26

POLITICAL  ECONOMY

tiating  the  experiences  relating  to  it,  as  I
have  put  it.  In  the  case  of  demand,  for
instance,  we  do  not  say,  if  we  are  careful
scientists,  that  this  book,  taken  as  an  isolated
fact,  is  worth  so  much  to  a  given  person,
because  it  cannot  be  thought  of  as  an  isolated
fact.  We  merely  say  that  this  book  makes  a
certain  difference  to  the  person  in  question
which  he  values  at  so  much.
Finally,  let  it  be  clearly  understood  that
we  are  not  treating  of  things  as  they  would
happen  in  a  community  of  thoroughly  selfish
people  who  thought  only  of  their  own  material
circumstances—in  short,  we  do  not  now  begin
our  economics  by  postulating  the  scarecrow
known  as  the  economic  man,  as  some  early
economists  did—unless  we  are  aiming  at  the
roughest  of  approximations.  On  the  contrary, ­
  we  take  people  as  they  are,  with  their
mixture  of  meanness  and  nobility,  but  in
studying  them  from  the  economic  point  of
view  we  ignore  everything,  for  the  time  being,
which,  as  a  cause,  is  not  economic,  or,  as  an
effect,  is  not  an  economic  reflex.  In  brief,
we  abstract  not  motives  and  impulses  of  a
particular  kind,  but  only  activities  or  aspects
of  activities  of  a  particular  kind.  So  when
a  recent  writer  exhorted  economists  “  once
and  for  ever  to  abolish  the  feverish,  over-