Ripples in a Pond
Movement, Energy, and Life's Struggle Against Entropy
As the last drops of rain slow to a drizzle and the clouds begin to part, the sun peeks out and casts a gentle glow. Glistening raindrops gently roll off leaves, plunging towards a pond in which bubbles tumble towards the sky. Each diving drop and bursting bubble adds a note to a brilliant symphony of ripples that dance across the pond’s surface. Watching the surface quiver with each delicate drop and burst, I can’t help but think to myself: those raindrops couldn’t help but fall; those bubbles couldn’t help but rise; that surface couldn’t help but ripple. These patterns of movement are familiar and predictable.
Yet, on that same surface, patterns of movement unlike those of falling raindrops or rising bubbles attract attention. Beneath it, shimmering fish flow. On it, water striders dart. Above it, seen from its reflective surface, the undersides of gulls glide across the sky. These patterns of movement are different. They’re familiar...but less predictable. I can’t be sure of where exactly the fish will flow, where the striders will dart, or where the gulls will glide.
Nevertheless, a familiar flame seems to burn behind these movements; at times turbulent like the licks of a flame, at times calm like softly glowing embers. But, unlike burning flames that release their energy with indifference, life clings to its energy, releasing it only in pursuit of a particular goal.
Today, we’ll be exploring the source of that release, the movement it creates, and why we can differentiate this movement from falling raindrops and flickering flames. We’ll start by examining movement itself and what causes it. Then, we’ll delve into a universal phenomenon that tends to pull everything apart and life’s perpetual struggle against this pull as it strives to hold itself together. Finally, we’ll consider why life bothers to struggle at all and how this struggle defines life. So, come along—let’s unravel the mysteries together and discover the hidden rhythms that make life move.
Forces
To understand the essence behind different types of movement, we’ll begin by getting a handle on movement itself.
Why do things move?
Bodies change their velocity1 because forces push or pull them. Resting bodies are brought to motion and moving bodies are brought to rest only when they are forced to. If you see something moving, a force got it going. If you see something resting, a force brought it to rest.
The raindrop falls because a gravitational force pulls it down. As it falls, air pushes up against its surface while intermolecular forces hold it together. Meanwhile, the bubble rises because the air inside it is lighter than the surrounding water. The heavier water around it sinks beneath, greedily occupying the space below and leaving the bubble with nowhere to go but up.
So, things move because forces cause them to. But what causes forces? Do they just appear out of nowhere, or do they arise from a more fundamental source?
Energy
Throughout the cosmos flows an ever-changing field, pulsing like a windswept blanket of tall grass. This field is comprised of what we call energy, dispersed upon which are nodes of concentrated energy that we call matter, continuously interacting and transforming, giving rise to the dynamic tapestry of the universe.
As far as we know, energy is the source of everything. Its most common definition in physics is the capacity to do work, where work can be considered as energy channeled in a way that produces a useful outcome. This definition of energy is self-referential: its definition includes itself. It kind of has to, because energy is everything—how can a definition of everything exclude itself?
Energy understood by us seems to always belong to one of two forms: kinetic or potential. Kinetic energy is involved in an object’s movement, whereas potential energy has the potential to move an object, that is, the potential to be converted into kinetic energy.2
Kinetic energy is a function of the mass of an object and the square of its speed, always involving some form of material propagation in the form of a wave. For instance, when a mechanical wave propagates through the metal of a tuning fork, energy is transferred to the surrounding air, across which waves of pressure traverse before eventually vibrating our eardrums. Another form of kinetic energy is thermal energy, which involves the movement of tiny particles whose activity produces the heat we feel on our skin.3
Potential energy, on the other hand, refers to stored energy. Examples include energy stored in the nucleus of an atom (nuclear energy), in bonds connecting atoms (chemical energy), or in the attractant field of a mass (gravitational energy). For instance, in our bodies there are sugars and fats which, when brought together with other chemicals, have their potential chemical energy converted into mechanical energy that moves the body.
In sum, there are two forms of energy: energy related to “movement” or “could produce movement.”
The conservation of energy
As the physical sciences have matured, humans have observed patterns relating to energy that are so profound, consistent, and reproducible that they have established themselves as laws.
