Flashcards in Fallacies Deck (35)
A fallacy is a mistake in reasoning
Define formal fallacy
A formal fallacy is an inference rendered invalid by a flaw in its syntax (form)
Outline the 5 main formal fallacies
affirming the consequent: p —> q, q, therefore p.
denying the antecedent: p—> q, -p, therefore -q.
affirming a disjunct: p v q, p, therefore -q.
denying a conjunct: -(p ^ q), -p, therefore q
undistributed middle: p —> q, r —> q, therefore r —> p.
Define informal fallacy
An informal fallacy is a type of mistake in reasoning that arises from the mishandling of the content of the propositions constituting the argument
State acronym for remembering formal fallacies
State the three types of informal fallacies
fallacies of relevance
fallacies of presumption
fallacies of ambiguity
Define fallacies of relevance
fallacies of relevance occur when the premises of an argument are not relevant to the conclusion
State the main fallacies of relevance
ad hominem e.g. tu quoque
Define ad hominem fallacy
argument directed not at the conclusion, but at the person who holds it
Define tu quoque fallacy
tu quoque: a person’s argument is wrong (unsound?) because they don’t act in accordance with it
Define ad ignorantiam fallacy
ad ignorantiam: a proposition is true (or false) because not yet proved otherwise
Define ad verecundiam fallacy
ad verecundiam: appeal to inappropriate authority
Define ad populum fallacy
ad populum: appeal to the majority
Define ad misericordiam fallacy
ad misericordiam: appeal to pity
Define ad baculum fallacy
ad baculum: appeal to force
Define ignoratio elenchi fallacy
ignoratio elenchi (irrelevant conclusion): premises are irrelevant to conclusion
Define fallacies of presumption
fallacies of presumption occur when an argument relies on unjustified assumptions
State the main fallacies of presumption
post hoc ergo propter hoc.
Define complex question
complex question: asking a question in such a way as to presuppose the truth of some conclusion. “Have you stopped beating your wife yet?”
Define false dilemma/dichotomy
false dilemma/ dichotomy: two alternative statements are held to be the only possible options when in reality there are more e.g. “I thought you were a good person, but you weren’t at church today.”
Define petitio principii
petitio principii (begging the Q): assuming the truth of what you intend to prove in order to prove it.
Define post hoc ergo propter hoc.
post hoc ergo propter hoc.: after the fact, therefore because of that fact. “The bigger a child's shoe size, the better the child's handwriting. Therefore, having big feet makes it easier to write.”
accident: presume the applicability of a generalisation to individual cases that the generalisation does not cover. E.g., inferring that penguins can fly from the fact they are birds.
Define converse accident
converse accident: Presume that what is true of a particular case is true of some generalisation of cases. Hasty generalisation.
Define fallacies of ambiguity
fallacies of ambiguity occur in arguments that rely on a term or phrase having multiple meanings in multiple propositions within the argument
State the main fallacies of ambiguity
Define equivocation fallacy
equivocation: argument relies on confusing the multiple meanings of the same word or phrase. “This Lloyds branch is a bank. Banks are next to rivers. Therefore, we must be next to a river.
Define fallacy of amphiboly
amphiboly: ambiguity is due to grammatical form. “The panda eats shoots and leaves.”
Define fallacy of accent
accent: ambiguity is due to differing stress on the same word or phrase. E.g., “I didn't take the test yesterday” stressed in six different places.