It is improbable that Bernhard is a rhino. It is probable that Julius is white. It is impossible that John got the football. It is certain that if either 'John got the football' or 'Julius is white' but not both then Mary went to the hallway. It is unlikely that if 'Bernhard is a rhino' or 'Julius is white' or both then Fred is in the office. There is a better than even chance that if 'John got the football' or 'Julius is white' or both then Lily is green.
There is a better than even chance that either 'Julius is white' or 'Fred is in the office' but not both.
There is a better than even chance that either 'Julius is white' or 'Fred is in the office' but not both.
It is highly unlikely that either 'Julius is white' or 'Fred is in the office' 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.
  0.7::factB.
  0.0::factC.
  %hop1
  1.0::factX:-xor(factC,factB).
  0.2::factY:-or(factA,factB).
  0.6::factZ:-or(factC,factB).

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

  query(conclusion).
  
Either 'Julius is white' or 'Fred is in the office' but not both.