It is improbable that Julius is a swan. It is impossible that Mary took the milk. There is a better than even chance that John moved to the garden. It is certain that if 'Mary took the milk' or 'John moved to the garden' or both then Jessica is a mouse. It is probably not the case that if 'Mary took the milk and John moved to the garden' then Daniel got the football. There is almost no chance that if either 'John moved to the garden' or 'Julius is a swan' but not both then Bernhard is green.
It is impossible that 'Julius is a swan and Mary took the milk'.
It is impossible that 'Julius is a swan and Mary took the milk'.
Chances are about even that 'Julius is a swan and Mary took the milk'.

  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
  0.1::factA.
  0.0::factB.
  0.6::factC.
  %hop1
  1.0::factX:-or(factB,factC).
  0.25::factY:-and(factB,factC).
  0.02::factZ:-xor(factC,factA).

  %hop2
  conclusion:-and(factA,factB).

  query(conclusion).
  
'Julius is a swan and Mary took the milk'.