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Informal fallacy

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An informal fallacy (also relevance fallacy, conceptual fallacy, soundness fallacy) is an argument that is formally valid but is unsound because of the falsity or irrelevance of one or more of its premises. Informal fallacies are often characterised by the fact that there is a disconnect of some kind between their premises and conclusions. Inappropriate generalisations and argument from ignorance are forms of informal fallacies. These tend to be more numerous and slightly more interesting than formal fallacies.

Informal fallacies are ad hoc, ad hominem, ambiguous, arguments from ignorance, non causa pro causa, circular, special pleading, or weak analogies.


P1: Half of all adult humans can grow beards.
P2: Sophia is an adult human female.
C: There is a 50% chance Sophia can grow a beard.

This is not a sound argument because the first premise is irrelevant. Because Sophia is a woman, we know she is in the portion of the population that is generally incapable of growing beards. The fact that half of the population can grow beards merits no consideration since we already know which half Sophia belongs in.


Dixiecrat Fallacy[edit]

See the main article on this topic: States' Rights Democratic Party

You know, it's really the Democrats who are racist. Want to know why? They're the party who started the KKK!

Usage of the Dixiecrat Fallacy and it's Lost Irony[edit]

"Next time one of those stupid liberals tells you you’re a racist, you tell him it was the dirty, filthy, stinkin’ ni***r-lovin' democRats what started the KKK. You tell 'em that and it'll blow their minds because they'll realize it's the ni***rs that are the real racists."

See also[edit]

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