What does fallacy mean definition

A reasoner who is supposed to address an issue but instead goes off on a tangent is properly accused of using the Fallacy of Avoiding the Issue. Also called missing the point, straying off the subject, digressing, and not sticking to the issue. The Fallacy of Avoiding the Question is a type of Fallacy of Avoiding the Issue that occurs when the issue is how to answer some question.

See Genetic Fallacy. It is time you bought one, too. Like its close cousin, the Fallacy of Appeal to the People, the Bandwagon Fallacy needs to be carefully distinguished from properly defending a claim by pointing out that many people have studied the claim and have come to a reasoned conclusion that it is correct.

What most everyone believes is likely to be true, all things considered, and if one defends a claim on those grounds, this is not a fallacious inference. A form of circular reasoning in which a conclusion is derived from premises that presuppose the conclusion.

Normally, the point of good reasoning is to start out at one place and end up somewhere new, namely having reached the goal of increasing the degree of reasonable belief in the conclusion.

The point is to make progress, but in cases of begging the question there is no progress. It is still an open question among logicians as to why some deductively valid arguments are considered to be begging the question and others are not.

Other logicians suggest that we need to look instead to surrounding circumstances, not to the psychology of the reasoner, in order to assess the quality of the argument. For example, we need to look to the reasons that the reasoner used to accept the premises. Was the premise justified on the basis of accepting the conclusion? A third group of logicians say that, in deciding whether the fallacy is present, more evidence is needed.

We must determine whether any premise that is key to deducing the conclusion is adopted rather blindly or instead is a reasonable assumption made by someone accepting their burden of proof.

The premise would here be termed reasonable if the arguer could defend it independently of accepting the conclusion that is at issue. Arguing for a conclusion that is not relevant to the current issue. Also called Irrelevant Conclusion. It is a form of the Red Herring Fallacy. Generalizing from a biased sample. Using an unrepresentative sample and overestimating the strength of an argument based on that sample. See Unrepresentative Sample. The Black-or-White fallacy or Black-White fallacy is a False Dilemma Fallacy that limits you unfairly to only two choices, as if you were made to choose between black and white.

You are placing me between a rock and a hard place. A critical thinker should attack the real man, not a caricatuzation of the man. Ditto for women, of course. This is another name for the Fallacy of Avoiding the Question. The Fallacy of Circular Reasoning occurs when the reasoner begins with what he or she is trying to end up with. The most well known examples of circular reasoning are cases of the Fallacy of Begging the Question.

Here the circle is as short as possible. However, if the circle is very much larger, including a wide variety of claims and a large set of related concepts, then the circular reasoning can be informative and so is not considered to be fallacious.

For example, a dictionary contains a large circle of definitions that use words which are defined in terms of other words that are also defined in the dictionary. Because the dictionary is so informative, it is not considered as a whole to be fallacious. However, a small circle of definitions is considered to be fallacious. In properly-constructed recursive definitions, defining a term by using that same term is not fallacious. Recursion step: If p is a stack of coins, then adding a coin on top of p produces a stack of coins.

For a deeper discussion of circular reasoning see Infinitism in Epistemology. See Appeal to the People and Traditional Wisdom. This fallacy occurs during causal reasoning when a causal connection between two kinds of events is claimed when evidence is available indicating that both are the effect of a common cause. Noting that the auto accident rate rises and falls with the rate of use of windshield wipers, one concludes that the use of wipers is somehow causing auto accidents.

You use this fallacy when you frame a question so that some controversial presupposition is made by the wording of the question. The question unfairly presumes the controversial claim that the policy really is a waste of money. It is the converse of the Division Fallacy.

Each human cell is very lightweight, so a human being composed of cells is also very lightweight. This is the most common kind of Fallacy of Selective Attention , and it is the foundation of many conspiracy theories. She loves me, and there are so many ways that she has shown it. When I called her and she said never to call her again, she first asked me how I was doing and whether my life had changed. When I suggested that we should have children in order to keep our marriage together, she laughed.

Confirmation bias often reveals itself in the fact that people of opposing views can each find support for those views in the same piece of evidence. Mistakenly supposing that event E is less likely than the conjunction of events E and F. Here is an example from the psychologists Daniel Kahneman and Amos Tversky. Suppose you know that Linda is 31 years old, single, outspoken, and very bright.

