THE next time you get caught in a downpour, don’t think about how wet you are getting – but how you are getting wet. Rain is, after all, just molecules composed of hydrogen and oxygen atoms, and there is nothing wet about hydrogen or oxygen on their own. There isn’t even anything wet about a single water molecule. Put lots of them together in the right conditions, however, and you will get wet.
The wetness of water is an example of an “emergent” property: a phenomenon that can’t be explained by the fundamental properties of something’s constituent parts, but rather manifests only when those parts are extremely numerous. Emergent phenomena are ubiquitous in nature and a proper grasp of how they come about could hold the key to solving some of our biggest mysteries.
“There is a sense in which nothing in science makes sense without emergence,” says Erik Hoel, a neuroscientist and author based in Cape Cod, Massachusetts.
In physics, for example, some materials exhibit superconductivity, where large numbers of electrons can move without resistance, and yet it isn’t always clear why. Neuroscientists, meanwhile, find that consciousness seems to emerge from some collective behaviour of neurons. In both cases, simply understanding the basic constituents of the system doesn’t explain the phenomenon in question, never mind allow you to recreate it from scratch.
“Ultimately, we want to explain under which circumstances we will see novel properties,” says Larissa Albantakis, a computational neuroscientist at the University of Wisconsin-Madison.
But the study of emergence is, by turns, promising and maddeningly difficult. The standard “reductionist” approach to scientific investigation breaks large-scale, or macroscopic, systems …
