LOGICAL FALLACIES

ARGUMENTUM AD HOMINEM (argument directed at the person)
This is the error of attacking the character or motives of a person who has stated an idea, rather than the idea itself. (e.g. pointing out that an opponent doesn't know how to spell some name or concept, or is too careless to do so correctly.)
ARGUMENTUM AD IGNORANTIUM (argument to ignorance)
This is the fallacy of assuming something is true simply because it hasn't been proven false. (Apart from anything else, are political or value statements possible to "prove"?)
ARGUMENTUM AD LOGICAM (argument to logic)
This is the fallacy of assuming that something is proven false simply because a proof or argument that someone has offered for it is invalid. (This fallacy often appears in competitive communities, because it is much easier to show the flaws in someone else's argument than to explain away the flaws in one's own.)
ARGUMENTUM AD MISERICORDIAM (argument or appeal to pity)
The English translation pretty much says it all. The problem with such an argument is that no amount of special pleading can make the impossible possible, the false true, the expensive costless, etc.
ARGUMENTUM AD NAUSEAM (argument to the point of disgust; i.e., by repetition)
This is the fallacy of trying to prove something by saying it again and again (teachers and instructors beware...). But no matter how many times you repeat something, it will not become any more or less true than it was in the first place.
ARGUMENTUM AD NUMERAM (argument or appeal to numbers)
This fallacy is the attempt to prove something by showing how many people think that it's true. But no matter how many people believe something, that doesn't necessarily make it true or right.
ARGUMENTUM AD VERECUNDIAM (argument or appeal to authority)
This fallacy occurs when someone tries to demonstrate the truth of a proposition by citing some person who agrees, even though that person may have no expertise in the given area.
CIRCULUS IN DEMONSTRANDO (circular argument)
Circular argumentation occurs when someone uses what they are trying to prove as part of the proof for that argument.
COMPLEX QUESTION
A complex question is a question that implicitly assumes something to be true by its construction, such as "Have you stopped beating your wife?"
CUM HOC ERGO PROPTER HOC (with this, therefore because of this)
This is the familiar fallacy of mistaking correlation for causation -- i.e., thinking that because two things occur simultaneously, one must be a cause of the other.
DICTO SIMPLICITER (spoken simply, i.e., sweeping generalization)
This is the fallacy of making a sweeping statement and expecting it to be true of every specific case -- in other words, stereotyping.
NATURALISTIC FALLACY
This is the fallacy of trying to derive conclusions about what is right or good (that is, about values) from statements of fact alone. This is invalid because no matter how many statements of fact you assemble, any logical inference from them will be another statement of fact, not a statement of value.
NON SEQUITUR (It does not follow)
This is the simple fallacy of stating, as a conclusion, something that does not strictly follow from the premises.
POST HOC ERGO PROPTER HOC (after this, therefore because of this)
This is the fallacy of assuming that A caused B simply because A happened prior to B. A favorite example: Red herring. This means introducing irrelevant facts or arguments to distract from the question at hand.
SLIPPERY SLOPE
This is the fallacy of arguing that adopting one policy or taking one action will lead to a series of other policies or actions also being taken, without showing a causal connection between the advocated policy and the consequent policies.
STRAW MAN
This is the fallacy of refuting a caricatured or extreme version of somebody's argument, rather than the actual argument they've made.
TU QUOQUE (you too)
This is the fallacy of defending an error in one's reasoning by pointing out that one's opponent has made the same error.

Last update: July 2000- Claude Aflalo
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