallacy of magical thinking occurs when a debater claims that by merely naming or providing a name for a phenomenon, he has in fact provided an argument in favor of his position.

"There are, of course, many who regard the concept of God as an exceedingly simple explanation of everything, and who regard scientific elucidations as either incomplete or ponderous. However, that is a self-delusion. Such views are generally held by people who do not understand the scientific method. Indeed, to believe that the assertion that God is an explanation (of anything, let alone everything) is intellectually contemptible, for it amounts to an admission of ignorance packaged into the pretence of an explanation. To aver that 'God did it' is worse than an admission of ignorance, for it shrouds ignorance in deceit."
"Religion - The Antithesis to Science", Oxford Chemistry Professor, Peter Atkins

Magical thinking is akin to the problem of "labeling" - the fallacious assumption that providing a name for an observed phenomenon provides us with information.

Special Plead

Special pleading is a fallacy in which a person applies standards, principles, rules to others while claiming special dispensation or exemption for themselves without providing adequate justification for the exemption.

In particular, special pleading occurs when when a person in logical discourse asserts that their claims lie outside of reason or logic itself.

Example: How can there be an equally godlike Father, Son and Holy Ghost in the same person? Answer: You don't grasp the ineffable mystery of the trinity.

You don't have to grasp the ineffable mystery, (and as stated, your opponent doesn't grasp it either!) If your opponent wants to maintain a belief in an argument, he must provide you with his evidence, not his own explicit admission that he has no evidence!

Remember that the basic premise of rational discourse is to present your reason for why you hold a belief. Stating that you don't know the reason is not a reason. And we cannot invalidate reason simply because reason doesn't give us what we want

From the Nikor Project (http://www.nizkor.org/features/fallacies/special-pleading.html):

From a philosophic standpoint, the fallacy of Special Pleading is violating a well accepted principle, namely the 'Principle of Relevant Difference'. According to this principle, two people can be treated differently if and only if there is a relevant difference between them.

There are cases which are similar to instances of Special Pleading in which a person is offering at least some reason why he should be exempt but the reason is not good enough to warrant the exemption. This could be called "Failed Pleading."

Warning signals: You've just asked your opponent for his reason for maintaining his proposition. He tells you the only problem is you - you just can't grasp, comprehend, or admire that the phenomena in question is a paradox that is (safely) beyond science or beyond reason. He is special pleading you.

False Criteria

Also known as the fallacy of questionable criteria. this is the application of irrelevant standards to the subject of the argument. It is a basic fallacy of assumption.

Extension

A particular type of false criteria fallacy that argues something is inferior just because it doesn't do something it was never intended to do.

Emotional Reasoning

Feelings are cues - they alert us to certain facts. Feelings may enhance belief. Feelings may lead us to a sense of conviction that a belief is true. But feelings, on their own, are not an argument, and in some cases, strong emotions may cloud reason.

Universal Skepticism

NOTE: This fallacy is also listed in the Rhetorical Appeals section the Appeal to Faith.

Universal skepticism is the claim that all epistemological positions - and reason itself, ultimately relies on faith - i.e we must have faith in first foundations in order to know anything.

By Nathaniel Branden: One of the most grotesque instances of the stolen concept fallacy may be observed in the prevalent claim—made by neo-mystics and old-fashioned mystics alike—that the acceptance of reason rests ultimately on "an act of faith." Reason is the faculty that identifies and integrates the material provided by the senses. Faith is the acceptance of ideas or allegations without sensory evidence or rational demonstration. "Faith in reason" is a contradiction in terms. "Faith" is a concept that possesses meaning only in contradistinction to reason. The concept of "faith" cannot antecede reason, it cannot provide the grounds for the acceptance of reason—it is the revolt against reason. One will search in vain for a single instance of an attack on reason, on the senses, on the ontological status of the laws of logic, on the cognitive efficacy of man's mind, that does not rest on the fallacy of the stolen concept. The fallacy consists of the act of using a concept while ignoring, contradicting or denying the validity of the concepts on which it logically and genetically depends. This fallacy must be recognized and repudiated by all thinkers, if truth and reality are their goal.

The claim that all beliefs ultimately rest upon an unsubstantiated, unjustified, desire driven beliefs (what we will properly defined as 'non contingent faith') is self refuting - If we cannot know anything with certainty, then we cannot be ascertained of the value of faith.

The Appeal to Faith is often used by fundamentalists to undermine classical logic (which they often confuse for all logic) or reason itself. Classical logic rests on axioms, not faith. Axioms do not need to be proven because they are already the foundation upon which we'd form any proof! They are self evident, atomic statements, that all other statements rely upon, which are defended through retortion. As held by defenders of classical logic, any attempt to refute an axiom leads to a self refutation. As Ayn Rand notes, axioms are supported by the fact that we cannot know anything,or make any claims, without illustrating their veracity. For these reasons, accepting axioms is not equitable with holding to a belief through non contingent faith.

Non-contingent or theological faith is simply the maintenance of a belief despite the lack of evidence, or even in the face of negating evidence. To confuse faith for a reasoned assumption is a gross error.

Faith is not a means to gain knowledge. Faith is an assertion that one can accept a belief without justification. It's an end to rational thought, not a beginning. Faith has never been shown to be anything more than believing what you want to believe no matter the reality. Faith depends on irrational thought and produces intransigence. Historically, people "of faith" have used the very next appeal that follows "to alter the opinions" of their opponents.

Naked Assertions and Related Fallacies

I am truly stunned that I have to even list this as a fallacy, but my experiences arguing with others shows this is clearly necessary.

A "naked" assertion is simply an assertion without any evidence, proof, or other support. It is usually based on the false presumption that since we all have "a right to an opinion", that this implies that our opinions must be automatically accepted as valid. What invariably proceeds the blunder of a "naked" assertion is the logical fallacy of "shifting the burden of proof" which further illustrates that the arguer has no concept of logic.

A common example of a Naked Assertion masquerading as a logical argument is found in Christian Presuppositionalism:

Archer says, "Without a good and holy God in heaven above, however, there is no solution to be found in freethinking or any other kind of thinking." Again no proof or justification is provided. Just another assertion that is supposed to be sufficient unto itself. Too bad I didn't think of that approach! Instead of devoting so much time and effort to reading and research, I could have just forgotten about all my studies, thrown away my notes, discarded my citations, and told it like it is. That certainly would have been easier. - Dennis McKinsey from Bible Errancy (http://mywebpages.comcast.net/errancy/issues/iss160.htm)

Fallacy of Belief as Proof

Closely related to the fallacy of a naked assertion is the fallacy of belief as proof. In fact, this fallacy is often used to support a naked assertion!

This fallacy occurs when one maintains that one's strong conviction is itself a proof, without any other evidence. As Sigmund Freud wrote in Future of an Illusion:

Your own convictions can not serve as proofs for me.

This fallacy stems from the confusion of that the intensity of one's beliefs indicates the veracity of one's beliefs. Try to remember that intensity of a belief in no way correlates with the veracity of a belief. Billions of people are sure and wrong. Every christian who knows that the christian god is real also "knows" that there are a billion Muslim fools.

Shifting the Burden of Proof

The burden of proof is always on the person asserting something. 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. The source of the fallacy is the assumption that something is true unless proven otherwise. This is not the case. You can't assume the truth of a proposition without proof. If we could assume truth until disproven, we would be stuck with the ridiculous conclusion that anything we said to be true, must be true, and would only become false when proven false. Reread the ignorantiam law if you are still confused.

This error, above nearly all others, indicates a lack of knowledge of the tenets of logic. Those who commit it require remedial learning.

Arguments from Ignorance

An Argument from Ignorance occurs when one makes a positive claim based on a lack of information. Basically, the claimant assumes that since something has not been proven false, it is therefore true. But you can't make claims without reason or evidence. All a lack of information can tell you is that you do not know. A claim's truth or falsity depends upon supporting or refuting evidence for the claim, not the lack of support for a contrary or contradictory claim.

The weakness of my argument does not imply the strength of yours - Sigmund Freud

An argument from ignorance often is merely an expression of one's desires and little more. The Skeptic's dictionary calls it "Wishful thinking".

See also Special plead, Shifting the Burdon of Proof, Correct by Default, Centipede Fallacy, Platonic Fallacy and Argument from Uncertainty.

