One thing that isn't mentioned in this essay is an appreciation of the concept of having a "preponderance of evidence." In U.S. law, for example, this concept is introduced directly through the burden of proof hierarchy (terms like reasonable suspicion, clear and convincing evidence, reasonable doubt, etc.).
While only DH4-DH6 can strictly prove an argument wrong, there are many, many situations in which it is infeasible to unilaterally determine "truth." In these cases, DH1-DH3 can be used to determine the probability of a statement being true.
Take ad hominem. Sure it's a weak form of argumentation, but it is reasonable to exercise a certain amount of skepticism based on the nature of the speaker. For example, the New York Post tends to be a more conservative newspaper, while the New York Times tends to be more liberal. Obviously, neither of these facts can definitively prove or disprove a statement, but they can inform an analysis of these papers' claims.
If I'm making a counter-argument I care about, I try to take a "defense-in-depth" approach and attack the original statement at all levels that are useful and try to establish credibility in all the ways I can. I don't think arguing well maps directly to using a higher form of rhetoric. At the end of the day, it depends on your audience. Just ask Karl Rove and James Carville. ;)
While only DH4-DH6 can strictly prove an argument wrong, there are many, many situations in which it is infeasible to unilaterally determine "truth." In these cases, DH1-DH3 can be used to determine the probability of a statement being true.
Take ad hominem. Sure it's a weak form of argumentation, but it is reasonable to exercise a certain amount of skepticism based on the nature of the speaker. For example, the New York Post tends to be a more conservative newspaper, while the New York Times tends to be more liberal. Obviously, neither of these facts can definitively prove or disprove a statement, but they can inform an analysis of these papers' claims.
If I'm making a counter-argument I care about, I try to take a "defense-in-depth" approach and attack the original statement at all levels that are useful and try to establish credibility in all the ways I can. I don't think arguing well maps directly to using a higher form of rhetoric. At the end of the day, it depends on your audience. Just ask Karl Rove and James Carville. ;)