Reasoning refers to the process of making sense of things around us. In order to understand our experiences, draw conclusions from information, and present new ideas, we must use reasoning. We often reason without being aware of it, but becoming more aware of how we think can empower us to be better producers and consumers of communicative messages. The three types of reasoning we will explore are inductive, deductive, and causal.
Inductive reasoning reaches conclusions through the citation of examples and is the most frequently used form of logical reasoning (Walter, 1966). While introductory speakers are initially attracted to inductive reasoning because it seems easy, it can be difficult to employ well. Inductive reasoning, unlike deductive reasoning, doesn’t result in true or false conclusions. Instead, since conclusions are generalized based on observations or examples, conclusions are “more likely” or “less likely.” Despite the fact that this type of reasoning isn’t definitive, it can still be valid and persuasive.
Some arguments based on inductive reasoning will be more cogent, or convincing and relevant, than others. For example, inductive reasoning can be weak when claims are made too generally. An argument that fraternities should be abolished from campus because they contribute to underage drinking and do not uphold high academic standards could be countered by providing examples of fraternities that sponsor alcohol education programming for the campus and have members that have excelled academically (Walter, 1966). In this case, one overly general claim is countered by another general claim, and both of them have some merit. It would be more effective to present a series of facts and reasons and then share the conclusion or generalization that you have reached from them.
You can see inductive reasoning used in the following speech excerpt from President George W. Bush’s address to the nation on the evening of September 11, 2001. Notice how he lists a series of events from the day, which builds to his conclusion that the terrorist attacks failed in their attempt to shake the foundation of America.
Today, our fellow citizens, our way of life, our very freedom came under attack in a series of deliberate and deadly terrorist acts. The victims were in airplanes or in their offices: secretaries, business men and women, military and federal workers, moms and dads, friends and neighbors. Thousands of lives were suddenly ended by evil, despicable acts of terror. The pictures of airplanes flying into buildings, fires burning, huge—huge structures collapsing have filled us with disbelief, terrible sadness, and a quiet, unyielding anger. These acts of mass murder were intended to frighten our nation into chaos and retreat. But they have failed. Our country is strong.
A great people has been moved to defend a great nation. Terrorist attacks can shake the foundations of our biggest buildings, but they cannot touch the foundation of America.
If a speaker is able to provide examples that are concrete, proxemic, and relevant to the audience, as Bush did in this example, audience members are prompted to think of additional examples that connect to their own lives. Inductive reasoning can be useful when an audience disagrees with your proposition. As you present logically connected examples as evidence that build to a conclusion, the audience may be persuaded by your evidence before they realize that the coming conclusion will counter what they previously thought. This also sets up cognitive dissonance, which is a persuasive strategy we will discuss later.
Reasoning by analogy is a type of inductive reasoning that argues that what is true in one set of circumstances will be true in another (Walter, 1966). Reasoning by analogy has been criticized and questioned by logicians, since two sets of circumstances are never exactly the same. While this is true, our goal when using reasoning by analogy in persuasive speaking is not to create absolutely certain conclusions but to cite cases and supporting evidence that can influence an audience. For example, let’s say you are trying to persuade a university to adopt an alcohol education program by citing the program’s success at other institutions. Since two universities are never exactly the same, the argument can’t be airtight. To better support this argument, you could first show that the program was actually successful using various types of supporting material such as statistics from campus offices and testimony from students and staff. Second, you could show how the cases relate by highlighting similarities in the campus setting, culture, demographics, and previous mission. Since you can’t argue that the schools are similar in all ways, choose to highlight significant similarities. Also, it’s better to acknowledge significant limitations of the analogy and provide additional supporting material to address them than it is to ignore or hide such limitations.
So how do we evaluate inductive reasoning? When inductive reasoning is used to test scientific arguments, there is rigorous testing and high standards that must be met for a conclusion to be considered valid. Inductive reasoning in persuasive speaking is employed differently. A speaker cannot cite every example that exists to build to a conclusion, so to evaluate inductive reasoning you must examine the examples that are cited in ways other than quantity. First, the examples should be sufficient, meaning that enough are cited to support the conclusion. If not, you risk committing the hasty generalization fallacy. A speaker can expect that the audience will be able to think of some examples as well, so there is no set number on how many examples is sufficient. If the audience is familiar with the topic, then fewer examples are probably sufficient, while more may be needed for unfamiliar topics. A speaker can make his or her use of reasoning by example more powerful by showing that the examples correspond to the average case, which may require additional supporting evidence in the form of statistics. Arguing that teacher salaries should be increased by providing an example of a teacher who works side jobs and pays for his or her own school supplies could be effectively supported by showing that this teacher’s salary corresponds to the national average (Walter, 1966).
