context: It is probably not the case that Mary moved to the office. It is unlikely that Greg is gray. It is probably the case that John went to the garden.
hypothesis: It is certain that 'John went to the garden and Greg is gray'.
valid_hypothesis: Chances are slight that 'John went to the garden and Greg is gray'.
invalid_hypothesis: It is certain that 'John went to the garden and Greg is gray'.
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
    0.25::factA.
    0.2::factB.
    0.7::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'John went to the garden and Greg is gray'.