God of the Gaps

God of the Gaps may also be referred to as a Correct by Default Fallacy. It is a compound fallacy, a combination of the False Dichotomy fallacy and Arguing from Ignorance. The reasoning here goes as follows: One person in a debate puts forth a naked assertion that their position is true and demands that the the opponent provide a satisfactory argument for his position. He then holds that the opponent cannot provide an alternative explanation. Therefore, the first arguer claims that his position MUST be true, since there is no alternative explanation. However, the arguer has not put forth any reason why his explanation is true, he merely assumes it is correct by default. The absence of other proposed explanations does not imply validity for his assertion. If this were true, and we followed this logic to its conclusion, we end up with this absurdity: ANY first explanation for a new phenomena must be true, since at that time no alternative exists!.

Here is a nice example of a response to this fallacy, by Brooks from the Bogus Beyond Belief website:

You keep saying that I am reading too much into your questions, implying that you are merely asking them out of idle curiosity. Hardly. You are attempting to use the so-called moral "argument" for God. You apparently hope that I will be unable to explain the basis for human morality, and that you then will be able to insert "God" as an explanation, sort of a round-about way of promoting Christianity. It is a great ploy to use, because it doesn't require you to provide those troublesome things known as real arguments and evidence. It relies on a lack of an explanation from the other side. There is a problem, however. You say that you "believe" that morality comes from "God." This is your *opinion*-you have not supported it with any evidence yet. Until you provide me with some evidence or arguments for this statement, it remains your opinion and nothing else, and this is true "whether it is acknowledged or not."

The Centipede Fallacy

The Centipede Fallacy is closely related to the God of the Gaps Fallacy and the Argument From Ignorance. It occurs when an arguer implies that your inability to explain how some concept or phenomena works implies that the phenomena therefore cannot work, or does not even exist. The name comes from fact that a centipede has no idea how to move hundreds of legs in unison, but he does so anyway.

Example: Since science cannot totally explain how the universe got here, its theories are false

This fallacy does not apply when a debater points out that the phenomena in question cannot work because it violates an observable law of physics, or that the precepts it is based on are in contradiction. In this case, he is not committing a fallacy... and in fact, if his premises are true, he is right - the phenomena is untrue.

Sorry, but that is how logic goes. Also see the Reification Error.

The Platonic Fallacy

The Platonic fallacy is a specific form of Centipede Fallacy, which in turn is a form of an Argument from Ignorance. It is based on the notorious difficulty in defining a concept, such as 'chair', in a way that gives both necessary and sufficient conditions for chairs., rules in only things that we consider chairs, and rules out anything that is not a chair.

The reason we find the application of categories to the real world so daunting is because categories are themselves artificial: we create them. The universe is a continuum, not a set of static categories, and as such, is under no obligation to fit into our categories.

The fallacy, therefore, occurs when one attempts to rely on this notorious difficulty in applying categories to the real world entities, as a grounds for holding to the concept of universals in lieu of holding to the more parsimonious category/continuum explanation.

Complex Proposition

Also known as compound proposition. This fallacy occurs when an argument includes more than one claim in the proposition and treats proof for one claim as proof for all the claims.

Argument from Uncertainty

This is a bit different from Arguing from Ignorance. Arguing from uncertainty occurs when one attempts to use the tentative nature of inductive claims as a reason, in of itself, to reject an inductive claim. Inductive claims are accepted or rejected on a probabilistic basis, as per their evidence.

Consider the following table:

Continuum of Truth

Absolute truth	Most likely true	Maybe true	Probably false	Defintely False
Tautologies	Theory of Gravity	Kant's Categories	"Big Foot"	Contradictions

Here we can see that whereas mountains of evidence exist to support the notion of gravity, there is but a dearth of evidence to support "Big Foot' Therefore, while both ideas lie along the continuum, they are hardly equitable in truth value. We can reasonably reject Big foot claims, while we can reasonably accept claims about gravity.

"Quite frequently I encounter people who equate lack of certitude with giant inferential leaps. Science deals with probabilities, often quite high probabilities, but not certitudes. It is one of the strengths of the scientific method as it acknowledges a chance of error(while maintaining rigorous standards to establish provisional acceptance of propositions).

It is a mistake to believe that a science consists in nothing but conclusively proved propositions, and it is unjust to demand that it should. It is a demand only made by those who feel a craving for authority in some form and a need to replace the religious catechism by something else, even if it be a scientific one. Science in its catechism has but few apodictic precepts; it consists mainly of statements which it has developed to varying degrees of probability. The capacity to be content with these approximations to certainty and the ability to carry on constructive work despite the lack of final confirmation are actually a mark of the scientific habit of mind." -- Sigmund Freud

Fallacy of the Golden Mean

Avoiding extremes does not guarantee correctness.

"He's a Capitalist, she's a Communist. I'm smack dab in the middle, so I must be right."

Fallacy of the Law of Averages

Gambler's Fallacy

Author A. K. Dewdney, from his book "200% of Nothing" speaks about a form of ignorance nearly as bad as illiteracy - innumeracy, or the ignorance of math. A particular form of innumeracy is citing the "law of averages" or the belief that if some statistically measured event has happened an inordinate amount of times, it must soon stop. A good example would be the roulette player who knows that black must now come up after a string of reds.

The contraposition is that if such a event has yet to occur, it must now be "due." This mentality is seen most in sports announcing, where an announcer might say "Jeter hit .320 on the season. He is currently in the middle of a slump, 1-11. He's due!"

The fact is, logically, every single event is separate from prior events. If Jeter's real average is .320, then at every at bat he has, approximately, a 30% chance of getting a hit. (This leaves out individual differences in pitchers, who may reduce or increase this percentage.)

The Conjunction Fallacy

This fallacy occurs when we presume the following equation to be true:

P(A + B) > P(A)

In order to understand this equation, use this key: P=probability, A, B = Propositions, and += AND, i.e. both A and B together. So the equation reads: the probability of a premise, in conjunction with another premise, being true is greater than the probability of just the one premise being true.

Stated abstractly, this seems a ridiculous error, and an easy fallacy to avoid. Assuming there is no causal connection between B and A, how can the possibility of both premises A AND B being true be more likely than just premise A , being true?! Yet, when we use specific premises, the conjunction fallacy seems a much more confusing issue:

Go ahead and try this one out:

Bill is a boring guy. Knowing this, which of the statements is more likely to be true?

Bill plays Jazz trumpet Bill plays jazz trumpet, and is an accountant

Are you tempted to say the second answer is more likely? Of course you are. This occurs because we never look at facts without using prior knowledge. We use schemas or stereotypes based on experience, to evaluate any facts. We "know" that boring people are often not jazz musicians, so in order to accept that a boring guy named Bill would play Jazz trumpet, we need to ground this incongruous knowledge with something that appears to be more likely to be true - i.e. that a boring guy is an accountant.

But the truth is, unless there is some strong causal relationship between being boring, playing the Jazz trumpet, and being an accountant, this is fallacious thinking. In lieu of any other information, it is more logical to state that the first response, "Bill plays Jazz trumpet", is correct, because it only makes one assumption, not two!

My apologies to all accountants, everywhere, as well as any boring guys named Bill.

Reification

Also known as Hypostatization, Reification error occurs when we treat a sign as a signifier - i.e. when we treat abstract concept as having an existence independent of the brain. This error also occurs when one makes the claim that since one can imagine some phenomenon, then this phenomenon must exist. This argument was used by Saint Anselm. See my entry on Anselm on my "Christian philosophers of the middle ages" page. Briefly, Anselm's argument was that since he could imagine a perfect being, then he must exist, since its "more perfect" for him to actually exist "extra-mentally".

The argument was so silly that it was refuted in his own time. Yet, 1000 years later, it still pops up. Here are the obvious refutations:

You can't imagine a perfect being. When you try, you usually come up with a contradiction - i.e. an all good, all powerful god who is restrained for some reason against stopping evil (I.e. he will allow a child to be repeatedly gang-raped, before going to hell for non belief, so that you and I have free will.)

You imagine plenty of things that don't exist: unicorns, pink elephants, well adjusted mature women... (ok, that last one strains credulity), so why is it that only this one imagination, god, must be true, while no one maintains that there are in fact unicorns?

