We doubt that Emily is a wolf. It is unlikely that John got the milk. It is impossible that Bernhard is a rhino. Chances are about even that if either 'John got the milk' or 'Bernhard is a rhino' but not both then Mary moved to the garden. It is almost certain that if 'John got the milk and Emily is a wolf' then Greg is a swan. It is almost certain that if 'John got the milk and Bernhard is a rhino' then Daniel left the apple.
It is highly likely that either 'John got the milk' or 'Bernhard is a rhino' but not both.
It is unlikely that either 'John got the milk' or 'Bernhard is a rhino' but not both.
It is highly likely that either 'John got the milk' or 'Bernhard is a rhino' 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
  0.2::factA.
  0.2::factB.
  0.0::factC.
  %hop1
  0.5::factX:-xor(factB,factC).
  0.95::factY:-and(factB,factA).
  0.95::factZ:-and(factB,factC).

  %hop2
  conclusion:-xor(factB,factC).

  query(conclusion).
  
Either 'John got the milk' or 'Bernhard is a rhino' but not both.