The first law of thermodynamics claims that energy can be neither created nor destroyed, only transformed from one form to another. This law is otherwise known as the conservation of energy.
A falling raindrop experiences a gradual transfer from potential gravitational energy to kinetic energy as it falls. When it impacts the surface of a pond, kinetic energy that was once primarily vertical disperses in all directions in the form of waves: waves disperse along the surface (we see these), into the air above (we hear these), and quietly throughout the water below. Eventually, the raindrop’s kinetic energy dissipates, settling into a water reservoir rich in potential energy. The raindrop’s energy does not disappear; it is transformed.
Now, returning to the question of where forces—the pushes and pulls that produce movement—come from. Forces don’t arise from nothing; that would violate the conservation of energy, which tells us that something can’t be made from nothing. Instead, forces are the impressions that various forms of energy make on an object. Whenever there’s movement, it’s because of the influence of kinetic energy; when something rests in equilibrium, it’s due to the balance of potential energy.
Imagine a pond’s surface as a delicate fabric that stretches, folds, and undulates in response to falling raindrops or rising bubbles. Just as forces cause objects to accelerate, deform, and change direction, the pond’s surface ripples and moves. These ripples don’t appear out of thin air—they arise from the transfer of kinetic energy from the raindrops and bubbles to the surface of the pond. Similarly, forces are the impressions left by energy, much like the pond’s surface is shaped by the energetic impacts of raindrops and bubbles.
Even when nothing is moving, forces are still at work, generated by stored, potential energy. Consider a leaf resting on the pond’s surface: gravitational potential energy pulls it down, while the electrostatic field of the water pushes it up. These energy fields generate forces that balance each other, creating a gentle equilibrium.
Meanwhile, the warps and wobbles on a pond’s surface perform on the backdrop of a much larger fabric: the ever-expanding fabric of spacetime. This notion of “ever-expansion” brings us to the second law of thermodynamics, which states that energy dissipates—that is, becomes more spread out and less orderly—over time and that this process cannot be stopped or reversed, only slowed.
Understanding the second law provides a crucial piece in understanding the familiar fire in each of us. To grasp how we became matter that matters, we need to try to get a handle on a phenomenon that always seems to find a way to slip through our fingers.
Entropy
The tendency for energy to dissipate in a closed system over time is known as entropy. Here, a system being closed means that energy cannot be added or removed from it, which keeps its total energy constant. Once a system is opened, however, energy can be added or removed from it; yet, opening a system also creates a vent for energy to escape, and since entropy is always positive, some energy will always be spreading out within and beyond the orderly confines of the system.
Entropy always being positive implies a universal unidirectionality towards disorder. This unidirectionality implies that entropy is an irreversible process. Regardless of whether a system is open or closed, regardless of whether we can reduce entropy, entropy will always be positive.4 The irreversibility of entropy helps to explain why, unlike our spatial directions, time travels in one direction. The arrow of time points in the direction of energy dissipation: towards positive entropy.
Entropy can also be understood as an ongoing process of converting potential energy into kinetic energy. If entropy is positive, energy must spread out, which requires matter to move, and movement necessitates kinetic energy. Thus, for energy to spread out more, more kinetic energy must be added. However, kinetic energy can’t create more kinetic energy; the increase must come from the transformation of potential energy into kinetic.
The gradual entropic expansion of the universe implies that the universe was once more compact—that is, that all energy was once more potential. Tracing this back to the beginning of time, it becomes clearer why human conceptions of the universe’s origin—whether religious or scientific—often converge on a single point or deity embodying ultimate potential. Since the initial release of this potential, the expansion of the universe has been a gradual unfolding of potential into kinetic energy. We’ll find later that life, when considered as a whole, follows similarly.
Before that, here’s an analogy to help drive home this concept of entropy. Think of a ship containing cargo. Let the ship represent an open system, and the cargo represent energy. As the ship moves, imagine its cargo slowly spilling out to sea. Over time, the spilling cargo becomes more dispersed and less organized. This spreading out symbolizes increasing entropy.
