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Ad Hominem Abusive Fallacy Definition Critical Thinking


A fallacy is a kind of error in reasoning. The list of fallacies below contains 224 names of the most common fallacies, and it provides brief explanations and examples of each of them. Fallacies should not be persuasive, but they often are. Fallacies may be created unintentionally, or they may be created intentionally in order to deceive other people. The vast majority of the commonly identified fallacies involve arguments, although some involve explanations, or definitions, or other products of reasoning. Sometimes the term "fallacy" is used even more broadly to indicate any false belief or cause of a false belief. The list below includes some fallacies of these sorts, but most are fallacies that involve kinds of errors made while arguing informally in natural language.

An informal fallacy is fallacious because of both its form and its content. The formal fallacies are fallacious only because of their logical form. For example, the Slippery Slope Fallacy has the following form: Step 1 often leads to step 2. Step 2 often leads to step 3. Step 3 often leads to ... until we reach an obviously unacceptable step, so step 1 is not acceptable. That form occurs in both good arguments and fallacious arguments. The quality of an argument of this form depends crucially on the probabilities. Notice that the probabilities involve the argument's content, not merely its form.

The discussion below that precedes the long alphabetical list of fallacies begins with an account of the ways in which the term "fallacy" is imprecise. Attention then turns to the number of competing and overlapping ways to classify fallacies of argumentation. For pedagogical purposes, researchers in the field of fallacies disagree about the following topics: which name of a fallacy is more helpful to students' understanding; whether some fallacies should be de-emphasized in favor of others; and which is the best taxonomy of the fallacies. Researchers in the field are also deeply divided about how to define the term "fallacy" itself, how to define certain fallacies, and whether any theory of fallacies at all should be pursued if that theory's goal is to provide necessary and sufficient conditions for distinguishing between fallacious and non-fallacious reasoning generally. Analogously, there is doubt in the field of ethics regarding whether researchers should pursue the goal of providing necessary and sufficient conditions for distinguishing moral actions from immoral ones.

Table of Contents

  1. Introduction
  2. Taxonomy of Fallacies
  3. Pedagogy
  4. What is a fallacy?
  5. Other Controversies
  6. Partial List of Fallacies
  7. References and Further Reading

1. Introduction

The first known systematic study of fallacies was due to Aristotle in his De Sophisticis Elenchis (Sophistical Refutations), an appendix to the Topics. He listed thirteen types. After the Dark Ages, fallacies were again studied systematically in Medieval Europe. This is why so many fallacies have Latin names. The third major period of study of the fallacies began in the later twentieth century due to renewed interest from the disciplines of philosophy, logic, communication studies, rhetoric, psychology, and artificial intelligence.

The more frequent the error within public discussion and debate the more likely it is to have a name. That is one reason why there is no specific name for the fallacy of subtracting five from thirteen and concluding that the answer is seven, though the error is common.

The term "fallacy" is not a precise term. One reason is that it is ambiguous. It can refer either to (a) a kind of error in an argument, (b) a kind of error in reasoning (including arguments, definitions, explanations, and so forth), (c) a false belief, or (d) the cause of any of the previous errors including what are normally referred to as "rhetorical techniques." Philosophers who are researchers in fallacy theory prefer to emphasize (a), but their lead is often not followed in textbooks and public discussion.

Regarding (d), ill health, being a bigot, being hungry, being stupid, and being hypercritical of our enemies are all sources of error in reasoning, so they could qualify as fallacies of kind (d), but they are not included in the list below. On the other hand, wishful thinking, stereotyping, being superstitious, rationalizing, and having a poor sense of proportion are sources of error and are included in the list below, though they wouldn't be included in a list devoted only to faulty arguments. Thus there is a certain arbitrariness to what appears in lists such as this. What have been left off the list below are the following persuasive techniques commonly used to influence others and to cause errors in reasoning: apple polishing, using propaganda techniques, ridiculing, being sarcastic, selecting terms with strong negative or positive associations, using innuendo, and weasling. All of the techniques are worth knowing about if one wants to reason well.

In describing the fallacies below, the custom is followed of not distinguishing between a reasoner using a fallacy and the reasoning itself containing the fallacy.

Real arguments are often embedded within a very long discussion. Richard Whately, one of the greatest of the 19th century researchers into informal logic, wisely said, "A very long discussion is one of the most effective veils of Fallacy; ...a Fallacy, which when stated barely...would not deceive a child, may deceive half the world if diluted in a quarto volume."

2. Taxonomy of Fallacies

There are a number of competing and overlapping ways to classify fallacies of argumentation. For example, they can be classified as either formal or informal. A formal fallacy can be detected by examining the logical form of the reasoning, whereas an informal fallacy depends upon the content of the reasoning and possibly the purpose of the reasoning. That is, informal fallacies are errors of reasoning that cannot easily be expressed in our system of formal logic (such as symbolic, deductive, predicate logic). The list below contains very few formal fallacies. Fallacious arguments also can be classified as deductive or inductive, depending upon whether the fallacious argument is most properly assessed by deductive standards or instead by inductive standards. Deductive standards demand deductive validity, but inductive standards require inductive strength such as making the conclusion more likely. Fallacies can be divided into categories according to the psychological factors that lead people to use them, and they can also be divided into categories according to the epistemological or logical factors that cause the error. In the latter division there are three categories: (1) the reasoning is invalid but is presented as if it were a valid argument, or else it is inductively much weaker than it is presented as being, (2) the argument has an unjustified premise, or (3) some relevant evidence has been ignored or suppressed. Regarding (2), a premise can be justified or warranted at a time even if we later learn that the premise was false, and it can be justified if we are reasoning about what would have happened even when we know it didn't happen.

Similar fallacies are often grouped together under a common name intended to bring out how the fallacies are similar. Here are three examples. Fallacies of relevance include fallacies that occur due to reliance on an irrelevant reason. In addition, Ad Hominem, Appeal to Pity, and Affirming the Consequent are some other fallacies of relevance. Accent, Amphiboly and Equivocation are examples of fallacies of ambiguity. The fallacies of illegitimate presumption include Begging the Question, False Dilemma, No True Scotsman, Complex Question and Suppressed Evidence. Notice how these categories don't fall neatly into just one of the categories (1), (2), and (3) above.

3. Pedagogy

It is commonly claimed that giving a fallacy a name and studying it will help the student identify the fallacy in the future and will steer them away from using the fallacy in their own reasoning. As Steven Pinker says in The Stuff of Thought (p. 129),

If a language provides a label for a complex concept, that could make it easier to think about the concept, because the mind can handle it as a single package when juggling a set of ideas, rather than having to keep each of its components in the air separately. It can also give a concept an additional label in long-term memory, making it more easily retrivable than ineffable concepts or those with more roundabout verbal descriptions.

For pedagogical purposes, researchers in the field of fallacies disagree about the following topics: which name of a fallacy is more helpful to students' understanding; whether some fallacies should be de-emphasized in favor of others; and which is the best taxonomy of the fallacies. Fallacy theory is criticized by some teachers of informal reasoning for its over-emphasis on poor reasoning rather than good reasoning. Do colleges teach the Calculus by emphasizing all the ways one can make mathematical mistakes? The critics want more emphasis on the forms of good arguments and on the implicit rules that govern proper discussion designed to resolve a difference of opinion. But there has been little systematic study of which emphasis is more successful.

4. What is a fallacy?

Researchers disagree about how to define the very term "fallacy." Focusing just on fallacies in sense (a) above, namely fallacies of argumentation, some researchers define a fallacy as an argument that is deductively invalid or that has very little inductive strength. Because examples of false dilemma, inconsistent premises, and begging the question are valid arguments in this sense, this definition misses some standard fallacies. Other researchers say a fallacy is a mistake in an argument that arises from something other than merely false premises. But the false dilemma fallacy is due to false premises. Still other researchers define a fallacy as an argument that is not good. Good arguments are then defined as those that are deductively valid or inductively strong, and that contain only true, well-established premises, but are not question-begging. A complaint with this definition is that its requirement of truth would improperly lead to calling too much scientific reasoning fallacious; every time a new scientific discovery caused scientists to label a previously well-established claim as false, all the scientists who used that claim as a premise would become fallacious reasoners. This consequence of the definition is acceptable to some researchers but not to others. Because informal reasoning regularly deals with hypothetical reasoning and with premises for which there is great disagreement about whether they are true or false, many researchers would relax the requirement that every premise must be true. One widely accepted definition defines a fallacious argument as one that either is deductively invalid or is inductively very weak or contains an unjustified premise or that ignores relevant evidence that is available and that should be known by the arguer. Finally, yet another theory of fallacy says a fallacy is a failure to provide adequate proof for a belief, the failure being disguised to make the proof look adequate.

Other researchers recommend characterizing a fallacy as a violation of the norms of good reasoning, the rules of critical discussion, dispute resolution, and adequate communication. The difficulty with this approach is that there is so much disagreement about how to characterize these norms.

In addition, all the above definitions are often augmented with some remark to the effect that the fallacies are likely to persuade many reasoners. It is notoriously difficult to be very precise about this vague and subjective notion of being likely to persuade, and some researchers in fallacy theory have therefore recommended dropping the notion in favor of "can be used to persuade."

Some researchers complain that all the above definitions of fallacy are too broad and do not distinguish between mere blunders and actual fallacies, the more serious errors.

Researchers in the field are deeply divided, not only about how to define the term "fallacy" and how to define some of the individual fallacies, but also about whether any general theory of fallacies at all should be pursued if that theory's goal is to provide necessary and sufficient conditions for distinguishing between fallacious and non-fallacious reasoning generally. Analogously, there is doubt in the field of ethics whether researchers should pursue the goal of providing necessary and sufficient conditions for distinguishing moral actions from immoral ones.

5. Other Controversies

How do we defend the claim that an item of reasoning should be labeled as a particular fallacy? A major goal in the field of informal logic is provide some criteria for each fallacy. Schwartz presents the challenge this way:

Fallacy labels have their use. But fallacy-label texts tend not to provide useful criteria for applying the labels. Take the so-called ad verecundiam fallacy, the fallacious appeal to authority. Just when is it committed? Some appeals to authority are fallacious; most are not. A fallacious one meets the following condition: The expertise of the putative authority, or the relevance of that expertise to the point at issue, are in question. But the hard work comes in judging and showing that this condition holds, and that is where the fallacy-label texts leave off. Or rather, when a text goes further, stating clear, precise, broadly applicable criteria for applying fallacy labels, it provides a critical instrument more fundamental than a taxonomy of fallacies and hence to that extent goes beyond the fallacy-label approach. The further it goes in this direction, the less it need to emphasize or event to use fallacy labels. (Schwartz, 232)

The controversy here is the extent to which it is better to teach students what Schwartz calls "the critical instrument" than to teach the fallacy-label approach. Is the fallacy-label approach better for some kinds of fallacies than others? If so, which others?

Another controversy involves the relationship between the fields of logic and rhetoric. In the field of rhetoric, the primary goal is to persuade the audience. The audience is not going to be persuaded by an otherwise good argument with true premises unless they believe those premises are true. Philosophers tend to de-emphasize this difference between rhetoric and informal logic, and they concentrate on arguments that should fail to convince the ideally rational reasoner rather than on arguments that are likely not to convince audiences who hold certain background beliefs. Given specific pedagogical goals, how pedagogically effective is this de-emphasis?

