Stevenson's theory of the persuasive definition has been applied only to abstract ethical theory and to philosophical discussions. It has perhaps been seen as not too widely significant when confined to that framework. But its implications are of sweeping significance once it is applied to media argumentation. It is shown in this chapter how many media arguments are based on emotively loaded words or phrases that raise questions about the values, verbal classifications, and definitions of these terms. The persuasive definition, or as it is sometimes called in statistics, the friendly definition, is the definition that is stacked in such a way as to put a positive spin on the argument of the definer. This chapter shows how persuasive definitions are extremely powerful media tools, and how they are often used to influence public policy arguments. Five cases based on the use of persuasive definitions in public policy arguments are presented, analyzed, and evaluated below. In all of these cases, the use of the persuasive definition as an argumentative technique had consequences that changed social policies in a way that led to significant gains in the interests of some advocacy groups and losses in the interests of others.

Using these rhetorical case studies, some basic dialectical problems are posed about the legitimacy of persuasive definitions, about how to reconstruct the chains of argumentation they are based on, and about how to evaluate them.