context: It is certain that Brian is a rhino. There is almost no chance that Mary went to the office. It is probable that Julius is gray. It is certain that if 'Mary went to the office and Julius is gray' then Jeff dropped the apple. We doubt that if either 'Julius is gray' or 'Mary went to the office' but not both then Jessica is a mouse. It is certain that if 'Mary went to the office' or 'Brian is a rhino' or both then John got the milk.
hypothesis: Chances are slight that 'Brian is a rhino and Julius is gray'.
valid_hypothesis: It is likely that 'Brian is a rhino and Julius is gray'.
invalid_hypothesis: Chances are slight that 'Brian is a rhino and Julius 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
    1.0::factA.
    0.02::factB.
    0.7::factC.
    %hop1
    1.0::factX:-and(factB,factC).
    0.2::factY:-xor(factC,factB).
    1.0::factZ:-or(factB,factA).
  
    %hop2
    conclusion:-and(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a rhino and Julius is gray'.