NOT and NULL: addendum to previous note

[Jon L White <JONL at MIT-MC>]

The merging of the functionality of NOT and NULL makes it
mechanically impossible to separate out the usages of null
as the nullist from those usages as "false";  this merger,
of course, was almost demanded by the lack of a "false"
distinct from null.   In fact, both names, NOT and NULL,
are probably around since antiquity, but there has not been
the two separate functionalities.