We doubt that John got the apple. It is highly unlikely that Emily is a mouse. We believe that Mary went to the hallway. It is almost certain that if 'John got the apple and Emily is a mouse' then Bernhard is white. There is a better than even chance that if 'Mary went to the hallway and John got the apple' then Lily is gray. There is a better than even chance that if 'Emily is a mouse' or 'John got the apple' or both then Brian is a swan.
It is highly unlikely that 'John got the apple' or 'Mary went to the hallway' or both.
There is a very good chance that 'John got the apple' or 'Mary went to the hallway' or both.
It is highly unlikely that 'John got the apple' or 'Mary went to the hallway' 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.
  0.05::factB.
  0.75::factC.
  %hop1
  0.95::factX:-and(factA,factB).
  0.6::factY:-and(factC,factA).
  0.6::factZ:-or(factB,factA).

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

  query(conclusion).
  
'John got the apple' or 'Mary went to the hallway' or both.