There is a better than even chance that Bernhard is a rhino. It is certain that John got the milk. Chances are about even that Gertrude is a cat. There is a very good chance that if 'Gertrude is a cat' or 'Bernhard is a rhino' or both then Daniel took the milk. There is little chance that if 'Bernhard is a rhino' or 'Gertrude is a cat' or both then Lily is white. There is a very good chance that if 'John got the milk and Bernhard is a rhino' then Sandra is in the kitchen.
It is highly unlikely that 'Bernhard is a rhino and John got the milk'.
There is a better than even chance that 'Bernhard is a rhino and John got the milk'.
It is highly unlikely that 'Bernhard is a rhino and John got 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
  0.6::factA.
  1.0::factB.
  0.5::factC.
  %hop1
  0.8::factX:-or(factC,factA).
  0.1::factY:-or(factA,factC).
  0.8::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Bernhard is a rhino and John got the milk'.