HU260
Constructing Deductive and Inductive Arguments
Grantham University
HU260 Strategies for Decision Making
Modus
Ponens
Modus Ponens, latin for “mode that affirms”, is the “rule of logic stating that if a
Conditional statement (‘if p then q’) is accepted and the antecedent (p) holds, then the
consequent (q) may be inferred” (Dictionary). One example of this form of argument is – if it
is an airplane, then it has wings. It is an airplane. Therefore, it has wings.
Modus
Tollens
Modus Tollens, latin for “the way that denies by denying”, is the “rule of logic stating
that if a conditional statement (‘if p then q’) is accepted, and the consequent does not hold (not
– q), then the negation of the antecedent (not -p) can be inferred” (Dictionary). An example of
this form of argument is – if it is an airplane, then it has wings. It does not have wings.
Therefore, it is not an airplane.
Hypothetical
Syllogisms
“Hypothetical syllogisms are short, two-premise deductive arguments, in which at least
one of the premises is a conditional or hypothetical, the antecedent or consequent of which also
appears in the other premise” (Beisecker). One example of a hypothetical syllogism is – if it
