have not had enough emphasis
before, you throw away all you have gained. In arguing nothing succeeds
like decision and certainty of utterance. Even dogmatism is better than
an appearance of wabbling. It is the men like Macaulay, who see
everything black and white with no shades between, who are the leaders
of the world's opinion. Sum up, then, wherever it is decent to do so, as
if there were only one side of the case, and that could be stated in
three lines.

54. The Power of Convincing. The convincing power of an argument
depends on its appeal to the reason of its readers. To put the same fact
in another way, an argument has convincing power when it can fit the
facts which it deals with smoothly and intelligently into the rest of
the reader's experience. If an argument on a complicated mass of facts,
such as the evidence in a long murder case, makes the reader say, "Yes,
now I see how it all happened," or an argument for the direct election
of United States senators makes him say, "Yes, that is a plain working
out of the fundamental principles of popular government," then he is
convinced. In this aspect argument merges into exposition. It is
significant that, as has already been noted, Matthew Arnold's argument
that Wordsworth is the greatest English poet after Shakespeare and
Milton, and Huxley's argument that the physical basis of animal and
plant life is the same, are both used in a book of examples of
exposition.[58] The essential difference between argument and exposition
from this point of view lies in the emphasis: normally an explanation
covers the whole case evenly; an argument throws certain parts and
aspects of the case into relief.

If, therefore, to be convincing, your argument must provide a reasonable
explanation of the whole state of affairs to which the case belongs, you
can use all the devices there are for clear and effective explanation. I
will therefore briefly review a few of these.

Of the value of an introduction which lays out the ground to be covered
I have already spoken. The more distinct an idea you can implant in your
readers' minds of the course you are going to follow in your argument,
the more likely they will be to follow it. Since the success of your
argument hangs on carrying them with you on the main issues, let them
know beforehand just what those issues are, and in such a way that they
can hold them with a minimum of effort. The value of a clear and, as it
were, maplike introdu