This fallacy can be much like the centipede fallacy (See centipede fallacy) when it is then used to make the claim that the abstract concept that you cannot define, therefore cannot exist. See also 'category error'

Category Error

A category error occurs when one attempts to use an invalid sensory modality, or manner of knowing a particular phenomena, such as trying to hear light, or feel an idea, and then holds that the failure of this modality or manner of knowing to detect the phenomena proves that the phenomena either does not exist, or that it exists in some 'immaterial form'.

An example would be the claim put forward by immaterialists that colors or numbers must be immaterial, since we cannot locate 'color' or "numbers" as physical objects within a brain. Yet the same arguer would not expect to find tiny actors and musicians inside his television set, he would expect to find electronics that interpret electrically transmitted data as audio-visual entities. So clearly there is some error here!

And there is. This error occurs because of a fallacy of composition - one presumes that the electro chemical impulses in neurons that make up ideas can be observed as if it were the number 2, rather than representative of the number 2, data points, which are inferred by the brain as the number 2.

See also: the fallacies of composition and division.

Circular Logic

Begging the Question

In Latin: Petito principii

Any argument that relies on its own conclusion as a premise.

"We must believe the there is a God because it is so taught in the Holy Scriptures, and we must believe in the veracity of the Holy Scriptures because they are the word of God"

Some people like to note that circular arguments are trivially valid. They are right: - circular arguments are valid. But the validity of a circular argument should not impress us seeing as the 'validity' stems from the fact that we are merely holding that a thing is identical to itself!

Deductive arguments work just like mathematical equations: a set of equivalences - we can even reformulate such arguments as tautologies. Therefore, the point of such arguments is to demonstrate some equivalence (or lack thereof) between two categories. So, yes, plugging the same statement into both a premise and the conclusion gives us an equality, but the fact that that the same exact statement gives us an equivalency is not exactly noteworthy! This is why we call this an informal fallacy - nothing is being proven here, we aren't demonstrating an equivalancy, the equivalency is already a given prior to the argument!

Complex Question

A specific form of circular logic, a complex question is a question that assumes its own conclusion so that any attempt to answer the question necessarily leads to accepting the conclusion. The most famous example of the complex question fallacy:

"Do you still beat your wife?"

If this question is answered, it becomes an argument with the conclusion that you have in fact beaten your wife at some point in time. The problem is that a complex question is really two questions that demand one answer. This can be committed out of ignorance, but it can also be a purposeful deception.

Another form of this fallacy is to ask for an explanation of something which is untrue or not yet established.

Meaningless Question

Questions with statements that commit the existential error - i.e., items that do not exist. The ultimate example: What happens when an irresistible force meets and immovable object? The proper response to this question is to point out that if there were a irresistible force, ipso facto there could not be an immovable object (and/or vice versa.) Most meaningless questions are equally incoherent, because they are basically built upon contradictions, or make reference to non existent entities.

Category Error

This error occurs when an inappropriate measure is used in regards to a certain entity, such as attempting to listen to light.

False Dichotomy

Also known as the fallacy of the excluded middle, the fallacy is committed when an argument presents a supposedly valid disjunctive premise, (an "Either... Or" argument) wherein the items presented either are not jointly exhaustive (a third choice exists) or are not mutually exclusive.

Example: You're either with us or against us.

Natural Law

Appeal to Nature

"Is implies Ought". The Appeal to Nature is a common fallacy in political arguments. One version consists of drawing an analogy between a particular conclusion, and some aspect of the natural world -- and then stating that the conclusion is inevitable, because the natural world is similar:

"The natural world is characterized by competition; animals struggle against each other for ownership of limited natural resources. Capitalism, the competitive struggle for ownership of capital, is simply an inevitable part of human nature. It's how the natural world works."

Another form of appeal to nature is to argue that because human beings are products of the natural world, we must mimic behavior seen in the natural world, and that to do otherwise is 'unnatural':

"Of course homosexuality is unnatural. When is the last time you saw two animals of the same sex mating?"

Of course, such arguers often also deny any connection to nature when it does not suit them, such as on evolution. (See inconsistency) Also, animals DO have homosexual encounters, so this entire argument is bullshit.

Finally, this fallacy occurs any time something is identified as being good or desirable because it appears to be a natural characteristic

• Everyone is basically self-interested, therefore pursuing one's self-interest is a virtue.
• Everyone wants to be wealthy so systems should be designed based on economic incentives.

The "Fallacy" Fallacy

Argumentum ad logicam. This is the "fallacy fallacy" of arguing that a conclusion is false because it has been presented as the conclusion of a fallacious argument. Remember always that fallacious arguments can arrive at true conclusions.

"Take the fraction 16/64. Now, canceling a six on top and a six on the bottom, we get that 16/64 = 1/4."

"Wait a second! That answer must be wrong. You can't just cancel the six!"

Fallacies of Weak Induction

Fallacies of Weak Induction can be differentiated from appeals to emotions in that they are actual attempts to support conclusions based on citing supporting evidence. However, a basic error in the argument prevents drawing a valid conclusion.

Sweeping Generalization

Also known as Accident - concluding that a legitimate generalization necessarily applies to a particular case.

Example:

The Bible says 'Thou shall not kill', so capital punishment is morally wrong"

Capital punishment may be morally wrong, but the general rule is likely misapplied here.

Hasty Generalization

secundum quid, also small sample biasis a conclusion drawn upon a too small or non representative (not randomly drawn) sample. This usually is seen in arguers who overly depend upon Case study a matter of preferring interesting examples over boring statistics - (again, See Rush Limbaugh). It's a truism that one good case study example impresses people more than a book full of statistics - a phenomenon well studied in psychology. But remember - one of the main reasons for the salience of a case study is its uniqueness.

Speaking of psychology, this fallacy is known in social psychology as the availability heuristic. In short, its the overuse of conclusions drawn from what is readily available in memory - which essentially is the small sample bias. It's one of the reasons that good scientists stress the need to consider many hypotheses and the need to examine many sides of an issue.

Example: Consumer's Report may say this radio is the safest, but my brother Irving got a shock when he used it - so I say it's the worst"

One final note: In the 1920s, the people of the city of Chicago began to complain to their mayor about the incredible upsurge in crime in their city. The Mayor investigated the situation and found that, statistically, crime had dropped during his time in office. He presented this information publicly, only to be booed. Finally, he went to the newspapers and asked them to play down their sensationalist style of presenting criminal news. Soon after his public approval ratings sored...

Anecdotal Evidence

A specific form of Hasty Generalization. One of the simplest and widely seen fallacies is the belief that one can prove a point based solely on anecdotal evidence. For example: "There's abundant proof that God exists and is still performing miracles today. Just last week I read about a girl who was dying of cancer. Her whole family went to church and prayed for her, and she was cured."

It's quite valid to use personal experience to illustrate a point; but such anecdotes don't actually prove anything to anyone. Your friend may say he met Elvis in the supermarket, but those who haven't had the same experience will require more than your friend's anecdotal evidence to convince them.

Anecdotal evidence can seem very compelling, especially if the audience wants to believe it. This is part of the explanation for urban legends; stories which are verifiably false have been known to circulate as anecdotes for years.

Fallacy of the Undistributed Middle

These fallacies occur if you attempt to argue that things are in some way similar, but you don't actually specify 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?"

Often the illogic of an argument is made more clear when we substitute. For example, consider the same argument form, with a substitution:

"Islam is based on faith, Christianity is based on faith, so isn't Islam a form of Christianity?"

OR

"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?"

Argument from Ignorance

Argumentum ad ignorantiam occurs when one's premises state that nothing is known with certainty about a subject, and one's conclusion states something certain. The most common error is to claim that when a certain thesis is not proven, the opposite thesis must be true. The fallacy is not committed if qualified researchers have failed after extensive and exhaustive attempts to demonstrate some phenomena, and the conclusion at hand states that what they have attempted to demonstrate is not so.

In short, this argument occurs when it's argued that something must be true, simply because it hasn't been proved false. Or, equivalently, when it is argued that something must be false because it hasn't been proved true. (Note that this isn't the same as assuming something is false until it has been proved true. In science, we assume that an unproven is not true. In law, for example, you're generally assumed innocent until proven guilty.) Here is an example:

"Of course the Bible is true. Nobody can prove otherwise."

