Book for Persuasion (Book)

Logos

Logos (Logical) means persuading by the use of reasoning. This will be the most important technique we will study, and Aristotle's favorite. We'll look at deductive and inductive reasoning, and discuss what makes an effective, persuasive reason to back up your claims. Giving reasons is the heart of argumentation, and cannot be emphasized enough. We'll study the types of support you can use to substantiate your thesis, and look at some of the common logical fallacies, in order to avoid them in your writing.

Logos (Greek for 'word') refers to the internal consistency of the message--the clarity of the claim, the logic of its reasons, and the effectiveness of its supporting evidence. The impact of logos on an audience is sometimes called the argument's logical appeal.

Finally, we come to the “argument” itself, the explicit reasons the arguer provides to support a position. There are many ways to describe the support provided in an argument, but a sample way to begin is to consider all the premises the author seems to supply. These can be scattered throughout the argument and expressed indirectly, so identifying premises is a judgment call in itself.

Next ask which of the premises are presented as objects of agreement that the arguer considers as given, elements of the argument taken for granted. Objects of agreement are basically either facts or values. Of course, the facts may not be facts and readers may not agree with the values assumed. Some of the premises will be supported further, but basically every argument has got to come down to certain objects of agreement that it presents as shared between arguer and audience.

You can also classify premises into the following categories. 1. Are they arguments based on definition? In other words, does the arguer make claims about the nature of things, about what terms mean, what features things have? 2. Does the arguer make analogies or comparisons? Does he or she cite parallel cases? 3. Are there appeals to cause and consequences? Arguing from consequence is especially common when policy issues are debated. 4. Does the arguer rely on testimony or authority by citing the received opinions of experts? Or does the author create some kind of authoritative reference group, citing public opinion on what most people think as support for his or her position?