context: We doubt that John went to the kitchen. It is probable that Greg is a rhino. It is highly likely that Mary dropped the apple.
hypothesis: There is a better than even chance that 'Mary dropped the apple and Greg is a rhino'.
valid_hypothesis: There is a better than even chance that 'Mary dropped the apple and Greg is a rhino'.
invalid_hypothesis: It is improbable that 'Mary dropped the apple and Greg is a rhino'.
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
    0.2::factA.
    0.7::factB.
    0.9::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary dropped the apple and Greg is a rhino'.