Second, the examples should be typical, meaning they weren’t cherry-picked to match the point being argued. A speaker who argues to defund the National Endowment for the Arts (NEA) because the organization supports art that is “pornographic and offensive” may cite five examples of grants given for projects that caused such controversy. Failing to mention that these examples were pulled from the more than 128,000 grants issued by the NEA would be an inappropriate use of inductive reasoning since the examples aren’t sufficient or typical enough to warrant the argument. Another way to support inductive arguments is to show that the examples are a fair sample, meaning they are representative of the larger whole. Arguing that college athletes shouldn’t receive scholarships because they do not have the scholastic merit of other students and have less academic achievement could be supported by sharing several examples. But if those examples were not representative, then they are biased, and the reasoning faulty. A speaker would need to show that the athletes used in the example are representative, in terms of their race, gender, sport, and background, of the population of athletes at the university.
Using inductive reasoning, speakers reach conclusions through the citation of examples.
Claire Sambrook – UM… – CC BY-NC 2.0.
Deductive reasoning derives specifics from what is already known. It was the preferred form of reasoning used by ancient rhetoricians like Aristotle to make logical arguments (Cooper & Nothstine, 1996). A syllogism is an example of deductive reasoning that is commonly used when teaching logic. A syllogism is an example of deductive reasoning in which a conclusion is supported by major and minor premises. The conclusion of a valid argument can be deduced from the major and minor premises. A commonly used example of a syllogism is “All humans are mortal. Socrates is a human. Socrates is mortal.” In this case, the conclusion, “Socrates is mortal,” is derived from the major premise, “All humans are mortal,” and the minor premise, “Socrates is a human.” In some cases, the major and minor premises of a syllogism may be taken for granted as true. In the previous example, the major premise is presumed true because we have no knowledge of an immortal person to disprove the statement. The minor premise is presumed true because Socrates looks and acts like other individuals we know to be human. Detectives or scientists using such logic would want to test their conclusion. We could test our conclusion by stabbing Socrates to see if he dies, but since the logic of the syllogism is sound, it may be better to cut Socrates a break and deem the argument valid. Since most arguments are more sophisticated than the previous example, speakers need to support their premises with research and evidence to establish their validity before deducing their conclusion.
A syllogism can lead to incorrect conclusions if one of the premises isn’t true, as in the following example:
- All presidents have lived in the White House. (Major premise)
- George Washington was president. (Minor premise)
- George Washington lived in the White House. (Conclusion)
In the previous example, the major premise was untrue, since John Adams, our second president, was the first president to live in the White House. This causes the conclusion to be false. A syllogism can also exhibit faulty logic even if the premises are both true but are unrelated, as in the following example:
- Penguins are black and white. (Major premise)
- Some old television shows are black and white. (Minor premise)
- Some penguins are old television shows. (Conclusion)
Like in the game of Clue, real-life detectives use deductive reasoning to draw a conclusion about who committed a crime based on the known evidence.
Causal reasoning argues to establish a relationship between a cause and an effect. When speakers attempt to argue for a particular course of action based on potential positive or negative consequences that may result, they are using causal reasoning. Such reasoning is evident in the following example: Eating more local foods will boost the local economy and make you healthier. The “if/then” relationship that is set up in causal reasoning can be persuasive, but the reasoning isn’t always sound. Rather than establishing a true cause-effect relationship, speakers more often set up a correlation, which means there is a relationship between two things but there are other contextual influences.