Advertising in magazines and on television is designed to achieve visual persuasion. And a hug or the fanning of fumes from freshly baked donuts out onto the sidewalk are occasionally used for visceral persuasion. There is some controversy among researchers in informal logic as to whether the reasoning involved in this nonverbal persuasion can always be assessed properly by the same standards that are used for verbal reasoning.

6. Partial List of Fallacies

Consulting the list below will give a general idea of the kind of error involved in passages to which the fallacy name is applied. However, simply applying the fallacy name to a passage cannot substitute for a detailed examination of the passage and its context or circumstances because there are many instances of reasoning to which a fallacy name might seem to apply, yet, on further examination, it is found that in these circumstances the reasoning is really not fallacious.

Abusive Ad Hominem

See Ad Hominem.


The Accent Fallacy is a fallacy of ambiguity due to the different ways a word or syllable is emphasized or accented. Also called Accentus, Misleading Accent, and Prosody.


A member of Congress is asked by a reporter if she is in favor of the President's new missile defense system, and she responds, "I'm in favor of a missile defense system that effectively defends America."

With an emphasis on the word "favor," her response is likely to be for the President's missile defense system. With an emphasis, instead, on the word "effectively," her remark is likely to be against the President's missile defense system. And by using neither emphasis, she can later claim that her response was on either side of the issue. For an example of the Fallacy of Accent involving the accent of a syllable within a single word, consider the word "invalid" in the sentence, "Did you mean the invalid one?" When we accent the first syllable, we are speaking of a sick person, but when we accent the second syllable, we are speaking of an argument failing to meet the deductive standard of being valid. By not supplying the accent, and not supplying additional information to help us disambiguate, then we are committing the Fallacy of Accent.


See the Fallacy of Accent.


We often arrive at a generalization but don't or can't list all the exceptions. When we then reason with the generalization as if it has no exceptions, our reasoning contains the Fallacy of Accident. This fallacy is sometimes called the "Fallacy of Sweeping Generalization."


People should keep their promises, right? I loaned Dwayne my knife, and he said he'd return it. Now he is refusing to give it back, but I need it right now to slash up my neighbors who disrespected me.

People should keep their promises, but there are exceptions to this generalization as in this case of the psychopath who wants Dwayne to keep his promise to return the knife.

Ad Baculum

See Scare Tactic and Appeal to Emotions (Fear).

Ad Consequentiam

See Appeal to Consequence.

Ad Crumenum

See Appeal to Money.

Ad Hoc Rescue

Psychologically, it is understandable that you would try to rescue a cherished belief from trouble. When faced with conflicting data, you are likely to mention how the conflict will disappear if some new assumption is taken into account. However, if there is no good reason to accept this saving assumption other than that it works to save your cherished belief, your rescue is an Ad Hoc Rescue.


Yolanda: If you take four of these tablets of vitamin C every day, you will never get a cold.

Juanita: I tried that last year for several months, and still got a cold.

Yolanda: Did you take the tablets every day?

Juanita: Yes.

Yolanda: Well, I'll bet you bought some bad tablets.

The burden of proof is definitely on Yolanda's shoulders to prove that Juanita's vitamin C tablets were probably "bad" -- that is, not really vitamin C. If Yolanda can't do so, her attempt to rescue her hypothesis (that vitamin C prevents colds) is simply a dogmatic refusal to face up to the possibility of being wrong.

Ad Hominem

Your reasoning contains this fallacy if you make an irrelevant attack on the arguer and suggest that this attack undermines the argument itself. "Ad Hominem" means "to the person" as in being "directed at the person."


What she says about Johannes Kepler's astronomy of the 1600s must be just so much garbage. Do you realize she's only fifteen years old?

This attack may undermine the young woman's credibility as a scientific authority, but it does not undermine her reasoning itself because her age is irrelevant to quality of her reasoning. That reasoning should stand or fall on the scientific evidence, not on the arguer's age or anything else about her personally.

The major difficulty with labeling a piece of reasoning an Ad Hominem Fallacy is deciding whether the personal attack is relevant or irrelevant. For example, attacks on a person for their immoral sexual conduct are irrelevant to the quality of their mathematical reasoning, but they are relevant to arguments promoting the person for a leadership position in a church or mosque.

If the fallacious reasoner points out irrelevant circumstances that the reasoner is in, such as the arguer's having a vested interest in people accepting the position, then the ad hominem fallacy may be called a Circumstantial Ad Hominem. If the fallacious attack points out some despicable trait of the arguer,  it may be called an Abusive Ad Hominem. An Ad hominem that attacks an arguer by attacking the arguer's associates is called the Fallacy of  Guilt by Association. If the fallacy focuses on a complaint about the origin of the arguer's views, then it is a kind of Genetic Fallacy. If the fallacy is due to claiming the person does not practice what is preached, it is the Tu Quoque Fallacy. Two Wrongs do not Make a Right is also a type of Ad Hominem fallacy.

Ad Hominem, Circumstantial

See Guilt by Association.

Ad Ignorantiam

See Appeal to Ignorance.

Ad Misericordiam

See Appeal to Emotions.

Ad Novitatem

See Bandwagon.

Ad Numerum

See Appeal to the People.

Ad Populum

See Appeal to the People.

Ad Verecundiam

See Appeal to Authority.

Affirming the Consequent

If you have enough evidence to affirm the consequent of a conditional and then suppose that as a result you have sufficient reason for affirming the antecedent, your reasoning contains the Fallacy of Affirming the Consequent. This formal fallacy is often mistaken for Modus Ponens, which is a valid form of reasoning also using a conditional. A conditional is an if-then statement; the if-part is the antecedent, and the then-part is the consequent. The following argument affirms the consequent that she does speaks Portuguese.


If she's Brazilian, then she speaks Portuguese. Hey, she does speak Portuguese. So, she is Brazilian.

If the arguer believes or suggests that the premises definitely establish that she is Brazilian, then the argumentation contains the fallacy. See the Non Sequitur Fallacy for more discussion of this point.

Against the Person

See Ad Hominem.


See Black-or-White Fallacy.


Any fallacy that turns on ambiguity. See the fallacies of Amphiboly, Accent, and Equivocation. Amphiboly is ambiguity of syntax. Equivocation is ambiguity of semantics. Accent is ambiguity of emphasis.


This is an error due to taking a grammatically ambiguous phrase in two different ways during the reasoning.


Tests show that the dog is not part wolf, as the owner suspected.

Did the owner suspect the dog was part wolf, or was not part wolf? Who knows? The sentence is ambiguous, and needs to be rewritten to remove the fallacy. Unlike Equivocation, which is due to multiple meanings of a phrase, Amphiboly is due to syntactic ambiguity, that is, ambiguity caused by multiple ways of understanding the grammar of the phrase.

Anecdotal Evidence

This is fallacious generalizing on the basis of a some story that provides an inadequate sample. If you discount evidence arrived at by systematic search or by testing in favor of a few firsthand stories, then your reasoning contains the fallacy of overemphasizing anecdotal evidence.


Yeah, I've read the health warnings on those cigarette packs and I know about all that health research, but my brother smokes, and he says he's never been sick a day in his life, so I know smoking can't really hurt you.


This is the error of projecting uniquely human qualities onto something that isn't human. Usually this occurs with projecting the human qualities onto animals, but when it is done to nonliving things, as in calling the storm cruel, the Pathetic Fallacy is created. There is also, but less commonly, called the Disney Fallacy or the Walt Disney Fallacy.


My dog is wagging his tail and running around me. Therefore, he knows that I love him.

The fallacy would be averted if the speaker had said "My dog is wagging his tail and running around me. Therefore, he is happy to see me." Animals are likely to have some human emotions, but not the ability to ascribe knowledge to other beings. Your dog knows where it buried its bone, but not that you also know where the bone is.

Appeal to Authority

You appeal to authority if you back up your reasoning by saying that it is supported by what some authority says on the subject. Most reasoning of this kind is not fallacious, and much of our knowledge properly comes from listening to authorities. However, appealing to authority as a reason to believe something is fallacious whenever the authority appealed to is not really an authority in this particular subject, when the authority cannot be trusted to tell the truth, when authorities disagree on this subject (except for the occasional lone wolf), when the reasoner misquotes the authority, and so forth. Although spotting a fallacious appeal to authority often requires some background knowledge about the subject or the authority, in brief it can be said that it is fallacious to accept the words of a supposed authority when we should be suspicious of the authority's words.


The moon is covered with dust because the president of our neighborhood association said so.

This is a Fallacious Appeal to Authority because, although the president is an authority on many neighborhood matters, you are given no reason to believe the president is an authority on the composition of the moon. It would be better to appeal to some astronomer or geologist. A TV commercial that gives you a testimonial from a famous film star who wears a Wilson watch and that suggests you, too, should wear that brand of watch is using a fallacious appeal to authority. The film star is an authority on how to act, not on which watch is best for you.

Appeal to Consequence

Arguing that a belief is false because it implies something you'd rather not believe. Also called Argumentum Ad Consequentiam.


That can't be Senator Smith there in the videotape going into her apartment. If it were, he'd be a liar about not knowing her. He's not the kind of man who would lie. He's a member of my congregation.

Smith may or may not be the person in that videotape, but this kind of arguing should not convince us that it's someone else in the videotape.

Appeal to Emotions

Your reasoning contains the Fallacy of Appeal to Emotions when someone's appeal to you to accept their claim is accepted merely because the appeal arouses your feelings of anger, fear, grief, love, outrage, pity, pride, sexuality, sympathy, relief, and so forth. Example of appeal to relief from grief:

[The speaker knows he is talking to an aggrieved person whose house is worth much more than $100,000.] You had a great job and didn't deserve to lose it. I wish I could help somehow. I do have one idea. Now your family needs financial security even more. You need cash. I can help you. Here is a check for $100,000. Just sign this standard sales agreement, and we can skip the realtors and all the headaches they would create at this critical time in your life.

There is nothing wrong with using emotions when you argue, but it's a mistake to use emotions as the key premises or as tools to downplay relevant information. Regarding the Fallacy of Appeal to Pity, it is proper to pity people who have had misfortunes, but if as the person's history instructor you accept Max's claim that he earned an A on the history quiz because he broke his wrist while playing in your college's last basketball game, then you've used the fallacy of appeal to pity.

Appeal to Force

See Scare Tactic.

Appeal to Ignorance

The Fallacy of Appeal to Ignorance comes in two forms: (1) Not knowing that a certain statement is true is taken to be a proof that it is false. (2) Not knowing that a statement is false is taken to be a proof that it is true. The fallacy occurs in cases where absence of evidence is not good enough evidence of absence. The fallacy uses an unjustified attempt to shift the burden of proof. The fallacy is also called "Argument from Ignorance."


Nobody has ever proved to me there's a God, so I know there is no God.

This kind of reasoning is generally fallacious. It would be proper reasoning only if the proof attempts were quite thorough, and it were the case that, if the being or object were to exist, then there would be a discoverable proof of this. Another common example of the fallacy involves ignorance of a future event: You people have been complaining about the danger of Xs ever since they were invented, but there's never been any big problem with Xs, so there's nothing to worry about.

Appeal to Money

The Fallacy of Appeal to Money uses the error of supposing that, if something costs a great deal of money, then it must be better, or supposing that if someone has a great deal of money, then they're a better person in some way unrelated to having a great deal of money. Similarly it's a mistake to suppose that if something is cheap it must be of inferior quality, or to suppose that if someone is poor financially then they're poor at something unrelated to having money.


