Chances are slight that Julius is gray. We doubt that Mary went to the hallway. Chances are about even that Jessica is a cat. There is almost no chance that if either 'Mary went to the hallway' or 'Julius is gray' but not both then John moved to the office. It is unlikely that if either 'Julius is gray' or 'Mary went to the hallway' but not both then Daniel took the apple. There is a very good chance that if 'Julius is gray' or 'Jessica is a cat' or both then Yann is tired.
Chances are slight that 'John moved to the office' or 'Julius is gray' or both.
Chances are slight that 'John moved to the office' or 'Julius is gray' or both.
It is highly likely that 'John moved to the office' or 'Julius is gray' 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
  0.1::factA.
  0.2::factB.
  0.5::factC.
  %hop1
  0.02::factX:-xor(factB,factA).
  0.2::factY:-xor(factA,factB).
  0.8::factZ:-or(factA,factC).

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

  query(conclusion).
  
'John moved to the office' or 'Julius is gray' or both.