What does your prediction of an acquaintance’s reaction to a piece of news have in common with the weather forecast? They are both based on models of incomprehensibly complex systems; models that approximate, but do not fully capture the underlying reality, and can therefore prove very wrong.

I use the term “model” here to mean any of the condensed mental constructs we use to represent a far more complex reality. These include concepts, principles, visual models such as maps, mathematical repr...