The physics of the urge for freedom

Why do individuals have the urge to be free, rather than being constrained? Why does everyone share this impulse? In a recent article, these questions were addressed through the lens of physics, examining concepts such as work [measured in joules] and power [measured in watts]. To enhance the flow of the narrative, the  readers are requested to place themselves in the story:

Think of the long journey of becoming human, a process known in science as anthropogenesis, or hominisation. The main events– artifacts and innovations—that empowered humans were fire, clothing, boating, domesticated animals, agriculture, engineering, writing, religion, and science. But more power to do what? To move, spread across the earth, cultivate, live longer, and generate even greater power.

The descriptor sapiens (wise) for the human species refers to the multitude of changes, moves, rhythms, and choices that individuals make instinctively. Individuals make such changes because they feel ‘right’, not ‘wrong’. And they make these changes without consulting others. 

Urges are manifestations of the grand phenomenon of design in nature, which is both unifying and predictable. The noun urge (from the Latin verb urgere) means to press hard, stimulate, incite, or drive forward. Similarly, urge refers to a persistent impulse toward an activity or goal. The related term instinct (from the noun instinctus in Latin) means to impel or instigate. Instinct is an inborn tendency to behave in ways characteristic of a species. It is a natural, not acquired mode of responding to stimuli.

The urge for freedom is the most common yet poorest defined desire. Following the publication of Freedom and Evolution, questions have often arisen about the meaning of ‘freedom’. The meaning of freedom becomes clearer when one imagines living under its opposite–a complete lack of freedom. 

Dog, man, and leash

Look at a man walking with his dog on a leash (Figure 1). The man is at ease, while the dog must run to keep up with him. What is the impact of the leash on the effort (power spent) of the man and dog? Does the combined effort increase or decrease with the leash?

Without a leash, the dog and the man tend to walk at speeds close to their most efficient speeds. These speeds correspond to the minima of the bucket-shaped curves shown in Figure 2. The speed indicated with a dot at the bottom of each curve represents a mathematical concept – a human abstraction–introduced by an artist who knows how to identify the point of ‘perfection’ (the minimum) on the curve. However, this point does not represent the actual walking speed of the man (mass M₁), or the dog (M₂).

Nature is fundamentally different; it is not perfect. Around the mathematical minimum, there exists a range of speeds where the mover achieves nearly the same level of energy efficiency. Animals sense the difference between greater effort and lesser effort, choose less effort by altering their speed, and, almost as if by magic, are ‘drawn’ toward the most economical speed.

The imagined perfect is singular, but the near-perfect are innumerable. This is the essence of the physics of diversity. Every moving design in nature is enrobed in diversity.

The leash compels the dog and the man to walk at the same speed V, which becomes the lone degree of freedom for the moving pair. As a result, both suffer. The man walks slower than is economically optimal, while the dog is forced to walk faster than its optimal speed. Both deviate from the minima of their respective curves. Consequently, the total effort exerted by the pair of the man and the dog should always be greater than when they are walking freely. Indeed, Figure 3 shows that the combined effort with the leash always exceeds the combined effort when they walk without it. 

The work difference between ‘with leash’ and ‘without leash’ is greater when the pair walks at speeds comparable with the speed of the free dog, and when the dog is smaller than the man. The difference becomes noticeably smaller when the pair walks at speeds that feel natural to the man, which is a common observation when men and women walk with their dogs.

Implications of the urge to have freedom

The physics of the ‘freedom urge’ is, in essence, nature itself. Its manifestations can be observed across many fields and in more complex models. Here is a starting point: 

1. When linked, the moving pair expends more work than when they are free.
2. When the speed of the pair is dictated by the larger individual, the large one walks freely, while the small one must run. The smaller suffers, while the larger remains unaware because the smaller cannot speak.
3. When the smaller body dictates the speed, the smaller walks freely, while the larger must reduce its speed, moving below its natural pace. 
4. When the leash is necessary, the pair walks more economically when the speed approaches that of the larger body.
5. Participants in organised movements (life, society) are not equal. Some are larger, others are smaller. Some are faster, and others are slower. Some consume more power (work), others consume less. Participants move with less effort when they are not coerced into moving together. Society is more economical this way.
6. Unnatural (coerced, collective) movement is inefficient, despite the argument that ‘economies of scale’ leads to better performance in larger groups. Economies of scale are an entirely different evolutionary phenomenon in nature, predictable from the same physics discussed in this article. Economies of scale refer to the natural tendency of larger movers (rivers, animals, or engines) to be more efficient than the smaller ones. Additionally, bodies coming together voluntarily (by choice) are more economical per capita. This natural trend is evident in Figure 4.

Above all else, the animals sense the difference between ease and difficulty and instinctively choose the easier option. Self-organisation occurs naturally and unwittingly. A person surrounded by family lives more easily and longer than when alone. Migratory birds travel enormous distances in V-shaped formations, humans form societies, and so on. The root of all these behaviours lies in the urge for freedom and other related impulses. 

The physics outlined above can be expanded in a similar manner by employing models that appear more complex due to the greater number of movers, each with potentially more degrees of freedom to change.

Conclusion (f) remains valid for all configurations. The penalty in work consumption increases as the model includes more participants, whether free or on the same leash, regardless of the group’s size. General conclusions such as (a)–(f) tend to be obscured by the ubiquitous presence of diversity, which refers to the innumerable (natural) deviations from the unique best—optimum, minimum, or maximum.

The ‘intangibles’ are tangible

The evolution of human society aligns with the conclusion (f). The leash can be viewed as a metaphor for the forced collectivization of agriculture (and much else) during communism in the USSR and its satellites. The ‘one size fits all’ approach should be questioned, understood, and explained to the younger generation. Is it part of nature, or is it unnatural and thus destined to fail? 

Most scientists consider human urges as intangibles – feelings and opinions – outside the realm of physics and not governed by natural laws. Figures 1-4 showed that the intangibles are tangible and teachable as physics at the high school level. Reality exists.

Perception reveals the reality of change, shape, object, beauty, speed, and rhythm. Reality is continuously tested for validation everywhere. For example, when a barn catches fire, the horse, the pig, and the man run for their lives; the perceived change (from no fire to fire) is the same because it is real. It is not relative.

The idea of intangibles in physics should interest all scientists, journals, robotics, and AI developers because it is impossible to create machines that replicate natural human abilities without understanding the physics behind animal urges.

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Journal reference

Bejan, A. (2024). The physics of the urge to have freedom. BioSystems, 243, 105277. https://doi.org/10.1016/j.biosystems.2024.105277