context: It is certain that John put down the apple. It is certain that Bill went to the garden. It is probably not the case that Bernhard is green.
hypothesis: Chances are about even that 'Bill went to the garden' or 'John put down the apple' or both.
valid_hypothesis: It is certain that 'Bill went to the garden' or 'John put down the apple' or both.
invalid_hypothesis: Chances are about even that 'Bill went to the garden' or 'John put down 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
    1.0::factA.
    1.0::factB.
    0.25::factC.
    
  
    %hop2
    conclusion:-or(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Bill went to the garden' or 'John put down the apple' or both.