Do cities have limits?

After last weeks interesting Do Cities have Limits Conference at the University of Glasgow, I have been thinking about some of the connections the event brought together. 

Particularly evident, considering the event was hosted by the Engineering Department was the split between the more positivist view of cities (and their limits) and the more intepretivist vision I felt. 

Perhaps this hints at something more fundamental; the more design based, functional language spoken by architects and engineers v (not versus) the 'messier' social issues and focus  that planners and urban designers take? 

Thoughts?....