An introduction to emergence: more, less or different than the sum of the parts?

The concept of emergence is often intuitively described as the phenomenon whereby the whole is “more than the sum of its parts.” The Dikke Van Dale dictionary defines emergent as “unexpected, occurring spontaneously,” suggesting that emergence also has to do with surprising behavior arising from the interactions of many components. But what exactly does this mean? When can we genuinely call a phenomenon emergent? In this lecture, we will explore the history of the concept of emergence in science and the philosophy of science, and examine different forms of emergent behavior through examples from mathematics and the natural sciences. Is the behavior of a whole truly more than what can be deduced from its constituent parts? Or does a higher level of description instead give rise to a simpler picture, in which many microscopic details disappear? Perhaps, then, the whole is not so much more, but rather less, or simply different, than the sum of its parts.

Wout Merbis is a methodologist at the Central Bureau of Statistics (CBS) and theoretical physicist at the University of Amsterdam and the Dutch Institute for Emergent Phenomena (DIEP). His research interests lie at the interface of applied mathematics and statistical physics of complex systems, with applications on socio-economic issues. An important part of his current work pertains to the hydrodynamic description of emerging phenomena in society, such as segregation, polarization and economic inequality.