It is impossible that Julius is a lion. Chances are about even that Lily is a rhino. It is almost certain that Daniel took the apple. There is a very good chance that if 'Julius is a lion' or 'Daniel took the apple' or both then Brian is a swan. Chances are about even that if 'Daniel took the apple' or 'Julius is a lion' or both then Jessica is a cat. It is almost certain that if 'Julius is a lion and Lily is a rhino' then Greg is yellow.
We believe that either 'Brian is a swan' or 'Greg is yellow' but not both.
We believe that either 'Brian is a swan' or 'Greg is yellow' but not both.
It is unlikely that either 'Brian is a swan' or 'Greg is yellow' 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
  0.0::factA.
  0.5::factB.
  0.95::factC.
  %hop1
  0.8::factX:-or(factA,factC).
  0.5::factY:-or(factC,factA).
  0.95::factZ:-and(factA,factB).

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

  query(conclusion).
  
Either 'Brian is a swan' or 'Greg is yellow' but not both.