Fallacy

Part 01

• Fallacy• In logic and rhetoric, a fallacy is a

misconception resulting from incorrect reasoning in argumentation. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor (e.g. appeal to emotion), or take advantage of social relationships between people (e.g. argument from authority). 

•  Fallacious arguments are often structured using rhetorical patterns that obscure the logical argument, making fallacies more difficult to diagnose. Also, the components of the fallacy may be spread out over separate arguments

Material fallacies

• The taxonomy of material fallacies is widely adopted by modern logicians and is based on that of Aristotle, Organon (Sophistici elenchi). This taxonomy is as follows:

• Fallacy of Accident or Sweeping Generalization: a generalization that disregards exceptions

• Example– Argument: Cutting people is a crime. Surgeons cut

people. Therefore, surgeons are criminals.– Problem: Cutting people is only sometimes a crime.– Argument: It is illegal for a stranger to enter

someone's home uninvited. Firefighters enter people's homes uninvited, therefore firefighters are breaking the law.

– Problem: The exception does not break nor define the rule; a dicto simpliciter ad dictum secundum quid (where an accountable exception is ignored).

• Converse Fallacy of Accident or Hasty Generalization: argues from a special case to a general rule

• Example– Argument: Every person I've met speaks English, so it

must be true that all people speak English.– Problem: Who one has met is a subset of the entire

set. One cannot have met all people.

• Also called reverse accident, destroying the exception, a dicto secundum quid ad dictum simpliciter

• Irrelevant Conclusion: diverts attention away from a fact in dispute rather than address it directly

• Example– Argument: Billy believes that war is justifiable,

therefore it must be justifiable.– Problem: Billy can be wrong. (In particular this

is an appeal to authority.)

• Affirming the Consequent: draws a conclusion from premises that do not support that conclusion by assuming Q implies P on the basis that P implies Q

• Example:– Argument: If people run barefoot, then their

feet hurt. Billy's feet hurt. Therefore, Billy ran barefoot.

– Problem: Other things, such as tight sandals, can result in sore feet.

– Argument: If it rains, the ground gets wet. The ground is wet, therefore it rained.

– Problem: There are other ways by which the ground could get wet (e.g. dew).