context: It is highly unlikely that Julius is a frog. It is highly likely that Mary went to the kitchen. It is almost certain that Greg is a lion. Chances are about even that if either 'Mary went to the kitchen' or 'Julius is a frog' but not both then Bernhard is yellow. There is a better than even chance that if 'Greg is a lion and Julius is a frog' then Lily is a swan. There is little chance that if 'Julius is a frog and Mary went to the kitchen' then John put down the milk.
hypothesis: It is highly likely that 'Lily is a swan' or 'Mary went to the kitchen' or both.
valid_hypothesis: It is highly likely that 'Lily is a swan' or 'Mary went to the kitchen' or both.
invalid_hypothesis: We doubt that 'Lily is a swan' or 'Mary went to the kitchen' 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
    0.05::factA.
    0.9::factB.
    0.95::factC.
    %hop1
    0.5::factX:-xor(factB,factA).
    0.6::factY:-and(factC,factA).
    0.1::factZ:-and(factA,factB).
  
    %hop2
    conclusion:-or(factY,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is a swan' or 'Mary went to the kitchen' or both.