It is certain that Julius is a swan. It is likely that Daniel put down the milk. It is certain that Lily is a rhino. It is likely that if 'Daniel put down the milk' or 'Lily is a rhino' or both then Winona is a sheep. We believe that if either 'Julius is a swan' or 'Lily is a rhino' but not both then Jeff left the apple. There is a very good chance that if 'Lily is a rhino' or 'Daniel put down the milk' or both then Bernhard is a frog.
It is unlikely that 'Julius is a swan' or 'Bernhard is a frog' or both.
It is certain that 'Julius is a swan' or 'Bernhard is a frog' or both.
It is unlikely that 'Julius is a swan' or 'Bernhard is a frog' or 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
  1.0::factA.
  0.7::factB.
  1.0::factC.
  %hop1
  0.7::factX:-or(factB,factC).
  0.75::factY:-xor(factA,factC).
  0.8::factZ:-or(factC,factB).

  %hop2
  conclusion:-or(factA,factZ).

  query(conclusion).
  
'Julius is a swan' or 'Bernhard is a frog' or both.