In a classic debate, two people stand toe to toe and argue, free form, about a clear claim, for a fixed time of an hour or more, in front of an attentive audience. The best moments in such a debate are awkward "silences": X makes a good point, and the audience can clearly see Y has no good response. Y may change the subject, but X may soon say "But what about that point I just made, what do you say to that?" If Y changes the subject again, an attentive audience can see clearly: Y has no good response to X’s point. Y’s silence speaks volumes.
Unfortunately, precious silences get lost in non-classic debate formats. If the debate has no fixed end time, Y may say "sorry, I have to go now." If there are only a few back and forth rounds, it may take most of those rounds just to clarify the claim, leaving too few rounds to clearly show a silence.
Debates in academic journals suffer this problem; usually X speaks, Y responds, X responds again, and the debate is over. Debates between bloggers are little better; if blogger Y responds to blogger X, usually X says nothing more. Even when bloggers have roughly equal status, they have too many good excuses to ignore someone’s point. So the fact that a point was ignored offers only weak evidence about its strength. When the bloggers have unequal status, it is almost hopeless; high status people usually ignore low status people, no matter how good or bad their points.
This issue was brought home in my recent medicine debate at CATO Unbound. I wrote a lead essay, three health policy experts of far higher academic status responded, and then we had a one week "informal discussion." I thought I made a sharp clear claim, that crude policies to "Cut Medicine In Half" are feasible and better than the status quo. The three respondents, however, chose to discuss other not-yet-feasible policies they liked more. My first informal comment tried to focus them back on my claim, but two of the three had little energy for further discussion. While they all named reasons for opposition, there were too few rounds to show clearly the weakness of those reasons. And from blogger reactions it seems no one reads the informal discussion anyway.
This is why I so lament, and am puzzled by, the rarity of the classic debate.