context: We believe that Lily is a lion. It is probable that Winona is a sheep. It is likely that Brian is a frog. We believe that if either 'Brian is a frog' or 'Winona is a sheep' but not both then Mary dropped the apple. It is probably not the case that if 'Brian is a frog' or 'Winona is a sheep' or both then Bernhard is white. It is highly likely that if 'Brian is a frog and Winona is a sheep' then Daniel put down the milk.
hypothesis: There is little chance that 'Bernhard is white and Daniel put down the milk'.
valid_hypothesis: There is little chance that 'Bernhard is white and Daniel put down the milk'.
invalid_hypothesis: It is highly likely that 'Bernhard is white and Daniel put down the milk'.
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.
    0.7::factB.
    0.7::factC.
    %hop1
    0.75::factX:-xor(factC,factB).
    0.25::factY:-or(factC,factB).
    0.9::factZ:-and(factC,factB).
  
    %hop2
    conclusion:-and(factY,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is white and Daniel put down the milk'.