He's rich, so he should be the president of our Parents and Teachers Organization.

Appeal to Past Practice

See Appeal to the People.

Appeal to Pity

See Appeal to Emotions.

Appeal to Snobbery

See Appeal to Emotions.

Appeal to the Gallery

See Appeal to the People.

Appeal to the Mob

See Appeal to the People.

Appeal to the Masses

See Appeal to the People.

Appeal to the People

If you suggest too strongly that someone's claim or argument is correct simply because it's what most everyone believes, then your reasoning contains the Fallacy of Appeal to the People. Similarly, if you suggest too strongly that someone's claim or argument is mistaken simply because it's not what most everyone believes, then your reasoning also uses the fallacy. Agreement with popular opinion is not necessarily a reliable sign of truth, and deviation from popular opinion is not necessarily a reliable sign of error, but if you assume it is and do so with enthusiasm, then you are using this fallacy. It is essentially the same as the fallacies of Ad Numerum, Appeal to the Gallery, Appeal to the Masses, Argument from Popularity, Argumentum ad Populum, Common Practice, Mob Appeal, Past Practice, Peer Pressure, and Traditional Wisdom. The "too strongly" mentioned above is important in the description of the fallacy because what most everyone believes is, for that reason, somewhat likely to be true, all things considered. However, the fallacy occurs when this degree of support is overestimated.


You should turn to channel 6. It's the most watched channel this year.

This is fallacious because of its implicitly accepting the questionable premise that the most watched channel this year is, for that reason alone, the best channel for you. If you stress the idea of appealing to a new idea held by the gallery, masses, mob, peers, people, and so forth, then it is a Bandwagon Fallacy.

Appeal to the Stick

See Appeal to Emotions (fear).

Appeal to Unqualified Authority

See Appeal to Authority.

Appeal to Vanity

See Appeal to Emotions.

Argument from Ignorance

See Appeal to Ignorance.

Argument from Outrage

See Appeal to Emotions.

Argument from Popularity

See Appeal to the People.

Argumentum Ad ....

See Ad .... without the word "Argumentum."

Argumentum Consensus Gentium

See Appeal to Traditional Wisdom.

Availability Heuristic

We have an unfortunate instinct to base an important decision on an easily recalled, dramatic example, even though we know the example is atypical. It is a specific version of the Confirmation Bias.


I just saw a video of a woman dying by fire in a car crash because she was unable to unbuckle her seat belt as the flames increased in intensity. So, I am deciding today no longer to wear a seat belt when I drive.

This reasoning commits the Fallacy of the Availability Heuristic because the reasoner would realize, if he would stop and think for a moment, that a great many more lives are saved due to wearing seat belts rather than due to not wearing seat belts, and the video of the situation of the woman unable to unbuckle her seat belt in the car crash is an atypical situation. The name of this fallacy is not very memorable, but it is in common use.

Avoiding the Issue

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.


A city official is charged with corruption for awarding contracts to his wife's consulting firm. In speaking to a reporter about why he is innocent, the city official talks only about his wife's conservative wardrobe, the family's lovable dog, and his own accomplishments in supporting Little League baseball.

However, the fallacy isn't used by a reasoner who says that some other issue must first be settled and then continues by talking about this other issue, provided the reasoner is correct in claiming this dependence of one issue upon the other.

Avoiding the Question

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. The fallacy occurs when someone's answer doesn't really respond to the question asked.


Question: Would the Oakland Athletics be in first place if they were to win tomorrow's game?

Answer: What makes you think they'll ever win tomorrow's game?

Bad Seed

Attempting to undermine someone's reasoning by pointing our their "bad" family history, when it is an irrelevant point. See Genetic Fallacy.

Bald Man

See Line-Drawing.


If you suggest that someone's claim is correct simply because it's what most everyone is coming to believe, then you're are using the Bandwagon Fallacy. Get up here with us on the wagon where the band is playing, and go where we go, and don't think too much about the reasons. The Latin term for this Fallacy of Appeal to Novelty is Argumentum ad Novitatem.


[Advertisement] More and more people are buying sports utility vehicles. 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. What is fallacious is to be swept up by the excitement of a new idea or new fad and to unquestionably give it too high a degree of your belief solely on the grounds of its new popularity, perhaps thinking simply that 'new is better.' The key ingredient that is missing from a bandwagon fallacy is knowledge that an item is popular because of its high quality.

Begging the Question

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.


"Women have rights," said the Bullfighters Association president. "But women shouldn't fight bulls because a bullfighter is and should be a man."

The president is saying basically that women shouldn't fight bulls because women shouldn't fight bulls. This reasoning isn't making any progress.

Insofar as the conclusion of a deductively valid argument is "contained" in the premises from which it is deduced, this containing might seem to be a case of presupposing, and thus any deductively valid argument might seem to be begging the question. 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. Some logicians suggest that, in informal reasoning with a deductively valid argument, if the conclusion is psychologically new insofar as the premises are concerned, then the argument isn't an example of the fallacy. 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.

Beside the Point

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

Biased Generalizing

Generalizing from a biased sample. Using an unrepresentative sample and overestimating the strength of an argument based on that sample.
See Unrepresentative Sample.

Biased Sample

See Unrepresentative Sample.

Biased Statistics

See Unrepresentative Sample.


See Black-or-White.


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.


Well, it's time for a decision. Will you contribute $20 to our environmental fund, or are you on the side of environmental destruction?

A proper challenge to this fallacy could be to say, "I do want to prevent the destruction of our environment, but I don't want to give $20 to your fund. You are placing me between a rock and a hard place." The key to diagnosing the Black-or-White Fallacy is to determine whether the limited menu is fair or unfair. Simply saying, "Will you contribute $20 or won't you?" is not unfair. The black-or-white fallacy is often committed intentionally in jokes such as: "My toaster has two settings—burnt and off." In thinking about this kind of fallacy it is helpful to remember that everything is either black or not black, but not everything is either black or white.

Cherry-Picking the Evidence

This is another name for the Fallacy of Suppressed Evidence.

Circular Reasoning

The Fallacy of Circular Reasoning occurs when the reasoner begins with what he or she is trying to end up with.

Here is Steven Pinker's example:

Definition: endless loop, n. See loop, endless.

Definition: loop, endless, n. See endless loop.

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. For example, here is an appropriate  recursive definition of the term "a stack of coins." Basis step: Two coins, with one on top of the other, is a stack of coins. 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.

Circumstantial Ad Hominem

See Ad Hominem, Circumstantial.

Clouding the Issue

See Smokescreen.

Common Belief

See Appeal to the People and Traditional Wisdom.

Common Cause

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.

However, it's the rain that's the common cause of both.

Common Practice

See Appeal to the People and Traditional Wisdom.

Complex Question

You use this fallacy when you frame a question so that some controversial presupposition is made by the wording of the question.


[Reporter's question] Mr. President: Are you going to continue your policy of wasting taxpayer's money on missile defense?

The question unfairly presumes the controversial claim that the policy really is a waste of money. The Fallacy of Complex Question is a form of Begging the Question.


The Composition Fallacy occurs when someone mistakenly assumes that a characteristic of some or all the individuals in a group is also a characteristic of the group itself, the group "composed" of those members. 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.

Confirmation Bias

The tendency to look for evidence in favor of one's controversial hypothesis and not to look for disconfirming evidence, or to pay insufficient attention to it. This is the most common kind of Fallacy of Selective Attention.


She loves me, and there are so many ways that she has shown it. When we signed the divorce papers in her lawyer's office, she wore my favorite color. When she slapped me at the bar and called me a "handsome pig," she used the word "handsome" when she didn't have to. 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. If she can laugh with me, if she wants to know how I am doing and whether my life has changed, and if she calls me "handsome" and wears my favorite color on special occasions, then I know she really loves me.

Using the Fallacy of Confirmation Bias is often a sign that one has adopted some belief dogmatically and isn't willing to disconfirm the belief, or is too willing to interpret ambiguous evidence so that it conforms to what one already believes.


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

Confusing an Explanation with an Excuse

Treating someone's explanation of a fact as if it were a justification of the fact. 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.

Respondent: I don't understand how you can be so insensitive as to condone those German atrocities.

Consensus Gentium

Fallacy of Argumentum Consensus Gentium (argument from the consensus of the nations). See Traditional Wisdom.


See Appeal to Consequence.

Converse Accident

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.


I've heard that turtles live longer than tarantulas, but the one turtle I bought lived only two days. I bought it at Dowden's Pet Store. So, I think that turtles bought from pet stores do not live longer than tarantulas.

The original generalization is "Turtles live longer than tarantulas." There are exceptions, such as the turtle bought from the pet store. 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.


See Suppressed Evidence.

Cum Hoc, Ergo Propter Hoc

Latin for "with this, therefore because of this." This is a False Cause Fallacy that doesn't depend on time order (as does the post hoc fallacy), but on any other chance correlation of the supposed cause being in the presence of the supposed effect.


Gypsies live near our low-yield cornfields. So, gypsies must be causing the low yield.

Curve Fitting

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. If you create your function by interpolating, that is, by drawing straight line segments between all the adjacent data points, or if you create a polynomial function that exactly fits every data point, it is likely that your function will be worse than if you’d produced a function with a smoother curve. 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 8:00 A.M. with one thermometer and get the temperature of 60.1 degrees. Then you measure the ocean at 8:05 A.M. with a different thermometer and get the temperature of 60.2 degrees; then at 8:10 A.M. and get 59.1 degrees perhaps with the first thermometer, and so. If you fit your curve exactly to your data points, then you imply that the ocean’s temperature is shifting all around every five minutes. 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.


During a controversy about the truth or falsity of atheism, the fallacious reasoner says, "Let's define 'atheist' as someone who doesn't yet realize that God exists."

Denying the Antecedent

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. A conditional is an if-then statement; the if-part is the antecedent, and the then-part is the consequent.


If she were Brazilian, then she would know that Brazil's official language is Portuguese. She isn't Brazilian; she's from London. So, she surely doesn't know this about Brazil's language.

Disregarding Known Science

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.


See Avoiding the Issue.


See Smokescreen.


Merely because a group as a whole has a characteristic, it often doesn't follow that individuals in the group have that characteristic. If you suppose that it does follow, when it doesn't, your reasoning contains the Fallacy of Division. It is the converse of the Composition Fallacy.


Joshua's soccer team is the best in the division because it had an undefeated season and won the division title, so their goalie must be the best in the division.


See Slippery Slope.

Double Standard

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.


See Black-or-White.


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.


Brad is a nobody, but since nobody is perfect, Brad must be perfect, too.

The term "nobody" changes its meaning without warning in the passage. 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.
If I call you an animal, then I’m speaking the truth.
Therefore, if I call you a swine, then I’m speaking the truth.


The Etymological Fallacy occurs whenever someone falsely assumes that the meaning of a word can be discovered from its etymology or origins.


The word "vise" comes from the Latin "that which winds," so it means anything that winds. Since a hurricane winds around its own eye, it is a vise.

Every and All

The Fallacy of Every and All turns on errors due to the order or scope of the quantifiers "every" and "all" and "any." This is a version of the Scope Fallacy.


Every action of ours has some final end. So, there is some common final end to all our actions.

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.


