ARGUMENTS IN STANDARD FORM
Because arguments come in all shapes and forms, it will help to have a standard way of presenting arguments. For centuries, logicians have used a format of the following kind:
(1) All men are mortal. (2) Socrates is a man.
(3) Socrates is mortal. (from 1–2)
The reasons (or premises) are listed and numbered. Then a line is drawn be- low the premises. Next, the conclusion is numbered and written below the line. The symbol “ “, which is read “therefore,” is then added to the left of the conclusion in order to indicate the relation between the premises and the conclusion. Finally, the premises from which the conclusion is supposed to be derived are indicated in parentheses. Arguments presented in this way are said to be in standard form.
The notion of a standard form is useful because it helps us see that the same argument can be expressed in different ways. For example, the follow- ing three sentences formulate the argument that was given in standard form above.
Socrates is mortal, since all men are mortal, and Socrates is a man.
All men are mortal, so Socrates is mortal, because he is a man.
All men are mortal, and Socrates is a man, which goes to show that Socrates is mortal.
More important, by putting arguments into standard form, we perform the most obvious, and in some ways most important, step in the analysis of an argument: the identification of its premises and conclusion.
Identify which of the following sentences expresses an argument. For each that does, (1) circle the argument marker (or markers), (2) indicate whether it is a reason marker or a conclusion marker, and (3) restate the argument in stan- dard form.
1. Since Chicago is north of Boston, and Boston is north of Charleston, Chicago is north of Charleston.
2. Toward evening, clouds formed and the sky grew darker; then the storm broke.
3. Texas has a greater area than Topeka, and Topeka has a greater area than the Bronx Zoo, so Texas has a greater area than the Bronx Zoo.
4. Both houses of Congress may pass a bill, but the president may still veto it.
5. Other airlines will carry more passengers, because United Airlines is on strike.
6. Since Jesse James left town, taking his gang with him, things have been a lot quieter.
7. Things are a lot quieter, because Jesse James left town, taking his gang with him.
8. Witches float because witches are made of wood, and wood floats.
9. The hour is up, so you must hand in your exams.
10. Joe quit, because his boss was giving him so much grief.