There is a better than even chance that Gertrude is a wolf. It is probably the case that Julius is white. Chances are slight that Lily is yellow. It is unlikely that if 'Gertrude is a wolf and Lily is yellow' then Antoine is hungry. It is probable that if 'Lily is yellow and Julius is white' then John left the football. There is a better than even chance that if 'Julius is white and Lily is yellow' then Brian is a rhino.
It is certain that either 'Antoine is hungry' or 'John left the football' but not both.
It is highly unlikely that either 'Antoine is hungry' or 'John left the football' but not both.
It is certain that either 'Antoine is hungry' or 'John left the football' 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
  0.6::factA.
  0.7::factB.
  0.1::factC.
  %hop1
  0.2::factX:-and(factA,factC).
  0.7::factY:-and(factC,factB).
  0.6::factZ:-and(factB,factC).

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

  query(conclusion).
  
Either 'Antoine is hungry' or 'John left the football' but not both.