Since the ship is an open system, its cargo hold can be refilled to replace what has been spilled. This refilling process represents adding energy into a system. By adding cargo, we can make up for our losses and maintain a higher level of organization within the ship. We can even try to use some of that cargo to slow down the leak. However, no matter how much cargo we add, the process of spilling will continue at some rate; it cannot be stopped.
The catch is, adding cargo requires other ships to deliver that cargo, and those ships spill cargo as well. Therefore, to sustain themselves, a system of ships must be formed, all spilling cargo as they move, all requiring cargo replenishment to sustain their functions and maintain order. The net effect is that the sea upon which these ships float becomes more and more littered with cargo. In other words, open systems that attempt to locally reduce their entropy necessarily increase the entropy of their surroundings.
This analogy roughly describes the systems that relentlessly protest against the exhausting scourge that is entropy. These systems are life itself.
Life
Let’s return to our scene with the pond. The falling raindrops, the rising bubbles, and the radiating ripples were all predictable movements. In fact, they are so predictable that their patterns can be expressed fairly reliably with formulas based on the conservation of energy. But even without explicit formulas, we have an implicit recognition of these patterns, hence why we think to ourselves that the raindrops couldn’t help but fall and the bubbles couldn’t help but rise.
The movements of life, on the other hand, are more elusive and complex. While life does (and must) comply with the laws of energy conservation and positive entropy, there are extra layers of complexity loaded into the movements of life. This additional complexity comes from life’s contentious relationship with entropy and the flurry of competition that unfurls when a network of actors swim against its current to keep their ships afloat.
In biology, the long-established theory on the force—the generator of movement—that gives rise to this competition is natural selection, which suggests that organisms best adapted to their environments are more likely to survive and pass on their genes to future generations.
Sometimes, we have difficulty believing that all there is to life is just survival and reproduction, especially when, at first glance, human behavior seems not to adhere to these principles. We run into this problem when we think natural selection occurs only at the level of the individual, but in reality natural selection occurs at various biological scales simultaneously. For instance, groups of organisms try to survive and reproduce insofar as it benefits the organisms that comprise it. This leads to the otherwise confusing tendency for individuals in social species to sacrifice their immediate genetic well-being for the benefit of a group to which they belong. In the human realm, think of the solider that sacrifices their life to help their nation flourish, or the priest that sacrifices their reproductive potential to help their religious community thrive. These roles, despite not producing offspring, exist because they helped groups succeed, and groups are subject to natural selection too!
Digression aside, life, at its essence, can be distinguished from non-life in its attempt to locally decrease its own entropy. Life are like the cargo ships; nonlife are like the cargo and sea.
By protesting against entropy, life protests against the arrow of time. This relentless attempt to decrease entropy is, in a way, an effort to slow down the passage of time within itself. Yet, as we saw in the ship analogy, local reductions in entropy increase the entropy of that locality’s surroundings. Therefore, by trying to slow down time within, life accelerates time beyond. By trying to become immortal, life proliferates mortals.
Life is a creative process. By decreasing entropy locally, life increases its potential to create more kinetic energy—to create more movement. And in this striving to increase its potential to create more movement, life, in a way, strives towards that point of ultimate potential that we traced back to the beginning of time. Meanwhile, as it builds potential, life inadvertently increases surrounding movement in both the present and future. Is life on Earth not gradually dispersing the planet’s potential energy—the concentrated matter that forms Earth and the solar energy it absorbs? Put differently, is Earth not unraveling itself?
In sum, life brings itself together like the past to expand itself like the future, creating a dynamic harmony in the present. Life is made in the image of the universe. It is a pattern that disintegrates its surroundings in pursuit of integrating itself, and its purpose seems to be to maintain and proliferate that pattern over space and time while entropy quietly pulls it apart. And due to this entropic resistance, maintaining that pattern takes work.
Work
When we defined energy, we defined it as the capacity to do work. But what is work?
There was no mention of work during our discussion of the falling raindrop and its transfer of potential energy into kinetic energy. Why is that?
Because there was no need: a falling raindrop is a benign process; the raindrop has no objective. It is only when objectives are introduced when work makes its entrance.
