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A '''logical fallacy''' is an error in [[formal logic|logical]] reasoning. While the common usage of the word ''fallacy'' would include ''any'' error in reasoning, in logic a fallacy is defined at a particularly [[deceit|deceptive]] argument which seems correct, but upon further examination is found to be incorrect.<ref name="copi">Copi, Irving M. and Carl Cohen. "Introduction to Logic, 12e". Pearson Education: 2005</ref>

A '''logical fallacy''' is an error in [[formal logic|logical]] reasoning. While the common usage of the word ''fallacy'' would include ''any'' error in [[reason]]ing, in logic a fallacy is defined at a particularly [[deceit|deceptive]] argument which seems correct, but upon further examination is found to be incorrect.<ref name="copi">Copi, Irving M. and Carl Cohen. "Introduction to Logic, 12e". Pearson Education: 2005</ref>

Logical fallacies fall into two general categories: formal fallacies and informal fallacies. Formal fallacies apply to [[deductive argument]]s, and are those which relate to an improper application of a rule, whereas informal fallacies apply to [[inductive argument]]s, and are those which involve the improper use of the content of an argument.

Logical fallacies fall into two general categories: formal fallacies and informal fallacies. Formal fallacies apply to [[deductive argument]]s, and are those which relate to an improper application of a rule, whereas informal fallacies apply to [[inductive argument]]s, and are those which involve the improper use of the content of an argument.

Logical fallacy ''is not'' the same as lying. A ''lie'' in logic is a premise that one offers while knowing that it is false.  

A logical fallacy ''is not'' the same as [[lie|lying]]. A ''lie'' in logic is a [[premise]] that one offers while knowing that it is false.  

The following is a catalog of informal logical fallacies, with each one given a separate heading, to make them easier to cite in other articles.

There are four general categories of fallacies: fallacies of relevance, fallacies of defective or weak induction, fallacies of presumption, and fallacies of ambiguity.

 

==Fallacies of Relevance==

==Fallacies of Relevance==

Fallacies of relevance are fallacies which are due to a lack of a relevant logical connection between premise and conclusion.

Fallacies of relevance are fallacies which are due to a lack of a relevant logical connection between [[premise]] and [[conclusion]].

===Appeal to force===

===Appeal to force===

An appeal to force (Lat: ''argumentum ad baculum'') is an argument which uses a threat of violence or force as a justification for the conclusion. An appeal to force argument follows the form:

An appeal to [[force]] (Lat: ''argumentum ad baculum'') is an argument which uses a threat of [[violence]] or force as a justification for the conclusion. An appeal to force argument follows the form:

*If person A does not accept P, then Q

*If person A does not accept P, then Q

===Appeal to pity===

===Appeal to pity===

Also called emotional appeal, (Lat: ''ad misericordiam'') this fallacy is characterized by a use of emotion as a justification for the conclusion. An appeal to pity follows the form:

Also called [[emotion]]al appeal, (Lat: ''ad misericordiam'') this fallacy is characterized by a use of emotion as a justification for the conclusion. An appeal to [[pity]] follows the form:

*Person A argues that P

*Person A argues that P

*Therefore P is true

*Therefore P is true

For example: "Yes, officer, I realize I was speeding, but you shouldn't give me a ticket because I was racing to see my wife who is in the hospital." While this argument uses an emotional appeal to convince the officer not to hand out a citation, there is no logical connection between the premise ("you shouldn't give me a ticket") and the conclusion ("I was racing to see my wife").

For example: "Yes, [[police|officer]], I realize I was speeding, but you shouldn't give me a ticket because I was racing to see my wife who is in the [[hospital]]." While this argument uses an emotional appeal to convince the officer not to hand out a citation, there is no logical connection between the premise ("you shouldn't give me a ticket") and the conclusion ("I was racing to see my wife").

===''Argumentum ad hominem''===

===''Argumentum ad hominem''===