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 didn't occur. Also, this fallacy is recognized by the very ones who use it - in other circumstances. For, while an apologist may maintain that a belief in god is validated by a lack of negating evidence, the apologist himself has absolutely no problem whatsoever denying the reality of other gods without his requirement for negating evidence.

See also: "Correct by Default Fallacy"

Argument from Silence

The Argument from Silence is the claim that since a person or document does not state X, then this person or document was unaware of the existence of X, without adequately demonstrating that the person in question would 1) have had the opportunity to be aware of X, and 2) knowing it, would have had the opportunity to make mention of it.

When one is able to demonstrate these issues, then one has made a valid Argument from Silence

According to Gilbert Garraghan (A Guide to Historical Method, 1946, p. 149)

To be valid, the argument from silence must fulfill two conditions: the writer[s] whose silence is invoked would certainly have known about it; [and] knowing it, he would under the circumstances certainly have made mention of it. When these two conditions are fulfilled, the argument from silence proves its point with moral certainty.

An example of a Fallacious Argument from Silence is given by Minicus Felix, a first century Roman writer whoe wrote about early Christians, claiming that they sacrificed infants:

"As for the initiation of new members, the details are as disgusting as they are well known. The novice himself, deceived by the coating of dough (covering a sacrificial infant), thinks the stabs are harmless. Then, it's horrible! They hungrily drink the blood and compete with one another as they divide his limbs. And the fact they all share knowledge of the crime pledges them all to silence. On the feast-day they foregather with all their children, sisters, mothers, people of either sex and all ages. Now, in the dark, so favorable to shameless behavior, they twine the bonds of unnamable passion, as chance decides. Precisely the secrecy of this evil religion proves that all these things, or practically all, are true."

An example of a valid Argument from Silence

Before Ignatius, not a single reference to Pontius Pilate, Jesus' executioner, is to be found. Ignatius is also the first to mention Mary; Joseph, Jesus' father, nowhere appears. The earliest reference to Jesus as any kind of a teacher comes in 1 Clement, just before Ignatius, who himself seems curiously unaware of any of Jesus' teachings. To find the first indication of Jesus as a miracle worker, we must move beyond Ignatius to the Epistle of Barnabas. Other notable elements of the Gospel story are equally hard to find. This strange silence on the Gospel Jesus which pervades almost a century of Christian correspondence cries out for explanation. It cannot be dismissed as some inconsequential quirk, or by the blithe observation made by New Testament scholarship that early Christian writers "show no interest" in the earthly life of Jesus. Something is going on here. - Earl Doherty's case for a non-historical Jesus.

No True Scotsman Fallacy

Otherwise known as the Fallacy of Redefinition. Suppose I assert that no Scotsman likes to play checkers. You counter this by pointing out that your friend Angus likes to play checkers. I then say "Ah, yes, but no true Scotsman likes to play checkers.

This is an example of an ad hoc change being used to shore up an assertion, combined with an attempt to shift the meaning of the words used original assertion; as well as "counting the hits and forgetting the misses" -you might call it a combination of fallacies. Whatever you call it, its a nasty attempt to alter reality to suit one's needs.

The fallacy of redefinition is a key component of the argument style of Chris "Mad Dog" Russo, who can be heard on WFAN radio. A good example can be heard nearly every day. The most recent example was his challenge for fans to find "One small market baseball team that is competitive." Seeing that small market Arizona won the world series last year, and that other small market teams such as Atlanta and San Diego have appeared in the world series within the last four years, fans found this challenge rather easy to meet. They phoned in and listed these cities, as well as other cites such as Seattle and Oakland that appeared in the playoffs only last year.

Obviously, any logical person, so thoroughly refuted, would be compelled to immediately withdraw the ludicrous claim. However, Russo responded by stating that each of those teams had big budgets and therefore they were not small market teams. In other words, Russo re-defined the term "small market" from meaning "a smaller city with a smaller population" (which is what it really means) to mean "a team with a smaller budget." But any sensible person realizes that "small market" indicates nothing more or less than a small market - regardless of what the budget of the team is.

Radio hosts tend to use the logical fallacy of redefinition often, since it allows their arguments to become moving targets, safe from logical rebuttals. With their argument safe from logical debunking, they are free to continue to spout pure idiocy, unchecked. Even more perversely, they can claim that their argument has never been "refuted". The best way to catch such a rhetorician is to insist that he define his terms (he won't) and stick to this one particular issue. (he'll sidestep to some other issue immediately) However, if you can pin him down, he will back off - until the next caller.

Ad Hoc

I'm thinking of putting this in the "Suspect Debate Tactics" section. The Ad Hoc fallacy occurs when we give an after-the-fact explanation to shore up an argument that has been negated by some new evidence and this explanation is made without restoring to an consistent policy, but solely because this explanation rescues the theory!

The two most common examples are cries of "translation error" and "out of context."

The problem with the cry of "translation error" is that to be consistent, one would need to check the entire document for translation errors, especially points that are not under criticism.

The problem with "out of context" is that "context" is often a subjective claim to begin with. Unless a statement is completely in discord with the immediate passages preceing or anteceding the statement, going back for "further context" is questionable at best.

Often this ad hoc explanation is nothing more than a special plead, dressed up to look like an argument. For example, if we assume that God treats all people equally, then the following is an ad hoc explanation: "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." The logical response would be "No... and that doesn't make sense, does it?"

See "Weak analogy".

Saliency

Saliency is a fallacy in which a very dramatic event is taken to outweigh a significant amount of statistical evidence. This sort of "reasoning" has the following form:

Dramatic or vivid event X is more memorable Therefore events of type X are likely to occur.

This sort of "reasoning" is fallacious because the mere fact that an event is particularly vivid or dramatic does not make the event more likely to occur, especially in the face of significant statistical evidence.

People often accept this sort of "reasoning" because particularly vivid or dramatic cases tend to make a very strong impression on the human mind. For example, if a person survives a particularly awful plane crash, he might be inclined to believe that air travel is more dangerous than other forms of travel. After all, explosions and people dying around him will have a more significant impact on his mind than will the rather dull statistics that a person is more likely to be struck by lightning than killed in a plane crash.

Weak Analogy

Overextended Analogy

A weak analogy occurs whenever two entities are considered comparable because of a superficial similarity. A typical analogy is usually drawn in the following manner:

Entity 1 is held to possess the attributes of A and B and C, Entity 2 is maintained to possess the attributes of A and B. Therefore, Entity 2 probably has attribute C.

However, any analogy made without a strong systematic, causal connection between possession of the attributes A and B AND possession of attribute C commits the fallacy of Weak analogy. An example may better clarify:

1) Hitler was a man who spoke German, wore a goofy mustache, and had an irrational hatred of Jews. 2) Einstein spoke German and had a goofy mustache - it follows that he had an irrational hatred of Jews.

This is a weak analogy because no causal connection can be drawn between speaking German and hating Jews (although BEING German and hating Jews might... no... of course not.) Not to sound like a broken record, but to hear fine examples of this, tune into Rush, between rehab visits...

The key element that a keen debater will learn from this entry is that the 'weak' or 'overextended' fallacy is often one drawn between an entity you support and an entity that shares superficial characteristics with your entity, plus one with clearly 'odious elements' that are not essential to the nature of the entity that you support or defend. For this reason, I call the overextended analogy the 'Hitler argument', for Hitler is the most popular historical felon used in the overextended analogy. Here is an example: Arguer: 'I believe in a woman's right to choose, therefore I support abortion.' Opponent: 'Gee, isn't that how Hitler would handle unwanted pregnancies?' Whether or not Hitler would handle the situation in a similar manner is not essential to this argument - after all, Hilter was also nice to dogs, so according to this logic, one would have to be mean to dogs to avoid being 'Hitlerian'. (By the way, just to show how off the mark this argument is, Hitler was AGAINST abortion.)

False Analogy

Also known as Imperfect analogy. In an analogy, we explain or define a phenomenon by making a comparison of this unknown entity to a known entity. An analogy is somewhat like a generalization in that it uses a specific, well known example, as its basis. However, whereas the generalization draws a conclusion about the whole class of objects from which the example is drawn, the analogy draws its conclusion about another specific example. The analogy makes the assumption, 'This unknown example is like that known example'. Now, the test of an analogy is this:

Is the unknown example like the known example in the -essential- areas being compared?

