There is almost no chance that Winona is a mouse. We doubt that Julius is gray. It is probably the case that John dropped the milk. There is a better than even chance that if 'Julius is gray and Winona is a mouse' then Bill went to the kitchen. There is a very good chance that if 'John dropped the milk and Julius is gray' then Greg is a swan. It is almost certain that if 'John dropped the milk and Winona is a mouse' then Brian is yellow.
It is impossible that 'Brian is yellow and Julius is gray'.
It is impossible that 'Brian is yellow and Julius is gray'.
There is a better than even chance that 'Brian is yellow and Julius is gray'.

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

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

  query(conclusion).
  
'Brian is yellow and Julius is gray'.