Adaptive matter that can learn by itself

Synopsis

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, “adaptive matter," in which many more is different. The ultimate example of adaptive 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). I propose that adaptive matter provides a unifying conceptual framework for understanding not only a wide range of living systems responsible for function, but also physical systems capable of being trained to develop special collective behaviors without using a processor.