context: It is certain that Mary got the football. Chances are about even that Julius is a swan. There is little chance that Bernhard is a lion. It is improbable that if either 'Mary got the football' or 'Julius is a swan' but not both then John took the apple. Chances are about even that if 'Bernhard is a lion and Julius is a swan' then Jessica is a cat. Chances are about even that if 'Julius is a swan and Bernhard is a lion' then Jeff discarded the milk.
hypothesis: There is little chance that 'John took the apple' or 'Bernhard is a lion' or both.
valid_hypothesis: There is little chance that 'John took the apple' or 'Bernhard is a lion' or both.
invalid_hypothesis: It is probable that 'John took the apple' or 'Bernhard is a lion' 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
    1.0::factA.
    0.5::factB.
    0.1::factC.
    %hop1
    0.1::factX:-xor(factA,factB).
    0.5::factY:-and(factC,factB).
    0.5::factZ:-and(factB,factC).
  
    %hop2
    conclusion:-or(factX,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'John took the apple' or 'Bernhard is a lion' or both.