Chances are slight that John moved to the garden. Chances are slight that Jason is tired. It is unlikely that Jessica is a cat. We doubt that if 'Jason is tired and Jessica is a cat' then Brian is a frog. It is certain that if either 'Jason is tired' or 'John moved to the garden' but not both then Sandra left the milk. It is highly likely that if 'John moved to the garden and Jason is tired' then Lily is green.
It is unlikely that 'Sandra left the milk' or 'Lily is green' or both.
It is unlikely that 'Sandra left the milk' or 'Lily is green' or both.
There is a very good chance that 'Sandra left the milk' or 'Lily is green' 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.
  0.1::factB.
  0.2::factC.
  %hop1
  0.2::factX:-and(factB,factC).
  1.0::factY:-xor(factB,factA).
  0.9::factZ:-and(factA,factB).

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

  query(conclusion).
  
'Sandra left the milk' or 'Lily is green' or both.