A Deadly Cascade

Abstract

Often, the world around us is more complex than we know. Of necessity, the models we build to explain the world simplify things by omitting many details. These omissions explain why experts are so often wrong. They also underlies serendipity, an important source of discovery in science. Because models cannot always predict the future behaviour of complex systems, we need to examine scenarios instead. Although we can refine models to account for new events and conditions, they will never be perfect, so unexpected trends and events continue to occur. When conditions change, things we disregard can become important and set off cascades of unexpected effects. This process is often involved in major accidents.

There is a science of simple things, and art of complicated ones. Science is feasible when the variables are few and can be enumerated; when their combinations are distinct and clear.¹