context: We believe that Daniel got the milk. We believe that Greg is a frog. It is unlikely that Emily is a wolf.
hypothesis: There is a very good chance that 'Greg is a frog' or 'Emily is a wolf' or both.
valid_hypothesis: There is a very good chance that 'Greg is a frog' or 'Emily is a wolf' or both.
invalid_hypothesis: There is little chance that 'Greg is a frog' or 'Emily is a wolf' 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
    0.75::factA.
    0.75::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-or(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is a frog' or 'Emily is a wolf' or both.