She's practically admitted that she intentionally yelled at that student while on the playground in the fourth grade. That's verbal assault. Then she said nothing when the teacher asked, "Who did that?" That's lying, plain and simple. 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.

Excluded Middle

See False Dilemma or Black-or-White.

False Analogy

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.

False Balance

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. Reporters regularly commit this fallacy in order to appear "fair and balanced."


The news report of the yesterday's city council meeting says, "David Samsung challenged the council by saying the Gracie Mansion is haunted, so it should not be torn down. 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." Then the news report stops there, covering up the facts that the preponderance of scientific evidence implies there is no such thing as being haunted, and that David Samsung is the well known "village idiot" who last month came before the council demanding a tax increase for Santa Claus' workers at the North Pole.

False Cause

Improperly concluding that one thing is a cause of another. The Fallacy of Non Causa Pro Causa is another name for this fallacy. Its four principal kinds are the Post Hoc Fallacy, the Fallacy of Cum Hoc, Ergo Propter Hoc, the Regression Fallacy, and the Fallacy of Reversing Causation.


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.

False Dichotomy

See False Dilemma or Black-or-White.

False Dilemma

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.


A pollster asks you this question about your job: "Would you say your employer is drunk on the job about (a) once a week, (b) twice a week, or (c) more times per week?

The pollster is committing the fallacy by limiting you to only those choices. What about the choice of "no times per week"? Think of the unpleasant choices as being the horns of a bull that is charging toward you. By demanding other choices beyond those on the unfairly limited menu, you thereby "go between the horns" of the dilemma, and are not gored. The fallacy is called the "False Dichotomy Fallacy" or the "Black-or-White" Fallacy when the unfair menu contains only two choices, and thus two horns.

False Equivalence

The Fallacy of False Equivalence is committed when someone implies falsely (and usually indirectly) that the two sides on some issue have basically equivalent evidence, while knowingly covering up the fact that one side’s evidence is much weaker. A form of the Fallacy of Suppressed Evidence.


A popular science article suggests there is no consensus about the Earth's age, by quoting one geologist who says she believes the Earth is billions of years old, and then by quoting Bible expert James Ussher who says he calculated from the Bible that the world began on Friday, October 28, 4,004 B.C.E. 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.

Far-Fetched Hypothesis

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.

Faulty Comparison

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 Questionable 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.

Shouldn't Durell hiking boots be compared with other hiking boots, not with tennis shoes?

Faulty Generalization

A fallacy produced by some error in the process of generalizing. See Hasty Generalization or Unrepresentative Generalization for examples.

Faulty Motives

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.


The councilman's argument for the new convention center can't be any good because he stands to gain if it's built.


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.


Some cats are tigers. Some tigers are animals. So, some cats are animals.

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:

Some women are Americans. Some Americans are men. So, some women are men.

Nearly all the infinity of types of invalid inferences have no specific fallacy names.

Four Terms

The Fallacy of Four Terms (quaternio terminorum) occurs when four rather than three categorical terms are used in a standard-form syllogism.


All rivers have banks. All banks have vaults. So, all rivers have vaults.

The word "banks" occurs as two distinct terms, namely river bank and financial bank, so this example also is an equivocation. 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. The assumption that it's a fair coin is important because, if the coin comes up heads five times in a row, one would otherwise become suspicious that it's not a fair coin and therefore properly conclude that the probably is high that heads is more likely on the next toss.


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.


Whatever your reasons are for buying that gift, they've got to be ridiculous. You said yourself that you got the idea for buying it from last night's fortune cookie. Cookies can't think!

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 using the Genetic Fallacy by paying too much attention to the genesis of the idea rather than to the reasons offered for it.

If I learn that your plan for building the shopping center next to the Johnson estate originated with Johnson himself, who is likely to profit from the deal, then my pointing out to the planning commission the origin of the deal would be relevant in their assessing your plan. Because not all appeals to origins are irrelevant, it sometimes can be difficult to decide if the Genetic Fallacy has been used. For example, if Sigmund Freud shows that the genesis of a person's belief in God is their desire for a strong father figure, then does it follow that their belief in God is misplaced, or is Freud's reasoning committing the Genetic Fallacy?

Group Think

A reasoner uses the Group Think Fallacy if he or she substitutes pride of membership in the group for reasons to support the group's policy. If that's what our group thinks, then that's good enough for me. It's what I think, too. "Blind" patriotism is a rather nasty version of the fallacy.


We K-Mart employees know that K-Mart brand items are better than Wall-Mart brand items because, well, they are from K-Mart, aren't they?

Guilt by Association

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. The fallacy occurs when we unfairly try to change the issue to be about the speaker's circumstances rather than about the speaker's actual argument. Also called "Ad Hominem, Circumstantial."


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.

Has any evidence been presented here that Acheson's actions are inappropriate in regards to communism? 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 1950s. In fact, Acheson was strongly anti-communist and the architect of President Truman's firm policy of containing Soviet power.

Hasty Conclusion

See Jumping to Conclusions.

Hasty Generalization

A Hasty Generalization is a Fallacy of Jumping to Conclusions in which the conclusion is a generalization. See also Biased Statistics.


I've met two people in Nicaragua so far, and they were both nice to me. 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. In this argument about Nicaragua, using the word "all" in the conclusion implies zero error margin. With zero error margin you'd need to sample every single person in Nicaragua, not just two people.


See Line-Drawing.


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.


Samantha: David is a totally selfish person.

Yvonne: I thought we was a boy scout leader. Don’t you have to give a lot of your time for that?

Samantha: Well, David’s totally selfish about what he gives money to. He won’t spend a dime on anyone else.

Yvonne: I saw him bidding on things at the high school auction fundraiser.

Samantha: Well, except for that he’s totally selfish about money.

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.

Hooded Man

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. You admitted you didn't know the hooded man over there in the corner, but the hooded man is Socrates.

Hyperbolic Discounting

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 person’s preferences are biased toward the present.


When asked to decide between receiving an award of $50 now or $60 tomorrow, the person chooses the $50; however, when asked to decide between receiving $50 in two years or $60 in two years and one day, the person chooses the $60.

If the person is in a situation in which $50 now will solve their problem but $60 tomorrow will not, then there is no fallacy in having a bias toward the present.


The error of inappropriately treating an abstract term as if it were a concrete one. Also known as the Fallacy of Misplaced Concreteness and the Fallacy of Reification.


Nature decides which organisms live and which die.

Nature isn't capable of making decisions. The point can be made without reasoning fallaciously by saying: "Which organisms live and which die is determined by natural causes." Whether a phrase commits the fallacy depends crucially upon whether the use of the inaccurate phrase is inappropriate in the situation. 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.

Ignoratio Elenchi

See Irrelevant Conclusion. Also called missing the point.

Ignoring a Common Cause

See Common Cause.

Incomplete Evidence

See Suppressed Evidence.


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.


I'm not racist. Some of my best friends are white. But I just don't think that white women love their babies as much as our women do.

That last remark implies the speaker is a racist, although the speaker doesn't notice the inconsistency.

Inductive Conversion

Improperly reasoning from a claim of the form "All As are Bs" to "All Bs are As" or from one of the form "Many As are Bs" to "Many Bs are As" and so forth.


Most professional basketball players are tall, so most tall people are professional basketball players.

The term "conversion" is a technical term in formal logic.

Insufficient Statistics

Drawing a statistical conclusion from a set of data that is clearly too small.


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. Reporting someone's beliefs or assertions or making claims about necessity or possibility can be such contexts. 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. But I happen to know Stalnaker is a spy for North Korea, so Michelle said she wants to meet a spy for North Korea 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. What was true of the person when described as “her new neighbor Stalnaker” is that Michelle said she wants to meet him, but it wasn’t legitimate for me to assume this is true of the same person when he is described as “a spy for North Korea.”

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). Intensionality is failure of extensionality, thus the name “Intensional Fallacy”.

Invalid Reasoning

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.


If it's raining, then there are clouds in the sky. It's not raining. 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.

Irrelevant Conclusion

The conclusion that is drawn is irrelevant to the premises; it misses the point.


In court, Thompson testifies that the defendant is a honorable person, who wouldn't harm a flea. The defense attorney uses the fallacy by rising to say that Thompson's testimony shows once again that his client was not near the murder scene.

Abstract: The argument whereby attention is drawn to a person's character or circumstances rather than evaluating that person's claims is characterized with examples and shown to be sometimes persuasive but normally fallacious. Not all are fallacious in the same manner. Related appeals in reasoning examined here include the ad personam, tu quoque, ex concessis, poisoning the well, guilt by association, ad feminam, and genetic fallacies, among others. Nonfallacious uses of argumentum ad hominem are also examined even though many logic textbooks mistakenly simply define all ad hominem arguments as fallacies.

  1. ad Hominem Fallacy: (abusive and circumstantial): the fallacy of attacking the character or circumstances of an individual who is advancing a statement or an argument instead of seeking to disprove the truth of the statement or the soundness of the argument. Often the fallacy is characterized simply as a personal attack.

    Informal Guide to ad Hominem

    Person L proffers claim y.

    Person L's circumstance or character is unsatisfactory (or desirable), or L does not act in accordance with y.

    Claim y is implausible or unlikely (in the case of unsatisfactory character), or claim y is plausible or likely (in the case of desirable character).

    1. The ad hominem abusive is the fallacy that that an agent's belief has not been proved (or is mistaken) because that person is somehow deficient as evidenced by some undesirable aspects of that person's character, personality, morality, or competence.[1] Consider this example:
      “After a 35-year career in agriculture, which took me to all corners of the world in segments ranging from animal productivity to plant protection, genetics, and biotechnology, I … reviewed Prince Charles' speech. I found foolishness and arrogant condescension.”[2]
    2. The ad hominem circumstantial is the fallacy that someone's belief has not been proved (or is mistaken because that person's position is motivated by actions or personal circumstances which most likely bias that person's judgment. This is a fairly typical example:
      “[Alger] Hiss still has a ragtag remnant of defenders, historical illiterates who are disproportionately academics. They often are the last to learn things because they have gone to earth in the groves of academe in order to live in an alternative reality.[3]
    3. Since the circumstantial variety of the ad hominem fallacy can often be regarded as a special case of the abusive in that it is an indirect personal attack, the distinction between the ad hominem abusive and the ad hominem circumstantial is in some contexts ignored as an inconsequential distinction.[3.1]

    4. Occasionally, in the literature, the definition of argumentum ad hominem includes arguments that someone's belief is true or probable because that person's character or circumstances is eminent or trustworthy.[4] Such virtue argumentation or positive ethotic arguments are relevant in the evaluation of evidence in witness testimony.[5] Christopher Johnson points out:
      [T]he stronger or coherent the character portrait that develops from consideration of these virtues and traits, the more compelling the ad hominem appeal, and the less the objection of ad hominem fallacy, in making a decision between arguments.”[6]
    5. Most textbook accounts of ad hominem arguments assume all instances are mistakes in reasoning since the evaluation of arguments depends on the nature or the argument rather than the character of the arguer. On this view, the argument, itself, is to be evaluated, not the individual adducing the argument. However, an ad hominem argument can be transposed as Merilee Salmon has proposed into a (formal) inductive argument[7] :
      Most of what person L states about subject S is true.
      Person L states claim c on subject S.

