If you are trying to convince a member of your school board that it would be well to introduce domestic science into the high school, and he already understands what is meant by the term “domestic science,” you not only waste time in explaining it, but you make him appear ignorant of what he already understands.  With him you should proceed at once to give your reasons for the advisability of the introduction of this branch into your school.  On the other hand, if you are talking with a member who does not understand the term, an explanation will be the first thing necessary.  It is evident, therefore, that the amount of explanation that we shall make depends upon the previous knowledge of the audience addressed.  If we explain too much, we prejudice our case; and if we explain too little, the reader may fail to appreciate the arguments that follow.

The point of the whole matter, then, is that explanation is the first step in argument, and that in order to determine the amount necessary we must consider carefully the audience for which our argument is intended.

+71.  Statement of Advantages and Disadvantages.+ An argument is often concerned with determining whether it is expedient to do one thing or another.  Such an argument frequently takes the form of a statement of the advantages that will follow the adoption of the course we recommend, or of the disadvantages that the following of the opposite course will cause.

If a corporation should ask for a franchise for a street railway, the city officials might hold the opinion that a double track should be laid.  In support of this opinion they would name the advantageous results that would follow from the use of a double track, such as the avoidance of delays on turnouts, the lessening of the liability of accidents, the greater rapidity in transportation, etc.  On the other hand, the persons seeking the franchise might reply that a double track would occupy too much of the street and become a hindrance to teams, or that the advantages were not sufficient to warrant the extra expense.

Concerning such a question there can be no absolute decision.  We are not discussing what is right, but what is expedient, and the determination of what is expedient is based upon a consideration of advantages or disadvantages.  In deciding, we must balance the advantages against the disadvantages and determine which has the greater weight.  If called upon to take one side or the other, we must consider carefully the value of the facts counting both for and against the proposition before we can make up our mind which side we favor.

You must bear in mind that a thing may not be an advantage because you believe it to be.  That which seems to you to be the reason why you should take some high school subject, may seem to your father or your teacher to be the very reason why you should not.  In writing arguments of this kind you must take care to select facts that will appeal to your readers as advantages.