J. Doyne Farmer

J. Doyne Farmer (born 22 June 1952) is an American complex systems scientist and entrepreneur with interests in chaos theory, complexity and econophysics.

He is Baillie Gifford Professor of Complex Systems Science at the Smith School of Enterprise and the Environment, Oxford University, where he is also director of the Complexity Economics programme at the Institute for New Economic Thinking at the Oxford Martin School.

Additionally he is an external professor at the Santa Fe Institute.

His current research is on complexity economics, focusing on systemic risk in financial markets and technological progress.

During his career he has made important contributions to complex systems, chaos, artificial life, theoretical biology, time series forecasting and econophysics.

He co-founded Prediction Company, one of the first companies to do fully automated quantitative trading.

While a graduate student he led a group that called itself Eudaemonic Enterprises and built the first wearable digital computer, which was used to beat the game of roulette.

Though born in Houston, Texas, Farmer grew up in Silver City, New Mexico.

He was strongly influenced by Tom Ingerson, a young physicist and Boy Scout leader who inspired his interest in science and adventure.

Scout activities included searching for an abandoned Spanish goldmine to fund a mission to Mars, a road trip to the Northwest Territories and backcountry camping in the Barranca del Cobre.

Farmer graduated from Stanford University in 1973 with a BS in physics and went to graduate school at the University of California, Santa Cruz, where he studied physical cosmology under George Blumenthal.

While still in graduate school, Farmer and his childhood friend Norman Packard formed a group called Eudaemonic Enterprises.

Their goal was to beat the game of roulette and use the proceeds to form a science commune.

The word eudaemonia comes from Aristotle and refers to a state of enlightenment derived from a life lived in accordance with reason.

They bought a roulette wheel and did an extensive experimental and theoretical study of its physics.

To execute their system, they built the first wearable digital computer, at roughly the same time as the first Apple desktop computer.

Farmer hand-coded the three-kilobyte program for the computer in machine language.

The program included a floating-point package, a sequencer to perform the calculation, and an operating system that functioned with toe inputs and vibrating outputs.

The earliest version of the computer was hidden under the armpits, but a later version was concealed in a shoe.

Their scheme took advantage of the fact that typically more than ten seconds elapse from the time the croupier releases the ball until bets are closed.

During this time one person measured the position and velocity of the ball and rotor using his big toe to click a switch in his shoe.

The computer used this information to predict the likely landing position of the ball.

A signal was relayed to a second person, who quickly placed the bets.

They made over eleven trips to Las Vegas, Reno and Tahoe, and achieved a 20% advantage over the house, but suffered persistent hardware problems.

This combined with their fear of violence at the hands of the casinos, so that they never played for high stakes and failed to realize the large sums they originally dreamed of.

After the roulette project Farmer switched his dissertation topic to chaotic dynamics and joined together with James P. Crutchfield, Norman Packard, and Robert Shaw to found the Dynamical Systems Collective (subsequently known by others as the Chaos Cabal).

Although they had the blessing of faculty members William L. Burke and Ralph Abraham, they essentially co-advised each other's PhD theses.

Their most important contribution was a method for state space reconstruction, that made it possible to visualize and study chaotic attractors based only on a single time series.

This has now been used to identify chaotic attractors and study their properties in a wide variety of physical systems.

In his PhD thesis in 1981 Farmer showed how varying a parameter of an infinite dimensional system could give rise to a sequence of successively more complicated chaotic attractors, resembling the transition to turbulence.

He later developed a method for nonlinear time series forecasting that has been used for exploiting low dimensional chaos to make better short term forecasts.

Other work included an improved method for state space reconstruction, and a derivation of the fundamental limits in which this becomes impossible, so that the dynamics become inherently random.

He and colleagues also developed a method for determining when chaos can be distinguished from the null hypothesis of a correlated linear random process.

After finishing his doctorate in 1981, Farmer took a post-doctoral appointment at the Center for Nonlinear Studies at Los Alamos National Laboratory and received an Oppenheimer Fellowship in 1983.

He developed an interest in what is now called complex systems and co-organized several seminal conferences in this area.

In 1988 he founded the Complex Systems Group in the Theoretical Division and recruited a group of postdoctoral fellows who subsequently became leaders in the field, including Kunihiko Kaneko, Chris Langton, Walter Fontana, Steen Rasmussen, David Wolpert, Stephanie Forrest, James Theiler and Seth Lloyd.

Farmer and Norman Packard developed the concept of metadynamics, i.e. co-evolving networks and dynamical systems.

For example, the nodes of the network might represent chemical species and the edges their possible reactions, whose kinetics give rise to a system of differential equations.

As new species are produced the set of reactions changes and the kinetics are in turn altered.

This concept was used to model the immune system and the origin of life.