She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice. Then you are asked to choose which is more likely: A Linda is a bank teller or B Linda is a bank teller and active in the feminist movement. If you choose B you commit the Conjunction Fallacy. Explaining a crime should not be confused with excusing the crime, but it too often is.

Speaker: The German atrocities committed against the French and Belgians during World War I were in part due to the anger of German soldiers who learned that French and Belgian soldiers were ambushing German soldiers, shooting them in the back, or even poisoning, blinding and castrating them. Fallacy of Argumentum Consensus Gentium argument from the consensus of the nations. See Traditional Wisdom. If we reason by paying too much attention to exceptions to the rule, and generalize on the exceptions, our reasoning contains this fallacy.

This fallacy is the converse of the Accident Fallacy. It is a kind of Hasty Generalization , by generalizing too quickly from a peculiar case.

So, I think that turtles bought from pet stores do not live longer than tarantulas. Rather than seeing this for what it is, namely an exception, the reasoner places too much trust in this exception and generalizes on it to produce the faulty generalization that turtles bought from pet stores do not live longer than tarantulas. Loud musicians live near our low-yield cornfields.

So, loud musicians must be causing the low yield. Curve fitting is the process of constructing a curve that has the best fit to a series of data points. The curve is a graph of some mathematical function.

The function or functional relationship might be between variable x and variable y, where x is the time of day and y is the temperature of the ocean. When you collect data about some relationship, you inevitably collect information that is affected by noise or statistical fluctuation.

If you create a function between x and y that is too sensitive to your data, you will be overemphasizing the noise and producing a function that has less predictive value than need be.

Your original error of too closely fitting the data-points is called the Fallacy of Curve Fitting or the Fallacy of Overfitting. You want to know the temperature of the ocean today, so you measure it at A. Then you measure the ocean at A. However, the temperature is probably constant, and the problem is that your prediction is too sensitive to your data, so your curve fits the data points too closely.

The Definist Fallacy occurs when someone unfairly defines a term so that a controversial position is made easier to defend. Same as the Persuasive Definition. You are using this fallacy if you deny the antecedent of a conditional and then suppose that doing so is a sufficient reason for denying the consequent. This formal fallacy is often mistaken for Modus Tollens, a valid form of argument using the conditional. This fallacy is committed when a person makes a claim that knowingly or unknowingly disregards well known science, science that weighs against the claim.

They should know better. This fallacy is a form of the Fallacy of Suppressed Evidence. John claims in his grant application that he will be studying the causal effectiveness of bone color on the ability of leg bones to support indigenous New Zealand mammals. He disregards well known scientific knowledge that color is not what causes any bones to work the way they do by saying that this knowledge has never been tested in New Zealand.

It is the converse of the Composition Fallacy. There are many situations in which you should judge two things or people by the same standard.

If in one of those situations you use different standards for the two, your reasoning contains the Fallacy of Using a Double Standard. I know we will hire any man who gets over a 70 percent on the screening test for hiring Post Office employees, but women should have to get an 80 to be hired because they often have to take care of their children.

This example is a fallacy if it can be presumed that men and women should have to meet the same standard for becoming a Post Office employee. Equivocation is the illegitimate switching of the meaning of a term that occurs twice during the reasoning; it is the use of one word taken in two ways. The fallacy is a kind of Fallacy of Ambiguity. Equivocation can sometimes be very difficult to detect, as in this argument from Walter Burleigh:.

If I call you a swine, then I call you an animal. The Etymological Fallacy occurs whenever someone falsely assumes that the meaning of a word can be discovered from its etymology or origins.

Since a hurricane winds around its own eye, it is a vise. In proposing this fallacious argument, Aristotle believed the common end is the supreme good, so he had a rather optimistic outlook on the direction of history. When we overstate or overemphasize a point that is a crucial step in a piece of reasoning, then we are guilty of the Fallacy of Exaggeration.

This is a kind of error called Lack of Proportion. Do you want to elect as secretary of this club someone who is a known liar prone to assault? Doing so would be a disgrace to our Collie Club. When we exaggerate in order to make a joke, though, we do not use the fallacy because we do not intend to be taken literally. The problem is that the items in the analogy are too dissimilar. When reasoning by analogy, the fallacy occurs when the analogy is irrelevant or very weak or when there is a more relevant disanalogy.

