The Inventor of Emergence: George Henry Lewes, in 1875

Emergence and complex systems: These concepts are more and more important, with the growth of the Internet, distributed intelligence, social media, and collective consciousness. “Emergence” refers to higher-level phenomena “emerging” from lower-level components, organized into complex systems. For example, mental states — like memory, attention, emotions — are said to emerge from neurons and their interactions. The biological brain is a complex system, with its many components interacting in multiple and different ways.

Today “emergence” is associated with the Internet and social media. But “emergence” isn’t so new, after all. It comes to us from the 19th century. The term “emergence” was coined in 1875 in a book by the British philosopher, George Henry Lewes. The issue at that time was: Why doesn’t all science ultimately reduce to physics? After all, everything in the world is composed of atoms. So the science of atoms and how they interact could, potentially, explain everything. If everything scientific reduced to physics, then all of the other sciences would potentially be unnecessary: biology, chemistry, neuroscience, psychology, sociology, you name it. If that seems wrong today, then it seemed even more wrong in the 19th century, when science was a lot more primitive than now. But you can’t just say it seems wrong; you need a scientific and logical argument for why everything doesn’t reduce to physics.

“Emergence” was the answer to why all science isn’t physics, even though everything in the world is made up of physical stuff. (This is still, basically, the answer of today’s philosophers of science.) In 1875, George Henry Lewes wrote about the difference between mechanical effects (which he called “resultants”) and chemical effects (which he called “emergents”). (Lewes was borrowing from a similar distinction made by John Stuart Mills in 1843.) Lewes’ example of emergence was the combination of hydrogen and oxygen to make water. Because water doesn’t have any of the properties of hydrogen or oxygen, its properties were “emergent” from the combination. Contrast that with a steam engine: It’s a complicated system, to be sure, but the properties of the whole system aren’t that different from the properties of the components, the metal, water, and coal that make up the engine’s operation. They are “resultants.”

I tell this history in my 2005 book Social emergence: Societies as complex systems.

You’ve probably already noticed a serious problem with the emergence argument: In 1875, Lewes didn’t know how hydrogen and oxygen combine to form water. But a few years later, scientists were able to explain water, and how the properties of water were explained by hydrogen, oxygen, and their combination. Water doesn’t seem so “emergent” any more. This is why the reductionists, the people that argue that everything can be explained by lower-level sciences, dismiss the emergence argument. Sure, they say, it seems to us that consciousness can’t be explained in terms of neurons and the brain. But just wait a couple of years, a couple of decades, and we’ll see that everything is really just neurons.

I was reminded of G. H. Lewes this weekend, when I read a book review of the new book Reading the Rocks  by Brenda Maddox. The book is about Victorian geologists (it sounds like a snooze-fest, but the review calls it “engaging” and “absorbing” and it sounds like my kind of book!) and it starts with the novelist George Eliot. It turns out that she was a geologist, as well as a novelist. She was introduced to geology by–guess who–George Henry Lewes. They spent vacations together, hammering at rocks.

One sentence in the book review jumped out at me: “Ms. Maddox traces the emergence of geology in Britain during the 19th century.” Emergence is everywhere! But we still don’t know for sure: Does it really happen? Or is it just a figure of speech?