Not quite reflections from a not quite physicist

On 31st October 2008 I submitted my physics PhD thesis to the Student Centre at UCL and concluded my unremarkable career as a physicist. As the 10 year anniversary of this moment approaches, I chose to reflect on how a physics training has shaped my thinking, and those of the cohorts of lapsed physicists that have come before me.

As I have written (e.g. here) and opined (e.g. many laborious in-person conversations) in the past, a physics training is a uniquely powerful background for doing many other things besides physics. Of course I cannot escape a strong confirmation bias. Yet discounting this as best I can, a skillset straddling maths, computational skills, statistics, empirical observation with a generous bias towards simplicity and universality seems to be an objectively smart choice in the 21st century.

A common criticism leveled at physicists, is the tendency to blindly employ techniques and analogies from physics to other domains. The results here are a mixed bag and when it’s bad, it’s really bad. It’s certainly easy and momentarily rewarding to poke fun at this phenomenon, even for an insider, and XKCD does a good job here


So why are physicists so inclined to repurpose their tools for other domains? I believe the answer lies in an often under-appreciated fact that physics itself is an endeavour that is underwritten by just such a cooptation. Physics is built on the fact that things that can be described as a matrix or a statistical ensemble or any other mathematical structure, more often than not inherit the useful mathematical properties of that description. That is, if you write down an equation for how the height of the water in a bathtub that is filling up increases, you can integrate it, solve it and find out the time needed for it to be full. Perhaps more impactfully, Heisenberg was able to rapidly advance quantum mechanics by formalising particles in terms of matrices and leaning on powerful linear algebra results to solve the equation of the hydrogen atom.

To understand the confidence, sometimes bordering on hubris, that physicists have in using their worldview outside of its original purview, you have to understand just how remarkable this fact is. The extent to which reasoning about physical systems can laterally translate into the mathematical and back again is truly astonishing. It is this very fact that enabled physicists to do amazing things like harness nuclear power and make semiconductors work.

These historical achievements invite another observation about the lost physicist wandering into uncharted territory. Early physicists such as Newton were of course able to be physicists because of their privilege and power. They were also more likely to be polymaths because there were not that many people who could read the requisite Greek and Latin.

But being a physicist has often conferred rather than accompanied a position of power (interestingly as Chrystia Freeland noted in Plutocrats, the majority of the world’s superrich are in fact mathematicians, but that is splitting hairs). The zenith of which was the team assembled for the Manhattan Project, including Fermi, Feynman and Oppenheimer. The success of which in facing down the Nazi Uranprojekt, literally decided the fate of the world.

So we know that through the course of the 20th Century, physics had evolved from an arcane philosophical hobby most likely requiring the student to take lectures in German, via a brief period saving the world from Nazism, to the brain power behind satellite communications, meteorology and consumer electronics. What then is the status of the physicist following the democratisation of these expertise (and the pace of this democratisation should astonish: IBM now allows anyone to run experiments on its quantum computers through the browser)?

Presently we are in an era when an explosion of important economic, social and political interactions are mediated through online platforms. It’s a 2012-era cliche to say that this has given rise to a data-driven gold rush, but that makes it no less true. Suddenly there are questions of critical importance to the species that do not resemble the questions that typical economists or social and political scientists answer. In short: the most pressing work in social science might look more like a gas than a randomised control trial.

I believe it is an under-appreciated phenomena that physicists are suddenly back in a position of power; solving some of the most important social phenomena facing the species: electioneering, personal finance, humanitarian response and so on. This typically comes with a pretty healthy paycheck. In quite a short space of time, the physics toolbox has proliferated across academic disciplines and industrial sectors and conferred considerable dominion and influence. In short, physicists try to be things other than physicists because it seems to pay.

To be suddenly catapulted into such a critical role in society is quite a come back for the humble physicist. Although, were we ever really that humble?