See also Faulty Comparison. The book Investing for Dummies really helped me understand my finances better. The book Chess for Dummies was written by the same author, was published by the same press, and costs about the same amount. So, this chess book would probably help me understand my finances, too. A specific form of the False Equivalence Fallacy that occurs in the context of news reporting, in which the reporter misleads the audience by suggesting the evidence on two sides of an issue is equally balanced, when the reporter knows that one of the two sides is an extreme outlier.

Councilwoman Miranda Gonzales spoke in favor of dismantling the old mansion saying its land is needed for an expansion of the water treatment facility. Both sides seemed quite fervent in promoting their position. Improperly concluding that one thing is a cause of another. My psychic adviser says to expect bad things when Mars is aligned with Jupiter. Tomorrow Mars will be aligned with Jupiter. So, if a dog were to bite me tomorrow, it would be because of the alignment of Mars with Jupiter.

A reasoner who unfairly presents too few choices and then implies that a choice must be made among this short menu of choices is using the False Dilemma Fallacy, as does the person who accepts this faulty reasoning.

The pollster is committing the fallacy by limiting you to only those choices. Think of the unpleasant choices as being the horns of a bull that is charging toward you. A form of the Fallacy of Suppressed Evidence. The article suppresses the evidence that geologists who are the relevant experts on this issue have reached a consensus that the Earth is billions of years old.

This is the fallacy of offering a bizarre far-fetched hypothesis as the correct explanation without first ruling out more mundane explanations. Look at that mutilated cow in the field, and see that flattened grass. Aliens must have landed in a flying saucer and savaged the cow to learn more about the beings on our planet. If you try to make a point about something by comparison, and if you do so by comparing it with the wrong thing, then your reasoning uses the Fallacy of Faulty Comparison or the Fallacy of Q uestionable Analogy.

We gave half the members of the hiking club Durell hiking boots and the other half good-quality tennis shoes. After three months of hiking, you can see for yourself that Durell lasted longer. You, too, should use Durell when you need hiking boots. A fallacy produced by some error in the process of generalizing. See Hasty Generalization or Unrepresentative Generalization for examples. An irrelevant appeal to the motives of the arguer, and supposing that this revelation of their motives will thereby undermine their reasoning.

A kind of Ad Hominem Fallacy. Formal fallacies are all the cases or kinds of reasoning that fail to be deductively valid. Formal fallacies are also called Logical Fallacies or Invalidities.

That is, they are deductively invalid arguments that are too often believed to be deductively valid. This might at first seem to be a good argument, but actually it is fallacious because it has the same logical form as the following more obviously invalid argument:.

Nearly all the infinity of types of invalid inferences have no specific fallacy names. The Fallacy of Four Terms quaternio terminorum occurs when four rather than three categorical terms are used in a standard-form syllogism. Without an equivocation, the four term fallacy is trivially invalid. This fallacy occurs when the gambler falsely assumes that the history of outcomes will affect future outcomes.

I know this is a fair coin, but it has come up heads five times in a row now, so tails is due on the next toss. The fallacious move was to conclude that the probability of the next toss coming up tails must be more than a half. A critic uses the Genetic Fallacy if the critic attempts to discredit or support a claim or an argument because of its origin genesis when such an appeal to origins is irrelevant.

Fortune cookies are not reliable sources of information about what gift to buy, but the reasons the person is willing to give are likely to be quite relevant and should be listened to.

The speaker is committing the Genetic Fallacy by paying too much attention to the genesis of the idea rather than to the reasons offered for it. Because appeals to origins are sometimes relevant and sometimes irrelevant and sometimes on the borderline, in those latter cases it can be very difficult to decide whether the fallacy has been committed.

Guilt by Association is a version of the Ad Hominem Fallacy in which a person is said to be guilty of error because of the group he or she associates with. Secretary of State Dean Acheson is too soft on communism, as you can see by his inviting so many fuzzy-headed liberals to his White House cocktail parties.

This sort of reasoning is an example of McCarthyism, the technique of smearing liberal Democrats that was so effectively used by the late Senator Joe McCarthy in the early s. A Hasty Generalization is a Fallacy of J umping to Conclusions in which the conclusion is a generalization. See also Biased Statistics. So, all people I will meet in Nicaragua will be nice to me.

In any Hasty Generalization the key error is to overestimate the strength of an argument that is based on too small a sample for the implied confidence level or error margin. You are hedging if you refine your claim simply to avoid counterevidence and then act as if your revised claim is the same as the original. You do not use the fallacy if you explicitly accept the counterevidence, admit that your original claim is incorrect, and then revise it so that it avoids that counterevidence.

