context: It is certain that Mary left the apple. There is little chance that Lily is a frog. It is highly likely that John grabbed the apple. It is impossible that if either 'Mary left the apple' or 'Lily is a frog' but not both then Brian is a rhino. It is probably not the case that if 'Lily is a frog and John grabbed the apple' then Bernhard is yellow. It is likely that if 'Mary left the apple and Lily is a frog' then Greg is green.
hypothesis: It is highly likely that 'John grabbed the apple' or 'Brian is a rhino' or both.
valid_hypothesis: It is highly likely that 'John grabbed the apple' or 'Brian is a rhino' or both.
invalid_hypothesis: We doubt that 'John grabbed the apple' or 'Brian is a rhino' 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.
    0.1::factB.
    0.9::factC.
    %hop1
    0.0::factX:-xor(factA,factB).
    0.25::factY:-and(factB,factC).
    0.7::factZ:-and(factA,factB).
  
    %hop2
    conclusion:-or(factC,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'John grabbed the apple' or 'Brian is a rhino' or both.