82 THE STATISTICAL VERIFICATION OF
Marshall, for no one will cover the whole field. The
detail that will pour into the research students’ library
will gradually make it more akin to physical investigation,
save that the tests must be repeated from time to time, as
no permanence of datain economicsis possible. But these,
instead of being mere checks superseding the past checks,
will have a dynamic relation to them, and this change
in itself must be the subject of analysis and theorizing,
which will again enrich the science on its abstract side.
Moreover, each investigation is a double check upon
a particular logical weakness of pure analysis. We can-
not think of the result of motives in the mass without
individualizing those motives first, and we know how
easy it is to go fatally wrong in passing from the par-
ticular to the general. It is here that statistical analysis
gives a backward check upon all such aggregations of
imaginary individuals, each of whom has a slightly dif-
ferent monetary measure of a particular unitary satis-
faction or effort, and each of whom responds differently
to a slight change, which is even more important.
There is a third way in which the analogy of physics
or chemistry must be inexact. The elements behave in
the same way whether the human mind is studying them or
not, whereas economic tendencies and principles change
because they are being studied. Obviously so much in
them as depends on human psychology, knowledge, or
will, undergoes profound change as the human mind
becomes conscious of what it is doing. As soon as we
have completely discovered and understand what governs
the business cycle it will probably almost cease to exist.
How does this University stand towards such a move-
ment as I have illustrated and outlined ? I think the
syllabus hardly concedes that radical changes are pos-
sible or desirable, still less that we should equip students
to take part in them. I should be the last to say that
somewhere in this country economics should not be studied
in particular juxtaposition to history and philosophy, as it
is studied in association with mathematics and science in
