One area in which I'd like to give further thought is looking at the formal (logical) language in which we can discuss risk. First order predicate calculus seems too powerful. My gut feel is that first order multiplicative intuitionistic linear logic would be suitable. In this logic, when you have riskA and riskB, then there are things that can happen that are not just the standard interactions of riskA and riskB. For a physical analogy, consider entangled photons, which can arise when we physically have a state of two photons, but there is no way in classical physics that we can model what entangled photons do. In fact, in classical physics they can't exist. Quantum physics has a similar structure to intuitionistic linear logic. The possible states with two photons "photonA and photonB" are more than you can get by just looking at the individual states of photonA and photon B - "riskA and riskB" is different from "riskA and riskB" (See the difference in the logical operator? The "and" is not the same.)

Lots more thinking to do.

What is risk?

For some reason I've been involved in discussions, over the last couple of days, as to what risk is. Some say its an event, some describe it as an emergent process from a complex organisation (Milliman), ISO31000:2009 say it's the effect of uncertainty on objectives. I think we need to make sure that we don't have a category error creeping into our thinking. A suitably generic notion of risk is that it's exposure to something that may be disadvantageous in some way. We can then start from here.