that points out the dangers of organized labor, the scientific
treatise that demonstrates the practicability of a sea-level canal on
the Isthmus are attempts to change existing conditions and ideas, and
thus come within the field of argumentation.

The practical benefit to be derived from the study and application of
the principles of argumentation can hardly be overestimated. The man
who wishes to influence the opinions and actions of others, who wishes
to become a leader of men in however great or however humble a sphere,
must be familiar with this art. The editor, the lawyer, the merchant,
the contractor, the laborer--men in every walk of life--depend for
their success upon bringing others to believe, in certain instances,
as they believe. Everywhere men who can point out what is right and
best, and can bring others to see it and act upon it, win the day.
Another benefit to be obtained from the study of argumentation is the
ability to be convinced intelligently. The good arguer is not likely
to be carried away by specious arguments or fallacious reasoning. He
can weigh every bit of evidence; he can test the strength and weakness
of every statement; he can separate the essential from the
unessential; and he can distinguish between prejudice and reason. A
master of the art of argumentation can both present his case
convincingly to others, and discover the truth in a matter that is
presented to him.

Argumentation can hardly be considered as a distinct art standing by
itself; it is rather a composite of several arts, deriving its
fundamentals from them, and depending upon them for its existence. In
the first place, since argumentation is spoken or written discourse,
it belongs to rhetoric, and the rules which govern composition apply
to it as strongly as to any other kind of expression. In fact, perhaps