We doubt that Bernhard is a lion. There is almost no chance that Jessica is a sheep. There is almost no chance that Greg is a rhino. We believe that if 'Bernhard is a lion' or 'Jessica is a sheep' or both then John got the apple. It is almost certain that if 'Bernhard is a lion' or 'Jessica is a sheep' or both then Mary went to the hallway. It is probable that if 'Greg is a rhino and Bernhard is a lion' then Brian is a lion.
There is a very good chance that 'Brian is a lion' or 'John got the apple' or both.
We doubt that 'Brian is a lion' or 'John got the apple' or both.
There is a very good chance that 'Brian is a lion' or 'John got 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
  0.2::factA.
  0.02::factB.
  0.02::factC.
  %hop1
  0.75::factX:-or(factA,factB).
  0.95::factY:-or(factA,factB).
  0.7::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Brian is a lion' or 'John got the apple' or both.