context: We believe that Brian is white. There is a better than even chance that Winona is a sheep. There is little chance that Julius is a rhino. It is improbable that if either 'Winona is a sheep' or 'Brian is white' but not both then Antoine is thirsty. It is probably not the case that if 'Brian is white' or 'Winona is a sheep' or both then John went to the bedroom. It is almost certain that if 'Brian is white' or 'Winona is a sheep' or both then Sandra took the milk.
hypothesis: It is highly likely that 'Brian is white' or 'Sandra took the milk' or both.
valid_hypothesis: It is highly likely that 'Brian is white' or 'Sandra took the milk' or both.
invalid_hypothesis: There is little chance that 'Brian is white' or 'Sandra took the milk' 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
    0.75::factA.
    0.6::factB.
    0.1::factC.
    %hop1
    0.1::factX:-xor(factB,factA).
    0.25::factY:-or(factA,factB).
    0.95::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-or(factA,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is white' or 'Sandra took the milk' or both.