As long as the similarities lie in the | areas about which the claim is made, argument by analogy constitutes proof. If the analogy draws its comparisons in an area not relevant to the claim, the argument will be faulty. Therefore, this fallacy occurs when a comparison between one phenomena and another is made based on a resemblance so superficial that the analogy clearly is nonsensical - i.e. there is no legitimate reason to claim that the two entities are similar. No logical evidence for the connection is made. Here is an example: Why should we sentimentalize over a few hundred thousand Native Americans who were ruined when our great civilization was being built? It may be that they suffered injustices, but, after all, you | can't make an omelet without breaking a few eggs. In order to make an omelet, one is required to crack open the eggs. In order to build a nation, it is not required that one rape and slaughter its native inhabitants.

False Continuum

This fallacy occurs where there is no definitive demarcation line between two things and it is therefore argued that they are the same.

This is the argument that "since ships are simply large boats then a ship and a boat is the same thing", or that "rock music is the same as pop music" because there's a certain amount of overlap between the two kinds of music.

Causal Fallacies

Note: I discuss causal fallacies in more detail on my Scientific Method page.

Causal fallacies occur because of scientific ignorance. The most common error is known as the 'correlation/causation error' - the assumption that two correlated phenomena have a causal relationship. This fallacy occurs when we assume that because two things have either a positive relationship (the more it rains, the more your knee itches) or a negative relationship (The more you watch tv, the less you exercise) that this means that one thing is the CAUSE of the other. This is not necessarily true, for while correlation is a necessary condition for causality, it is not a sufficient reason for a causality. There are are two types of correlational/causational errors. They follow below: DIRECTIONALITY ERROR The direction between cause and effect is reversed. Saying that carrying your umbrella with you makes it more likely to rain is an example. THIRD VARIABLE ERROR - This occurs when one takes correlational data and assumes a causal relationship. One thing is held to to cause another, when in fact they are both the joint effects of an underlying cause.

See also the section on "necessary and sufficient" causes.

False Cause

A false cause fallacy is any fallacy wherein one fails to demonstrate a causal link.

Post Hoc Ergo Propter Hoc

Also referred to as Non Cause Pro Causa, this is the fallacy found in ritualistic thinking. This fallacy occurs when events are seen to be causally connected when in fact no such causal connection has been established. Basically one event is asserted to be the cause of a later event simply by virtue of having happened earlier. In scientific research, this is referred to as the dreaded correlation/causality error. . Example: "I asked Father Pio to pray for a cancer patient. 11 days later, he had a spontaneous recovering. Therefore Father Pio worked a miracle!" - Pope John Paul II.

Warning catchphrase to look for: In general, consider the scientific education of the arguer. Do they fail to present empirical evidence? Not refer to charts/data? Do they seem to freely use the term "This proves I am right"? (A NO NO for scientific thinkers.) If so, the speaker may not understand the limits of correlational evidence.

Cum hoc ergo prompter hoc

Also known as concomitant variation, this causal fallacy is a special case of Pot hoc, in that the two events are said to occur simultaneously.

Complex Cause

This fallacy is similar to post hoc ergo propter hoc, except that the putative causal entity given in the argument may play a causal role. However, it is also likely that other causes exist, or that several factors work interactively.

Example:

"Literacy rates have steadily declined since the advent of television. Clearly television viewing impedes learning."

This may be a valid point. However, the fallacy is to assume that television is the sole cause, or even the most important cause. The correlation/causality error may take place here, leading go the possibility of the 'directionality' error - i.e. that some other factor reduce literacy rates, which led people to watch more tv! Or it may be that there is the third variable problem at work - some other factor may have led to a reduction in literacy and an increase in television viewing.

See also the "Texas Sharpshooter Fallacy"

Insignificance

Related to complex cause, here one entity is held to cause another, and it does play a part in the causality, but it is insignificant compared to other causes of the effect. You'll often see this fallacious claim in conjunction with therapies and medicines - hell, with just about any consumer product. Recall the old commercial phrase "part of a complete breakfast!" - (sure, so is the table cloth) that captures the concept quite well.

Fallacy of Regression

The regressive fallacy occurs when one fails to take into account that any measured phenomena will inevitably fluctuate for various reasons, and instead immediately claims that some change over time MUST be be due to the cause of some purported independent variable. The e tendency for any measurable variable to move toward the average expected measure for that variable and away from extremes was called "regression" by Sir Francis Galton - i.e. regression toward the mean.

Nearly anything you measure will fluctuate over time - your mood, your physical well being, the stock market, sports teams performances. The regressive fallacy is one key argument against the legitimacy of the purported PLACEBO effect. Simply put, there may be no real placebo effect at all... what is really occurring in medical research is that positive responses after placebo may be measuring regressive factors - such as natural healing over time.

Necessary vs. Sufficient conditions

A necessary condition is a condition that must be present to bring about some effect. A sufficient condition possesses, as one of its attributes, the necessary condition, along with other attributes that are not necessary to bring about the effect. The fallacy occurs when we mistakenly assume that the the secondary attributes of the sufficient condition are somehow necessary conditions.

Example: let's imagine that the desired effect we want is to shatter a window. We realize that force that exceeds the tensile strength of the window is a necessary condition for breaking the window. A hammer thrown at 30 mph. at the window is a sufficient condition for breaking a window. The fallacy occurs when we attempt to argue that is it necessary to possess something metal to break a window, or even something material to break a window.

Transductive Reasoning

The causal fallacies above are related in that they are both examples of transductive reasoning. Transductive reasoning is how pre-schoolers' reason. Because preoperational children (children typically under the age of 8 who have not yet reached Piaget's concrete operations stage, see my entry on Piaget) are not yet logical thinkers, their explanations are often based on collections of disconnected facts and contradictions. This means that young children tend not to reason from general laws to specific instances (deduction) or from evidence to general conclusions (induction) but from a specific events to other specific event (Transductive reasoning). Piaget called this transductive reasoning. Because their worldviews are not yet internally consistent, pre-schoolers tend to see causal connections between events simply because of their connections in contiguity. (Source: Development Through the Lifespan, Laura Berk, 1999)

What this means is that they form opinions on causal connections non logically. Here is a good example from the above cited text:

Mother: Why does it get dark at night? Child: Because that's when we go to bed!

Compare this answer from a four year old to the pope's statements from the false cause entry above:

Reporter: Why did the cancer disappear? Pope: Because father Pio prayed!

The transductive reasoning of a four year old is at work in both statements. In the child, it's cute. In the adult figurehead representing spiritual and intellectual leadership for a billion people, it's nearly beyond frightening.

Slippery Slope

Another popularly known fallacy, this is actually an offshoot of the false cause fallacy. It occurs when an arguer claims one event must lead to a successive chain of less desirable consequences -without offering any other proof.

Example: "If we vote for Clinton, a known pot smoker, soon the whole Whitehouse will be filled with drug addicts."

Fallacy of the Pre-Determined Outcome

This is a current favorite of mine, and I learned it from Michael Kay, a talented and intelligent sports announcer for the New York Yankees. Go Yankees!

Kay often runs into fans who say something akin to: "If only player x had gotten on base, then player y's home run right after x's at bat would have won the game."

Kay counters that we cannot assume player y would have hit the homerun in this hypothetical situation, because we have changed what led up to y's homerun so that all future outcomes are now in doubt - i.e. the playing field is literally changed. For specific examples, Kay would point out that after walking player x, the opposing pitcher might have been substituted, or that player y may have become more anxious knowing that the game was now on the line and struck out. In fact, aliens from outer space, who had placed wagers on the Yankee's opponents, may have chosen that instant to attack and annihilate Yankee stadium. There is simply no way to know for certain what would happen next. Whatever the specifics, we can never assume that an outcome would be exactly the same as it is now, if we were to hypothetically go back and change variables that led up to the outcome. The flaw in the assumption here is that the arguer is assuming that he can keep whatever outcomes that please him, while denying those that do not, when in fact all variables in outcomes are connected and can never be separated.

