Facts So Romantic

The Noise None of Us Can Live Without

Photograph by Steve Rotman / Flickr

Noise is one of my favorite things in the universe. I don’t mean the neighbor’s rusty old lawnmower thundering you out of bed on a Sunday morning; like everybody else, I despise that kind of noise. No, what I am talking about is noise as the scientist understands it: a limitation of deterministic systems. As intractable randomness, noise may be an unlikely source of all things creative—the root of all progress, motion, and free will.

The modern creation “myth” is a story of bottom-up emergence—be it the beginning of the universe from a simple energetic state or our understanding of living systems as complex assemblies of molecules. At the very bottom of this reality are physical forces and symmetries—and noise. They’re equally fundamental. The very universe began as a random quantum fluctuation. Quantum mechanics tells us, for instance, that we cannot predict the time at which a high-energy state (say of a radioactive atom) transitions into a low energy state. This unpredictability creates a background of noise amplified by the unimaginably large number of random collisions and interactions of all particles making up our reality.

This omnipresence of noise raises one vexing question in particular: If we are immersed in randomness, how come so much of the world seems so orderly? There are three answers—two familiar and one perhaps less so. The first familiar answer is that noise, averaged over many, many particles, becomes order. This is what happens in a gas, for example, where doing proper statistics on the random motions of gas molecules explains why a bicycle pump gets hot when we use it to compress air. The other familiar answer is that noise is constrained by physical laws and symmetries. This explains how atoms, stars, planets, and galaxies emerged from primordial chaos after the big bang.

The third answer is the one we are looking for. This answer comes into play where information interacts with matter. Take evolution, for example: Here is a mechanism that feeds on randomness and noise to extract order and information. How does it do that? It uses a ratcheting mechanism—a mechanism that takes randomness and filters it to create progress. For evolution, the randomness comes from mutations and sexual recombination, and the filtering comes from natural selection. Both are needed: Randomness creates novelty, and natural selection sifts for advantageous changes.

Subconsciously, our brain rejects the many nonsensical associations, only to allow us to become conscious of it when a newly generated idea makes “sense”.

On a smaller scale, molecular ratchets drive much of our body. The molecular machines in our bodies, which transport chemical cargo through our cells, are animated by the random motions of water molecules surrounding them. They absorb this motion through their sophisticated, asymmetric molecular structures, like a mechanical filter. A macroscopic equivalent is the ratchet on my mechanical wristwatch. Even if I move the wheel randomly back-and-forth, the asymmetric teeth on the ratchet inside the watch only allows movements in the correct direction to wind up the watch’s spring. (The molecular machines in our cells are more sophisticated, but the principle is similar.)

What does this have to do with creativity, agency, and free will? The puzzling thing about creativity is that it is hard to imagine how any deterministic process could lead to new ideas and insights. There must be a generator of new ideas somewhere. Let me therefore propose that the generator of new ideas is noise—random thermal, electrical noise in the subconscious processes of our brains. It’s similar to what happens when we dream.

When we dream, this random noise, unconstrained by sensory inputs, enters our awareness in the form of feelings, and the semi-conscious brain tries to explain the random feelings and images, constructing stories. “Ordered connections can sometimes be established only in the presence of noise,” says psychiatry researcher David Kahn, who studies consciousness and dreams at Harvard Medical School. “Thus, the dreaming brain, isolated from…sensory constraints, becomes subject to subtle influences that might exert sizable patterning effects on neural activity.” Such effects, he says, might be “felt experientially as the conscious flow of the dream.” When we are awake, on the other hand, this noise is reduced as long as the brain is busy interpreting what our senses see, hear, etc. When this chatter excites past associations or something we have been thinking about, we become aware of it.

Our brain, although constrained by what we have known and experienced, is capable of making novel choices from the background noise it generates.

New ideas, then, may be the result of a noisy novelty generator in our subconscious generating random associations that are subsequently filtered by our brain. Subconsciously, our brain rejects the many nonsensical associations, only to allow us to become conscious of it when a newly generated idea makes “sense”. In Thinking, Fast and Slow, Daniel Kahneman argued that we do many things without being conscious of them. There are systems in the brain, he says, that “decide” if something should become a conscious thought. Together, the noisy novelty generator and the filtering by our brain seem to ratchet up new ideas seemingly from nowhere.

There is no proof for this idea, but it fits everyday experience. Often, when we think hard about a problem, we do not immediately come to a solution. But the hard thinking is needed—it primes our subconscious to generate random ideas, conducting a true “brainstorm”. The subconscious brain continues to juggle the possibilities and, only when the pieces fell into place, makes us aware of it. We all have experienced this. Here’s Alan Lightman, for example, describing the sudden insight he had when he made his first discovery in physics:

I’d been working on this for months, and I began sleeping in my graduate room office, keeping cans of sardines in the drawer to eat—living there, basically. And then one morning I woke up with this buzz in my head, and I was seeing very deeply into this physics problem. The sensation I had was the sensation I’ve had when I’ve been planing, in which your boat, if the wind is strong, can get on top of the water and suddenly all of the water resistance vanishes, and you feel like you’re skimming across the water like a stone. It’s an incredible physical sensation. I felt like all the resistance had gone to zero, just flying along, and I ran into the kitchen, took out my pages of calculation, saw where I’d gone wrong, and began working feverishly; in about five or six hours I had the answer to the problem.

Random noise creates the possibilities, and our thoughts and experiences filters them. Our brains ratchet order from chaos.

How about agency, or free will? Having it seems difficult for a deterministic machine as well as for a purely random one. Combining the two, though, allows us to have the cake and eat it, too, argues Daniel Dennett, a philosopher and cognitive scientist: In his 1978 book Brainstorms, he writes, “When we are faced with an important decision, a consideration-generator whose output is to some degree undetermined produces a series of considerations, some of which may of course be immediately rejected as irrelevant by the agent (consciously or unconsciously).” Our brain, although constrained by what we have known and experienced, is capable of making novel choices from the background noise it generates.

We are, it seems, neither complete slaves to our environment or experience, nor are we tossed about by pure randomness. What makes us human is that our brains can ratchet up choice and creativity from a sea of randomness.


Peter Hoffmann is a professor of physics at Wayne State University and the associate dean of research in the College of Liberal Arts and Sciences.

The lead photograph is courtesy of Steve Rotman via Flickr.


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