context: It is probable that Mary left the milk. It is probably the case that Julius is a lion. It is probably the case that Emily is a mouse. There is little chance that if 'Julius is a lion and Emily is a mouse' then Brian is a swan. It is likely that if either 'Julius is a lion' or 'Emily is a mouse' but not both then John went to the hallway. It is highly likely that if 'Julius is a lion' or 'Mary left the milk' or both then Lily is white.
hypothesis: It is probably not the case that 'Lily is white' or 'Brian is a swan' or both.
valid_hypothesis: There is a very good chance that 'Lily is white' or 'Brian is a swan' or both.
invalid_hypothesis: It is probably not the case that 'Lily is white' or 'Brian is a swan' 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
    0.7::factA.
    0.7::factB.
    0.7::factC.
    %hop1
    0.1::factX:-and(factB,factC).
    0.7::factY:-xor(factB,factC).
    0.9::factZ:-or(factB,factA).
  
    %hop2
    conclusion:-or(factZ,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is white' or 'Brian is a swan' or both.