context: There is almost no chance that Julius is white. There is almost no chance that Bernhard is a swan. It is likely that Brian is a rhino. It is probably the case that if either 'Bernhard is a swan' or 'Julius is white' but not both then Winona is a wolf. It is probably not the case that if either 'Bernhard is a swan' or 'Julius is white' but not both then John went to the garden. It is probably the case that if 'Bernhard is a swan' or 'Brian is a rhino' or both then Fred dropped the milk.
hypothesis: Chances are about even that 'Fred dropped the milk' or 'Winona is a wolf' or both.
valid_hypothesis: Chances are about even that 'Fred dropped the milk' or 'Winona is a wolf' or both.
invalid_hypothesis: It is almost certain that 'Fred dropped the milk' or 'Winona is a wolf' 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
    0.02::factA.
    0.02::factB.
    0.7::factC.
    %hop1
    0.7::factX:-xor(factB,factA).
    0.25::factY:-xor(factB,factA).
    0.7::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-or(factZ,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Fred dropped the milk' or 'Winona is a wolf' or both.