e. Modern investigation has, no doubt, revealed certain economic
laws which we may fairly say operate with reasonable certainty, but
this is a very different proposition from that which would make the
conclusions of economists in all directions as absolute as those of
mathematicians. Political economy, in fact, does not differ greatly in
this respect from history, because both deal with subjects where the
conditions and sympathies of men and women play a large part, and
where human passions are deeply engaged. In fields like these, where
the personal equation of humanity plays a controlling part, it is
absurd to attempt to argue as if we were dealing with a mathematical
formula. There may be a philosophy of political economy as there is
of history; there may be scientific methods of dealing with it and
certain economic laws, subject to many exceptions, which we may
consider to be established, but nevertheless it is as far from being
an exact science as one can conceive. The exact science notion is the
misconception of cloistered learning which can build impregnable
systems where there are none to attack them, but which has no idea of
the practical difficulties of an unsympathetic world where the
precious system must meet every possible objection and not merely
those devised by its framers. In discussing a question of political
economy, therefore, it is well to bear in mind that we are handling a
subject where new facts are always entering in to modify old
conclusions, and where there are many conditions, the effect of which
it is impossible to calculate.

In the third place, the ardent tariff reformer at the present moment
always discourses upon his subject as if he had some perfectly new
truth to lay before the world from which it would be as impossible to
differ, unless one was illiterate or corrupt, as from the conclusion
of Galileo in regard to the movement of the earth. In one of our
recent political campaigns I quoted an argument of Hamilton's in favor
of protection from his famous Report of Manufactures. Thereupon one of
my opponents in a public speech, referring to this quotation, said it
would be as sensible to adopt Hamilton's views on the tariff as to go
back to stage coaches simply because those vehicles were the means of
conveyance in Hamilton's time. I could not help wondering what my
learned opponent would have thought if I had retorted that, by parity
of reasoning, we ought to reject the "Wealth of Natio