It is certain that Antoine is thirsty. It is almost certain that Julius is a swan. It is probably the case that Brian is green. We believe that if 'Brian is green and Julius is a swan' then Bernhard is a rhino. It is highly likely that if either 'Brian is green' or 'Julius is a swan' but not both then John discarded the apple. It is certain that if either 'Julius is a swan' or 'Brian is green' but not both then Mary went to the office.
There is a very good chance that either 'Bernhard is a rhino' or 'Mary went to the office' but not both.
There is a very good chance that either 'Bernhard is a rhino' or 'Mary went to the office' but not both.
We doubt that either 'Bernhard is a rhino' or 'Mary 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
  1.0::factA.
  0.95::factB.
  0.7::factC.
  %hop1
  0.75::factX:-and(factC,factB).
  0.9::factY:-xor(factC,factB).
  1.0::factZ:-xor(factB,factC).

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

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