The raindrop has no purpose and thus no active constraint on energy release; energy gets released in whatever direction meets the least amount of resistance. But our biologically driven friends—the fish, the striders, the gulls—all have a purpose. And so, they channel the energy within towards an aim beyond. This is work: energy channeled in a direction that achieves the aims of a goal-oriented actor.
When a fish moves its tail, a strider springs its legs, or a gull flaps its wings, potential energy stored in sugars and fats gets converted into mechanical energy, which contracts muscles that yield bodily movement. The share of input energy that moves the body towards its goal is what we call work.
Throughout this process, however, some energy is always dissipated and lost to surroundings. The second law of thermodynamics guarantees this. This energy dissipates in the form of heat produced by friction of muscles rubbing against body parts, fluids rubbing against vessels, air rubbing against skin, and so on. Heat is just thermal energy that excites a surrounding medium (such as air or water molecules), but more importantly, in this case it’s kinetic energy that can’t be used by the greedy biological agent to achieve its goals. Since energy is precious to life, we call the energy that is lost to our surroundings waste. This is the cargo lost at sea.
Waste, and our desire to reduce it, brings us to efficiency.
Efficiency
The efficiency of a process can be expressed with the ratio between the amount of energy a thermodynamic system uses and the amount of that energy that gets channeled towards its goal. The more input energy that gets channeled into useful movement (moving what we want), rather than useless movement (moving what we don’t want), the more efficient the system.
This useless movement is like entropy, which is why entropy is sometimes defined as the energy unavailable to do work. Another term we can use for this useless movement is waste heat. When those pesky particles surrounding us receive some of our energy, we grumble to ourselves: “That energy should have moved us not them…How useless, what a waste!”
We saw earlier that inanimate movement doesn’t produce work, it merely ebbs and flows in a benign flux of energy. The terms useful and useless have no bearing on something like an open flame. The flame just is. For the same reason, the movement of a flame is neither efficient nor inefficient. It is an unbiased process with no concept of attachment; the flame has nothing to waste.
But living movements are biased, attaching themselves to objectives and evolving in accordance with those objectives. Again, for all living processes those objectives seem to be to survive so that life can reproduce. If those terms feel too clinical and diminish from the poetry of life, you may prefer expressions like nurturing so that we can flourish. In political terms, think of it as conserving so that we can progress. In economic terms, to sustain so that we can prosper. In religious terms, it’s like divine provision leading to creation. Philosophically, it’s akin to accruing wisdom in the pursuit of love5.
Whatever you call it, life seems to be a process that gathers energy and channels it towards those objectives. And it strives to do this efficiently. More efficient systems are more likely to sustain and proliferate themselves since, by definition, less efficient systems do less productive work—meaning, they survive and reproduce less effectively.
Efficiency can also be closely tied to predictive power. The more certain we are of an outcome, the less energy we waste on confusion-induced uncertainty, so long as that certainty is grounded in reality. This is why uncertainty is also referred to as Shannon entropy in information theory. Earlier, we established that life is an entropy-reducing process. When we observe our nervous systems, which process information and predict outcomes, we find that they strive to reduce the uncertainty of those predictions—in essence, to reduce entropy.
But life can’t predict the future, as much as it tries to. Predicting the future of the inanimate can be done with decent fidelity, which is why we found the movement of the raindrops, bubbles, and ripples predictable. But life’s path is laid upon a landscape that is constantly being reshaped by life itself. Each living thing attempts to predict a path where energy can be best used to aid in its survival and reproduction, but in doing so molds the world to its own ends and transforms the reality it’s trying to predict. Multiply this transformation across an innumerable population of living things all trying to do the same thing and you’re left with an unbelievably complex, and thus less predictable, landscape. Life is order that generates chaos.
Suffering
Like flint striking steel, it’s the friction between entropy and life that ignites the fire fueling our adventure—the same fire we saw in the fish, the striders, and the gulls.
This friction defines life. Life is suffering.
So long as you’re swimming against the relentless current of entropy, you are living; and so long as you’re alive, you’ll be swimming.