To use causal reasoning effectively and ethically, speakers should avoid claiming a direct relationship between a cause and an effect when such a connection cannot be proven. Instead of arguing that “x caused y,” it is more accurate for a speaker to say “x influenced y.” Causal thinking is often used when looking to blame something or someone, as can be seen in the following example: It’s the president’s fault that the economy hasn’t recovered more. While such a statement may garner a speaker some political capital, it is not based on solid reasoning. Economic and political processes are too complex to distill to such a simple cause-effect relationship. A speaker would need to use more solid reasoning, perhaps inductive reasoning through examples, to build up enough evidence to support that a correlation exists and a causal relationship is likely. When using causal reasoning, present evidence that shows the following: (1) the cause occurred before the effect, (2) the cause led to the effect, and (3) it is unlikely that other causes produced the effect.
Review of Types of Reasoning
- Inductive. Arguing from examples to support a conclusion; includes reasoning by analogy. Examples should be sufficient, typical, and representative to warrant a strong argument.
- Deductive. Deriving specifics from what is already known; includes syllogisms. Premises that lead to a conclusion must be true, relevant, and related for the argument to be valid.
- Causal. Argues to establish a relationship between a cause and an effect. Usually involves a correlation rather than a true causal relationship.
For specific popular misconceptions, see List of common misconceptions.
In reasoning to argue a claim, a fallacy is reasoning that is evaluated as logically incorrect and that undermines the logical validity of the argument and permits its recognition as unsound. Regardless of their soundness, all registers and manners of speech can demonstrate fallacies.
Because of their variety of structure and application, fallacies are challenging to classify so as to satisfy all practitioners. Fallacies can be classified strictly by either their structure or content, such as classifying them as formal fallacies or informal fallacies, respectively. The classification of informal fallacies may be subdivided into categories such as linguistic, relevance through omission, relevance through intrusion, and relevance through presumption. On the other hand, fallacies may be classified by the process by which they occur, such as material fallacies (content), verbal fallacies (linguistic), and again formal fallacies (error in inference). In turn, material fallacies may be placed into the more general category of informal fallacies as formal fallacies may be clearly placed into the more precise category of logical or deductive fallacies[clarification needed]. Yet, verbal fallacies may be placed in either informal or deductive classifications; compare equivocation which is a word or phrase based ambiguity, e. g. "he is mad", which may refer to either him being angry or clinically insane, to the fallacy of composition which is premise and inference based ambiguity, e. g. "this must be a good basketball team because each of its members is an outstanding player".
Faulty inferences in deductive reasoning are common formal or logical fallacies. As the nature of inductive reasoning is based on probability, a fallacious inductive argument or one that is potentially misleading, is often classified as "weak".
The conscious or habitual use of fallacies as rhetorical devices are prevalent in the desire to persuade when the focus is more on communication and eliciting common agreement rather than the correctness of the reasoning. One may consider the effective use of a fallacy by an orator as clever but by the same token the reasoning of that orator should be recognized as unsound, and thus the orator's claim, supported by an unsound argument, will be regarded as unfounded and dismissed.
Main article: Formal fallacy
A formal fallacy is an error in logic that can be seen in the argument's form. All formal fallacies are specific types of non sequiturs.
A propositional fallacy is an error in logic that concerns compound propositions. For a compound proposition to be true, the truth values of its constituent parts must satisfy the relevant logical connectives that occur in it (most commonly: <and>, <or>, <not>, <only if>, <if and only if>). The following fallacies involve inferences whose correctness is not guaranteed by the behavior of those logical connectives, and hence, which are not logically guaranteed to yield true conclusions.
Types of propositional fallacies:
A quantification fallacy is an error in logic where the quantifiers of the premises are in contradiction to the quantifier of the conclusion.
Types of Quantification fallacies:
Formal syllogistic fallacies
Syllogistic fallacies – logical fallacies that occur in syllogisms.
Main article: Informal fallacy
Informal fallacies – arguments that are fallacious for reasons other than structural (formal) flaws and usually require examination of the argument's content.
- Appeal to the stone (argumentum ad lapidem) – dismissing a claim as absurd without demonstrating proof for its absurdity.
- Argument from ignorance (appeal to ignorance, argumentum ad ignorantiam) – assuming that a claim is true because it has not been or cannot be proven false, or vice versa.
- Argument from incredulity (appeal to common sense) – "I cannot imagine how this could be true; therefore, it must be false."
- Argument from repetition (argumentum ad nauseam, argumentum ad infinitum) – signifies that it has been discussed extensively until nobody cares to discuss it anymore; sometimes confused with proof by assertion
- Argument from silence (argumentum ex silentio) – assuming that a claim is true based on the absence of textual or spoken evidence from an authoritative source, or vice versa.
