Logical Fallacies
Formal Fallacies
Propositional Fallacies
- affirming the consequent: “if A, then B; B, therefore A”
- affirming a disjunct - “Given A or B, and A is true, therefore B is false”
- denying the antecedent - “If A, then B; not B, therefore not A”
- association fallacy - asserts that properties of one thing must also be properties of another thing, if both things belong to the same group
- fallacy fallacy - if an argument contains a fallacy, its conclusion must be false
Informal Fallacies
- Ad hominem - using personal attack to make an argument
- Tu quoque - Criticizing someone’s personal behavior as not aligning with their argument, thus implying hypocrisy
- Bulverism - an argument is flawed or false because of the arguer’s suspected motives, social identity, or other characteristic associated with the arguer’s identity
- tone policing
- red herring - something that mislead or distract from a relevant or important question
- special pleading - ignore unfavorable evidence
- loaded question - A question that contains a controversial assumption
- false dilemma - misrepresent an issue by offering only two options
- strawman - refuting an argument different from the one actually under discussion
- circular reasoning - reasoner begins with what they are trying to end with
- fallacy of composition - infers that something is true of the whole from the fact that it is true of some part of the whole
- fallacy of division - something that is true for a whole must also be true of all or some of its parts
- burden of proof fallacy - tries to remove their need to provide proofs
- no true Scotsman - defend a generalization of a group by label counter-examples as “not true enough”
- personal incredulity - deems a proposition false if it contradicts one’s personal expectations or beliefs
- ambiguity fallacy - an argument is based on an ambiguous term or phrase
- appeal to ignorance - asserts that a proposition is true because it has not yet been proven false or vice versa
- irrelevant conclusion - presenting an argument without address the issue in question
- genetic fallacy - arguments or information are dismissed or validated based solely on their source of origin rather than their content
- middle ground fallacy
- sunk cost
- faulty analogy - saying two things are liking in other way just because they are liking in one way
- definist fallacy - Defining a term in such a way that makes one’s position much easier to defend
- etymological fallacy - Argue that the true meaning of a word is its oldest or original meaning
- false equivalence
- moralistic fallacy - assuming that an aspect of nature which has socially unpleasant consequences cannot exist
- nirvana fallacy - comparing actual things with unrealistic, idealized alternatives or assume there is a perfect solution to a particular problem
- psychologist’s fallacy - assume subjective experience reflects the true nature of an even
- retrospective determinism - because something happened under some circumstances, it was therefore bound to happen due to those circumstances
- courtier’s reply - respondent to criticism claims that the critic lacks sufficient expertise to pose any criticism
- I’m entitled to my opinion
- two wrongs make a right
Equivocation
- equivocation - use of a particular word in multiple senses within an argument
Faulty Generalization
- hasty generalization - reaching an generalization based on insufficient evidence
- argument from anecdote - Anecdote arguments are presented as arguments
- base rate fallacy - Conflation between prior and posterior probability
- cherry picking - pointing to individual cases of data that confirm a position while ignoring the rest
Questionable Causes
questionable cause
Questionable causes are fallacies that falsely identify the cause of events.
Fallacies of questionable cause include:
Link to original
- correlation implies causation
- Texas sharpshooter fallacy - differences in data are ignored, but similarities are overemphasized
- fallacy of the single cause - assume that there is a single cause of an outcome when in reality it may be caused by a number of causes
- slippery slope fallacy - claims one event or action will lead to another, more extreme event or action
Appeals
- proof by assertion - repeatedly restate regardless of contradiction and refutation
- appeal to authority - when a claim is assumed to be true because it was made by a perceived authority figure
- appeal to nature
- appeal to emotion
- appeal to tradition
- appeal to popularity
- appeal to accomplishment
- appeal to consequence - argue based on whether the premise leads to desirable or undesirable consequences
- appeal to novelty
- chronological snobbery - the thinking, art, or science of an earlier time is inherently inferior to that of the present