Generational amnesia

from Wikipedia

The effects of parents choosing not to have their children vaccinated has been in the news again recently, after an outbreak of measles at Disneyland, apparently transmitted by an unvaccinated woman. This sort of thing seems to keep coming up. For a deep and personal reflection on the issue, have a look at this blog post. For me this paragraph is key:

What happened was that some parents decided not to immunize their children. As it is extremely contagious, measles does not need much of an opportunity to regain a foothold. That opportunity was provided by a false belief in some parents that immunization was unnecessary or even harmful. Parents who were too young to have experienced the disease became more fearful of the vaccine than the disease and their unvaccinated children became innocent victims.

It seems that sometimes we solve problems so well, we stop believing that they need to be solved.

Every generation want to think for themselves, and we’re not very good at reasoning about things we have no experience of, no matter what our grandparents tell us. This generational independence is good for freeing us from unnecessary traditions and the poor decisions of the past, but depressingly, it also seems to condemn us to repeating history.

Information and Entropy

As a physicist, I hope that we will be able to develop a general mathematical theory of complex systems. But complex systems don’t fit into traditional statistical physics theory. They are not in equilibrium, and are full of correlations and strong interactions. Complex systems can increase their complexity spontaneously over time. (Darwin’s theory of evolution is an explanation of one way that this can happen, for example.) This increase could be thought of as an increase in information content, since the more complex a system is, the more bits of information are needed to describe it. This is measured by Shannon entropy. But information theory doesn’t tell us how to relate this to other important quantities like energy. For that we should have been talking about thermodynamic entropy instead. Chris Adami has an interesting discussion on his blog about information entropy, thermodynamic entropy and how they’re related.

Power polls

Nate Silver’s predictions for the US elections, on his fivethirtyeight blog, have received a lot of attention since the actual election results agreed extremely well with his predictions. Silver’s results have been held up as an example of the power of numbers as opposed to, for example pundit opinions, and rightly so. Silver’s results shouldn’t be a surprise. Much of the hard work was already done by the pollsters, and the aggregated predictions published by Silver and others mainly serve to underline the power of polling. Even much simpler analysis, such as a simple five-poll average  gave very accurate results.

While they are not really the same thing, his analysis has something in common with what we try to do in Complex Systems: good data combined with reasonable assumptions and a careful application of statistical principles can give simple, but powerful, results.
On the topic of pundits, the vindification of numerical analysis, and the wildly innacurate predictions of some pundits might suggest that, come the next election, numerical analysis will supplant those pundits. But I doubt this will happen. This conclusion misunderstands the role of TV pundits. Their main role is not to give accurate predictions. Their task is to make TV interesting, by providing lively discussion, and to give arguments in support of a particular point of view. In fact, it might even be better for them to not give accurate predictions: if every network lined up pundits all repeating more or less the same careful estimates, there wouldn’t be as much entertainment value.

Networks in Green Chicago

I’ve just returned from a week in Chicago. Well, technically Evanston, but Chicago looms large on the horizon. I was at NetSci’12, the biggest network science conference of the year, held at Northwestern University. NetSci is always a highlight for me. Representing things with networks can be an extremely powerful tool, and once you start to think about it, almost any complex system has a networky element to it. This means that NetSci has a very broad scope, and I heard fascinating talks on topics such as economics, epidemics, social networks, mobility, communications, ecology, gene interactions, …the list goes on and on. Another great thing about NetSci is that the first two days are dedicated to satellite symposia. These are independently organised workshops on more focussed topics. This year I went to LangNetSci, about all things networky related to language, and Netonets, about networks of networks and their importance to infrastructure and systemic risk. Both of these workshops were well worth the time, and there was hearty discussion and a real sense of collegiality in both, which continued through the main conference.

Where talent wants to live

Paul Callaghan, one of New Zealand’s leading scientists, makes a forceful and compelling case for why the obvious avenues to economic growth won’t work, and why New Zealand should instead aim to grow its economy through niche, high tech businesses. Investment in research and development is one important ingredient in achieving this end. Well worth the 20 minutes viewing time.