It's useful; I shouldn't be too hard on it. I've just seen some
   FAR REACHING conclusions in the past that, in the end, were
   based solely upon the mirror test and a LOT of speculation on
   the part of the author, whether one who worked in the sciences,
   or popular writers, or whomever. That's why I give it a little
   extra criticism.

   But when used properly and interpreted with its limitations kept
   in check, it's a useful test.