- Argument to moderation (false compromise, middle ground, fallacy of the mean, argumentum ad temperantiam) – assuming that the compromise between two positions is always correct.
- Begging the question (petitio principii) – providing what is essentially the conclusion of the argument as a premise.
- Circular reasoning (circulus in demonstrando) – the reasoner begins with what he or she is trying to end up with; sometimes called assuming the conclusion.
- Circular cause and consequence – the consequence of the phenomenon is claimed to be its root cause.
- Continuum fallacy (fallacy of the beard, line-drawing fallacy, sorites fallacy, fallacy of the heap, bald man fallacy) – improperly rejecting a claim for being imprecise.
- Correlative-based fallacies
- Divine fallacy (argument from incredulity) – arguing that, because something is so incredible/amazing/ununderstandable, it must be the result of superior, divine, alien or paranormal agency.
- Double counting – counting events or occurrences more than once in probabilistic reasoning, which leads to the sum of the probabilities of all cases exceeding unity.
- Equivocation – the misleading use of a term with more than one meaning (by glossing over which meaning is intended at a particular time).
- Ambiguous middle term – a common ambiguity in syllogisms in which the middle term is equivocated.
- Definitional retreat – changing the meaning of a word to deal with an objection raised against the original wording.
- Motte-and-bailey fallacy – The arguer conflates two similar positions, one modest and easy to defend (the "motte") and one much more controversial (the "bailey"). The arguer advances the controversial position, but when challenged, they insist that they are only advancing the more modest position.
- Ecological fallacy – inferences about the nature of specific individuals are based solely upon aggregate statistics collected for the group to which those individuals belong.
- Etymological fallacy – reasoning that the original or historical meaning of a word or phrase is necessarily similar to its actual present-day usage.
- Fallacy of accent – a specific type of ambiguity that arises when the meaning of a sentence is changed by placing an unusual prosodic stress, or when, in a written passage, it's left unclear which word the emphasis was supposed to fall on.
- Fallacy of composition – assuming that something true of part of a whole must also be true of the whole.
- Fallacy of division – assuming that something true of a thing must also be true of all or some of its parts.
- False attribution – an advocate appeals to an irrelevant, unqualified, unidentified, biased or fabricated source in support of an argument.
- Fallacy of quoting out of context (contextomy, quote mining) – refers to the selective excerpting of words from their original context in a way that distorts the source's intended meaning.
- False authority (single authority) – using an expert of dubious credentials or using only one opinion to sell a product or idea. Related to the appeal to authority fallacy.
- False dilemma (false dichotomy, fallacy of bifurcation, black-or-white fallacy) – two alternative statements are held to be the only possible options when in reality there are more.
- False equivalence – describing a situation of logical and apparent equivalence, when in fact there is none.
- Fallacy of many questions (complex question, fallacy of presuppositions, loaded question, plurium interrogationum) – someone asks a question that presupposes something that has not been proven or accepted by all the people involved. This fallacy is often used rhetorically so that the question limits direct replies to those that serve the questioner's agenda.
- Fallacy of the single cause (causal oversimplification) – it is assumed that there is one, simple cause of an outcome when in reality it may have been caused by a number of only jointly sufficient causes.
- Furtive fallacy – outcomes are asserted to have been caused by the malfeasance of decision makers.
- Gambler's fallacy – the incorrect belief that separate, independent events can affect the likelihood of another random event. If a fair coin lands on heads 10 times in a row, the belief that it is "due to the number of times it had previously landed on tails" is incorrect.
- Historian's fallacy – occurs when one assumes that decision makers of the past viewed events from the same perspective and having the same information as those subsequently analyzing the decision. (Not to be confused with presentism, which is a mode of historical analysis in which present-day ideas, such as moral standards, are projected into the past.)
- Historical fallacy – a set of considerations is thought to hold good only because a completed process is read into the content of the process which conditions this completed result.
- Homunculus fallacy – a "middle-man" is used for explanation; this sometimes leads to regressive middle-men. Explains without actually explaining the real nature of a function or a process. Instead, it explains the concept in terms of the concept itself, without first defining or explaining the original concept. Explaining thought as something produced by a little thinker, a sort of homunculus inside the head, merely explains it as another kind of thinking (as different but the same).