      Claim c is probably true.
      Christian Dahlman, et. al have proposed an intriguing formal approach to the ad hominem arguments which provides a more consistent and thorough description its subtypes. They propose reconstruction of ad hominem arguments as deductively valid arguments with a false premise and then classify the kind of arguments in terms of the kind of false premise.[7-1] This approach works well as a principle of organization, but neglects the character of informal arguments as providing degrees of support and different standards of evidence rather than limiting informal logic to appraisal in terms of deductive inferences.[7-2]

      Presently, informal logic is characterized by its lack of formal structure and can be viewed as an activity of discourse where an arguer's character or circumstances lend credibility to that individual's claims. So, on this point of view, informal logic is concerned with pragmatic analysis of dialectical interaction in discourse rather than the textual analysis of the logic of statements as is realized in deductive logic. Argumentative discourse, oral or written, is meant to resolve a difference of opinion, but sometimes the use of an ad hominem fallacy is a tactic to disqualify an opponent's arguments from the discussion.

  2. Argumentum ad Hominem: reasoning by appealing to the character or circumstances of an individual who is advancing a claim in order to determine the plausibility of that claim. The argumentum ad hominem is not always fallacious, an individual's personal character and circumstances are sometimes logically related to the issues under discussion.[8] As Douglas Walton notes, “Evaluation of each individual case should be made in relation to the corpus of argument and the context of dialogue.”[9]

    1. The informal fallacy of argumentum ad hominem occurs when an examination of issues is discontinued in pursuance of an irrelevant personal attack against the advocate of the issues — e.g., impeaching the testimony of a reliable eye witness to a felony.

      1. When an examination of issues is logically benefited by reference to the character or circumstances of an individual, no informal fallacy occurs — e.g., impeaching the testimony of a visually impaired eye witness to a felony.

      2. Note that for the argumentum ad hominem fallacy to occur, (1) an irrelevant appeal is made and (2) a (logical) argument must be present.

    2. The commonsensical assumptions upon which the argumentum ad hominem is based generally include (1) the belief that flawed persons are not credible or logical or, as well, in a different case, (2) the belief that decent persons are trustworthy and reasonable.

    3. The fallacy version of ad hominem draws its appeal from the technique of “getting personal.” But the fallacy does not occur when unfavorable evidence adduced for the accused proponent is logically dependent on the argument being put forward by the proponent. If the grounds for the claim are logically independent of the antagonist's argument, then the claim, not being relevant, is to be assessed in accordance with other (relevant) reasons. As James Cargile writes, “[E]vidence that the source of a claim is likely to be wrong is not evidence against the claim. The tendency to overlook this is the essential feature of the ad hominem fallacy.[10]

    4. Unfortunately, a criterion of relevance (or for that matter, a criterion of irrelevance) associating the circumstances and character of an arguer to the arguer's argument is extraordinarily difficult to establish for all types of ad hominem arguments. What is relevant to a particular argument depends upon the context within which the argument is proposed. Currently, difficult cases are hashed out in reasoned dialogue, although, it must be admitted, the fallaciousness of many individual occurrences of argumentum ad hominem is in dispute in the current informal fallacy literature. This defeasibility of ad hominem arguments is shown by the presence of other factors in some arguments which render exception to the charge of fallacious reasoning. For the most part, relevance in informal logic is taken to be undefined: a primitive term or an intuitive notion.[10-1]

      Simply criticizing an adversary as a digression from a controversy is not an ad hominem fallacy unless the personal attack is intended to dismiss the adversary's arguments unrelated to the adversary's character.

      Stephen Toulmin states, ”[R]elevance is a substantive matter, to be discussed in science by scientists, in law by lawyers, and so on. there are very few ‘conditions of relevance’ of an entirely general kind that hold good in all fields and forums and apply to apply types of arguments.[10-2]
  3. Although there is no generally accepted consensus, many logicians today distinguish several prevailing indistinct varieties of fallacies related to the argumentum ad hominem fallacy:

    1. In the ad personam fallacy the statement or argument at issue is dropped from consideration or is completely ignored, and the adversary's character or circumstances is subjected to personal attack.[11] Recently in several logic textbooks, the ad personam is taken to be a name replacement for the traditional ad hominem because ad hominem, which means “‘to’ or ‘toward’ a human being (or the person),” might be misinterpreted if the Latin phrase is translated to mean “‘to’ or ‘toward’ the man.” This latter translation may well be part of the reason some recent writers have added the separate fallacy of ad feminam to their list of informal fallacies[12], a fallacy defined as an attack on a woman's character or circumstances in order to cast doubt on her claims.

      1. Consider this example of an ad personam (which can also be classified as either an ad hominem abusive fallacy or a name calling fallacy):
        “Secretary of State John Kerry says that there is less violence than usual in the world right now. Meanwhile the Director of National Intelligence, James Clapper, says the opposite, that terrorism is more violent and dangerous than ever. Since Clapper is Director of National Intelligence, maybe Kerry should have the title Director of National Stupidity.“[13]
      2. A well known ad personam example of the ad hominem (circumstantial) variety is Voltaire's criticism of Rousseau's Emile, or Treatise on Education by reason of Rousseau's dereliction of his own children:
        “Excessive pride and envy have destroyed Jean-Jacques, my illustrious philosopher. That monster dares speak of education! He abandoned his children and the tramp with whom he made them.”[14]
        Voltaire dismisses Rousseau's theory of education on account of Rousseau's hypocrisy in sending his children, on the occasion of their birth, to the Paris Foundling Hospital.

    2. The tu quoque fallacy, where the proponent responds to an ad hominem attack with the same accusation against the person to whom the proponent is confronting, is a narrower form of the ad hominem circumstantial fallacy. In other words, rather than trying to disprove an accuser's proposed argument against one's own position, one responds by asserting that the same kind of argument applies to the accuser. The inconsistency of a claimant is shown by accusing the claimant of the same sort of allegation for which a proponent has been denounced. Consequently, what the accuser accuser does and what the accuser says are shown to be at variance.

      Informal Guide to Tu Quoque

      Person L proffers negative claim y against person M.

      Person M retorts same negative claim y applies against person L.

      Person M is exonerated.

      Whenever the response in kind to an advocates' claim or argument does not involve a personal attack either of character or circumstances, the tu quoque fallacy would not be considered a type of ad hominem fallacy.[15]

      1. In cross examination or in debate, the tu quoque fallacy is sometimes depicted as “My argument might be bad, but yours is worse.” Thus, the conversational implication is my argument is good by way of comparison. Note that this fallacy is usually only rhetorically effective in the presence of a third party.[16]

      2. If the basis of dispute is the criticism of a someone's argument, the fallacy can be summarized as “O.K., I understand your criticism of my contention, but the same criticism you point out applies to your thinking as well.” As Aristotle wrote, “[F]or it is the absurdity of impudence to arraign others for the very same things of which we ourselves have been guilty,”[17] and again, “The second way is, when a defender discredits his accuser, by retorting his own accusations.”[18]

      3. E.g., consider this anecdote told by an early feminist social reformer:
        “In the discussion after a Forum lecture in Boston, an address on some aspect of the Woman question, a man in the gallery, who evidently took exception to a dull rose fillet I wore in my hair, demanded to know how women could expect to equal men ‘so long as they took so much time fixing up their hair and putting ribbons in it’? There was some commotion, and cries of ‘Put him out!’ but I grinned up at him cheerfully and replied, ‘I do not think it has been yet established whether it takes a woman longer to do her hair than it does a man to shave.’ This was not an answer at all, but it seemed to please every one but the inquirer.”[19]
        Notice how the lecturer recognizes the irrelevancy of her response to the audience member's impertinent remark.

      4. The imputation of tu quoque can be defended by pointing out essential differences between the accusation of the arguer and the accusation of the critic. However, the supposed difference of transgressions can only be determined individually by sorting out the transgressions.

      5. A fallacy closely related to tu quoque is the fallacy of two wrongs make a right — in fact, some logic texts equate the two fallacies. The two wrongs-fallacy attempts to rationalize the rightness of a wrong action on the basis that the action is merely a justified response to a previous occurring wrong action of another or of a similar kind.

        1. Since the relationships among the ad hominem circumstantial, the tu quoque and the two wrongs fallacy are classified differently in the current logic literature, it's perhaps prudent not to insist upon distinct definitions.

        2. Usually, however, in the two wrongs fallacy, the first wrong is not taken as an ad hominem recrimination, whereas in the tu quoque fallacy, the initial wrong is taken as an ad hominem attack.[19-1]

        3. A fairly typical example of the two-wrongs fallacy is that reported of a London music dealer who was brought before the London Magistrates' Court charged with pirating music:
          “His excuse, such as it was, had not even the merit of novelty, although he pleaded that he sold pirated music on principle and not for profit! He said that there was a music right in London, which certainly paid royalties to authors who could command their prices, but they said nothing of the small authors, whom they bled for all they were worth. The charge for music was extortionate and exorbitant, but he had no wish to rob an author, who had a right to the value of his work.[19-2]
          The music dealer pleaded that since the publisher paid composers so meagerly and sold the music so substantially, he was justified in freebooting. The magistrate noted the two-wrongs fallacy that robbing a music publisher does not benefit the author of the music and so ruled guilty and imposed a fine.

    3. The argument from commitment (or what is sometimes designated the ex concessis argument) is a purported proof relative to a specific person's previous behavior or belief. The fallacy occurs whenever an opponent is charged with taking a position or acting in such a manner which conflicts with, or is inconsistent with, some previous position to which the opponent has accepted. The basis of the fallacy is the comparison of two conflicting positions of the proponent with whom someone is deliberating. The point of the charge of mistaken reasoning is since the two positions differ, the later position must be mistaken.[20]

      Informal Guide to Ex Concessis

      Person L proffers claim c.
      Person L previously held views inconsistent with claim c

      Claim c is implausible or unlikely.

      1. This form of the fallacy is committed when someone is accused of being hypocritical and is personally accused of not believing in, or not acting in accordance with, commitments he has taken on another occasion. Nevertheless, the reason this argument is defective is that even hypocrites are capable of espousing good arguments.[21]

      2. Interestingly, in the 1850's, William and Robert Chambers argued that this kind of argumentum ad hominem can be viewed as legitimate in cases where the conclusion is the exception to a rule. The preceding belief is expressed in the book of Exodus, where God said to Moses:
        “Ye shall keep the sabbath therefore: for it is holy unto you: every one that defileth it shall surely be put to death: for whosoever doeth any work therein, that soul shall be cut off from among his people.”[22]
        Yet, in the Gospel of Luke, Jesus justifies to a group of Pharisees (religious leaders who based Judaism in part on the Laws of Moses) his task of healing on the Sabbath as follows as an exception to the law:
        “2 And, behold there was a certain man before him which had the dropsy.
        3 And Jesus answering spake unto the lawyers and Pharisees, saying, Is it lawful to heal on the sabbath day?
        4 And they held their peace. And he took him, and healed him, and let him go;
        5 And answered them, saying, Which of you shall have an ass or an ox fallen into a pit, and will not straightaway pull him out on the sabbath day?
        6 And they could not answer him again to these things.”[23]
    4. Obviously, a simple inconsistency in thought or action is not a fallacy unless the inconsistency is part of the same argument under consideration. The ex concessis variety of the ad hominem fallacy occurs when the previous commitment or position is not specifically germane to the specific subject under consideration.

