Anchor: You cannot defend against what I saw.
Entailed: There is nothing that can be told to make what I saw untrue. 
Contradiction: What I saw can be easily defended and changed.
Contradiction: Alexander the Great held power in the second century BC.
Contradiction: Agricultural labor or services for a specified employer or employers fall into the category of H-2A aliens, non-immigrants.
Contradiction: Columbus never made a trip to Jamaica.
Contradiction: Currently, there is no peer accounting system.