Logical Fallicies Flashcards
Anecdotal fallacy
- using a personal experience or an isolated example instead of sound reasoning or compelling evidence.
Appeal to probability
– is a statement that takes something for granted because it would probably be the case (or might be the case).[2][3]
Argument from fallacy
– assumes that if an argument for some conclusion is fallacious, then the conclusion is false.[4]
Base rate fallacy
– making a probability judgment based on conditional probabilities, without taking into account the effect of prior probabilities.[5]
Conjunction fallacy
– assumption that an outcome simultaneously satisfying multiple conditions is more probable than an outcome satisfying a single one of them.[6]
Masked man fallacy (illicit substitution of identicals)
– the substitution of identical designators in a true statement can lead to a false one.[7]
Unwarranted assumption fallacy
- The fallacy of unwarranted assumption is committed when the conclusion of an argument is based on a premise (implicit or explicit) that is false or unwarranted. An assumption is unwarranted when it is false - these premises are usually suppressed or vaguely written. An assumption is also unwarranted when it is true but does not apply in the given context.
Affirming a disjunct
– concluded that one disjunct of a logical disjunction must be false because the other disjunct is true; A or B; A; therefore not B.[8]
Affirming the consequent
– the antecedent in an indicative conditional is claimed to be true because the consequent is true; if A, then B; B, therefore A.[8]
Denying the antecedent
– the consequent in an indicative conditional is claimed to be false because the antecedent is false; if A, then B; not A, therefore not B.[8]
Existential fallacy
an argument has a universal premise and a particular conclusion.[9]
Affirmative conclusion from a negative premise (illicit negative)
– when a categorical syllogism has a positive conclusion, but at least one negative premise.[9]
Fallacy of exclusive premises
– a categorical syllogism that is invalid because both of its premises are negative.[9]
Fallacy of four terms (quaternio terminorum)
– a categorical syllogism that has four terms.[10]
Illicit major
– a categorical syllogism that is invalid because its major term is not distributed in the major premise but distributed in the conclusion.[9]
Illicit minor
– a categorical syllogism that is invalid because its minor term is not distributed in the minor premise but distributed in the conclusion.[9]
Negative conclusion from affirmative premises (illicit affirmative)
– when a categorical syllogism has a negative conclusion but affirmative premises. [9]
Fallacy of the undistributed middle
– the middle term in a categorical syllogism is not distributed.[11]
Informal fallacies
– arguments that are fallacious for reasons other than structural (formal) flaws and usually require examination of the argument’s content.[12]
Appeal to the stone (argumentum ad lapidem
) – dismissing a claim as absurd without demonstrating proof for its absurdity.[13]
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.[14]
Argument from (personal) incredulity (divine fallacy, appeal to common sense)
– I cannot imagine how this could be true, therefore it must be false.[15][16]
Argument from repetition (argumentum ad infinitum)
– signifies that it has been discussed extensively until nobody cares to discuss it anymore.[17][18]
Argument from silence (argumentum e silentio)
– where the conclusion is based on the absence of evidence, rather than the existence of evidence.[19][20]
Argument to moderation (false compromise, middle ground, fallacy of the mean, argumentum ad temperantiam
) – assuming that the compromise between two positions is always correct.[21]
Argumentum ad hominem
– the evasion of the actual topic by directing an attack at your opponent.
ergo decedo
– where a critic’s perceived affiliation is seen as the underlying reason for the criticism and the critic is asked to stay away from the issue altogether.
Begging the question (petitio principii
) – providing what is essentially the conclusion of the argument as a premise.[22][23][24][25]
(shifting the) Burden of proof (see – onus probandi)
– I need not prove my claim, you must prove it is false.
Circular reasoning (circulus in demonstrando)
– when the reasoner begins with what he or she is trying to end up with; sometimes called assuming the conclusion.
Circular cause and consequence
– where 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.[26]
Correlation proves causation (cum hoc ergo propter hoc)
– a faulty assumption that correlation between two variables implies that one causes the other.[27]
Suppressed correlative
– where a correlative is redefined so that one alternative is made impossible.[28]
Equivocation
– the misleading use of a term with more than one meaning (by glossing over which meaning is intended at a particular time).[29]
Ambiguous middle term
– a common ambiguity in syllogisms in which the middle term is equivocated.[30]
Ecological fallacy
– inferences about the nature of specific individuals are based solely upon aggregate statistics collected for the group to which those individuals belong.[31]
Etymological fallacy –
which reasons that the original or historical meaning of a word or phrase is necessarily similar to its actual present-day usage.[32]
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.[33]
Fallacy of division
– assuming that something true of a thing must also be true of all or some of its parts.[34]
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)
– refers to the selective excerpting of words from their original context in a way that distorts the source’s intended meaning.[35]
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.[36]
False equivalence
– describing a situation of logical and apparent equivalence, when in fact there is none.
Fallacy of many questions (complex question, fallacy of presupposition, 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[37])
– 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.[38]
Hedging
– using words with ambiguous meanings, then changing the meaning of them later.
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.[39] (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.)