Chances are about even that Bernhard is green. It is impossible that John got the apple. It is probably not the case that Mary grabbed the milk. We doubt that if either 'Bernhard is green' or 'John got the apple' but not both then Greg is a lion. It is highly likely that if 'Bernhard is green' or 'Mary grabbed the milk' or both then Lily is a rhino. It is probably not the case that if either 'Mary grabbed the milk' or 'John got the apple' but not both then Brian is white.
There is little chance that 'Bernhard is green and Mary grabbed the milk'.
There is little chance that 'Bernhard is green and Mary grabbed the milk'.
We believe that 'Bernhard is green and Mary grabbed 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
  0.5::factA.
  0.0::factB.
  0.25::factC.
  %hop1
  0.2::factX:-xor(factA,factB).
  0.9::factY:-or(factA,factC).
  0.25::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Bernhard is green and Mary grabbed the milk'.