Blue Manifesto Letter from the Editor
Playlist
Not Full Enough
Henri Bergson on Possibility and Creation
The Many Lives of Energy
Anna-Sofia Lesiv
No one can say what energy is. The last, most precise definition came from Richard Feynman when he said it was a “certain quantity” that “does not change in the manifold changes which nature undergoes.” It’s an elusive description, careful to make no comment on any actual characteristics.
No one has seen the true face of energy. We have all felt the wind at our backs, heard the roar of an engine, or basked in the glow of electric light, but these are only its echoes. Becoming aware of energy’s secret role behind all physical phenomena took centuries, but since then, we have still only managed to speak about it through metaphor and analogy.
These days, one might hear it referred to as “the capacity to do work.” It’s a rather utilitarian coloring on a force so fundamental to the fabric of nature, but it reveals our predilection for the economic. This is simply the latest mask that we have stretched over energy’s slippery, enigmatic essence. Our attempts to define energy, derive meaning from it, over the years have resembled nothing less than a Rorschach test exposing our values, our relationship to Nature and to ourselves.
The prime law in question, alluded to by Feynman in his definition, is that of the conservation of energy. Even in the classical world, where chemistry was alchemy and physics was natural philosophy, there was an appreciation for the conservation of mechanical forces. Whether on Earth or among the heavenly bodies, mechanics ruled the day. In 1686, Gottfried Leibniz proposed that there was a finite quantity of “force” in the world. He called this vis viva, a living force, possessed by objects in motion. He also made allowance for the existence of a vis mortua, a dead force, possessed by stationary objects with the capacity to produce a living force, like a compressed coil or a lifted ball.
It was not an exact system of accounting. For years, Descartes and Leibniz warred over whether the exact measure conserved was momentum, force through time, or what we now call kinetic energy, force through space.
In retrospect, we know that both were right. Their statements were not mutually exclusive, but at the time, pinning down the distinctions gave way to frustration and animus. Despite the haze of confusion that surrounded the characterization of this force, both men were certain of its fixed quantity in the universe. It was a profound revelation, and, in the mind of Descartes, a mark of the Creator’s perfection. In his Principles of Philosophy, Descartes wrote “In the beginning He created matter, along with its motion and rest; and now, merely by regularly letting things run their course, He preserves the same amount of motion and rest in the material universe as He put there in the beginning.”
Even so, the principles of mechanics didn’t tell the whole story. Other phenomena, like whatever was going on inside of Alessandro Volta’s electric pile, the world’s first battery, remained a mystery. So too, was the case with heat. Heat was long believed to be an invisible, all-pervasive substance called “caloric,” and by the mid-18th century, machines were already converting hot, rushing steam from boilers into the mechanical motions of gears and shafts. There already existed a latent intuition that the nature of heat and mechanical motion were connected. Clearly one could be transformed into the other, as the Industrial Revolution’s steam engines proved, but it would take a French engineer, Sadi Carnot, to formalize these insights.
The steam engine, Carnot showed, operated on principles identical to those in classical mechanics. The movement of heat from a warm body, the boiler, to a cold body, the cooler, which drove the fluid motion powering the engine, was exactly equivalent to the fall of an object held up above the ground. Carnot’s insight was to show that it was the existence of this differential, the hot versus cold, high versus low, taut versus loose, that allowed for motion, Leibniz’s vis viva, or living force to be generated. If the steam engine’s boiler and cooler were the same temperature, no work could possibly be performed. The potential resided in the imbalance.
The insight catalyzed an investigation into the relations between all other physical phenomena too. When Michael Faraday proved that electricity could be induced with mechanical motion, there was no question that all such forces were linked. They manifested themselves so differently in reality, but they all conformed to the same principle of conservation. A new concept would need to be introduced to contain these ideas. That concept was energy.
The word itself was borrowed from antiquity. Energia was used by Aristotle in Ethics and Rhetoric to imply activity, vigor or a notion of actualization from potential. The Industrial Revolution gave it a new identity. Coal-burning steam engines showed that the potential for movement or activity didn’t just exist within animate prime movers, like cattle or people, but in the inanimate things around us, too. Energy was hiding inside all things. Energy could be extracted from them, and energy could do our bidding.
