Chances are slight that Bernhard is a swan. It is highly unlikely that Antoine is thirsty. Chances are slight that John got the milk. We believe that if either 'Antoine is thirsty' or 'Bernhard is a swan' but not both then Emily is a sheep. It is unlikely that if either 'John got the milk' or 'Antoine is thirsty' but not both then Jessica is a mouse. There is almost no chance that if 'Antoine is thirsty and John got the milk' then Greg is a frog.
It is highly likely that either 'Jessica is a mouse' or 'Bernhard is a swan' but not both.
It is improbable that either 'Jessica is a mouse' or 'Bernhard is a swan' but not both.
It is highly likely that either 'Jessica is a mouse' or 'Bernhard is a swan' but not 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
  0.1::factA.
  0.05::factB.
  0.1::factC.
  %hop1
  0.75::factX:-xor(factB,factA).
  0.2::factY:-xor(factC,factB).
  0.02::factZ:-and(factB,factC).

  %hop2
  conclusion:-xor(factY,factA).

  query(conclusion).
  
Either 'Jessica is a mouse' or 'Bernhard is a swan' but not both.