Chances are about even that John went to the kitchen. We believe that Jessica is a sheep. It is certain that Lily is white. We doubt that if 'Lily is white' or 'Jessica is a sheep' or both then Sumit is tired. It is probably the case that if 'John went to the kitchen' or 'Jessica is a sheep' or both then Julius is gray. It is highly unlikely that if either 'John went to the kitchen' or 'Jessica is a sheep' but not both then Brian is white.
It is improbable that 'Lily is white' or 'Sumit is tired' or both.
It is certain that 'Lily is white' or 'Sumit is tired' or both.
It is improbable that 'Lily is white' or 'Sumit is tired' 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
  0.5::factA.
  0.75::factB.
  1.0::factC.
  %hop1
  0.2::factX:-or(factC,factB).
  0.7::factY:-or(factA,factB).
  0.05::factZ:-xor(factA,factB).

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

  query(conclusion).
  
'Lily is white' or 'Sumit is tired' or both.