Anchor: However (and this can be proved mathematically), although such systems exist, none of them can be explicitly described.
Entailed: There is no explicit way to explain these systems.
Contradiction: There are many people who have been able to describe such systems.
Contradiction: A child sits in a chair in a restaurant
Contradiction: A black dog runs through water.
Contradiction: Several men are scuba diving.
Contradiction: You'll immeditely know if he says anything racist.