07. The Wisdom of Run & Tumble: What E. coli Can Teach Us About Moving Forward
Artwork by Galit Shachaf
I don’t know about you, but I sometimes feel an immense pressure to always be on the move. Towards what? Everything. Family, career, personal growth—it doesn’t matter, as long as I keep moving. Sometimes you move just to have something to talk about, like when I was single, or when I moved to Australia and dreaded the innocent question – any plans for this weekend? You feel compelled to provide an interesting answer because movement equals busyness and busyness equals life.
Then came kids, bringing a new flurry of busyness with extracurriculars, sports, playdates, etc. On top of that, there's the internal drive for personal growth—to learn more, experiment, and explore. Always moving, aiming forward, hopefully in the right direction.
But how often do we pause to review our movement? What if the most effective strategy isn't purposeful forward motion, but a balance of direction and deliberate randomness? For this lesson, we can look to one of the smallest navigators on Earth.
A Lesson in Movement from Escherichia coli
Let's explore the world of bacterial movement using Escherichia coli as our guide. To get around, E. coli uses its tail-like propeller, called flagella, to execute a sophisticated two-part strategy: the "Run and Tumble."
Run: A directed, straight movement where the flagella rotate counter-clockwise, propelling the bacterium forward.
Tumble: A brief, random reorientation where the flagella fly apart and rotate clockwise, causing the bacterium to spin in place before running in a new, random direction.
In a neutral environment, this process results in a "random walk." But when the bacterium senses something—like an attractant (e.g. food) or a repellent (e.g. a toxin)—its behaviour changes.
The Run and Tumble Dynamic.
From:
Subramanian, G., & Nott, P.R. (2012). The Fluid Dynamics of Swimming Microorganisms and Cells. Journal of the Indian Institute of Science, 91, 283-314.
The "Run and Tumble": A Strategy of Random Precision
When E. coli senses it's moving towards a higher concentration of an attractant, it extends the "run" phase, delaying the "tumble." This results in longer, smoother journeys in the favourable direction. Conversely, if it’s moving away from food or towards a threat, it increases the frequency of its tumbles, allowing it to quickly change course.
At first, this seems counterintuitive.
Why waste energy on random tumbles once a good direction is found? Wouldn't it be more efficient to just run?
But no. In fact, the tumble is essential.
Without it, the bacterium would be locked into a single trajectory, unable to adapt or fine-tune its path. The tumble is a purposeful mechanism for reorienting and navigating efficiently. It’s how the bacterium samples its environment, ensuring it finds the best path, not just the first one.
It’s a small investment in randomness for a massive competitive advantage.
The Philosophical Power of the Tumble
What can this microbial strategy teach us about our own lives? The idea that randomness is not a bug in the system, but a feature, is central to many philosophical models of free will.
The two-stage model of free will, developed by philosophers like William James and Robert Kane, proposes that our decisions involve two steps:
Generating Possibilities: An initial stage of randomness or indeterminacy, where our minds generate a range of alternative options for action, often unconsciously.
Deliberate Choice: A second stage where we use our will to evaluate these options based on our values, reasons, and goals, and select one.
This model suggests that true agency requires a balance: too much determinism, and we have no real choice. Too much randomness, and our actions lack purpose. The "tumble" is the creative engine that prevents us from getting stuck in rigid, habitual patterns, while the "run" is our deliberate, focused choice.
Purposeful randomness. Artwork by Galit Shachaf
Embrace the Tumble
Just like E. coli, we thrive when we balance our goal-oriented “runs” with moments of intentional “tumbles”. When we introduce a bit of randomness—trying something new- maybe a random blog about microbial mindset 😉?, shooting in different directions, or simply allowing our minds to wander—we generate new possibilities. We prevent ourselves from becoming stuck.
From this expanded set of options, we can then apply our conscious will, evaluating which path best aligns with our long-term goals and identity. This dynamic enables creative breakthroughs and flexible adaptation, helping us move toward our goals with a stronger sense of purpose.
So, should we always be in movement? Yes, definitely.
But should we pause to introduce some randomness? Heck, yes.
Be like E. coli. Embrace the tumble. Embrace some randomness.
You might just find a better direction, or at the very least, you’ll enjoy the exploration of new possibilities.
Not to be random but you may find yourself caught beneath the landslide in a champagne supernova in the sky…