Why Standard Form?

Teaching students how to translate syllogisms into standard categorical form occupies several lessons in Introductory Logic. Lessons 11 and 12 explain how to translate categorical statements into standard form, which is then emphasized while learning about the Square of Opposition in Lessons 13-18. Lesson 19 teaches students how to distinguish premises and conclusions, in part so that in Lesson 20 they will understand how to identify the major and minor premises, so that they may know how to arrange a syllogism in standard order. Finally, Lessons 21 and 22 teach them how to identify the syllogism form using mood and figure. All this occurs before the students begin to learn how to determine the validity of a syllogism.

Given this time and effort, it is not surprising that many students get the notion that standard categorical form is of central importance in formal logic. But this is not so. It is the concept of validity that is of prime importance. All the time spent on standard form is intended for these two related purposes: to make syllogisms easy to analyze for validity, and to teach students that the validity of a syllogism is a function of the form only, not of the meaning of the statements.

This process is similar to a scientist who, in his effort to understand the behavior of falling objects, simplifies his experiment to the point of dropping two objects of the same shape, from the same height, allowing of them only a difference in weight. Once he sees their behavior in this simplified system, he can more readily understand the behavior of objects of different weights and shapes falling from different heights. In the same way, once a logic student learns to properly analyze standard syllogisms for validity, he will be prepared to go on to analyzing arguments in normal English.