DEMAND

47

as  of  his  independent  individuality,  but  also
that  an  individual’s  system  of  demand,  taken
as  a  whole,  tends  to  settle  into  a  particular
form.  Some  appreciable  shock  is  needed  to
shake  it  out  of  this  form.  Hence  it  is  common
to  say  that  expenditure  is  settled  by  standards
of  life.  By  a  standard  of  life  is  meant  the
common  form  which  expenditure  tends  to
assume  in  any  given  class  of  the  community,
or  the  modes  of  disposing  of  income  which  are
typical  of  a  class.  For  some  purposes  it  is
convenient  to  distinguish  between  the  individual’s ­
  standard  of  living  and  the  standard
of  living  of  the  class  to  which  he  belongs.  The
former  is  usually  a  species  of  the  latter—the
latter  modified  by  his  idiosyncrasies.  It  is
only  in  exceptional  cases  that  the  standard
of  any  person  is  actually  in  conflict  with
the  standard  of  his  class.  The  individual’s
standard  is  largely  settled  by  his  habits,  and
habitual  action  is  universally  more  difficult
to  modify  than  action  which  is  not  habitual.
I  intend  now,  despite  its  alleged  difficulty,
to  introduce  a  conception  about  which  there
has  been  much  controversy,  but  one  which,
nevertheless,  in  my  opinion,  is  likely  to  play  in
the  future  a  leading  part  both  in  the  development ­
  of  economic  theory  and  in  the  practical
application  of  economic  teaching.  It  is  one