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1. Logical fallacy: An argument that is structurally invalid because its
premises do not suffice to logically determine the truth of its
conclusion; error in reasoning; faulty argumentation.
a. Conditional fallacies (Invalid conditional forms)
•Affirming the consequent: if P then Q; Q; Therefore, P
•Denying the antecedent: if P then Q; Not P; Therefore,
b. Quantifier scope fallacy: The mistake of inferring a specific
statement from its unspecific version; misordering a universal
quantifier and an existential quantifier, resulting in an invalid
inference; mistaken reasoning that what is true for all/every/each
(universal quantifier) of something is also true for some/a/the/one
(existential quantifier) of that thing. (EXAMPLES IN BOOK)
c. Equivocation: A fallacy that involves changing the definition of
terms in different premises or conclusions of a single argument.
(EXAMPLES IN BOOK)
2. Evidential fallacy: An argument that fails to show its conclusion to be
reasonably likely because the state of information is too weak to
support the conclusion. / Failure to make conclusion reasonable
even in inductive or heuristic terms.
a. Argument from ignorance: We have no evidence that P; Therefore,
it is not the case P