The Rise and Fall of Complexity
Presented by Prof. William SEITZ
Type: Oral presentation
In chemistry and physics, the passage of time results in the increase of entropy of the universe – so that entropy is sometimes referred to as the “arrow of time”. Entropy, however, is also commonly associated with disorder so that biological evolution seems contrary since ecosystem order (or complexity) often (but not always) seems to increase through time. In this lecture we explore an evolution that is entirely consistent with the increase of entropy, but is based on the concept of increasing “mixedness”. Mixing, unlike entropy, is only partially ordered. An essential aspect of every partial order is that some states are not comparable – in other words if you have 2 states, A and B then A is neither more nor less mixed than B. In the lecture we will explore the mixing partial order and focus on incomparability of states. A dramatic plot showing incomparability vs. entropy is given. The shape of this curve is then interpreted in terms of the rise and fall of complexity as systems evolve.