Module Three: Understanding Logic and Reasoning

Module Introduction

The sole and ultimate end of logic is the eviction of truth…

~ George Campbell, The Philosophy of Rhetoric

In the first module, we learned more about critical reading and some of the more prominent formal approaches to rhetorical studies. The second module outlined some strategies for critical viewing, critical listening, and assessing multimodal arguments. This important third module offers instruction on basic forms of logic, logical fallacies, and strategies for responding to arguments.

As Campbell notes above, logic is concerned with the systematic pursuit of argumentative validity. The study of logic (as with many subjects in the field of rhetoric) dates back to Aristotle’s influential theories on the art of persuasion. As Annette T. Rottenberg and Donna Haisty Winchell note in The Structure of Argument , there are many ways in which we attempt to discover the various “truths” of our daily lived experience, including “observing the world, selecting impressions, making inferences, [and] generalizing. In this process, Aristotle identified two forms of reasoning: induction and deduction. Both forms, he realized, are subject to error” (296). These errors can result from drawing conclusions based on a pool of observations that is either too small or which lacks sufficient representation of the issues in question. A successful argument often rests on the balance of reputable data, so it is critical for those that are advancing claims to locate a body of credible information to suit their communication activity.

How much support is sufficient to create a successful argument? That is often dictated by the context of the communication act. The Florida Times-Union , the daily paper serving the metropolitan area of Jacksonville, Florida, for instance, asks that writers sending letters to the editor keep their pieces to around seventy-five words. With such a small canvas, a skillful letter might only include an example or two in support of the larger argument. In many collegiate writing courses, instructors will often determine a minimum number of resources for a given assignment. Take some time to study the guidelines of the assignment before you begin researching your subjects. If any of these instructions is unclear to you, don’t hesitate to communicate with your instructors to ensure that you are providing them with the essay they want to read. This review will also help you determine what a useful pool of supporting data might look like, and it will initiate the process of creating a plan on where to find your resources and how to organize them. (1)


Upon completion of this module, the student will be able to:

  • Distinguish between inductive and deductive reasoning.
  • Describe the features of basic logic.
  • Identify and explain common logical fallacies. (1)


  • Online Learning Unit