  Philosopher Benardete challenged both the conventional wisdom and the
received mathematical treatment of zero, dot, nine recurring. An initially
puzzling passage in Benardete on the intelligibility of the continuum reveals
challenging insights into number systems, the foundations of modern analysis,
and mathematics education. A key concept here is, in Terry Tao's terminology,
that of an ultralimit.
  Keywords: real analysis; infinitesimals; decimal notation; procedures vs
ontology
