Anchor: The second is an economic argument which presumes that the Postal Service as a monopolist is an efficient provider of delivery.
Entailed: Monopolistic service providers are sometimes assumed to operate efficiently.
Contradiction: The Postal Service does not operate as a monopoly.
Contradiction: People are walking along the beach.
Contradiction: Proof!
Contradiction: The girls are inside looking out at the rain.
Contradiction: Something was odd about the stain.