context: There is little chance that Brian is a swan. There is little chance that Greg is a frog. It is likely that John got the apple. It is almost certain that if 'Brian is a swan and Greg is a frog' then Bill left the milk. It is improbable that if either 'John got the apple' or 'Greg is a frog' but not both then Mary went to the bedroom. It is certain that if 'Greg is a frog' or 'John got the apple' or both then Bernhard is white.
hypothesis: There is little chance that 'Bernhard is white' or 'John got the apple' or both.
valid_hypothesis: We believe that 'Bernhard is white' or 'John got the apple' or both.
invalid_hypothesis: There is little chance that 'Bernhard is white' or 'John got the apple' 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
    0.1::factA.
    0.1::factB.
    0.7::factC.
    %hop1
    0.95::factX:-and(factA,factB).
    0.1::factY:-xor(factC,factB).
    1.0::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-or(factZ,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is white' or 'John got the apple' or both.