There is a very good chance that Bernhard is a swan. It is unlikely that Mary left the milk. It is highly unlikely that Jessica is a cat. There is little chance that if either 'Jessica is a cat' or 'Mary left the milk' but not both then Lily is gray. There is a better than even chance that if 'Mary left the milk and Bernhard is a swan' then John took the apple. It is probably the case that if 'Mary left the milk and Bernhard is a swan' then Yann is tired.
It is highly likely that 'Mary left the milk' or 'Lily is gray' or both.
We doubt that 'Mary left the milk' or 'Lily is gray' or both.
It is highly likely that 'Mary left the milk' or 'Lily is gray' 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
  0.8::factA.
  0.2::factB.
  0.05::factC.
  %hop1
  0.1::factX:-xor(factC,factB).
  0.6::factY:-and(factB,factA).
  0.7::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Mary left the milk' or 'Lily is gray' or both.