Suffering isn’t necessarily a bad thing. We find suffering meaningful when we do it efficiently and towards a beneficial end. We can be efficient at pursuing vice, be ineffectual at pursuing virtue, or not pursue anything at all; each option leads to misery. Hence three conditions must be satisfied to produce a meaningful life: effort, efficiency, and right direction. We must try, learn, and care. Courage, wisdom, and love. When these virtues are embodied, enduring discomfort becomes more bearable.
As we’re flooded by the constant current of entropy, swimming in the right direction means facing its full force. It means leaning into suffering and thereby leaning into life itself. This is why following the right path is often the most difficult. When we’re swept away by the current—whether by swimming in the right direction but not well enough; swimming aimlessly as we’re pulled backwards; or, even worse, swimming downstream toward our demise—we’re less alive. We’re swept towards meaninglessness and, equivalently, lifelessness. If all we do is float downstream, what then distinguishes us from the inanimate also carried along by the current?
Life disdains inefficient, unnecessary suffering and loves efficient, necessary suffering. And, insofar as to live is to love, love and productive suffering are one and the same. To love is to suffer with purpose. This begs the question: In an age where technology increasingly suffers on our behalf, will love begin to fade? Will life become more lifeless? Will we artificially create hardships to restore meaning to our lives? Are we destined to see the rise of fabricated sufferings among those who suffer little and, in their deprivation of meaning and purpose, crave it all the more?
For those who feel like life has no meaning, it’s because something prefers you feel that way. Meaningless behavior is more predictable, similar to the inanimate floating downstream. Therefore, living systems are drawn to induce meaninglessness in those they exploit, as more predictability makes exploitation more efficient. Another byproduct of life’s disdain for entropy, and thus love for efficiency, is that it prefers that those it disregards suffer on its behalf towards its aims. Ironically, this exploitative imbalance leads to meaninglessness on all sides: the exploiter starves itself of meaning by knowing not what it means to suffer and the exploited toil towards an end of little benefit to them.
Before blaming others, keep in mind that we also exploit ourselves. Revisit the previous paragraph, but consider the exploiter and exploited as either your present self or your future self. Excessive indulgence occurs when present exploits future; excessive self-denial occurs when future exploits present. Most of us tend to tilt towards indulgence, since immediate needs are more tangible and thus provoke more tangible feelings; whereas future needs are hazier, leading to more ambiguous feelings that can be more difficult to act on.
Excesses of indulgence and denial can be better understood when viewed through a survival-reproduction lens: excess indulgence over-prioritizes selfish survival in the present, while excess denial over-prioritizes selfless reproduction in the future. However, we build nothing when acting solely for ourselves, and we can’t sustain ourselves—let alone build—when acting solely for others. Survival cannot be sustained without reproduction, and reproduction cannot be sustained without survival.
Only through harmony does love burn bright. The bee loves the flower, and the flower loves the bee. Since their existence depends on each other, they tend to each other. Whether the flower or bee is conscious of this tender love is irrelevant; their harmonious ways of being confirm it. When relationships are approached as a game to be won, harmony fades, leaving each side bound for loss and the relationship bound for meaninglessness. Yet, like with the flowers and bees, those who relinquish the idea of playing to win and instead embrace the idea of playing to keep playing are those destined to move with purpose and create more movement with purpose in life’s ever-unfolding drama.
The essence of this principle—that life moves with purpose and creates more movement with purpose—is what first caught our attention at the pond, allowing us to distinguish the movement of the falling raindrops from the gliding gulls soaring up above. We feel a sense of kinship with the gull because the gull, like us, moves with purpose. And one day, the gull will die. Its material will cease to move with purpose and melt back into the inanimate. But its energy, its memory, its spirit will live on in the bodies and behaviors of its offspring and ecological community. In time, entropy will spread its ashes—its matter and energy—across the globe and the cosmos beyond.
After all, energy can be neither created nor destroyed.
Velocity is speed in a particular direction.
Kinetic is derived from the Greek kinētikós, meaning to “put in motion”, potential from the Latin potent “being able.”
Temperature, which puts a number to the heat we feel, relates to the average kinetic energy of particles in a substance.
As a friend once told me, no matter how many times you clean your room, it will positively get messy again. Entropy in action!
The word philosophy itself is derived from the Greek words philo- (meaning “love”) and -sophia (meaning “wisdom”).