Semantic Fallacies

This category is up of problems concerning purposeful or accidental vagueness. They include: Vagueness, Equivocation/Semantic fallacy, Euphemisms, Amphiboly, Accent and the fallacies of analogy - Composition and Division.

Vagueness

Also known as weasel words. These types of fallacies occur when premises contain terms that are so fuzzy as to be practically meaningless.

Example: Purchases of "Chi rings" are told that if you wear the ancient Asian power ring, it will increase your Chi, your life force, and lead to maximized health. Just what is Chi, or life force? What exactly is 'maximized health'? The answer to that question usually is "Anything even remotely positive that happens after wearing a Chi ring"

Equivocation

Also known as Conflation. The purposeful or erroneous transposition of meaning when the same word is used in two premises (or a premise and a conclusion), that is actually used in two different senses. This is also known as 'Weasel Words' - the use of which allow unscrupulous arguers to change their meaning after the fact. 'I didn't mean that, I meant this...'

A simple example: 'Banks have money. Rivers have banks. Therefore, whoever owns a river has a lot of money' Perhaps a person who could own a river would have a lot of money, but this point is not proven here. The error is apparent - it hinges on the claim that the word 'bank' has the same meaning in each premise. A more complex form, from an argument posed by the theist, J. P. Moreland from the book 'Does God Exist': 'Information must ultimately derive from an intelligent source. DNA possesses information - therefore, DNA shows design by an intelligent force- this force must be God'. Leaving aside the Kierkegaardian leap made from the premise to the conclusion, which commits the fallacy of missing the point (Why does it HAVE to be God? How about Allah? Zeus? Aliens from another dimension? The sole reason for choosing God seems to be that the arguer is a christian.) the error here is that the word 'information', when used in explaining the code in DNA, is used in a second sense - as a metaphor. The word 'blueprint' could have been used, yet no one would seriously suggest that there are real, miniature blueprints in DNA. If they did, perhaps then they could claim the existence of very tiny draftsmen. Equivocation happens purposely as well:

That all depends on what the meaning of 'is' is. - William Jefferson Clinton.

This fallacy is also known in classic Aristotelean logic as the fallacy of four terms.

Warning Catchphrase to look for: Examine analogies and metaphors carefully, especially when an analogy differs greatly from the phenomena discussed. (I.E. God is like a flower...) Ask for precising or operational definitions of words, even simple words, when they are used in argument form. Few words are univocal - with just one meaning.

Euphemism

This fallacy involves the use of a different word for a word we wish to avoid using, yet still containing the SAME meaning that we need to transmit. This is done to purposely obscure or confuse the reader to the true motives of the arguer, to make the reader or listener believe one desires to commit to one action when one really is favoring the opposite, or merely avoid making embarrassing admissions outright. In some cases the motivation is merely to aesthetically please - such as calling a toilet the 'necessarium' in front of the hoity-toity. The worst misuses of euphemisms may occur to people unaware that they are in fact using it - self delusion.

Here is an infamous example of a euphemism being used to avoid making an embarrassing admission: One commits a crime by failing to comply with a law, so Dinkins is using a euphemism. This allows him to avoid the politically embarrassing situation of admitting in public that he is a law breaker, it not only fails, it also serves to show him as a cowardly liar.

It is no coincidence that I have chosen to use a politician as an example of euphemisms, for they are the worst offenders of this brand of fallacy - watch for how our government works. (I.e. - The Korean Conflict instead of War). For example, consider:

Republicans create new policies - Clinton Flip Flops. Clinton was a pothead - George W. Bush had a 'substance abuse problem'. Clinton has affairs - Henry Hide had a youthful indiscretion (in his 40s). Clinton raises taxes - Reagan 'enhanced government revenues'.

Lastly, consider the following three step transitions from good connotation to bad connotation, while all the words used have the same denotation. This method best explains the range of possible word choice when speaking about the very same phenomena:

I am firm; you are obstinate; he is a pigheaded fool. I have reconsidered it; you have changed your mind; he is going back on his word. I failed to comply with the law; you committed a crime; he is a felonious social deviant.

Warning Catchphrase to look for: The solution to uncovering this fallacy is simple in theory, but difficult in practice - as a logician you must ask the meaning of terms when you are unsure of them. If some military figure tells you that there will be a 'predawn vertical insertion' find out what the crap this means. (It means armed troops are going to parachute into some hostile country, and start killing poor bastards - but they don't want to tell you it that way...) Don't just pretend to be smart, ask and BE smart. If the military figure reveals that there has been some 'friendly collateral damage', be honest with yourself and say to him 'what the hell is friendly damage, buddy?!' You'll find out that it means that innocent bystanders were killed during a battle or a bombing mission. Again, the military guy ain't too pleased to tell you this. Asking someone what they mean takes on the risk of 'looking dumb' but remember, that is the very thought process being taken | advantage of in a euphemism! When Reagan looked America in the eye and spoke of revenue enhancements, he knew the average Republican voter had no idea what he meant, and that none of them would risk admitting ignorance to find out. That's how people trick you - by using your own hang-ups against you! Note: The opposite of Euphemism is 'dysphemism', which is the act of replacing a favorable term with a nasty, unfavorable term.

Fallacy of Composition

The fallacy of composition occurs when we erroneously transpose of a characteristic of a part of a system, or a person, to be characteristic of the whole, or the whole personality. It's similar to the fallacy of small sample bias/hasty generalization. Example: Oxygen and Hydrogen are both gases, it follows that H2O is also a gas' Another example: Al Gore agrees with the Unibomber on several environmental issues. It follows that Gore is just as reckless, uncaring and irresponsible as the Unibomber. The philosophical argument known as the 'Tragedy of the Commons' is an argument that relies on the composition fallacy. This is a philosophical argument that points out that what is good for individuals in society might have terrible ramifications for all members of said society if all members were to follow the same behavior - i..e one polluter benefits, many polluters suffer.

Fallacy of Division

The reverse of the composition fallacy - when a characteristic of the whole is erroneously transferred to one or more of its parts. Example: Water is a liquid, it follows that oxygen and hydrogen must also be liquids' A special case of the fallacy of division is the the clustering illusion or the Texas-sharpshooter fallacy. The Texas sharpshooter fallacy is the name epidemiologists give to the clustering illusion - the clustering illusion is the intuition that random events which occur in clusters are not really random events, i.e, finding a statistically unusual number of cancers in a given neighborhood--such as six or seven times greater than the average.

When this rate is re-connected to the overall population, we see that such a high localized rate is not all rare or even unexpected. Much depends on where you draw the boundaries of the neighborhood. The illusion is due to selective attention based on a false assumption: that a given rate for a phenomenon will be perfectly uniform across all members of that group. The term refers to the story of the Texas sharpshooter who shoots holes in the side of a barn and then draws a bull's-eye around the bullet holes: as long as the sharpshooter gets to pick where the target is afterwards, he will always remain a sharp shooter!

Amphiboly

When an argument depends upon a statement (Not just a word or phrase) that is ambiguous due to a grammatical error. This can occur from poor punctuation or a dangling participle.

Accent

Accent is a form of fallacy through shifting meaning. In this case, the meaning is changed by altering which parts of a statement are emphasized. For example: 'We should NOT SPEAK ILL of our friends' and 'We should not speak ill of our FRIENDS' Be particularly wary of this fallacy on the internet, where it's easy to misread the emphasis of what's written.

Suspect Debate Tactics

I've always wanted to add in a section on dirty debate tactics. These are not 'fallacies' so much as they are either ignorant flaws or purposeful attempts to twist reality in order to convince another of your position. I will start out by looking more closely at rhetoric techniques, and then I will examine a few debate styles that are more than just a little bit suspect... ">

Rhetoric of Imperatives

This rhetorical tactic occurs whenever we state terms in absolutes where an absolute does not exist, such as claiming that we must do something, (logical necessity) or that we should do something (a moral necessity). Whenever an arguer speaks in absolute shoulds and musts, (without conditionals) he is a rhetorician, not a logician. In psychological terms, this is known as Karen Horney's "tyranny of the shoulds" or Albert Ellis' "shoulding yourself" and "mustifications".

Consider the following rhetorical plea: We must save the rainforests!

