context: Chances are about even that Jeff discarded the milk. Chances are about even that Brian is gray. It is highly likely that Mary went to the kitchen.
hypothesis: There is little chance that 'Jeff discarded the milk' or 'Mary went to the kitchen' or both.
valid_hypothesis: It is almost certain that 'Jeff discarded the milk' or 'Mary went to the kitchen' or both.
invalid_hypothesis: There is little chance that 'Jeff discarded the milk' or 'Mary went to the kitchen' 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
    0.5::factA.
    0.5::factB.
    0.9::factC.
    
  
    %hop2
    conclusion:-or(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Jeff discarded the milk' or 'Mary went to the kitchen' or both.