Abstract

In 1972 Phil Andersen articulated the motto of condensed matter physics as “More is different.” However, for most condensed matter systems many more is quite similar to more. Here I argue for a class of condensed matter, “tunable matter,” in which many more is more different—the behaviors of more and of many more can be quite different. A familiar example of tunable matter is the brain, whose cognitive capabilities increase as size increases from 302 neurons (C. Elegans) to a million neurons (honeybees) to 100 billion neurons (humans). Tunable matter extends far beyond the Hopfield model, which exemplifies this behavior. Indeed, I propose that tunable matter provides a unifying conceptual framework for understanding emergent collective function in a wide class of biological systems. Finally, I will discuss new non-biological systems capable of being trained to develop desired complex collective behaviors without using a processor.