It is probably not the case that Winona is a wolf. It is improbable that Gertrude is a mouse. It is probably the case that Bernhard is green. There is little chance that if 'Winona is a wolf and Gertrude is a mouse' then Emily is a sheep. There is a very good chance that if either 'Winona is a wolf' or 'Gertrude is a mouse' but not both then Fred put down the apple. It is certain that if either 'Gertrude is a mouse' or 'Winona is a wolf' but not both then John went to the garden.
It is improbable that either 'Winona is a wolf' or 'Fred put down the apple' but not both.
It is improbable that either 'Winona is a wolf' or 'Fred put down the apple' but not both.
It is likely that either 'Winona is a wolf' or 'Fred put down the apple' 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
  0.25::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.1::factX:-and(factA,factB).
  0.8::factY:-xor(factA,factB).
  1.0::factZ:-xor(factB,factA).

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

  query(conclusion).
  
Either 'Winona is a wolf' or 'Fred put down the apple' but not both.