One reason that public intellectuals might seem smaller than they used to be is that they don't wander as far off their area of specialization as in the past. While Galbraith might have been comfortable riffing about culture and Buckley could talk economics, this sort of thing is rarer today.

I'm with Richard Posner in thinking that this is a good thing, since as a general rule public intellectuals are less likely to have penetrating insights when they're talking about subject in which they have no extant knowledge. This doesn't vitiate the role of the public intellectual: as the specialization of knowledge has progressed, it becomes more difficult for the same person to flourish in their specialized field and make that knowledge accessible to the public. This does create a market niche, however, for “second order intellectuals” to emerge, bridging the gap between first order intellectuals and the informed public.

Another reason that public intellectuals might seem smaller than they used to be is that they can measure the response to their public musings more accurately than in the past. As I pointed out last week, blogs now play an important role in policing the thinking class. When public intellectuals generate shoddy work, bloggers are perfectly willing to cry foul. Consider, for example, the responses to William Kristol's columns, last year's reaction to Michael Ignatieff's mea culpa on Iraq, or disenchantment with Paul Krugman's robotic commentary on the Democratic primary.

Again, this is a good thing. The best public intellectuals (I'd put Brooks in this category, by the way) should be able to respond to criticism and improve their commentary; the worst should fade from view (As a personal aside, I know that my paper on this topic has profited from the blog responses to the initial draft).

One negative reason for a decline in mega-public intellectuals is the rise in partisanship. It has become tougher for someone like a Milton Friedman or a Michael Harrington to be accepted across the political spectrum as a legitimate authority because they have staked out a clear ideological position that is anathema to half the pundit class.

I'm less than thrilled with this trend, but it does get to an interesting tension between promoting democratic discourse and preserving the authority of expertise. The thing about public intellectuals is that they're trying to walk a tightrope between these two poles -- trafficking in their expertise to make a public intervention -- and this is tough to do in any era.

To conclude then -- if we're living in a world where there are more public intellectuals, but they're more responsive to criticism and less willing to venture way beyond their areas of competence -- well, then let me dance on the grave of "mega-public intellectuals."