Making a Splash; Breaking a Neck: The Development of Complexity in Physical Systems

The fundamental laws of physics are very simple. They can be written on the top half of an ordinary piece of paper. The world about us is very complex. Whole libraries hardly serve to describe it. Beyond this, any living organism exhibits a degree of complexity quite beyond the capacity of our libraries. This complexity has led some thinkers to suggest that living things are not the outcome of physical law but instead the creation of a (super)-intelligent design.

In this talk, we examine the development of complexity using examples drawn from studies of the flow of simple materials. Examples include splashing water, the formation of a thin neck as one mass of fluid separates into two, swirls in gases heated over a flame, and jets thrown up from beds of sand. We watch complexity develop in front of our eyes. Mostly, we are able to understand and explain what we are seeing. We do our work by following a succession of very specific situations. In following these specific problems, we soon get to broader issues: predictability and chaos, mechanisms for the generation of complexity and of simple laws, and finally the question of whether there is a natural tendency toward the formation of complex 'machines'.