Ironically, a term used by Aristotle to convey a sense of realization and strength came to describe a highly abstract mathematical idea invented to relate the symmetries observed between physical phenomena. Energy didn’t exist, but it existed everywhere. James Clerk Maxwell, the Scottish physicist who first observed the equivalence between electricity, light, and magnetism noted that “in the study of any new phenomenon our first inquiry must be, ‘How can this phenomenon be explained as a transformation of energy?’”
However stabilizing it must have felt to unify all of nature’s exploits under the same tent, beholden to the same fundamental law, the consequences of this new idea soon led to a rather terrifying conclusion. This was because of yet another insight offered by the steam engine. At the time, no experiments to empirically prove that energy was perfectly conserved in its myriad transformations had succeeded.
Every experiment yielded some amount of energy missing. Sadi Carnot, in an attempt to devise an ideal steam engine, realized that a perfect transfer of energy was actually impossible: some quantity would always be lost as heat. So whereas classical mechanics saw motion perfectly conserved through reversible cause and effect, the steam engine instead suggested an irreversibility, a directionality to events. Heat only moved from hot to cold, never the other way around.
Mechanics became irreversibly transformed into thermodynamics, which included an addendum to the timeless conservation law, a second law to reflect the observation that over time, differentials dissipated and imbalances equilibrated. Physics predicted the universe as a unidirectional march from order to entropy. The end would come when all potentials vanished, the ability to do work disappearing alongside them.
Innocent beliefs in a predictable world matured into an anxiety about the unrelenting passage of time, every second delivering us one step closer to total inertia. Physicists began to worry that time for humanity might literally be running out. Not yet familiar with the nuclear forces powering the enduring heat of the Sun, William Thomson, later Lord Kelvin, worried that “inhabitants of the earth cannot continue to enjoy the light and heat essential to their life, for many million years longer, unless sources now unknown to us are prepared in the great storehouse of creation.”
Physics painted the entire universe with the brushstroke of energy, revealing eddies of potential everywhere, but entropy taught us to see these resources as temporary. The economist Nicholas Georgescu-Roegen wrote that “the entropy law is the most economic in nature of all natural laws.” If economics is concerned with making decisions over scarce goods, potential energy is the fundamental universal scarcity.
The tenets of neoclassical economics were an outgrowth of the physical laws discovered during the Industrial Revolution. The economist Philip Mirowski wrote, "Although it was ultimately called ‘energy’ in physics and ‘utility’ in economics, it was fundamentally the same metaphor, performing many of the same explanatory functions in the respective contexts, evoking many of the same images and emotional responses, not to mention many of the same mathematical formalisms.”
The abstraction known as energy became an edifice upon which we built the world. Economics taught us to view potential energy as a resource, while physics revealed the tricks by which we could harness its powers. The more energy we could access, the longer we could delay stasis.
There is something revealing about humanity’s urge to escape the prophesied heat death and outrun entropy. It was an attempt to outrun the rules we had ensnared ourselves with. After all, the newly enshrined natural laws failed to properly account for one crucial phenomenon—life.
Energy didn’t dissipate from living things, it concentrated in them. Civilizations were maxima of energy, they didn’t merely expend potentials, they generated them. Cities, pyramids and towers were monuments of negative entropy. Human beings didn’t simply tumble into troughs dictated by paths of least resistance, they waged daily battles with the physical laws keeping them weak and low. It was this capacity to act and overcome that composed the original meaning of energia.
When the contemporary technical, utilitarian garb is shed from the idea of energy, its original nature as a poetic concept appears completely intact. Energy, after all, is a capacious idea that holds inside it a fierce discursive potential, a constant battle between notions of permanence and decay, the eternal imprint of God’s perfection and the prognosis of our end.
Energy has lived many lives. Like a giant snowball accumulating mass as it rolls down a hill, the idea of energy has taken on historical, technical and economic baggage for centuries. Not only does it not exist, it remains an unresolved concept whose true meaning and implications are not only still in flux, but constantly destabilized by new revelations like potential energies appearing in vacuums and newfangled debates over the validity of the law of conservation.
If anything, energy is a field of potential, whose true meaning and revelatory power depends on the eye of the beholder. If poetry exists to express how we perceive the world, then science affords a kind of poetry of the physical world. Energy is merely the language in which it is expressed.
Anna-Sofia Lesiv is the founder of the digital publication Foundations & Frontiers, where she profiles emerging technologies.