This is an error in reasoning due to confusing the knowing of a thing with the knowing of it under all its various names or descriptions. You claim to know Socrates, but you must be lying. The Fallacy of Hyperbolic Discounting occurs when someone too heavily weighs the importance of a present reward over a significantly greater reward in the near future, but only slightly differs in their valuations of those two rewards if they are to be received in the far future.

The error of inappropriately treating an abstract term as if it were a concrete one. In a poem, it is appropriate and very common to reify nature, hope, fear, forgetfulness, and so forth, that is, to treat them as if they were objects or beings with intentions. In any scientific claim, it is inappropriate. This occurs when an arguer presupposes some aspect of their own ideology that they are unable to defend.

Senator, if you pass that bill to relax restrictions on gun ownership and allow people to carry concealed handguns, then you are putting your own voters at risk. The arguer is presupposing a liberal ideology which implies that permitting private citizens to carry concealed handguns increases crime and decreases safety. If the arguer is unable to defend this presumption, then the fallacy is committed regardless of whether the presumption is defensible.

See Irrelevant Conclusion. Also called missing the point. The fallacy occurs when we accept an inconsistent set of claims, that is, when we accept a claim that logically conflicts with other claims we hold. Most professional basketball players are tall, so most tall people are professional basketball players. A pollster interviews ten London voters in one building about which candidate for mayor they support, and upon finding that Churchill receives support from six of the ten, declares that Churchill has the majority support of London voters.

This fallacy is a form of the Fallacy of Jumping to Conclusions. The mistake of treating different descriptions or names of the same object as equivalent even in those contexts in which the differences between them matter. In these contexts, replacing a description with another that refers to the same object is not valid and may turn a true sentence into a false one. Michelle said she wants to meet her new neighbor Stalnaker tonight.

Michelle said no such thing. The faulty reasoner illegitimately assumed that what is true of a person under one description will remain true when said of that person under a second description even in this context of indirect quotation. Extensional contexts are those in which it is legitimate to substitute equals for equals with no worry.

But any context in which this substitution of co-referring terms is illegitimate is called an intensional context. Intensional contexts are produced by quotation, modality, and intentionality propositional attitudes.

An invalid inference. An argument can be assessed by deductive standards to see if the conclusion would have to be true if the premises were to be true. If the argument cannot meet this standard, it is invalid. An argument is invalid only if it is not an instance of any valid argument form. The Fallacy of Invalid Reasoning is a formal fallacy. Therefore, there are no clouds in the sky. This invalid argument is an instance of Denying the Antecedent.

Any invalid inference that is also inductively very weak is a Non Sequitur. The testimony of Thompson may be relevant to a request for leniency, but it is irrelevant to any claim about the defendant not being near the murder scene.

This fallacy is a kind of Non Sequitur in which the premises are wholly irrelevant to drawing the conclusion. The Is-Ought Fallacy occurs when a conclusion expressing what ought to be so is inferred from premises expressing only what is so, in which it is supposed that no implicit or explicit ought-premises are need. There is controversy in the philosophical literature regarding whether this type of inference is always fallacious.

This argument would not use the fallacy if there were an implicit premise indicating that he is a person and that persons should not torture other beings. Hold on. And, if you stop to think about it, there may be other factors you should consider before making the purchase, such as size, appearance, and gas usage. The Fallacy of Lack of Proportion occurs either by exaggerating or downplaying or simply not noticing a point that is a crucial step in a piece of reasoning.

You exaggerate when you make a mountain out of a molehill. You downplay when you suppress relevant evidence. The Genetic Fallacy blows the genesis of an idea out of proportion. Did you hear about that tourist getting mugged in Russia last week? And then there was the awful train wreck last year just outside Moscow where three of the twenty-five persons killed were tourists.

The speaker is blowing these isolated incidents out of proportion. Millions of tourists visit Russia with no problems. Another example occurs when the speaker simply lacks the information needed to give a factor its proper proportion or weight:.

The speaker does not realize all experts agree that electric and magnetic fields caused by home wiring are harmless. However, touching the metal within those wires is very dangerous. Being vague is not being hopelessly vague.

Dwayne can never grow bald. Loaded language is emotive terminology that expresses value judgments. When used in what appears to be an objective description, the terminology unfortunately can cause the listener to adopt those values when in fact no good reason has been given for doing so. Also called Prejudicial Language. Asking a question in a way that unfairly presumes the answer.

