context: It is certain that Sandra dropped the milk. There is a very good chance that Lily is yellow. It is certain that Winona is a sheep. It is certain that if 'Lily is yellow' or 'Winona is a sheep' or both then Brian is a frog. Chances are slight that if 'Sandra dropped the milk' or 'Lily is yellow' or both then John took the apple. There is a better than even chance that if 'Winona is a sheep and Lily is yellow' then Mary went to the bedroom.
hypothesis: It is certain that 'Winona is a sheep' or 'Lily is yellow' or both.
valid_hypothesis: It is certain that 'Winona is a sheep' or 'Lily is yellow' or both.
invalid_hypothesis: We doubt that 'Winona is a sheep' or 'Lily is yellow' or both.
problog: 
    and(A,B) :- A,B.
    or(A,B) :- A;B.
    nand(A,B) :- not(and(A,B)).
    nor(A,B) :- not(or(A,B)).
    xor(A,B) :- or(A,B), nand(A,B).
  
    %hop0
    1.0::factA.
    0.8::factB.
    1.0::factC.
    %hop1
    1.0::factX:-or(factB,factC).
    0.1::factY:-or(factA,factB).
    0.6::factZ:-and(factC,factB).
  
    %hop2
    conclusion:-or(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Winona is a sheep' or 'Lily is yellow' or both.