There is little chance that Jessica is a mouse. We doubt that Bernhard is white. Chances are slight that Brian is gray. It is highly likely that if 'Bernhard is white and Brian is gray' then Gertrude is a cat. It is probably the case that if 'Bernhard is white and Jessica is a mouse' then Mary went to the office. It is likely that if either 'Jessica is a mouse' or 'Bernhard is white' but not both then Daniel grabbed the apple.
There is a very good chance that either 'Daniel grabbed the apple' or 'Brian is gray' but not both.
It is probably not the case that either 'Daniel grabbed the apple' or 'Brian is gray' but not both.
There is a very good chance that either 'Daniel grabbed the apple' or 'Brian is gray' 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.
  0.2::factB.
  0.1::factC.
  %hop1
  0.9::factX:-and(factB,factC).
  0.7::factY:-and(factB,factA).
  0.7::factZ:-xor(factA,factB).

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

  query(conclusion).
  
Either 'Daniel grabbed the apple' or 'Brian is gray' but not both.