The essential property of "flow" is that a
decrease of something in one region is accompanied
by a simultaneous increase of that thing in a
neighboring region. There is no requirement that
the flowing thing be a substance. There are lots
of perfectly good things that are not substances.
This posting is the position of the writer, not that of Charlotte,
Wilbur, or Templeton.
This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.