It is improbable that Lily is white. We doubt that Mary moved to the office. We believe that Greg is gray. It is certain that if 'Greg is gray' or 'Lily is white' or both then Jason is thirsty. Chances are slight that if 'Greg is gray' or 'Lily is white' or both then Brian is a rhino. There is a very good chance that if 'Lily is white' or 'Mary moved to the office' or both then John dropped the apple.
It is highly likely that 'John dropped the apple' or 'Lily is white' or both.
It is probably not the case that 'John dropped the apple' or 'Lily is white' or both.
It is highly likely that 'John dropped the apple' or 'Lily is white' 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.
  0.75::factC.
  %hop1
  1.0::factX:-or(factC,factA).
  0.1::factY:-or(factC,factA).
  0.8::factZ:-or(factA,factB).

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

  query(conclusion).
  
'John dropped the apple' or 'Lily is white' or both.