ent, and demonstrable as Euclid; and which was denounced by
their opponents as mechanical, materialistic, fatalistic, and
degrading. After triumphing for a season, it has been of late years
often treated with contempt, and sometimes banished to the limbo of
extinct logomachies. It is condemned as 'abstract.' Of all delusions
on the subject, replies a very able and severe critic,[336] there is
none greater than the belief that it was 'wholly abstract and
unpractical.' Its merits lay in its treatment of certain special
questions of the day; while in the purely scientific questions it was
hopelessly confused and inconsistent. Undoubtedly, as I have tried to
point out, Malthus and Ricardo were reasoning upon the contemporary
state of things. The doctrine started from observation of facts; it
was too 'abstract' so far as it neglected elements in the concrete
realities which were really relevant to the conclusions. One cause of
confusion was the necessity of starting from the classification
implied in ordinary phrases. It is exemplified by the vague use of
such words as 'capital,' 'value,' 'supply and demand.' Definitions, as
is often remarked,[337] come at the end of an investigation, though
they are placed at the beginning of an exposition. When the primary
conceptions to be used were still so shifting and contradictory as is
implied in the controversies of the day, it is no wonder that the
formulae should be wanting in scientific precision. Until we have
determined what is meant by 'force' we cannot have a complete science
of dynamics. The economists imagined that they had reached the goal
before they had got rid of ambiguities hidden in the accepted
terminology. Meanwhile it will be enough if I try to consider broadly
what was the nature of the body of statements which thus claimed to be
an elaborated science.

Ricardo's purpose was to frame a calculus, to give a method of
reasoning which will enable us to clinch our economic reasoning. We
are to be sure that we have followed out the whole cycle of cause and
effect. Capitalists, landowners, labourers form parts of a rounded
system, implying reciprocal actions and reactions. The imposition of a
tax or a tariff implies certain changes in existing relations: that
change involves other changes; and to trace out the total effect, we
must understand what are the ultimate conditions of equilibrium, or
what are the processes by which the system will adjust itself to the
new cond