- Inflation of conflict – The experts of a field of knowledge disagree on a certain point, so the scholars must know nothing, and therefore the legitimacy of their entire field is put to question.
- If-by-whiskey – an argument that supports both sides of an issue by using terms that are selectively emotionally sensitive.
- Incomplete comparison – insufficient information is provided to make a complete comparison.
- Inconsistent comparison – different methods of comparison are used, leaving one with a false impression of the whole comparison.
- Intentionality fallacy – the insistence that the ultimate meaning of an expression must be consistent with the intention of the person from whom the communication originated (e.g. a work of fiction that is widely received as a blatant allegory must necessarily not be regarded as such if the author intended it not to be so.)
- Ignoratio elenchi (irrelevant conclusion, missing the point) – an argument that may in itself be valid, but does not address the issue in question.
- Kettle logic – using multiple, jointly inconsistent arguments to defend a position.[dubious– discuss]
- Ludic fallacy – the belief that the outcomes of non-regulated random occurrences can be encapsulated by a statistic; a failure to take into account unknown unknowns in determining the probability of events taking place.
- McNamara fallacy (quantitative fallacy) – making a decision based only on quantitative observations, discounting all other considerations.
- Mind projection fallacy – one's subjective judgments are "projected" to be inherent properties of an object, rather than being related to personal perception of that object.
- Moralistic fallacy – inferring factual conclusions from purely evaluative premises in violation of fact–value distinction. For instance, inferring is from ought is an instance of moralistic fallacy. Moralistic fallacy is the inverse of naturalistic fallacy defined below.
- Moving the goalposts (raising the bar) – argument in which evidence presented in response to a specific claim is dismissed and some other (often greater) evidence is demanded.
- Naturalistic fallacy – inferring evaluative conclusions from purely factual premises in violation of fact–value distinction. For instance, inferring ought from is (sometimes referred to as the is-ought fallacy) is an instance of naturalistic fallacy. Also naturalistic fallacy in a stricter sense as defined in the section "Conditional or questionable fallacies" below is an instance of naturalistic fallacy. Naturalistic fallacy is the inverse of moralistic fallacy.
- Naturalistic fallacy fallacy (anti-naturalistic fallacy) – inferring an impossibility to infer any instance of ought from is from the general invalidity of is-ought fallacy, mentioned above. For instance, is does imply ought for any proposition , although the naturalistic fallacy fallacy would falsely declare such an inference invalid. Naturalistic fallacy fallacy is an instance of argument from fallacy.
- Nirvana fallacy (perfect solution fallacy) – solutions to problems are rejected because they are not perfect.
- Onus probandi – from Latin "onus probandi incumbit ei qui dicit, non ei qui negat" the burden of proof is on the person who makes the claim, not on the person who denies (or questions the claim). It is a particular case of the argumentum ad ignorantiam fallacy, here the burden is shifted on the person defending against the assertion. Also known as shifting the burden of proof.
- Post hoc ergo propter hoc Latin for "after this, therefore because of this" (faulty cause/effect, coincidental correlation, correlation without causation) – X happened, then Y happened; therefore X caused Y. The Loch Ness Monster has been seen in this loch. Something tipped our boat over; it's obviously the Loch Ness Monster.
- Proof by assertion – a proposition is repeatedly restated regardless of contradiction; sometimes confused with argument from repetition (argumentum ad infinitum, argumentum ad nauseam)
- Prosecutor's fallacy – a low probability of false matches does not mean a low probability of some false match being found.
- Proving too much – using a form of argument that, if it were valid, could be used to reach an additional, undesirable conclusion.
- Psychologist's fallacy – an observer presupposes the objectivity of his own perspective when analyzing a behavioral event.
- Red herring – a speaker attempts to distract an audience by deviating from the topic at hand by introducing a separate argument the speaker believes is easier to speak to.
- Referential fallacy – assuming all words refer to existing things and that the meaning of words reside within the things they refer to, as opposed to words possibly referring to no real object or that the meaning of words often comes from how we use them.
- Regression fallacy – ascribes cause where none exists. The flaw is failing to account for natural fluctuations. It is frequently a special kind of post hoc fallacy.
