DEMAND

57

The  reader  can  judge  for  himself  whether
the  alleged  fecundity  of  the  marginal  method
is  borne  out  by  its  application  to  demand.  We
have  strictly  observed  the  limitations  which
render  analysis  of  social  facts  so  difficult.
We  have  taken  the  experiences  of  a  person  in
respect  of  his  wanting  or  demanding  as  an
indivisible  whole,  as  we  are  told  that  we  must
by  the  most  competent  psychologists.  And
we  have  made  no  suspicious  assumptions  about
the  basis  of  these  experiences  ;  for  indeed  we
have  made  no  assumptions  at  all  as  regards
their  basis,  but  have  on  the  contrary  accepted
as  our  data  the  bare  facts  of  wanting  and
demanding  as  they  are  directly  revealed.
But  the  door  has  not  thereupon  been  shut
against  our  scientific  aspirations.  By  the
marginal  method,  the  simple  device  in  this
case  of  watching  the  differences  made  to  the
totality  of  a  person’s  experience—by  differentiating ­
  experience,  as  it  is  expressed  in  the
first  chapter—we  have  reached,  under  the
guidance  of  Dr.  Marshall  in  particular,  generalisations, ­
  which  are  adequately  explanatory  of
demand  for  economic  purposes  and  illuminating ­
  (particularly  the  doctrine  of  consumer’s
surplus)  from  the  point  of  view  of  a  philosophy
of  life,  and  which,  as  will  transpire  later,  in
conjunction  with  other  generalisations  having