When I was in graduate school at the University of Chicago I took a graduate level physics course on non-equilibrium statistical mechanics. I struggled in that course. There were some kids in there that were just off the charts. I ended up with what one might call a "gentleman's B." But I did spend quite a bit of time thinking about and visualizing what was happening in the systems we studied in that course. A few years later, when I started learning about the economic analysis of law, I started thinking about how, with lots of simplifying assumptions, markets could be modeled as physical systems. And this got me to thinking about how non-equilibrium statistical mechanics might have some interesting applications to the study of economics.
Earlier this year, I started reading Charlie Munger, another ex-physicist who has spent some time thinking about markets. I read about what he describes as the "lollapalooza effect," which sometimes occurs in markets, and realized that it was basically a description of spontaneous symmetry breaking.
To see the connection, you have to make a lot of simplifying assumptions about how people behave. Charlie's strength as an investor is probably due to his ability to sense inarticulately when his simplifying assumptions are strong enough to be trusted and when they should be kept under watch. But here's how one physicist has come to visualize the lollapalooza effect of broken symmetry:
People can be modeled as particles in a potential. The contours of the
potential are determined by the opportunity costs of engaging in
various activities (driving, working, playing, everything). So you
have a manifold that includes a variety of local equilibria
corresponding to various states of the world. It gets messy fast
determining the shape of these contours because the contours of the
manifold (i.e., the opportunity costs of various activities) are
themselves a function of the previous activities of the particles.
There's enough energy (capital) in the system to keep
the particles bouncing around in one local equilibrium, but not enough
for many (or any) of them to bounce out into a new equilibrium. But
every once in a while, there's a perturbation to the system (an exogenous shock), which
drives enough of the particles into a particular direction at a high
enough energy to move them into a new local equlibrium in which they have
different and new local symmetries. Local symmetry just means what you would see if you were an ant in the particle's position on the manifold. If the particles can store
information and communicate (this is where we completely lose the physicists if we haven't lost them already), they've now got a larger map of their
system.
Scale invariance (a tool used by physicists to describe transitions between equilibria) occurs in political or economic revolutions when so much energy gets
added to the system that local symmetries are no longer important. The particles just bounce around so fast that they don't even notice the contours.
Once things settle down, they'll tend to settle into new and
different local equlibrium. But it's often difficult to predict with certainty which local equilibria the particles will fall into.
Revolutions are messy and difficult to control. The exception might be for a catalyzed phase transition in which one particle or small group of particles act as "seed crystals," so that everybody ends up moving with them into a new local equilibrium.
Firms and even governments are spontaneously self-assembled
organizations of particles that result from the symmetries of
particular local equilibria given the amount of energy (capital) available to sustain the organization. Just like water can take the form of a solid, liquid, or vapor given the amount of energy (measured as a temperature distribution) and its interactions with surrounding molecules (including other water molecules), people will self-assemble into different kinds of private and public institutions in order to minimize the amount of capital required to sustain their assembly.
Incidentally, the concept of
allocative efficiency in economics (i.e., the principle of maximizing
utility over the manifold for every particle) corresponds pretty closely to the extremization of hamiltonians and lagrangians in physics. But the transactions costs of engaging in
social and economic transactions between particles are dissipative
forces (i.e., stickiness to the manifold) that have to be assumed away to do the calculations and find the most efficient equations of motion (i.e., institutional design). So it's no surprise that the Coase Theorem has to assume away transactions costs in order to say that the default local equilibrium assigned by government doesn't matter.
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