- Reification (concretism, hypostatization, or the fallacy of misplaced concreteness) – a fallacy of ambiguity, when an abstraction (abstract belief or hypothetical construct) is treated as if it were a concrete, real event or physical entity. In other words, it is the error of treating as a "real thing" something that is not a real thing, but merely an idea.
- Retrospective determinism – the argument that because an event has occurred under some circumstance, the circumstance must have made its occurrence inevitable.
- Special pleading – a proponent of a position attempts to cite something as an exemption to a generally accepted rule or principle without justifying the exemption.
- Wrong direction – cause and effect are reversed. The cause is said to be the effect and vice versa.
Faulty generalizations – reach a conclusion from weak premises. Unlike fallacies of relevance, in fallacies of defective induction, the premises are related to the conclusions yet only weakly buttress the conclusions. A faulty generalization is thus produced.
- Accident – an exception to a generalization is ignored.
- No true Scotsman – makes a generalization true by changing the generalization to exclude a counterexample.
- Cherry picking (suppressed evidence, incomplete evidence) – act of pointing at individual cases or data that seem to confirm a particular position, while ignoring a significant portion of related cases or data that may contradict that position.
- Survivorship bias – a small number of survivors of a given process are actively promoted while completely ignoring a large number of failures
- False analogy – an argument by analogy in which the analogy is poorly suited.
- Hasty generalization (fallacy of insufficient statistics, fallacy of insufficient sample, fallacy of the lonely fact, hasty induction, secundum quid, converse accident, jumping to conclusions) – basing a broad conclusion on a small sample or the making of a determination without all of the information required to do so.
- Inductive fallacy – A more general name to some fallacies, such as hasty generalization. It happens when a conclusion is made of premises that lightly support it.
- Misleading vividness – involves describing an occurrence in vivid detail, even if it is an exceptional occurrence, to convince someone that it is a problem.
- Overwhelming exception – an accurate generalization that comes with qualifications that eliminate so many cases that what remains is much less impressive than the initial statement might have led one to assume.
- Thought-terminating cliché – a commonly used phrase, sometimes passing as folk wisdom, used to quell cognitive dissonance, conceal lack of thought-entertainment, move on to other topics etc. but in any case, end the debate with a cliché—not a point.
Red herring fallacies
A red herring fallacy, one of the main subtypes of fallacies of relevance, is an error in logic where a proposition is, or is intended to be, misleading in order to make irrelevant or false inferences. In the general case any logical inference based on fake arguments, intended to replace the lack of real arguments or to replace implicitly the subject of the discussion.
Red herring – argument given in response to another argument, which is irrelevant and draws attention away from the subject of argument. See also irrelevant conclusion.
- Ad hominem – attacking the arguer instead of the argument.
- Poisoning the well – a subtype of ad hominem presenting adverse information about a target person with the intention of discrediting everything that the target person says.
- Abusive fallacy – verbally abusing the opponent rather than arguing about the originally proposed argument.
- Appeal to motive – dismissing an idea by questioning the motives of its proposer.
- Kafka-trapping – A sophistical and unfalsifiable form of argument that attempts to overcome an opponent by inducing a sense of guilt and using the opponent's denial of guilt as further evidence of guilt.
- Tone policing – focusing on emotion behind (or resulting from) a message rather than the message itself as a discrediting tactic.
- Traitorous critic fallacy (ergo decedo) – a critic's perceived affiliation is portrayed as the underlying reason for the criticism and the critic is asked to stay away from the issue altogether.
- Appeal to authority (argumentum ad verecundiam) – an assertion is deemed true because of the position or authority of the person asserting it.
- Appeal to consequences (argumentum ad consequentiam) – the conclusion is supported by a premise that asserts positive or negative consequences from some course of action in an attempt to distract from the initial discussion.
- Appeal to emotion – an argument is made due to the manipulation of emotions, rather than the use of valid reasoning.
- Appeal to fear – an argument is made by increasing fear and prejudice towards the opposing side
- Appeal to flattery – an argument is made due to the use of flattery to gather support.
- Appeal to pity (argumentum ad misericordiam) – an argument attempts to induce pity to sway opponents.
- Appeal to ridicule – an argument is made by presenting the opponent's argument in a way that makes it appear ridiculous.
- Appeal to spite – an argument is made through exploiting people's bitterness or spite towards an opposing party.
