It is almost certain that Winona is a mouse. Chances are slight that Lily is a frog. It is highly likely that Bill went to the kitchen. It is probably not the case that if either 'Bill went to the kitchen' or 'Lily is a frog' but not both then Bernhard is gray. It is probable that if 'Lily is a frog and Bill went to the kitchen' then John discarded the milk. Chances are about even that if 'Bill went to the kitchen and Winona is a mouse' then Julius is green.
It is improbable that 'Lily is a frog and Winona is a mouse'.
It is improbable that 'Lily is a frog and Winona is a mouse'.
There is a very good chance that 'Lily is a frog and Winona is a mouse'.

  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
  0.95::factA.
  0.1::factB.
  0.9::factC.
  %hop1
  0.25::factX:-xor(factC,factB).
  0.7::factY:-and(factB,factC).
  0.5::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Lily is a frog and Winona is a mouse'.