It is highly unlikely that John went to the office. We doubt that Lily is a rhino. It is certain that Brian is white. Chances are slight that if either 'John went to the office' or 'Lily is a rhino' but not both then Julius is gray. It is unlikely that if either 'Lily is a rhino' or 'John went to the office' but not both then Greg is a swan. It is probable that if 'John went to the office and Lily is a rhino' then Jessica is a wolf.
It is probably not the case that either 'Lily is a rhino' or 'John went to the office' but not both.
It is probably not the case that either 'Lily is a rhino' or 'John went to the office' but not both.
It is probable that either 'Lily is a rhino' or 'John went to 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
  0.05::factA.
  0.2::factB.
  1.0::factC.
  %hop1
  0.1::factX:-xor(factA,factB).
  0.2::factY:-xor(factB,factA).
  0.7::factZ:-and(factA,factB).

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

  query(conclusion).
  
Either 'Lily is a rhino' or 'John went to the office' but not both.