that, contrary to standard belief, the market shares of many technology companies could be predicted with great accuracy, even if the underlying changes in technology changed frequently.

The bottom line is that small changes in the communication structure can affect decisions.

There is thus a recursive, reflexive loop at the heart of the economy.4 Complexity economics asks how this loop drives the behavior of the system over time, i.e., how will the pattern of the system today shape individual decisions which will then collectively create the pattern of the system tomorrow.

The big advantage of physicists—I think Doyne Farmer may have once said this to me—is not what they have learned, the tools. It’s how they have learned to think. In particular, physicists are quite good at being very, very broad, taking tools from all over the place. That is something that economists are very, very remiss in. It is a b—tch to try

Camera.” In finance, when people start to notice patterns in markets, they trade on them and can create a positive-feedback loop, exaggerating their effect. Bill Miller later reminded us that the practice of arbitrage in markets can do the opposite and create a dampening feedback loop.

She explained that an externality was not irrelevant, but, rather, uncounted—a consequence without a cost.

By physics, I mean approximation, compression, mechanism, optimization. Data science is not that. Data science is not science. I think it’s important that we make that statement.

And they are instantiated as a distributed processing system on human beings. They don’t particularly care about human beings. Their motives are inscrutable, to the extent that they have any, except that they’d like to get bigger. They’ve run on people. They’re implemented on people. But they are not people. They are not persons in any meaningful

Events with one bank can trigger events in other banks in the network, and so systemic risk—overall risk to the system as a whole—is not the summation of independent events, but it is reflected in domino-style avalanches of various sizes and duration.