Further, the dictionary defines both the English and the American
game. If your opponent should take either of these definitions, he
would not have much chance of convincing an American audience that it
was correct. Or if he should define football according to the rules of
the game as it was played five or ten years ago, he would be equally
ineffective.

You, on the other hand, announce that in your discussion you will use
the term "football" as that game is described in _Spaulding's present
year's rule book for the American game_, and that every reference you
make to plays allowed or forbidden will be on the basis of the latest
ruling. You then have a definition based on the history of the
question. As you can see, the case for or against English football
would be different from that of the American game. In the same way the
case for or against football as it was played ten years ago would be
very different from the case of football as it is played today.

All this does not mean that definitions found in dictionaries or other
works of reference are never good; it means simply that such
definitions should not be taken as final until the question has been
carefully reviewed. Try to think out for yourself the meaning of the
question. Decide what it involves and how it has arisen, or could
arise in real life. Then, when you do outside reading on the subject,
keep this same idea in mind. Keep asking yourself: "How did this
question arise? Why is it being discussed?" You will be surprised to
find that when you are ready to answer that question you will have
most of your reading done, for you will have read most of the
arguments upon it. Then you are ready to make it clear to the
audience.