      1. A good example of the ex concessis fallacy constructed by Scott Aikin is entitled “Altarbor Atheist”:
        [Person] A: There's no answer to the problem of evil God doesn't exist — if he does, he's certainly not worthy of our worship.
        [Person] B: You can't possibly really believe that — you were an altarboy.[24]
      2. The ex concessis form of the fallacy is committed when an interlocutor states that his opponent's argument must be mistaken because his opponent has previously given an argument which is inconsistent with the present argument. But the fact that the opponent might, at one time, have believed something different from what the present argument provides, does not necessarily imply the present argument or claim is mistaken.

      3. Schopenhauer clarifies another variant of this form of fallacious reasoning: “Should your opponent be in the right, but luckily for your contention, choose a faulty proof, you can easily manage to refute it, and then claim you have refuted his whole position. This trick … is, at bottom, an expedient by which an argumentum ad hominem is put forward … ” [25]

      4. Here's a typical example of the Ad hominem ex concessis fallacy:
        “[An] octogenarian professor from the University of Texas named Lino Graglia … dutifully informed the committee that ‘a law ending birthright citizenship should and likely would survive constitutional challenge.’ But consider the source: a man who by his own account takes ‘a very limited view of the power of the Supreme Court‘ and breezily dismisses contrary precedents.”[26]
  4. Other fallacies associated with, or overlapping with, the main types of ad hominem outlined above include the personal attack, name calling, and poisoning the well, guilt (or honor) by association, and the genetic fallacy.

    1. The personal attack fallacy is often regarded as a harsh ad hominem abusive fallacy, but it can also occur as an ad hominem circumstantial fallacy. Note the disproportionate criticism in the following example:
      “We hold that the deceitful and vacuous writings presented by Lyotard, and by many of his fellow postmodernists, are texts that purposely lead their readers to stray into errancy. … Often, they reject all and any truth, and merely spread ignorance and mendacity. Hence, these deceitful vacuous writings belong in the dustbin of history!”[27]
    2. The fallacy of name calling, also often a variant of the ad hominem abusive fallacy, occurs on those occasions where loaded or negatively-slanted epithets or appellations characterizing a speaker are used to cast doubt on the worth of the speaker's beliefs. Often such insults are used to devalue the opposition's arguments or beliefs.

      1. For the name-calling fallacy to occur, the critic must have used irrelevant name calling as a reason for doubting the advocate's argument or conclusion. Thus, any evidence of the name's propriety is not necessarily evidence against the argument or conclusion itself.

      2. The following point of view is a typical example of name calling:
        “Justice Antonin Scalia was right. Not about gay marriage, of course. Scalia is so antediluvian he has trouble forcing himself to call it by its proper name.”[28]
        The ad hominem fallacy occurs here since the writer asserts that the reason Supreme Court Justice Scalia does not use the proper term for same sex marriage is that the Justice is antediluvian.

      3. Note that simply using abusive names to belittle a person is not fallacious in itself. Occasionally name calling is done in order to divert attention away from the argument under discussion. The following passage seems fallacious, but it is an instance of nonargumentative name calling. Lexically, the example can be properly termed an ad hominem, but, logically, not an ad hominem fallacy.
        “Politicians and lawyers pretend they are important people doing important work, but often they're important because they are parasites. They feed off others, while creating no wealth of their own.[29]
    3. The fallacy of poisoning the well is, in a sense, a kind of preemptive ad hominem argument. In poisoning the well, a disputant claims that an adversary's arguments cannot be trusted to be credible because of an adversary's prior fixed opinion or previous commitment. Such a person is said to be untrustworthy in present assertions because, it is claimed, that person has always been prejudiced and narrow-minded. In nearly all poisoning-the-well examples a person's motives are used to attempt to discredit the claims of that person and so are instances of the ad hominem circumstantial fallacy.[30]

      Poisoning the Well Informal Guide

      Person L proclaims person M has an objectionable standpoint or associations.

      Person M's claims are implausible or unlikely.

      1. Since we normally assess the truth of a claim by a body of existing beliefs, if the existing belief-set is suspect, then our ability to assess the claim is seriously undermined. So in the fallacy of poisoning the well, odious information about an adversary is preemptively adduced in order to discredit any possible response made by the opponent.[31]

        The fallacy is illustrated in the following example where a conservative British politician's assessment of the European Union referendum and Brexit are thwarted by this criticism:
        “The poisonous rancour of Norman Tebbit is nothing new, but even their lordships gasped at his complaint about ‘looking after foreigners and not the British.’”[32]
      2. E.g., consider the following example of accusing an opponent of the kind of fixed bias implicit in poisoning the well:
        “Michael closed his eyes as if to shut out the world around him. ‘You'll never understand what it means to swear allegiance to the flag and to your country. You'll never understand what it means to be a soldier.’
        [Samantha] ‘You're right, Michael, I don't understand, and I will never understand why men have to kill each other. It is beyond my comprehension why you had to fight in this useless war. A war that is so wrong and should have never happened.’”[33]
        Michael's argument here is that since Samantha cannot understand what it means to be a soldier, she cannot understand the values of a soldier.

      3. In gender studies, for example, poisoning the well occurs when it is sometimes assumed that women and men will never understand each other's point of view because of their inherent differences. From the outset, this assumption forestalls the possibility of a common neutral understanding and sets up an irremediable barrier to meaningful interactive discourse. When examined, such a presupposition would imply that no one could ever understand anything inherently different from one's own point of view. Ultimately, examples such as this one are fraught with difficulties similar to the intractable problem of other minds. For this reason, these types of poisoning the well can be rhetorically defended via a tu quoque maneuverer:
        Mary: Your views on limited government can have no possible standing because you're a Republican, and it's a view all Republicans are necessarily possessed by.

        John: Well, of course, you cannot understand the need for a limited government since that wouldn't support your own interests as a Democrat.
        I.e., John returns the same kind of biased-based poisoning-the-well disqualification to Mary.[34]

    4. The fallacy of guilt by association, a fallacy resembling in some ways poisoning the well, often makes use of ad hominem considerations. In the fallacy of guilt by association, the contentions or arguments of a proponent are judged on the basis of the proponent's discredited or suspicious affiliations. Thus, the adversary's position is attacked on the grounds that the adversary belongs to some kind of questionable or suspect social group. The allegation is as follows: because the advocate is somehow affiliated with a discredited enterprise, the agent's claims are not credible. The positive analogue of this fallacy is honor by association where an advocate is connected to an esteemed group and is thereby considered credible. The fallacy of honor by association is one aspect of the cognitive bias first named by Edward Thorndike as the halo effect. Psychologically, a person is often judged in accordance with judgments about associated persons, but this judgment only carries logical import when that association is relevant to the issue at hand.[34-a]

      Informal Guide to Guilt (or Honor) By Association

      Person L proffers claim c.
      Person L has qualities in common with disreputable (or reputable, if by honor) group G.

      Person L's character is disreputable (or reputable, if by honor) or claim c is implausible (or plausible, if by honor).

      1. Many instances of this fallacy are instances of what Stuart Chase has termed “guilt-by-verbal-association,” and not physical association. These examples are clearly imparted as examples of the syllogistic formal fallacy of the undistributed middle term. Chase formalizes an example which was used by the real estate lobby during the McCarthy era in the U.S.:
        Communists are in favor of government housing.
        Sen. Taft is in favor of government housing.

        Therefore Sen. Taft is a Communist.
        As Chase points out, “It is the standard bludgeon of what we now call ‘McCarthyism.”[34-1]

      2. And here's a more recent example of what might be called guilt-by-physical-association:
        “[Rep. Michele] Bachmann has raised questions about Huma Abedin, a Muslim-American, who is deputy chief of staff to Secretary of State Hillary Clinton. Bachmann's concern is Abedin's relatives in the Middle East some of whom — such as Abedin's mother — she claims ‘are connected to Muslim Brotherhood operatives and/or organizations.’ Abedin's job, according to Bachmann, ‘affords her routine access to the secretary and to policy making.’ And, as a result of that access, says Bachmann, ‘the State Department, and in several cases, the specific direction of the secretary of state, have taken actions recently that have been enormously favorable to the Muslim Brotherhood and its interests.’” [35]
    5. The genetic fallacy can converge with the ad hominem circumstantial and abusive fallacies, but not all variations involve personal attacks. The genetic fallacy is an irrelevant attempt to refute or establish a claim or argument on the basis of its origin or history. The mistake in reasoning occurs because the historical temporal or causal origins of a viewpoint is confused with its logical or justifiable merit.[36] In examples of the genetic fallacy the discourse of a historical account is different from the discourse of an analytical account. Some logicians maintain that ad hominem arguments involve single person and group sources whereas genetic arguments involve only group or circumstantial sources — other logicians do not make this distinction.

      Informal Structure of Genetic Fallacy

      Standpoints of a group or circumstance x are the historical source of conception or claim y.

      [Where standpoint or circumstance x or aspects of x are irrelevant to understanding conception or claim y.]

      Conception or claim y is unlikely.

      The source of how evidence is obtained is often irrelevant to logical significance of the evidence. I.e., the logical correctness of an argument is usually independent of the source or historical origin of that argument. The correctness of a conception should be judged on its own basis rather than judged on the basis of its sources or adherents.

      1. If the origin of an argumentative claim arises from an agent or person of some kind, the cogency of that claim or belief is not justified when the source is not logically related to the claim. A claim is to be justified on the basis of its own merit.

        1. Here's a brief allusion to a fallacy which can be properly reconstructed as an ad hominem fallacy or a genetic fallacy:
          “Would one regard a theorem in mathematics less praiseworthy because its discoverer was uneducated, or otherwise disreputably credentialed?”[37]
        2. James William Lett provides two interesting examples of this type of genetic fallacy:
          “Alfred Russell Wallace reportedly conceived the principle of natural selection while in a delirium; to dismiss the theory of evolution of that basis would be to commit the genetic fallacy. Postmodernists who reject scientific claims to knowledge on the grounds that those claims emerged from the hegemonic discourse of a powerful elite are likewise guilty of the genetic fallacy.”[38]
          Note the overlap in Lett's Postmodernist example of the genetics fallacy with the fallacy of poisoning the well.

      2. A second type of genetic fallacy occurs often in the sciences where an entity, state, or activity is reduced to, or identified with, the phenomena or physical processes which occasion it.

        1. E.g., William R. Klemm appears to commit this fallacy when he writes:
          “[C]onsciousness is constituted by neural events and does not have to intervene in neural processes because consciousness is a neural process.”[39]
          Simply because consciousness arises from neural events, it does not necessarily follow that consciousness, itself, is the same thing as a series of neural events.

        2. The mind-brain identity theory is often challenged on the same basis:
          “The classic mind-brain identity theory, according to which pain is necessarily C-fiber stimulation, does not allow for pain to be anything other than C-fiber stimulation.”[40]
          The basis for the charge of mistaken reasoning is the claim that since pain originates in C-fiber stimulation, pain is nothing but C-fiber stimulation.

      3. A third type of genetic fallacy is the presumption that a descriptive historical account of the origin of biological, psychological or ethical aspects of organisms is always sufficient for a logical understanding or a normative justification.

