Chances are about even that Gertrude is a cat. There is a very good chance that Julius is white. It is almost certain that Lily is a rhino. It is likely that if 'Lily is a rhino' or 'Julius is white' or both then Bernhard is gray. It is improbable that if 'Lily is a rhino' or 'Julius is white' or both then Brian is white. There is a better than even chance that if 'Julius is white and Gertrude is a cat' then John dropped the milk.
We believe that 'Julius is white and Lily is a rhino'.
We believe that 'Julius is white and Lily is a rhino'.
We doubt that 'Julius is white and Lily is a rhino'.

  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.
  0.8::factB.
  0.95::factC.
  %hop1
  0.7::factX:-or(factC,factB).
  0.1::factY:-or(factC,factB).
  0.6::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Julius is white and Lily is a rhino'.