Text: Based on this faulty assumption, Landsburg then goes on to make the assertion that since our grandchildren are going to be so rich, they won't mind being reduced to seeing things like trees only in photographs, and they might prefer inheriting the proceeds of economic development to inheriting the redwoods, anyway.
Entailment: Landsburg believes that our grandchildren are going to be very rich.
Contradiction: Landsburg is an advocate of preserving redwood forests.