premise: Two people connected to ropes wearing bright orange helmets are sitting on a rocky crag high in the mountains. hypothesis: People sit on a couch.
contradiction: A couch is not the same as a rocky crag.|contradiction: People do not usually sit on a couch when they are outside sitting in the mountains.|contradiction: If people are sitting on a rocky crag high in the mountains, it is not possible for them to be seated on a couch.