By Hamilton Coimbra Carvalho

I live in São Paulo, the biggest city in Brazil, home to some 12 million people—20 million if you count the outskirts, which have been sprawling for three decades.

That makes it a good place to observe the phenomenon I research: complex social problems. In academia, this concept refers to problems like corruption, crime and traffic—problems that, in practice, cannot be solved. They must simply be mitigated or managed.