It is improbable that John discarded the apple. It is impossible that Julius is a swan. It is almost certain that Greg is yellow. It is highly unlikely that if either 'Greg is yellow' or 'Julius is a swan' but not both then Emily is a wolf. It is highly unlikely that if 'Greg is yellow and Julius is a swan' then Bernhard is a frog. There is a better than even chance that if 'Julius is a swan and Greg is yellow' then Lily is a lion.
It is impossible that 'Julius is a swan and Lily is a lion'.
It is impossible that 'Julius is a swan and Lily is a lion'.
Chances are about even that 'Julius is a swan and Lily is a lion'.

  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
  0.1::factA.
  0.0::factB.
  0.95::factC.
  %hop1
  0.05::factX:-xor(factC,factB).
  0.05::factY:-and(factC,factB).
  0.6::factZ:-and(factB,factC).

  %hop2
  conclusion:-and(factB,factZ).

  query(conclusion).
  
'Julius is a swan and Lily is a lion'.