An exceptive syllogism uses two premises: a conditional proposition and a categorical premise affirming or denying one of its sides.
Connected conditional: affirming the antecedent establishes the consequent; denying the consequent denies the antecedent. The two converse patterns are not generally productive.
True disjunction: both affirmation-to-denial and denial-to-affirmation are valid.
Exclusion of conjunction: only affirmation-to-denial is valid.
Exclusion of emptiness: only denial-to-affirmation is valid.
The book next turns to induction (istiqrāʾ), where a general judgment is proposed from an examination of particular cases.