- Wishful thinking – a decision is made according to what might be pleasing to imagine, rather than according to evidence or reason.
- Appeal to nature – judgment is based solely on whether the subject of judgment is 'natural' or 'unnatural'. (Sometimes also called the "naturalistic fallacy", but is not to be confused with the other fallacies by that name)
- Appeal to novelty (argumentum novitatis, argumentum ad antiquitatis) – a proposal is claimed to be superior or better solely because it is new or modern.
- Appeal to poverty (argumentum ad Lazarum) – supporting a conclusion because the arguer is poor (or refuting because the arguer is wealthy). (Opposite of appeal to wealth.)
- Appeal to tradition (argumentum ad antiquitatem) – a conclusion supported solely because it has long been held to be true.
- Appeal to wealth (argumentum ad crumenam) – supporting a conclusion because the arguer is wealthy (or refuting because the arguer is poor). (Sometimes taken together with the appeal to poverty as a general appeal to the arguer's financial situation.)
- Argumentum ad baculum (appeal to the stick, appeal to force, appeal to threat) – an argument made through coercion or threats of force to support position.
- Argumentum ad populum (appeal to widespread belief, bandwagon argument, appeal to the majority, appeal to the people) – a proposition is claimed to be true or good solely because majority or many people believe it to be so.
- Association fallacy (guilt by association and honor by association) – arguing that because two things share (or are implied to share) some property, they are the same.
- Bare assertion fallacy, also known as ipse dixit – a claim that is presented as true without support, as self-evidently true, or as dogmatically true. This fallacy relies on the implied expertise of the speaker or on an unstated truism.
- Bulverism (psychogenetic fallacy) – inferring why an argument is being used, associating it to some psychological reason, then assuming it is invalid as a result. It is wrong to assume that if the origin of an idea comes from a biased mind, then the idea itself must also be a falsehood.
- Chronological snobbery – a thesis is deemed incorrect because it was commonly held when something else, clearly false, was also commonly held.
- Fallacy of relative privation ("not as bad as") – dismissing an argument or complaint due to the existence of more important problems in the world, regardless of whether those problems bear relevance to the initial argument. For example, First World problem.
- Genetic fallacy – a conclusion is suggested based solely on something or someone's origin rather than its current meaning or context.
- Judgmental language – insulting or pejorative language to influence the recipient's judgment.
- Moralistic fallacy (the inverse of naturalistic fallacy) – statements about what is, on the basis of claims about what ought to be.
- Naturalistic fallacy (is–ought fallacy, naturalistic fallacy) – claims about what ought to be, on the basis of statements about what is.
- Pooh-pooh – dismissing an argument perceived unworthy of serious consideration.
- Straw man fallacy – an argument based on misrepresentation of an opponent's position.
- Texas sharpshooter fallacy – improperly asserting a cause to explain a cluster of data.
- Tu quoque ("you too", appeal to hypocrisy, I'm rubber and you're glue, Whataboutism) – the argument states that a certain position is false or wrong or should be disregarded because its proponent fails to act consistently in accordance with that position.
- Two wrongs make a right – occurs when it is assumed that if one wrong is committed, an "equal but opposite" wrong will cancel it out.
- Vacuous truth – a claim that is technically true but meaningless, in the form of claiming that no A in B has C, when there are no A in B. For example, claiming that no mobile phones in the room are on when there are no mobile phones in the room at all.
Conditional or questionable fallacies
- Broken window fallacy – an argument that disregards lost opportunity costs (typically non-obvious, difficult to determine or otherwise hidden) associated with destroying property of others, or other ways of externalizing costs onto others. For example, an argument that states breaking a window generates income for a window fitter, but disregards the fact that the money spent on the new window cannot now be spent on new shoes.
- Definist fallacy – involves the confusion between two notions by defining one in terms of the other.
- Naturalistic fallacy – attempts to prove a claim about ethics by appealing to a definition of the term "good" in terms of either one or more claims about natural properties (sometimes also taken to mean the appeal to nature) or God's will.
- Slippery slope (thin edge of the wedge, camel's nose) – asserting that a relatively small first step inevitably leads to a chain of related events culminating in some significant impact/event that should not happen, thus the first step should not happen. It is, in its essence, an appeal to probability fallacy.
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