It is certain that Daniel took the milk. It is probably not the case that Julius is gray. It is probably the case that Jessica is a cat. Chances are about even that if 'Daniel took the milk' or 'Jessica is a cat' or both then Bernhard is a swan. It is probably the case that if 'Jessica is a cat' or 'Julius is gray' or both then Brian is a swan. There is a very good chance that if 'Julius is gray' or 'Jessica is a cat' or both then John went to the hallway.
Chances are about even that 'John went to the hallway and Brian is a swan'.
Chances are about even that 'John went to the hallway and Brian is a swan'.
It is almost certain that 'John went to the hallway and Brian is a swan'.

  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.
  0.25::factB.
  0.7::factC.
  %hop1
  0.5::factX:-or(factA,factC).
  0.7::factY:-or(factC,factB).
  0.8::factZ:-or(factB,factC).

  %hop2
  conclusion:-and(factZ,factY).

  query(conclusion).
  
'John went to the hallway and Brian is a swan'.