Obscuring the issue by using overly-technical logic tools, especially the techniques of formal symbolic logic, that focus attention on trivial details. A form of Smokescreen and Quibbling. A fallacy of reasoning that depends on intentionally saying something that is known to be false.

When the Fallacy of Jumping to Conclusions is due to a special emphasis on an anecdote or other piece of evidence, then the Fallacy of Misleading Vividness has occurred. Yes, I read the side of the cigarette pack about smoking being harmful to your health. But let me tell you about my uncle. He even won a ski race at Lake Tahoe in his age group last year. You should have seen him zip down the mountain. He smoked a cigarette during the award ceremony, and he had a broad smile on his face.

In fact, what this map really showed was the fallacy of aggregates — and how statistics can mask real cultural shifts. Every time the thermometer drops, another anti-science politician mocks climate change as a fallacy.

But here he falls victim to a prevalent fallacy : the confusion of means with ends. Wasn't I committing the Lump of Labor Fallacy , assuming that the jobs that were disappearing meant permanent unemployment? An underlying fallacy of Socialism is the concept that poverty or at least extreme poverty, can be banished from the world.

I remark only the fallacy of reasoning from a wide average, to cases necessarily differing greatly from any average.

A fallacy of misobservation may be either negative or positive; either Non-observation or Mal-observation. By the last clause I presume is meant, that it is not susceptible of any other proof; for otherwise, there would be no fallacy.

This is a fallacy of overlooking; or of non-observation, within the intent of our classification. A sentence that fails to be grammatical is not correctly structured, and so fails to be a sentence at all technically speaking.

Likewise, an argument that fails to be valid is not correctly structured for its type , and so fails to be an argument at all technically speaking. For Deductive arguments, the modern concept of validity tells us whether an utterance is a well-formed Deductive argument, not whether we should be persuaded by it.

A Deductive argument is well-formed when it is impossible for the premisses to be true while the conclusion is false. A doctrine of well-formedness can also be developed for Inductive and Retroductive arguments. My paper, "Deductively valid, inductively valid, and retroductively valid syllogisms," Transactions of the Charles S. Peirce Society , vol. In the extended sense, it would be true to say that all arguments, both fallacious and non-fallacious, are valid for their type , simply because any utterance that failed to be valid would fail to qualify as an argument of the specified type.

Having dispensed with the concept of validity as a criterion of good reasoning, it remains to consider what criteria should be used instead. In the above definition I have simply used the non-committal phrase "good reasoning," in the hope that it will stand in for whatever criteria we ultimately decide to adopt. Good reasoning is reasoning that tends, in the long run, to produce true conclusions. In the end, the measure of good reasoning is that it tends to move us closer to the truth.

However, a fallacy is not just any type of reasoning that might lead to a false conclusion. Even perfectly legitimate patterns of reasoning might lead to a false conclusion from time to time, simply because uncertainty is a necessary feature of the logical landscape. Whenever we generalize from a sample Inductive reasoning we run the risk that our sample--however carefully we draw it--might not accurately represent the population from which it was drawn.

Induction is notoriously unreliable, and Retroduction is worse! Even a Deduction guarantees a true conclusion only when its premisses are true.

However, for all their faults, Deduction, Induction and Retroduction, used with appropriate care, can lead us to the truth in the long run.

Fallacies occur when something undermines or subverts this general tendency. An argument is generally considered to be fallacious not merely because it commits an error, but because there is some risk that someone might be taken in by the error. A fallacy is not just bad reasoning, but bad reasoning that appears to be good.

This is an idea that has its origin with Aristotle. In the Sophistical Refutations Aristotle spends quite a bit of time explaining that sophistical reasoning mimics good reasoning, i. Johnson argues that we should drop this aspect of the definition on the grounds that it renders the concept of fallacy wholly subjective.

An argument is fallacious only if it appears to someone to be good reasoning. Yet, appearance is subjective, and we surely want to be able to identify fallacies by some objective criteria rather than by subjective reactions. I find the idea that fallacies are a counterfeit of legitimate reasoning to be highly revealing, and I am reluctant to give the notion up, even for Johnson, whose views are otherwise similar to my own. Fortunately, I don't believe it is necessary to do so in order to make our criteria objective.

Johnson does not see a problem in identifying arguments that fail to be good reasoning; he even offers some specific criteria distinguishing bad reasoning from good reasoning.