Formal Fallacies Flashcards
What is a formal fallacy?
An error in the argument’s logical structure
What are all formal fallacies types of?
Non sequitur
What is the fallacy of Appeal to Probability?
A statement that takes something for granted because there is a possibility of it being the case
What is the fallacy of Argument from Fallacy (aka the fallacy fallacy)
The assumption that, if a particular premise for a conclusion is false, the conclusion itself must be false
What is a Base Rate Fallacy?
Making a probability judgement based on conditional, individuating probabilities, without accounting for the effect of prior ‘Base Rate’ probabilities
What is a Conjunction Fallacy?
The assumption that specific conditions are more probably than a single general one
What is a Non-sequitur Fallacy?
Where the conclusion does not logically follow the premise
What is the Masked-man Fallacy?
Sometimes called the ‘Illicit Substitution of Identicals’, or the ‘Epistemic Fallacy’
Wrongly assuming that if two or more names or description refer to the same thing, they can be freely substituted with one another, This mistake usually hinges on epistemic flaws in knowing something to be true
What is a propositional fallacy?
An error of one or many compound propositions in which the truth values of a statement do not satisfy the relevant logical connectives
What is the fallacy of affirming a disjunct?
Concluding that one disjunct of a logical disjunction (an ‘or’ statement) must be false because the other is true i.e. A or B; A, therefore not B
What is the fallacy of affirming the consequent?
The antecedant in an indicative conditional (an ‘if… then’ statement) is claimed to be true because the consequent is true i.e. if A, then B; B, therefore A
What is the fallacy of denying the antecedent?
The consequent in an indicative conditional (an ‘if… then’ statement) is claimed to be false because the antecedent is false i.e. if A, then B; not A, therefore not B
What is a quantification fallacy?
A logical error where the quantifiers of the premises are in contradiction to the quantifier of the conclusion
What is an existential fallacy?
An argument that has a universal premise and a particular conclusion which does not logically follow i.e.
1 - All trespassers will be prosecuted
2 - Some of those prosecuted are trespassers
What is a formal syllogistic fallacy?
Logical fallacies that occur in syllogisms
What is a syllogism?
A kind of logical argument that applies deductive reasoning to arrive at a conclusion based on two propositions that are asserted or assumed to be true.
What is the fallacy of Affirmative Conclusion from a Negative Premise (Illicit Negative)?
A categorical syllogism has a positive conclusion, but at least one negative premise i.e no fish are dogs, and no dogs can fly, therefore all fish can fly
What is the Fallacy of Exclusive Premises
A categorical syllogism that is invalid because both its premises are negative - two negative premises cannot give a logical foundation for a conclusion as they will invariably be independent statements which are no directly related
What is the Fallacy of Four Terms (Quaternio Terminorum)?
A categorical syllogism that has four terms - two premises are not enough to connect four different terms since, in order to establish connection, there must be one term common to both premises i.e. All fish have fins; All goldfish are fish; All humans have fins
What is the Fallacy of Illicit Major?
A categorical syllogism that is invalid because its major term is undistributed in the major premise but distributed in the conclusion i.e. 1. All dogs are mammals, 2. No cats are dogs, 3. Therefore, no cats are mammals
What is the Fallacy of Illicit Minor?
A categorical syllogism that is invalid because its minor term is undistributed in the minor premise but distributed in the conclusion i.e. 1. All A are B, 2. All A are C, 3. Therefore, all C are B
What is the Fallacy of Negative Conclusion from Affirmative Premises (Illicit Affirmative)?
A categorical syllogism that has a negative conclusion but affirmative premises - the inability of affirmative premises to reach a negative conclusion is usually cited as one of the basic rules of constructing a valid categorical argument i.e. All colonels are officers; All officers are soldiers: Therefore, no colonels are soldiers
What is the Fallacy of the Undistributed Middle?
The middle term in a categorical syllogism is not distributed i.e. 1. All Z is B, 2. All Y is B, 3. Therefore, all Y is Z (B is not distributed and so is invalid)
