context: It is probable that Bernhard is a frog. We doubt that Julius is white. It is probable that Winona is a wolf. It is probably the case that if either 'Bernhard is a frog' or 'Julius is white' but not both then Emily is a wolf. Chances are slight that if 'Bernhard is a frog' or 'Winona is a wolf' or both then Brian is a rhino. We doubt that if either 'Bernhard is a frog' or 'Julius is white' but not both then Mary dropped the milk.
hypothesis: It is highly likely that 'Brian is a rhino and Mary dropped the milk'.
valid_hypothesis: There is almost no chance that 'Brian is a rhino and Mary dropped the milk'.
invalid_hypothesis: It is highly likely that 'Brian is a rhino and Mary dropped the milk'.
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
    0.7::factA.
    0.2::factB.
    0.7::factC.
    %hop1
    0.7::factX:-xor(factA,factB).
    0.1::factY:-or(factA,factC).
    0.2::factZ:-xor(factA,factB).
  
    %hop2
    conclusion:-and(factY,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a rhino and Mary dropped the milk'.