It is certain that Julius is a lion. It is probable that Mary went to the office. It is likely that Daniel left the apple. It is likely that if 'Julius is a lion' or 'Mary went to the office' or both then Bernhard is a frog. There is a very good chance that if 'Mary went to the office and Daniel left the apple' then Greg is a swan. Chances are slight that if either 'Mary went to the office' or 'Julius is a lion' but not both then Lily is yellow.
It is almost certain that either 'Bernhard is a frog' or 'Greg is a swan' but not both.
Chances are about even that either 'Bernhard is a frog' or 'Greg is a swan' but not both.
It is almost certain that either 'Bernhard is a frog' or 'Greg is a swan' 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
  1.0::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.7::factX:-or(factA,factB).
  0.8::factY:-and(factB,factC).
  0.1::factZ:-xor(factB,factA).

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

  query(conclusion).
  
Either 'Bernhard is a frog' or 'Greg is a swan' but not both.