context: Chances are slight that Daniel dropped the apple. It is likely that Lily is a rhino. We believe that Emily is a mouse. It is improbable that if either 'Lily is a rhino' or 'Emily is a mouse' but not both then Mary grabbed the milk. There is a better than even chance that if either 'Daniel dropped the apple' or 'Emily is a mouse' but not both then Greg is a swan. It is unlikely that if either 'Daniel dropped the apple' or 'Emily is a mouse' but not both then John went to the bedroom.
hypothesis: It is probably the case that 'Mary grabbed the milk' or 'Daniel dropped the apple' or both.
valid_hypothesis: There is little chance that 'Mary grabbed the milk' or 'Daniel dropped the apple' or both.
invalid_hypothesis: It is probably the case that 'Mary grabbed the milk' or 'Daniel dropped 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.
    0.7::factB.
    0.75::factC.
    %hop1
    0.1::factX:-xor(factB,factC).
    0.6::factY:-xor(factA,factC).
    0.2::factZ:-xor(factA,factC).
  
    %hop2
    conclusion:-or(factX,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary grabbed the milk' or 'Daniel dropped the apple' or both.