In Response to: Paul Los ’ Attention to kinds of claims in argument evaluation

Paul Los's central claim is distinctly insightful: In evaluating arguments, both for premise and connection adequacy, we need to take into account the types of statement constituting the argument. Is a premise an is-claim or an ought-claim? Does the argument seek to establish an is-claim or an ought-claim? I completely agree and endorse his proposal (Step 2 of his argument evaluation procedure) that in evaluating premises, determining what type of statement is involved is required. Indeed, I believe this should be the first step in premise evaluation. In these comments, then, I want to indicate ways in which I believe Los's project should be developed. First, rhetoricians have long maintained that distinguishing types of statements for purposes of argument construction is necessary and proper. This goes back to classical rhetoric. As Kruger (1975) points out, early Latin rhetoricians in effect distinguished questions of description, interpretation, and evaluation. How we construct an argument will be influenced by whether the claim we are trying to establish concerns whether something happened (Did the American plane enter Chinese air space?), what sort of thing happened (Was this incursion deliberate provocation or an accident due either to human or mechanical error?), or whether what happened is the kind of thing which can be justified (If the incursion was a provocation, did the United State