It is unlikely that Bernhard is a lion. Chances are slight that Bill left the milk. It is probably not the case that Mary dropped the milk. It is improbable that if 'Bernhard is a lion and Bill left the milk' then Antoine is hungry. There is a very good chance that if either 'Mary dropped the milk' or 'Bernhard is a lion' but not both then John moved to the office. It is unlikely that if 'Mary dropped the milk and Bernhard is a lion' then Greg is a rhino.
There is almost no chance that 'Mary dropped the milk and Bill left the milk'.
There is almost no chance that 'Mary dropped the milk and Bill left the milk'.
There is a better than even chance that 'Mary dropped the milk and Bill left the milk'.

  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
  0.2::factA.
  0.1::factB.
  0.25::factC.
  %hop1
  0.1::factX:-and(factA,factB).
  0.8::factY:-xor(factC,factA).
  0.2::factZ:-and(factC,factA).

  %hop2
  conclusion:-and(factC,factB).

  query(conclusion).
  
'Mary dropped the milk and Bill left the milk'.