This post is in response to a Jon Geeting post at Keystone Politics. In general, my musings about density are misunderstood. Talent is agglomerating in cities. More precisely, talent is agglomerating in urban places of employment. The workers benefiting from Manhattan density can and do reside in a Connecticut neighborhood. When discussing the positive externalities from greater density, the matter is where the jobs are located. Talent density is rather beside the point.
I go even further than the conventional thinking about the relationship between economic geography of employment and greater density. I argue that migration matters more. The magic is migration. Without migration, knowledge doesn't diffuse. If you pack in one million people who all know the same things, then density won't do much of anything save cause problems.
Density is an effect, not a cause. Density needs to managed. The assimilation of outsiders (i.e. migrants) should be facilitated That's where planners and placemaking come in. Employing placemaking to attract talent and achieve greater densities has the cause and effect backwards.
As Peter Taylor exclaims, cities are extraordinary. "Urbanism and human development" are positively linked. That's an about face from the 1960s and 1970s when urbanism and human development were at odds. See my post from yesterday, which Geeting references. Now that cities are seen as solutions instead of problems, how do we best deal with that attraction? The demand to be a part of an urban economy comes with great costs as well as benefits. "Pro-density land use planning" might be one of the solutions to the problems associated with an increasingly urban world.