We believe that Jessica is a wolf. It is impossible that Winona is a sheep. There is a better than even chance that Brian is green. It is likely that if 'Jessica is a wolf and Brian is green' then Daniel left the apple. It is almost certain that if 'Winona is a sheep and Jessica is a wolf' then John went to the garden. It is certain that if 'Jessica is a wolf and Brian is green' then Mary put down the milk.
We believe that either 'Jessica is a wolf' or 'John went to the garden' but not both.
We believe that either 'Jessica is a wolf' or 'John went to the garden' but not both.
There is almost no chance that either 'Jessica is a wolf' or 'John went to the garden' 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
  0.75::factA.
  0.0::factB.
  0.6::factC.
  %hop1
  0.7::factX:-and(factA,factC).
  0.95::factY:-and(factB,factA).
  1.0::factZ:-and(factA,factC).

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

  query(conclusion).
  
Either 'Jessica is a wolf' or 'John went to the garden' but not both.