        E.g., Peter Godfrey-Smith points to the tenuousness of Thomas Nagel's suggestion that the use of reason should be justifiable on the basis of its biological origin:
        “Nagel does not merely ask for an explanation of how our powers of reasoning come to exist, and how they came to work as well as they do, but also asks that the evolutionary story give us ‘grounds for trusting’ them. This is a demand, though, that no evolutionary account needs to meet.[41]
      4. A fourth form of the genetic fallacy is based upon a distinction made by Hans Reichenbach which “springs from a confusion of context of discovery and context of justification.”
        “The act of discovery escapes logical analysis; there are no logical rules in terms of which a ‘discovery machine’ could be constructed that would take over the creative function of the genius. But it is not the logician's task to account for scientific discoveries; all he can do is to analyze the relation between given facts and a theory presented to him with the claim that it explains these facts. In other words, logic is concerned only with the context of justification.”[42]
        1. The context of discovery is examined through descriptive and explicative methods of empirical inquiry, whereas the context of justification is the logical analysis of the resultant outcomes of discovery. Karl Popper states, “The question how it happens that a new idea occurs to a man … may be of great interest to empirical psychology; but it is irrelevant to the logical analysis of scientific knowledge. This latter is concerned not with question of fact … but on with questions of justification or validity.”[43]

        2. Reichenbach and Popper, notwithstanding, in some arguments factors in the context of discovery are relevant to the import of the conclusion. Often discoveries are made solely by logical reasoning in mathematics and the theoretical sciences. As well, justification in various modes of inquiry often evolves as addition data is adduced. Falsification by means of further discovery can alter theoretical conclusions. In such cases, a premise stating a relationship between discovery and theory can be correctly part of the context of justification. Obviously, such genetic arguments as these require valuation on a case-by-case basis.

          E.g., in some cases the evolutionary and historical origins of psychological, religious, political, and ethical metaphysical entities or doctrines are rendered less likely since they are satisfactorily accounted for on empirical principles and the principle of simplicity — including such areas of inquiry as the varieties of conflicting religious beliefs including interpretation of doctrines; altered states of consciousness including mystical, out-of-body, and deja vu experiences; and varieties of conflicting political systems; as well as biological origins of some ethical intuitions.[44]

      5. Richard Kitchener considers a number of arguments against the genesis–justification distinction, including arguments against the kinds of genetic arguments raised above:
        (1) the fact–norm distinction,
        (2) the discovery–justification distinction,
        (3) the conceptual–empirical distinction, and, following Quine,[44-1]
        (4) the analytic–synthetic distinction.
        His arguments indirectly indicate that a genetic epistemology is possible; hence, Kitchener effectively shows the possibility of the relevance of discovery or genesis of an idea to its justification.[44-2] Consequently, with genetic arguments, the question of relevance is crucial in assessing the inferential legitimacy of the argument.

      6. In the following definitions from Dagobert Runes' Dictionary of Philosophy, Ledger Wood limits the application of the genetic fallacy to instances where the original source is deprecated:
        Genetic Fallacy: The misapplication of the genetic method resulting in the depreciatory appraisal of the product of a historical or evolutionary process because of its lowly origin.

        Genetic Method: Explanation of things in terms of their origin or genesis.”[45]
        The definition of the genetic fallacy, however, is inaccurate since the definition of “fallacy” is broadened here to include an error of explanation involving negative emotive significance, whereas in logical inquiry, the term “fallacy” is usually defined in terms of a mistake in reasoning in arguments. I.e., the mistakes in reasoning are not that the explanation is in error and that the appraisal is negative (or positive). The mistake of the genetic fallacy is in the denial of the truth of an issue on the basis of the irrelevancy of its historical origins.

      7. Not all genetic accounts are defective arguments, and many are controversial. In some cases cognizance of the origins of a viewpoint or conclusion is in fact an inference to the best explanation in inductive argumentation. An evolutionary account of the development of the origin of religious or logical thinking is not always an irrelevant consideration in assessing its trustworthiness even though such an account is not deductively certain.

        1. Kim Sterelny concludes: “[T]he so-called ‘genetic fallacy’ (the erroneous supposition that a defect in the genesis of something is evidence that discredits the thing itself) need be no fallacy. A causal account of the origins and maintenance of belief can undermine that belief's rational warrant.”[46]

        2. The structure or correctness of a conception or argument is not necessarily logically independent of the prevailing conditions under which it came to be discovered. Sometimes the understanding of a conception is constitutively reliant on the circumstances of its discovery and development. Thus, a historically descriptive account of how a judgment commences is sometimes essentially relevant to the epistemological status of that judgment. In general, if the argument involves a justification for a person's belief, then how that person arrived at that belief can be relevant. However, if the argument is about the truth of the belief, then how that person arrived at that belief is unlikely to be relevant.

  5. Several considerations for evaluating ad hominem passages deserve comment:

    1. In the examination of scientific, literary or philosophical works, looking at the author's character or circumstance can sometimes provide insight into that individual's standpoint. In other words, ad hominem considerations can show motives and can sometimes provide a frame of reference for deeper comprehension. However, these perspectives do not ordinarily demonstrate the truth or falsity of the ideas. Consider the following passage:
      “John Stacy … made the connection between the radical power of Byron's poetics and his Satanic as well as melancholic genius. Accusing Byron of a ‘misanthropy run mad,’ of trying ‘to make the world believe he is miserable, and to persuade it to be as miserable as himself’, the author writes ‘I grant him genius …, an eloquence of poetry …’”47]
      The suggestion that the brilliance of Lord Byron's poetry might be due to his manic-depressive illness is a literary insight into the possible literary effect of specific characteristics of Byron's personality. No fallacy occurs here because no argument is present.

    2. The character of a person is often relevant for an evaluation of the sincerity of views being offered and so can be relevant for pragmatic decision-making.

      E.g., D. M. Varisco explains the necessity of having awareness of Edward Said's circumstances in order to make sense of Said's 1978 polemical book Orientalism objecting to the presumption of Western superiority in its patronizing description of the Eastern World:
      “From the start the reactions to Orientalism ranging from the ad hoc to the ad hominem, read into Said the critic as well and as poorly as into what the critic was saying. Said's origins and political activism as an Arab-American intellectual can hardly be left out of analysis.”[48]
    3. A fallacy might occur in passages such as these if the work were to be considered misguided and discredited solely because of the degenerate character and circumstances of the author. The essential question in judging whether or not an ad hominem argument is a fallacy is whether or not the author's character and circumstances are logically relevant to the assertions or the arguments in the work itself.

  6. Non-fallacious uses of the ad hominem can occur in diverse descriptive and rhetorical contexts. When evidence about a person's character or circumstances is adduced to disclose the motive for that person's assertion, rather than to dispute the assertion itself, such instances often involve the presence of a causal explanation rather than the presence of an argument.

    1. In arguments where the character or circumstances are relevant to the substance of the argument, no fallacy occurs. E.g., the following passage is not fallacious:
      “If [Thomas] Jefferson's relationship with [Sally] Hemings began in the late 1780's, it would mean that he began to back away from a leadership position in the anti-slavery movement just around the time that his affair with Sally Hemings started. Jefferson's stated reservations about ending slavery included a fear that emancipation would lead to racial mixing and amalgamation. His own interracial affair now personalizes this issue, while adding a dimension of hypocrisy.”[49]
      The hypothesis is proposed that Jefferson's relationship with Hemings abated his reservations toward the anti-slavery movement.

    2. Moreover, if a speaker merely responds to an accusation pertaining to his character or circumstances by retorting that the accuser also has the same or similar character or circumstances, no fallacy necessarily occurs if there is no (logical) argument present. In other words, if a disputant's rejoinder of the same non-argumentative accusation exhibits the rhetoric of tu quoque, it is not necessarily an instance of the tu quoque fallacy unless the claim is implicit that the rejoinder is intended to disqualify some sort of argumentative criticism from the accuser.

      Consider this example of a non-fallacious tu quoque and simple name-calling from a play:
      “BLONDEL (indignantly).—You are not one of my century, or you would not be so discourteous. Sir, you are an anachronism.

      TELL.—Sir, you are another.”[50]
      In this exchange, there is just an exchange of incivility.

    3. The truth or falsity of a what is said does not depend on the character of the person saying it, unless what is said is directly applicable to the person saying it. E.g., William James famously distinguishes two philosophical temperaments:
      “The history of philosophy is a clash of human temperaments. … Of whatever temperament a professional philosopher is, he tries, when philosophizing, to sink the fact of his temperament. … Yet his temperament really gives him a stronger bias than any of his more strictly objective premises. …I think you will practically recognize the two types of mental make-up that I mean … by the titles ‘tender-minded’ and ‘tough-minded’ respectively.”[51]
      If James were to claim that all philosophers were either tender-minded or tough-minded, but as a philosopher, he is not in either camp, then the argumentum ad hominem against him would not be deemed fallacious on account of the inconsistency of his claims.

    4. Under the U.S. Federal Rules of Evidence and Case Law there are seven proper methods of impeachment in cross-examination:

      1. Bias, interest, and motive
      2. Prior inconsistent statements
      3. Contradictory facts
      4. Prior convictions
      5. Character for untruthfulness
      6. Conduct probative of untruthfulness
      7. Learned Treatises (other admissible statements, e.g. testimony of an expert witness)[51.1]

      Circumstances such as these would ordinarily be relevant factors in judging the veracity of an individual's statements.

    5. In brief, if the characteristics of a person constitute a disconfirming instance of what that person claims, then an argumentum ad hominem is not a fallacious. If the person making a claim individually embodies a counterexample which disproves that person's own claim, then it is not a fallacy to point out this fact to that person. At the same time, many ad hominem arguments provide some evidence and in those cases cannot be considered completely irrelevant arguments.

  7. A number of logicians have argued that the argumentum ad hominem is not ever a fallacy. They argue the ad hominem has been thought fallacious since its instances do not meet the conventional logical standards of deductive validity or inductive correctness or probability.

    1. On this view, in most everyday contexts of reasoning, validity or formal inductive plausibility is out of place. Nevertheless, ad hominem considerations, it is argued, do render some evidence, however weak, and so should not be thereby presupposed to be impertinent.[52] This standpoint serves to emphasize the constitutive contextual nature of informal fallacy identifications.

    2. As mentioned before, when the character or circumstances of an individual are relevant to what that person advances as a claim, the fallacy of ad hominem does not occur. For this reason, Douglas N. Walton has proposed re-naming the ad hominem abusive as the ad hominem direct to reflect the fact that the argumentum ad hominem describes both fallacious and non-fallacious arguments.[53]

      Again, as Cummings aptly notes:
      An inquiry that assumes a hierarchical structure, in which reasoning proceeds linearly from propositions that are well known to propositions that are less well known, is ill-equipped to accommodate the reasoning strategies that occur in contexts of knowledge deprivation and epistemic uncertainty.[54]
    3. Alan Brinton argues for a rhetorical rather than a logical approach to ad hominem arguments when ad hominem arguments involve the kind of rhetorical appeal based upon the speaker's character or personality when having to make a practical decision in situations of everyday uncertainty. He writes:
      “[T]he most appropriate occurrences (and probably most actual occurrences) of the ad hominem — especially in the public sphere — are to be found in contexts which are in the appropriate ways analogous to the contexts of classical oratory. It is most obviously (although not exclusively) in deliberative contexts that the ad hominem has a place and should be regarded as an acceptable form of argument. These are contexts in which there is a concern with matters of policy and practice.”[55]
      Consequently, the context in which ad hominem occurs is an essential factor in its evaluation.

