There is a better than even chance that Julius is a lion. It is impossible that Mary got the football. We doubt that Bernhard is a rhino. It is probably the case that if either 'Mary got the football' or 'Julius is a lion' but not both then Winona is a sheep. It is probably the case that if 'Mary got the football and Bernhard is a rhino' then Fred put down the apple. It is improbable that if 'Julius is a lion' or 'Mary got the football' or both then Brian is a swan.
We doubt that either 'Julius is a lion' or 'Winona is a sheep' but not both.
We doubt that either 'Julius is a lion' or 'Winona is a sheep' but not both.
It is certain that either 'Julius is a lion' or 'Winona is a sheep' 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.
  0.0::factB.
  0.2::factC.
  %hop1
  0.7::factX:-xor(factB,factA).
  0.7::factY:-and(factB,factC).
  0.1::factZ:-or(factA,factB).

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

  query(conclusion).
  
Either 'Julius is a lion' or 'Winona is a sheep' but not both.