There is little chance that Sandra took the milk. It is improbable that Jessica is a cat. It is probably not the case that Brian is green. There is a better than even chance that if 'Brian is green' or 'Sandra took the milk' or both then Lily is a frog. We believe that if 'Jessica is a cat' or 'Brian is green' or both then Mary moved to the office. It is certain that if 'Sandra took the milk and Brian is green' then John got the apple.
It is probably the case that 'John got the apple' or 'Brian is green' or both.
It is probably not the case that 'John got the apple' or 'Brian is green' or both.
It is probably the case that 'John got the apple' or 'Brian 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.
  0.25::factC.
  %hop1
  0.6::factX:-or(factC,factA).
  0.75::factY:-or(factB,factC).
  1.0::factZ:-and(factA,factC).

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

  query(conclusion).
  
'John got the apple' or 'Brian is green' or both.