We believe that John dropped the apple. There is almost no chance that Bill went to the garden. We doubt that Brian is a swan. It is likely that if 'Bill went to the garden' or 'Brian is a swan' or both then Jessica is a mouse. It is almost certain that if either 'Brian is a swan' or 'John dropped the apple' but not both then Julius is a frog. There is a very good chance that if either 'John dropped the apple' or 'Bill went to the garden' but not both then Bernhard is a lion.
We believe that 'Bernhard is a lion' or 'John dropped the apple' or both.
We believe that 'Bernhard is a lion' or 'John dropped the apple' or both.
It is highly unlikely that 'Bernhard is a lion' or 'John dropped the apple' 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
  0.75::factA.
  0.02::factB.
  0.2::factC.
  %hop1
  0.7::factX:-or(factB,factC).
  0.95::factY:-xor(factC,factA).
  0.8::factZ:-xor(factA,factB).

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

  query(conclusion).
  
'Bernhard is a lion' or 'John dropped the apple' or both.