context: There is almost no chance that Emily is a sheep. Chances are slight that Julius is a swan. Chances are about even that Bernhard is a rhino. It is probably the case that if either 'Julius is a swan' or 'Emily is a sheep' but not both then Lily is green. It is likely that if 'Emily is a sheep' or 'Bernhard is a rhino' or both then Greg is a frog. There is little chance that if 'Julius is a swan' or 'Bernhard is a rhino' or both then John left the football.
hypothesis: Chances are slight that 'Lily is green' or 'Julius is a swan' or both.
valid_hypothesis: Chances are slight that 'Lily is green' or 'Julius is a swan' or both.
invalid_hypothesis: It is probably the case that 'Lily is green' or 'Julius 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
    0.02::factA.
    0.1::factB.
    0.5::factC.
    %hop1
    0.7::factX:-xor(factB,factA).
    0.7::factY:-or(factA,factC).
    0.1::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-or(factX,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is green' or 'Julius is a swan' or both.