This statement is pure rhetoric, because it makes a claim that saving the rainforest is a logical necessity. If the statement is reworded to read: We should save the rainforest! it again makes the error of false imperatives, this time on a moral basis.

In order to make these into logical statements, the use of a should, or a must, MUST include a conditional statement: We should save the rainforest, or we may perish from this earth! (Note that the inclusion of the word "may" makes this a logical and possible truth.) "We should save our forests, or face facts that we environmentally uncaring!" Again, this presents the original statement in logical terms.

Question Begging Epithets

This ploy occurs when slanted language is used to reaffirm what we wish to prove but have not proven yet. It is a form of rhetoric. See my rhetoric section for more. No right-thinking American could support this measure, a cunning plot hatched in back rooms by corrupt politicians.

How can you believe the statistical analysis provided by corrupted researchers living off tobacco industry grants?

Be careful. Every negatively phrased question is not the fallacy of question begging epithets. For example, one could say "No competent medical doctor practices trepaning (cutting open heads to release evil spirits)." The statement is valid as long as the practice in question would violate known precepts of one's profession.

Catastrophizing

Also known in cognitive therapy as "fortune telling." This occurs when you predict the future negatively without considering other, more likely outcomes. Both conservatives and liberals are guilty of this. Conservatives ask us to spend billions to save us from immanent doom from the Russians. Liberals demand attention and money must be given to environmental concerns, or the world will perish.

Inconsistency

This is another example of poor debate style. It occurs when one uses one system or argument in one case, and then denies it or fails to apply it, in another case. It can occur either in self denigrating or self deferential manner. Carl Sagan's example from Candle In The Dark: Our government prudently plans for the worst of which an adversary is potentially capable, but thriftily ignores scientific projections on environmental dangers as "unproven." In psychology, the self denigrating manner of inconsistency is known as "disqualifying the positive" or the type of negative self appraisal that occurs during depression wherein a person ignores their good features and achievements and dwells upon the bad.

This fallacy can also be referred to as the EVERYONE BUT ME PHENOMENA when speakers specifically use a method that they find to be flawed only when it is used by another. The implied presumption is that EVERYBODY BUT ME is wrong if this argument is used. It is the narcissistic and irrational mindset where a thinker, believer in, or supporter of, some system of thought who accepts the invalidity of his justifications or proofs only when OTHERS use it in the service of defending beliefs in discord with the believer/thinker.

Certainly many examples exist in the secular world, but I will choose to pick on religion yet again. A fine example occurs in the debate between Christians and Mormons. Christians deny the contentions that an Angel named Maroni visited Joseph Smith and gave him golden plates containing new scripture. However, this contention differs not a whit from biblical proofs of Christianity that also depend on purported angelic visitation.

What to look for There are at least 2 logical deductions possible when inconsistency occurs: 1) Angelic evidence is too easy to fake, therefore both religions are unproven commodities or 2) Unfortunately both contentions are on equal footing, and Christianity must find other ways to prove Christianity's truth. (The natural desire to point to a greater preponderance of angelic visitation in Christianity is pointless if the very phenomenon itself is under fire as a questionable proof. See the Preponderance of Bullshit/Garbage fallacy.)

Some fine thinkers would recognize the reality of Angelic proofs and would choose option 1 - ending the dilemma right there. Other equally gifted thinkers would vote for choice number 2, and seek other proofs for their prospective religion. The problem is that many others would simply fall prey to the "everybody but me is crazy" phenomena - and hold that others who use the same arguments are wrong while they somehow are still correct - because they are somehow better or different - i.e. rational.

A therapist and a reporter are talking and the therapist is asked: Have you ever had two Napoleon complex patients at once at your clinic? Yes, he responds. Really? What happens when the meet?

Oh, that's easy - they immediately realize the truth - the other guys is nuts.

Red Herring

A red herring occurs when your opponent adds in information that is connected in some way to the current discussion, but in no way has any bearing on the argument at hand. A good example would be an argument I entered into recently:

Opponent: Where do you think Christianity shows up in Folwer's famous hierarchy of faiths?

Myself: Very low, I am afraid. Christianity, with all its tenets, its dogma, would appear, ipso facto, at his conventional stage. Stage 3 of the 7.

Opponent: Aha! But Folwer himself is Christian!

Myself: Yes... but this has no bearing on the matter! The only way it could is if you are insinuating that Folwer, because of his status as a Christian, would purposely shape his theory of faiths to ensure Christianity made the top of the list. But if this happened, then you would still be refuted, because you would be admitting the theory was biased! Therefore, the fact Folwer was a Christian has no bearing here whatsoever!

Red herrings can be used purposefully to draw away attention from the point of the argument. I've seen tons of good examples on Brooks's Bogus Beyond Belief website where Christian apologists insist that Brooks (the website author) stop trying to debate the logical contradictions he finds in the bible, and instead devote his energy to studying Greek or Latin versions of the bible to uncover the "true meanings".

Just an aside here - but if apologists need to spend so much time going back to older biblical sources (and not of course, original sources, which don't exist), just what kind of job did the biblical translators do? And if these amateur apologists are so much better at transcribing the older sources, why aren't they writing newer and more correct versions of the bible?

Black Holing

Black 'holing" refers to the endless void of a black hole in space, and it occurs in a debate when an opponent attempts to stall all discourse by continually demanding that you justify each and every future attempt to justify your position. For example, your opponent replies to the claim "psychology states that X is true" by demanding that you define "psychology". When you reply, he then demands that you define the terms used to define 'psychology', and so on, ad infinitum.

We can rightly hold that our opponent is black holing us when our level of justification reaches claims that even our opponent holds to... For example, if the person defined psychology as "the study of human behavior, thought and emotion" and his opponent stated "define thought" he would be black-holing his opponent, if he already agreed as to what the meaning of the word 'thought" entailed.

Strawman Fallacy

In the straw man fallacy, an arguer oversimplifies, or purposely distorts an opponent's argument (sets up the straw man), in order that he may attack it more easily (knock it down), and then claims that the opponent's position has been refuted.

The opposite of the Straw Man fallacy is the IRON MAN FALLACY, when an arguer purposely (and deceptively) makes his argument out to be much stronger than he himself knows it to be.

Additional point: An intriguing side note is that an opponent using the straw man fallacy is tipping
you off that he is actually afraid to openly debate your real position, preferring instead to attack
a much weaker version of your position. The same is true when he commits the iron man fallacy - he 
is tacitly conceding that his real position is weak.

Preponderance of Garbage Defense

Any argument that offers up numerous arguments or bits of evidence, that if taken one by one, or case by case, would be easily refuted is defense through a preponderance of garbage. The feeling is that the sheer number of arguments proves the case even if each single bit of evidence itself is weak. Sometimes the "coincidence" of the sheer number of cases itself is held to be proof so this is also referred to as a CONSENSUS OF INDEPENDENTLY ARRIVED AT CONCLUSIONS.

A good example would be evidence for UFOs. No UFO case has ever satisfactorily shown evidence of UFOs being of alien visitation. However, the consensus is that the overwhelming pile of weak evidence illustrates that they do exist, since what else would best describe this consistent phenomena?

The truth of course that this defense is specious. The sheer number of cases itself does nothing to verify any phenomena, just as the sheer weight or number of pages in one book over another does not indicate the initial book's superiority.

I was a member of the U.S. Air Force Scientific Advisory Board committee that investigated the Air Force's UFO study - called "Project Blue Book"... They had state-of-the-art technology in file retrieval. You asked about a given UFO incident and, somewhat like sweaters and suits at the dry cleaners, impressive reams of files made their way past you, until the engine stopped when the file you wanted arrived before you. But what was in those files wasn't worth much. - Carl Sagan, Demon Haunted World, pg 82.- On how impressive amounts of useless evidence can gain the appearance of credible information.

What to look for: If in any important debate, your opponent insists on numerating countless facts, 
yet never bothers to delve into any one fact deeply, you may be dealing with a garbage dealer - one 
who is hoping that sheer weight of citations will intimidate you. A good example would be amateur 
theologians who point to hundreds of proven biblical "prophecies" without stopping to examine the 
fact that some of them really weren't prophecies in the first place, and the rest cannot be shown to
have actually prophesied anything. In fact, its quite possible that these debators not even aware 
that the number quoted is sheer nonsense. They've just been won over by the "number." Other examples
are more insidious: people such as creationist Kent Hovind, who's "debating style" consists solely 
of systematically spewing out refuted idea after refuted idea, but with such speed that the 
presentation gives the illusion to some that, "well, there must be something in all of that..." 