  8. The following examples of the argumentum ad hominem are fairly straight-forward and are only briefly explained. In each case, note whether or not the character and/or circumstances of the individual being depicted are germane to the claims made.

ad Hominem Examples

  1. “Condoleezza Rice, former U.S. Secretary of State, responding to a question about former Secretary of Defense Donald Rumsfeld's criticism of her in his memoir: ‘Don can be a grumpy guy. We all know that.’”[56]

    Comment: Rather than addressing Mr. Rumsfeld's criticism, Ms. Rice ignores the question, imputes ill-temper to him, and thereby commits the ad hominem fallacy.

  2. “[W]hen consultant/pundit/Democrat Hilary Rosen commented on CNN that Ann Romney had never held a job (and therefore was ill-suited to advise her husband on women's employment concerns), … the Catholic League … tweeted: ‘Lesbian Dem Hilary Rosen tells Ann Romney she never worked a day in her life. Unlike Rosen, who had to adopt kids, Ann raised 5 of her own.’”[57]

    Comment: The allusion as to whether reared children are adopted or not is not directly relevant in the context provided for the purpose of deliberating women's employment concerns; thus, the ad hominem fallacy occurs.

  3. “In America, the go-to guy on ADHD is Dr. Russell Barkley … Barkley is on record saying that although behavior therapy (behavior modification) can be a useful supplementary treatment, no approach to ADHD has ever or is probably ever going to completely replace pharmaceutical therapy. In this regard it is significant to note that Barkley has had ties to … the developer of the popular ADHD drug Strattera.”[58]

    Comment: Normally the evidence for the truth or falsity of the claim would be, strictly speaking, independent of Dr. Barkley's past connections. However, Dr. Barkley's expertise cannot be entirely disregarded since his testimony and experience is relevant to the issue being discussed. Although biased innuendo is expressed against Dr. Barkley in the original dialogue, this does not necessarily result in an informal fallacy being committed since the fact of much of Dr. Barkley's background is relevant. Nevertheless, this consideration does not entirely justify Dr. Barkley assessment. The best that can be said is that calling attention to Dr. Barkley's association with the developer of an ADHD drug is uncharitable.

  4. ”President Trump is apparently convinced that his son-in-law, who serves officially as a senior adviser, can fix anything. Make that everything. … Kushner is supposed to bring the mindset and practices of the business world to the public sector. Given that his father went to jail for crimes including tax evasion, and that his boss declared four businesses bankruptcies, we can only hope Kushner looks far afield for role models.”[59]

    Comment: The implicit argument is that Jared Kushner is unlikely to be successful in his duties by the reasons that his father is a felon and Donald Trump declared bankruptcies. Hence, the ad hominem circumstantial fallacy (guilt by association) is committed.

  5. “Once he [Benjamin F. Butler] was cross-questioning a witness in his characteristic manner (with him politeness, or even humanity, was out of the question). The judge interrupted to remind him that the witness was a Harvard professor. ‘I know it, your Honor,’ replied Butler; ‘we hanged one of them the other day.’”[60]

    Comment: Mr. Butler argues that his rude cross examination of a Harvard professor is unexceptional since a Harvard professor was hanged recently — implying the witness' character is determinable by association with other Harvard professors. Again, the ad hominem circumstantial fallacy (guilt by association) is committed.

  6. ”[The New York Times] chronicled the enormous benefits French citizens receive. Paid child care, free higher education, free health care, a mandatory five weeks of paid vacation, monthly government payments for each child … There comes a point when ideology has to be put aside and what's good for the country must be embraced. France is a selfish nation that is going down the drain economically because the folks there want stuff and economics be damned.”[61]

    Comment: Although Mr. O'Reilly provides cogent reasons that government regulation and high taxes are part of an unsustainable economy, assessing reasons for this conclusion by attacking the character of the French people as wanting stuff, not caring about economics, and being selfish, is not directly relevant: ad hominem abusive.

  7. “Marvin Greenberg … spent many painful years in the garment business. As he sees it, consumers willing to pay more for better — and American — made clothes will remain a definite minority. The vast shopping public demands basement-scraping prices on two-for-one deals. Patriotism ends at the cash register. He's seen it happen. ‘Back in the '50's there was a union protest in Fall River (Mass.) about saving jobs, stopping imports,’ Greenberg recalls. ‘People carrying signs were wearing imported clothes.’”[62]

    Comment: Assuming an implicit argument, the conversational implication is that Americans will not pay more for American apparel good because even American garment workers themselves do not do so. Also the reasoning is based on one group of workers to a conclusion about all Americans and the fallacy of converse accident is suggested. Nevertheless, the implicit argument qualifies as a weak inductive argument rather than a clear fallacy.

  8. “The recent hype about global warming comes from the Intergovernmental Panel on Climate Change. Most of its members are serious scientists. But reporters don't realize that those scientists, like bird flu specialists, have every incentive to hype the risk. If their computer models (which so far have been wrong) predict disaster, they get attention and money. If they say, “I'm not sure,” they get nothing.”[63]

    Comment: The ad hominem fallacy occurs since Mr. Stossel ignores the empirical issues relating to global warming by claiming that the conclusions of the scientists on the Intergovermental Panel are not as much based on empirical evidence as they are based upon scientists attempting to secure recognition and government funding.

  9. “Actress Salma Hayek has just been honoured at Equality Now's ‘Make Equality Reality’ event, for co-founding ‘Chime for Change’, which fights for women's rights around the world. At the ceremony, which also honoured Gloria Steinem, Hayek said: ’I am not a feminist. If men were going through the things women are going through today, I would be fighting for them with just as much passion. I believe in equality.‘ … This is about the astonishing persistence of what I'd term small-f feminist-woman. … The kind of woman, such as Hayek, who accepts an award for helping women at an event also honouring Gloria Steinem (Gloria Steinem!) and then has the graceless gall to use it as an opportunity to announce that she isn't a feminist … You have to wonder — what's with these women and their seemingly all-consuming need to distance themselves from feminism? An unworthy thought crawls through my brain: is this a man-pleasing exercise … Or does it go yet deeper, darker, than that, into the realms of female self-hatred? … While some may view this as an overreaction to some red carpet waffling, to me, this is about small-f feminist-woman and how her unique brand of self-hatred is taking far too long to die out.”[64]

    Comment: In addition to the verbal disagreement concerning the meaning of feminism, Ms. Hayek is accused of either “man pleasing” behavior or “female self-hatred” for her statement that she is not a feminist. The journalist commits an ad hominem abusive attack decorated with a persuasive definition and the fallacy of complex question.

  10. “Norman Vincent Peale, a broadcast preacher and author of The Power of Positive Thinking … said [Adlai] Stevenson was unfit to be president because he was divorced. Stevenson said: “I find the Apostle Paul appealing and the Apostle Peale appalling.”[65]

    Comment: Mr. Peale and Mr. Stevenson both commit the fallacy of ad hominem. Mr. Peale's personal attack turns on a non causa pro causa (that being divorced is a cause a being unfit for the presidency), and Mr. Stevenson's attack turns on name-calling.

  11. Huey Long (Louisiana senator, 1935): “[L]et us take a look at this NRA [Roosevelt's 1933 National Recovery Administration] that they opened up around here two years ago. They had parades and Fascist signs just as Hitler, and Mussolini. They started the dictatorship here to regiment business and labor much more than anyone did in Germany or Italy. The only difference was in the sign. Italy's sign of he Fascist was a black shirt. Germany's sign of the Fascist was a swastika. So in America they sidetracked the Stars and Stripes, and the sign of the Blue Eagle was used instead. And they proceeded with the NRA.‘[66]

    Comment: Huey Long, politician and populist, poisons the well by associating the Roosevelt administration with Fascists Hitler and Mussolini in order to castigate the National Recovery Administration, a New Deal agency. However, Long's analogue is not totally misguided as in the same year this speech was broadcast, the Supreme Court ruled the NRA unconstitutional since it violated the Constitution's separation of powers.

  12. “Traditional empiricism insists that the social identity of the observer is irrelevant to the ‘goodness’ of the results of research. It is not supposed to make a difference to the explanatory power, objectivity, and so on of the research's results if the researcher or the community of scientists are white or black, Chinese or British, rich or poor in social origin. But feminist empiricism argues that women (or feminists, male and female) as a group are more likely than men (non-feminists) as a group to produce claims unbiased by androcentrism, and in that sense objective results of inquiry. It argues that the authors of the favored social theories are not anonymous at all: they are clearly men, and usually men of the dominant classes, races, and cultures. The people who identify and define scientific problems leave their social fingerprints on the problems and their favored solutions to them.”[67]

    Comment: Certainly the claim that feminists as a group are more likely than nonfeminists to be unbiased by androcentrism (i.e., taking a masculine point of view) is trivially true. Nonetheless, the conclusion drawn that feminists are more likely to produce objective claims of inquiry than those produced by traditional empiricism does not logically follow from this tautology. Further evaluation of this argumentative passage depends to a great extent on the context of the presentation and the background assumptions upon which the argument is based. Nevertheless, the author argues that feminists, unlike nonfeminists, are not androcentric and thus produce claims which are objective results of inquiry. Since the adequacy of scientific theories is measured in part by comparison of observed results to expected results (an independent confirmation whose veracity is not dependent upon whether or not the originators of the hypotheses in question happen to be androcentric or gynocentric), the genetic fallacy occurs in this quoted selected passage. Note that biased selections of empirical observations in order to present specific points of view, whether complied intentionally or unintentionally, are precluded by traditional empiricism as improper scientific method. Additionally, scientific theories and hypotheses are repeatedly experimentally tested in accordance with procedural methods in observation and experiment as part of the normal course of scientific development. Thus, there is a justifiable “logical distinction between the psychological processes which occur when a scientist thinks of new ideas and the logical argument which exhibits the degree to which those ideas are supported by the facts and other evidential considerations.”[68]

Some judge of authors' names, not work, and then
Nor praise nor blame the writings, but the men.

Alexander Pope, The Works of Alexander Pope, vol. II, An Essay on Criticism (London: Longman Brown, and Co. 1847), 357.


argumentum ad hominem, ad feminam, lit. ‘the argument to a man, to a woman,’ refutation of a man's argument by an example drawn from his own conduct.” Sir Walter Scott, Redgauntlet (London: Oxford University Press, 1912), 501.
In accordance with the proliferation of fallacies in the last fifty years, the argumentum ad feminam in the sense of attempting to discredit a woman's claim by appeal to her character or circumstances may well become mainstream. If so, then recognition might follow, as it has recently with the ad hominem, that the ad feminam argument would not be necessarily fallacious by definition.↩
“[W]e must be closed to compromise. No one need try to convince me otherwise. The effort is futile; my conviction is absolute.” [Charles M. Blow, “The Death of Compassion,” The New York Times (23 Feb. 2017)].
A stance such as this one leads credence to the ad hominem charge of bias since the author is so deeply entrenched in a partisan issue that he refuses to consider any possible evidence for an opposing view.

Even so, to some extent, everyone has deeply rooted fixed opinions: “There is still another kind of prejudice similar to that just considered — namely, the judgments which are born of other minds and which, nevertheless, we come to appropriate as our own. the reasons in which such judgments are grounded we have never examined ourselves — possibly we could never understand even if they were presented to us with elaborate explanation; and yet the second-hand judgments cannot be eliminated wholly from our body of knowledge without an incalculable loss. ” [John Grier Hibben, “A Defence of Prejudice,” Scribner's Magazine, 43 no. 1 (Jan. 1908), 118.]↩