There is almost no chance that Bernhard is a rhino. It is highly unlikely that Greg is a lion. Chances are slight that Mary got the milk. It is likely that if 'Bernhard is a rhino and Mary got the milk' then Julius is a swan. It is likely that if either 'Greg is a lion' or 'Mary got the milk' but not both then Lily is a swan. It is almost certain that if 'Greg is a lion' or 'Bernhard is a rhino' or both then John went to the kitchen.
It is probable that 'Julius is a swan' or 'Bernhard is a rhino' or both.
There is almost no chance that 'Julius is a swan' or 'Bernhard is a rhino' or both.
It is probable that 'Julius is a swan' or 'Bernhard is a rhino' or both.

  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
  0.02::factA.
  0.05::factB.
  0.1::factC.
  %hop1
  0.7::factX:-and(factA,factC).
  0.7::factY:-xor(factB,factC).
  0.95::factZ:-or(factB,factA).

  %hop2
  conclusion:-or(factX,factA).

  query(conclusion).
  
'Julius is a swan' or 'Bernhard is a rhino' or both.