arge us very much
what he chose. He could put up his price, and we would hardly be aware
of it. And, as by lowering his price he could not tempt us to buy any
more, price reductions would be few and far between. But fortunately
there are always some people who do know what the price is, even when
they are buying collars and ties; and who will adjust the amount they
buy in accordance with the price. It is these worthy people who make
the laws of demand work out as we well know they do. It is they who
will curtail their consumption if the price has fallen and it is they
who constitute the seller's problem, and help to keep down prices for
the rest of us. The rest of us--it is well to be quite blunt about
it--simply do not count in this connection. We have no cause then to
plume ourselves that we have disproved the truth of economic laws when
we declare that we seldom weigh the utility of anything against its
price. All that this shows is that our actions are too insignificant
to be described by economic laws since they exert no appreciable
influence on the price of anything. And this in turn shows the extreme
importance of grasping clearly the conception of the margin. Just as
it is the marginal purchase, so it is the marginal purchaser who
matters. It is the man who, before he buys a motor bicycle, weighs the
matter up very carefully indeed and only just decides to buy it, whose
demand affects the price of motor bicycles. It is the utility which
_he_ derives that constitutes the marginal utility, which is roughly
measured by the price.

As to the housewife, I am not prepared to concede that my picture is
in essentials very fanciful. She may be a creature of habits and
instincts like the rest of us, but most habits and instincts affecting
household expenditure are based ultimately on _some_ calculation, if
not one's own, and reason has a way of paying, as it were, periodic
visits of inspection, and pulling our habits and instincts into line,
if they have gone far astray. I am not satisfied that the housewife
does not envisage the utility of a sixth pound of sugar as something
distinct from the utility of the other five; she may buy it, for
example, with the definite object of giving the children some sugar on
their bread, and she may have a very clear idea as to the price which
sugar must not exceed before she will do any such thing. Possibly I
may exaggerate. I have the profound respect of the incorrigibly
wasteful male