premise: A man looks back while laughing and walking.
hypothesis: A man walks and hears a funny joke and starts to laugh.
explanation_1: Just because a man is laughing doesn't mean he hear a funny joke
explanation_2: Not all man looks back hears a funny joke.
explanation_3: The first sentence said nothing about hearing a funny joke.
premise_logic: exists e3 e1 e2 p1 x1.(while(e1,e3) & Actor(e3,x1) & v_walk(e3) & while(e1,e2) & Actor(e2,x1) & v_laugh(e2) & exists s1.(Theme(s1,x1) & a_back(s1)) & Topic(e1,p1) & Actor(e1,x1) & v_look(e1) & n_man(x1))
hypothesis_logic: exists e3 e2 e1 p1 s1 x1 x2 x3 x4.(Topic(e3,p1) & Actor(e3,x4) & v_start(e3) & exists e4.(Actor(e4,x4) & v_laugh(e4)) & n_man(x4) & Theme(e2,x3) & Actor(e2,x2) & v_hear(e2) & n_joke(x3) & a_funny(s1) & Theme(s1,x3) & n_man(x2) & Actor(e1,x1) & v_walk(e1) & n_man(x1))