Intellectual Dishonesty

This the yet another fallacy that talk show conservatives and theists toss around without knowing what it means. "Intellectual dishonesty' is a form of plagiarism, which is defined as the use of ideas and phrases in the writings of others as one’s own without crediting the original author.

In laymen's parlance, intellectual dishonesty is often defined as the presentation of an argument in support or defense of something that one does not actually support or believe in.

Suppressed Evidence

Closely related to intellectual dishonesty, suppressed evidence is offering only the positive (or negative) attributes of an argument, depending on the needs of the arguer. Important factors relevant to the conclusion are avoided because they present problems for the arguer. This could possibly be committed out of ignorance, but is much more likely done by unscrupulous arguers who seek to take advantage of an opponent's naiveté. You should buy this used car, because it has new tires, a rebuilt engine, and has no rust. (It also has a bad clutch, an oil leak...) In cases where one suspects it is an honest mistake, the fallacy of suppressed memory is more gently referred to as SELECTIVE MEMORY.

Disadvantageous Comparison Error

The disadvantageous comparison error occurs whenever someone accidentally, or purposely seeks to prove a point by comparing the most favorable characteristics of a phenomena to the least favorable characteristics of a competing phenomena, while ignoring the negatives of the first and the positives of the latter. This allows for a distorted view that takes the debaters away from the truth.

The most commonly seen version of this error is known as "the historical disadvantageous comparison error" and it typically occurs out of nostalgia - i.e. the cognitive phenomena that tends to romantize our past because of our youthful inability to recognize the true complexity of our childhood. Example:

Debator 1: Clearly the 1950s were a more idealic times... look at how peaceful our schools were. Debator 2: Oh really? Why not ask a black person how they feel about that. You know, those 'other' students who were trying to get in the schools, but kept being knocked over by firehoses?

Postdiction

This fallacy occurs when one creates a "prediction" after the fact. This is typically done through the use of a ambiguously worded statement that is retro-fitted to be a "prediction". Next, the facts pertaining to the supposedly predicted event are called upon. Those that can be made to fit the "prediction" are used, and those that do not fit are discarded. The process is subject to numerous biases, such as 'hindsight bias" which makes events appear more "predictable" than they actually are.

Predictions are only of value if they are 1) falsifiable and 2) capable of actually predicting the event!

Insertionism

This fallacy, or more correctly, deceitful debate tactic, occurs when there is an unwarranted and unsubstantiated insertion of words or new meanings into a statement or argument. In the Christian apologetic work, An Encyclopedia of Biblical Difficulties Gleason Archer argues against the existence of biblical contradictions. In one case, he argues against these contradictions:

John 6:46 "Not that any man hath seen the Father, save he which is of God, he hath seen the Father."

1 John 4:12 "No man hath seen God at any time. If we love one another, God dwelleth in us, and his love is perfected in us."

Versus

Gen. 32:30 "And Jacob called the name of the place Peniel: for I have seen God face to face, and my life is preserved."

Exod. 33:11 "And the LORD spake unto Moses face to face, as a man speaketh unto his friend."

Well, that seems a clear contradiction, right? I mean the last quote even stresses that god appeared 'as a man speaks to his friend.'

Well, nothing is so clear that an apologist cannot muddy it up. In his argument, Archer claims that "God showed His face through an angel (as at the interview with Moses at the burning bush ( Ex. 3:2-6), or else through his glory cloud,..."

Yet, the Bible clearly states that Moses (Ex. 33:11) and Jacob (Gen.32:30) saw God face to face, not "through an angel" or "through His glory cloud." Archer is guilty of insertionism--the unwarranted and unsubstantiated insertion of words into a Biblical verse to escape contradictions or a mistake.

Remember this: In an argument, the evidence is sacrosanct. We can't ever play around with the evidence itself. We can use evidence, cite it, compile it in statistics, but once you go rewriting the evidence itself to suit your needs, you've tainted the entire process. Once you start adding things to the evidence itself, you've basically broken the basic rule of argument - you're being dishonest. (***) You're entitled to your own opinion but not your own facts. That Archer rewrites god in order to settle a "biblical difficulty" makes this an especially galling and egregious violation of this fallacy.

By the way, even the title of the book: An Encyclopedia of Biblical Difficulties commits a fallacy. The use of the word "difficulties" is unwarranted, because this debate is about biblical contradictions, not "difficulties." So, Archer commits the fallacy of euphimism.

But then again, what other recourse does a christian have in debate anyway?

Stacking the Deck

From the book "Attacking Faulty Reasoning", 5th Ed. by T. Edward. Stacking the deck is a form of selective attention, where one studiously ignores counter evidence to one's position. Damer writes: A method of thinking that allows blind adherence to claims or to assumptions from which such claims may be inferred without proper attention to counterevidence obstructs the discovery of truth. Such thinking also violates the principle of fallibility, which says that every nondefinitional claim has the inherent possibility of being false.

Misuse of Statistics

The suspect debate tactic of 'misusing statistics' is a complicated subject, requiring an examination of the skills related to the scientific method. Seeing as it is a complex subject, it is clear that many debaters misuse statistics out of ignorance (although a debater is always responsible for accidents due to his ignorance).

Misusing statistics out of ignorance

My favorite example would be a website I found once, which purported to prove that rock stars died, on average, much earlier than other people. He then claimed that this proved that god was punishing rock stars for being evil

On the surface, the argument looked good. It certainly would convince a fundy.

However, a quick perusal of the flaws in this research will help guide us through the various modes in which ignorance of science leads to misuse of statistics.

1) First, without realizing it, this fellow is making a disadvantageous comparison. (See above.) Rock music has only been around since the mid 1950s, whereas people have been living for thousands of years. So to compare the life spans of people performing an art form for only the last 60 years to all other people is unfair.

2) Next, we should pause and consider that the rock stars on his list are all DEAD. So, this means that only dead rocks stars are included on the list. This means that, of course, all rock stars who are still alive, and in their 60's and 70's are not included on the list!

3) Next, we have a definitional problem here. Just what is a rock star? The answer seems to be: anyone even remotely connected to rock and roll who has DIED.

4) Next, what sorts of death are included? It appears all deaths, even the possibility of deaths without any 'evil connotation are included. (death by natural causes, death by illness.)

In short, these stats are nonsense. They are built up through ignorance of statistical methodology. Recall this brief point in relation to statistical comparisons: We must always consider all the elements that need to be compared.

In the above example, this person included only 3 of the 4 typical phenomena that must be examined.

   1 elements that support my view
   2 elements that support my opponents view
   3 elements that debunk my view (and don't support his)
   4 elements that debunk my opponents view (and don't support mine) 

Most bad statisticians leave out number 2 and especially 3. In this case, this fellow left out rock stars who are still alive. If he were to include their advanced ages, the 'discrepancy' between the lives of rock stars and ordinary people would disappear.

There are three kinds of lies: lies, damned lies, and statistics.

Benjamin Disraeli (1804 - 1881)

Of course, it is also possible to purposely distort information through statistics. The most common example would be using purposely misleading charts. In making a chart it is necessary to start with a true zero point, if possible. if we do not, we can create a chart that appears to have a great difference between two phenomena when no such difference exists. Here is a nice example. In this chart, it would appear that candidate A has a great lead over candidate b. However, when we make an honest chart, and begin at a true zero point, look what happens: Then, when we replace the 'error bars' which every honest and scientific chart must have: We see that not only is there no large difference, there isn't even a significant difference In fact, statistically we can say that the two candidates have statistically equal support

Insertionism and misuse of statistics are basically one step above the last, and most dishonest of all suspect debate tactics: Lying.

Those interested in testing their knowledge of informal fallacies should try this page:

http://www.humboldt.edu/~act/HTML/tests.html

There are four tests covering informal fallacies.

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References

• Copi, I. M, Cohen, C., (2001), "Introduction to Logic", 11th Edition.
• Hurely, P. J. (2000) A Concise Introduction to Logic - 7th Edition

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