It is probably the case that Bernhard is a frog. We doubt that Bill moved to the office. It is certain that Brian is a rhino. It is probable that if either 'Bill moved to the office' or 'Bernhard is a frog' but not both then Mary discarded the apple. There is a very good chance that if either 'Brian is a rhino' or 'Bernhard is a frog' but not both then Emily is a cat. It is highly unlikely that if 'Bill moved to the office and Brian is a rhino' then Lily is yellow.
It is certain that either 'Brian is a rhino' or 'Lily is yellow' but not both.
It is certain that either 'Brian is a rhino' or 'Lily is yellow' but not both.
It is probably not the case that either 'Brian is a rhino' or 'Lily is yellow' 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
  0.7::factA.
  0.2::factB.
  1.0::factC.
  %hop1
  0.7::factX:-xor(factB,factA).
  0.8::factY:-xor(factC,factA).
  0.05::factZ:-and(factB,factC).

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

  query(conclusion).
  
Either 'Brian is a rhino' or 'Lily is yellow' but not both.