Chances are about even that John went to the kitchen. It is probably the case that Lily is a lion. It is highly likely that Winona is a wolf. It is unlikely that if either 'Winona is a wolf' or 'Lily is a lion' but not both then Julius is a swan. Chances are about even that if either 'Lily is a lion' or 'John went to the kitchen' but not both then Greg is green. It is highly unlikely that if 'John went to the kitchen' or 'Lily is a lion' or both then Brian is a frog.
Chances are about even that either 'John went to the kitchen' or 'Winona is a wolf' but not both.
Chances are about even that either 'John went to the kitchen' or 'Winona is a wolf' but not both.
It is certain that either 'John went to the kitchen' or 'Winona is a wolf' 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
  0.5::factA.
  0.7::factB.
  0.9::factC.
  %hop1
  0.2::factX:-xor(factC,factB).
  0.5::factY:-xor(factB,factA).
  0.05::factZ:-or(factA,factB).

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

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