Anchor: Sisler characterized a change in light extinction of one deciview as a small but perceptible scenic change under many circumstances.
Entailed: One deciview is a substantial enough unit of air quality to be visible, the smallest possible measurement while still distinguishable by the naked human eye.
Contradiction: No human can distinguish a single deciview's worth of air pollution. 
Contradiction: That is true, we still are.
Contradiction: The elevators have lots of people in them.
Contradiction: It was a really great date.
Contradiction: George and Bill were fighting at the MMA event.