About

Netplexity is the informal web site of Tim Evans, a senior lecturer (something like an Assistant Professor in North America) in the Physics Department and in the Complexity and Networks programme at Imperial College London.

I have always wanted to know why things are the way we find them.  I like to find a sweeping principle that can explain some feature seen in many different situations.  I’m much less interested in the details of each case.  So I’ve never been too interested in how to tune an engine to get a car to go faster. However the principle that air resistance rises as the square of speed can be applied widely.  It means that each improvement made in engine power produces diminishing returns in terms of top speeds.

While trained as a theoretical physicist, I have always seen physics as just one view of the world.  I have been lucky enough to study fundamental physics, to look at our theories for the basic constituents of all matter, to ask how they were created for the whole universe.  However I do not see these as the apex of knowledge, just a point on a sphere of our understanding.  There are other ways of looking at the world.  So the social scientist might ask why were were asking these questions or how we organise ourselves in looking at these questions.  So why do we want to drive faster and faster, doe it achieve anything?

It has only been in recent years though that I have felt my expertise might be able to look at these wider questions.  With the appearance of large data sets on biological and social systems over the last two decades, one can start to apply ideas from statistical mechanics to look at problems in areas previously disconnected from physics. So with enough data on the speed of cars one can look at statistical distributions for speeds, look at how they might be explained by simple models and if, despite all the myriad differences in human behaviour, one can understand that one or two simple rules might explain a large proportion of the data.

This application of  ideas from statistical mechanics is part of the field of Complexity. There is no simple definition of what this means. It often involves understanding why patterns emerge on broad scales in a system where many small pieces are interacting in complex, almost unpredictable ways. I found Philip Ball’s book, “Critical Mass”, was an enjoyable non-technical introduction to questions in this area. I have been particularly interested in the way that describing systems in terms of complex networks might help us to reveal some of these general principles.

These are grand ideas.  There is no guarantee that we will find such principles outside physical science.  One of the challenges is to see if I can adapt my physical science view of the world to learn from the experts in other fields, not just in terms of what they know but in terms of how they ask questions in their world.  Sometimes the questions I try to ask are just the wrong sort of question, the experts can indicate that the answers they can find are not the simple yes or no ones I am used to.  At the same time, it maybe physical science can play a role and answer different types of question.  The great thing is to try to listen, to suggest and to enjoy the process as much as the results.