It is highly unlikely that Jessica is a cat. It is improbable that Fred discarded the apple. There is a better than even chance that Brian is a lion. It is probable that if 'Fred discarded the apple and Jessica is a cat' then Julius is a swan. It is probably the case that if either 'Fred discarded the apple' or 'Jessica is a cat' but not both then John went to the kitchen. It is unlikely that if either 'Jessica is a cat' or 'Brian is a lion' but not both then Bernhard is gray.
There is a better than even chance that 'Julius is a swan' or 'Brian is a lion' or both.
There is a better than even chance that 'Julius is a swan' or 'Brian is a lion' or both.
It is improbable that 'Julius is a swan' or 'Brian is a lion' 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
  0.05::factA.
  0.1::factB.
  0.6::factC.
  %hop1
  0.7::factX:-and(factB,factA).
  0.7::factY:-xor(factB,factA).
  0.2::factZ:-xor(factA,factC).

  %hop2
  conclusion:-or(factX,factC).

  query(conclusion).
  
'Julius is a swan' or 'Brian is a lion' or both.