The NYT has an article about the proliferation of things too complex to understand -- Afghanistan, Iraq, the modern economy, collateralized debt obligations, health care reform, the 10,000 page manual for US accounting standards -- with some gloomy vibes:
There is a lot of end-of-days talk when it comes to this subject. You will find a strain of it in the work of Joseph Tainter, an anthropologist at the University of Utah and the author of “The Collapse of Complex Societies.” In the book, Mr. Tainter examines three ancient civilizations, including the Roman Empire, and explains how complexity drove them to ruin, essentially by bankrupting them.
Here's a more hopeful note, along with a warning. Complex systems do not necessarily have to be understood by any one person for them to work well. They just need to have rules and incentives for the participants that make them self-correcting.
For example, supply and demand manages the allocation of millions of goods to millions of different users in our economy without anyone in charge. When a good is in excess supply, people act so that its price goes down. When a good is in excess demand, people act so that its price goes up. The system self-corrects. (Ideological code word alert -- just because I gave this example doesn't mean I am some extreme free market fanatic that believes the market solves everything and we don't ever need government for anything ever. It just means I understand supply and demand.)
Here's the warning. Where complexity gets us into trouble is when somebody creates some complex, impossible-to-understand-or-manage thing that is NOT self-correcting. I will leave it to the readers which items on the above list are in that category.