There is a literature on how best to regulate systems in the face of such Knightian uncertainty. It suggests some guideposts for regulation of financial systems. First, keep it simple. Complex control of a complex system is a recipe for confusion at best, catastrophe at worst. Complex control adds, not subtracts, from the Knightian uncertainty problem. The US constitution is four pages long. The recently-tabled Dodd Bill on US financial sector reform is 1,336 pages long. Which do you imagine will have the more lasting impact on behaviour?

Second, faced with uncertainty, the best approach is often to choose a strategy which avoids the extreme tails of the distribution. Technically, economists call this a “minimax” strategy – minimising the likelihood of the worst outcome. Paranoia can sometimes be an optimal strategy….

Third, simple, loss-minimising strategies are often best achieved through what economists call “mechanism design” and what non-economists call “structural reform”. In essence, this means acting on the underlying organisational form of the system, rather than through the participants operating within it. In the words of economist John Kay, it is about regulating structure not behaviour…

I personally sympathize with simpler controls for the banking industry.