“This book is new” and “This book is not new” concern a specified individual. There is no universal or particular quantifier; contradiction requires the same identified subject and predicate.
By contrast, “Every book is new” quantifies over a class. Its contradictory is “Some book is not new.”
Thus the tests differ:
Singular propositions — exact affirmation and denial about one individual.
Quantified propositions — the proper reversal of quantity as well as quality.
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Contradiction: Definition, Conditions and Application to Propositions
“This book is new” and “This book is not new” concern a specified individual. There is no universal or particular quantifier; contradiction requires the same identified subject and predicate.
By contrast, “Every book is new” quantifies over a class. Its contradictory is “Some book is not new.”
Thus the tests differ:
Singular propositions — exact affirmation and denial about one individual.
Quantified propositions — the proper reversal of quantity as well as quality.