The Normality Assumption

It follows, as a matter of definition, from the claims of the previous two chapters that no one can be the author of an argument unless she believes that argument to be cogent for at least one person. More specifically, every author believes that her argument is cogent for all the members of her (non-empty) intentional audience. But since this is a definitional claim, it doesn't tell us anything about who, as a matter of fact, is included within the author's intentional audience. It doesn't identify the individuals for whom the author believes her argument to be cogent. And to answer that empirical question, we need to probe more deeply into the author's epistemic state. We need to explore the author's conception of the composition of her intentional audience.

While a large number of possibilities exist, we'll be most interested in one particular standard case. We'll say that an argument A is normal, within a specific context C, just in case, within C, its author consistently believes A to be cogent both for herself and for all the members of her social audience. That is, a normal author – the author of a normal argument – consistently believes that she herself, as well as those whom others perceive to be the targets of her argument, ought to be persuaded by her own argument. It follows that a normal author consistently believes that the members of her social audience are members of her intentional audience as well.