It is highly unlikely that John moved to the office. It is impossible that Mary went to the hallway. It is likely that Bernhard is yellow. Chances are about even that if 'John moved to the office' or 'Bernhard is yellow' or both then Julius is white. There is a better than even chance that if 'John moved to the office' or 'Bernhard is yellow' or both then Sandra took the football. It is highly unlikely that if either 'Bernhard is yellow' or 'Mary went to the hallway' but not both then Daniel got the milk.
It is highly likely that either 'John moved to the office' or 'Julius is white' but not both.
It is probably not the case that either 'John moved to the office' or 'Julius is white' but not both.
It is highly likely that either 'John moved to the office' or 'Julius is white' 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
  0.05::factA.
  0.0::factB.
  0.7::factC.
  %hop1
  0.5::factX:-or(factA,factC).
  0.6::factY:-or(factA,factC).
  0.05::factZ:-xor(factC,factB).

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

  query(conclusion).
  
Either 'John moved to the office' or 'Julius is white' but not both.