False premise
A false premise is an incorrect proposition that forms the basis of an argument or syllogism. Since the premise (proposition, or assumption) is not correct, the conclusion drawn may be in error. Howev
Inconsistent triad
An inconsistent triad consists of three propositions of which at most two can be true. For example: 1.
* Alice loves me. 2.
* If Alice loves me, then she would have sent flowers. 3.
* Alice has not
Negative conclusion from affirmative premises
Negative conclusion from affirmative premises is a syllogistic fallacy committed when a categorical syllogism has a negative conclusion yet both premises are affirmative. The inability of affirmative
Fallacy of exclusive premises
The fallacy of exclusive premises is a syllogistic fallacy committed in a categorical syllogism that is invalid because both of its premises are negative. Example of an EOO-4 type invalid syllogism E
Illicit major
Illicit major is a formal fallacy committed in a categorical syllogism that is invalid because its major term is undistributed in the major premise but distributed in the conclusion. This fallacy has
Fallacy of four terms
The fallacy of four terms (Latin: quaternio terminorum) is the formal fallacy that occurs when a syllogism has four (or more) terms rather than the requisite three, rendering it invalid.
Converse accident
The fallacy of converse accident (also called reverse accident, destroying the exception, or a dicto secundum quid ad dictum simpliciter) is an informal fallacy that can occur in a statistical syllogi
Illicit minor
Illicit minor is a formal fallacy committed in a categorical syllogism that is invalid because its minor term is undistributed in the minor premise but distributed in the conclusion. This fallacy has
Fallacy of the undistributed middle
The fallacy of the undistributed middle (Latin: non distributio medii) is a formal fallacy that is committed when the middle term in a categorical syllogism is not distributed in either the minor prem
Affirmative conclusion from a negative premise
Affirmative conclusion from a negative premise (illicit negative) is a formal fallacy that is committed when a categorical syllogism has a positive conclusion and one or two negative premises. For exa
Affirming a disjunct
The formal fallacy of affirming a disjunct also known as the fallacy of the alternative disjunct or a false exclusionary disjunct occurs when a deductive argument takes the following logical form: A o
Politician's syllogism
The politician's syllogism, also known as the politician's logic or the politician's fallacy, is a logical fallacy of the form: 1.
* We must do something. 2.
* This is something. 3.
* Therefore, we
Modal scope fallacy
A fallacy of necessity is a fallacy in the logic of a syllogism whereby a degree of unwarranted necessity is placed in the conclusion.
Accident (fallacy)
The fallacy of accident (also called destroying the exception or a dicto simpliciter ad dictum secundum quid) is an informal fallacy and a deductively valid but unsound argument occurring in a statist
Immediate inference
An immediate inference is an inference which can be made from only one statement or proposition. For instance, from the statement "All toads are green", the immediate inference can be made that "no to
Existential fallacy
The existential fallacy, or existential instantiation, is a formal fallacy. In the existential fallacy, one presupposes that a class has members when one is not supposed to do so; i.e., when one shoul