The graceful machine

On the strange wonder of walking

Also published on my Substack, Wombat Safari

We rarely give it much thought because walking is so familiar and automatic that it has become almost invisible to us.

We walk from A to B, to the fridge, to work, to the corner shop, down the hall, and out the door. In daily life, it’s treated as nothing more than a means of movement.

However, walking is an incredibly complex task, and the simplicity with which we perform it is deceptive.

Controlled by the nervous system, the act of walking demands the precise coordination of bones, joints, muscles, tendons, ligaments, and the connective tissues that make up the musculoskeletal system. This process continually recalibrates to respond to changes in terrain, shifts in balance, and environmental interruptions. And it’s done not through conscious calculation but through a form of embodied intuition.

This miracle is so commonplace that we forget how extraordinary it truly is. However, roboticists have discovered just how difficult it is to replicate.

It’s hard being a bipedal robot

When engineers attempt to replicate walking in machines, they quickly encounter practical challenges inherent to the task. Designing a robot that can walk, even on flat surfaces, involves addressing numerous interrelated issues, such as joint control, force distribution, balance maintenance, gait adaptation, energy efficiency, and environmental sensing.

We see walking as a repetitive and simple activity. However, it is a surprisingly dynamic process. Walking is a form of controlled falling. Humans continuously fall forward and use one foot after the other to regain their balance. The centre of mass moves forward, and the legs swing and land in a way that prevents us from toppling over.

Replicating this action in bipedal robots requires engineers to coordinate multiple factors: where to place the foot, how fast to swing the leg, how to shift the centre of mass, and how to manage external disturbances. These adjustments happen so seamlessly in humans that we rarely think about them, yet they are tricky to replicate.

While bipedal robots can perform impressive acrobatics, they represent decades of research and millions of dollars’ worth of investment. These robots are remarkable in their range of actions, their high levels of stability and fluidity in movement, and, most importantly, in the way they learn to make decisions through feedback. However, they still fall short of human performance in terms of control, energy consumption, dexterity, and adaptability.

What does this tell us?

First, walking is not merely a mechanical function. It is cognitive. The philosopher Alva Noë and others in the field of ‘enactive cognition’ have argued that consciousness is not something that occurs in the brain, but rather is enacted through the body’s dynamic engagement with the world.

Walking, then, is not just a means of transport. It is a fundamental way we think and perceive the world. The child who learns to walk is also developing the ability to perceive depth, assess risk, navigate their environment, and balance their agency with the surroundings. Walking trains not just the muscles, but also the mind.

Secondly, walking connects us to the world in ways that no technology can replicate. Machines don’t walk for the same reasons we do. Walking carries meaning. We walk in grief. We walk to celebrate. We walk for causes. We walk to clear our heads. We walk to remember who we are.

“Solvitur ambulando,” a phrase attributed to St Augustine, translates to: “It is solved by walking.”

The psychologist James Gibson once described perception as an active form of exploration. Walking is perhaps the most fundamental way we engage in this exploratory perception. As we walk, we interact with the features of the environment that invite us to take action.

A curb invites a leap, a path encourages us to stride, and a sudden sound prompts a turn. This seamless reciprocity between our moving bodies and the world lends walking its richness. And this is precisely what proves so difficult to simulate in artificial systems: not just movement, but responsiveness; not just coordination, but adaptability.

Today, we quantify our steps, track our gait, and measure our pace. We walk on treadmills with screens and through shopping malls. We walk distracted.

The world keeps calling us back to it

Every time a robot stumbles, it reminds us of what we take for granted. When we fall ill or become frail and lose the ability to walk unaided, we suddenly become aware of how much of who we are resides in this seemingly simple act.

To understand what it means to be human, we should pay attention to our footsteps.

Walking is an immersion in the world, a constant negotiation between stability and adventure. It is a task of stunning complexity executed with unconscious ease.

We don’t need to make walking seem mysterious. However, we should steer clear of downplaying its significance.