Research articlesThe principle underlying all evolution, biological, geophysical, social and technological
Abstract
This article addresses the main research areas identified in the call for contributions to this special issue. With examples from published articles and books, the present article shows that all the identified areas are already covered by the universal principle underlying all evolution: the constructal law (1996), i.e. the physics law of design evolution in nature (free morphing, flowing, moving systems). The universal principle of evolution belongs in thermodynamics because thermodynamics is a universal science and evolution is a universal phenomenon. The principle unites the natural sciences with the social sciences, and the living with the non-living. It unifies the world of science and its languages (energy, economy, evolution, sustainability, etc.), and brings together the natural and artificial flow architectures, the human made and the not human made. The principle establishes firmly in physics the reality that humans are part of nature. With the principle, physics extends its coverage over phenomena that were previously considered out of reach: social organization, economics and human perceptions. Such phenomena are physical, i.e. facts. The entire world depends on the science of useful things, and benefits greatly from a physics discipline with freedom, life, wealth, time, beauty and future.
This article is part of the theme issue 'Thermodynamics 2.0: bridging the natural and social sciences (Part 1)'.
1. Bridging the natural sciences and social sciences together
The universal principle underlying all evolution belongs in thermodynamics because thermodynamics is a universal science and evolution is a universal phenomenon. The principle is the constructal law [1–7], i.e. the physics law of evolutionary architectures (freely morphing, flowing, moving) everywhere, in any system. The principle underpins the science of form, freedom to change and evolution. This principle is distinct from the second law of thermodynamics (cf. §3). The expanding literature supported by the universal principle of evolution is being reviewed regularly in peer-reviewed journals and books. Examples are presented chronologically in [5–50].
In the present article, I address one by one the main research areas identified in the call for contributions to this special issue. With examples from published articles and books, I show that all the identified areas are already covered in the literature based on the universal principle underlying all evolution.
In brief, evolutionary design unites the natural sciences with the social sciences, and the living with the non-living. This principle unifies the world of science and its languages (energy, economy, evolution, sustainability, etc.). It brings together the natural and artificial flow architectures, the human made and the not human made. The principle establishes firmly in physics the reality that humans are part of nature, and that the immediate environment—the niche—belongs to the human being.
2. Living and non-living, from the same point of view
Like every piece of research that is original, the universal principle underlying all evolution is autobiographical, about its author. The first part of my career was devoted to fundamentals of engineering sciences, or applied physics, namely the physics domain of thermodynamics, heat transfer and fluid flow (cf. §3). I was deeply immersed in thermodynamics, its laws, history, personalities, places and languages. This work is summarized chronologically in my first books, from 1982 to 1996 [51–54], and it shows my own evolution in a discipline that was thought to be mature, dead and rigid. Proceeding against method, I made two distinctive changes in the discipline:
First, I brought the disciplines of heat transfer and fluid flow into thermodynamics by teaching how the relative movement (heat, fluid, solid on solid) constitutes the testable physics of irreversibility, i.e. the physical (palpable) reality of the second law. See in figure 1 the merger of the heat transfer line with the thermodynamics of the 1850s.
Second, I became intrigued by the separation between engineering thermodynamics and the thermodynamics spoken in other cubicles of academia: physics, chemistry, biology, cosmology, economics, etc. In engineering, the heating (therme, Gr.) and the power (dynamis, Gr.) are clear, in plain view. The thermodynamics book is full of drawings of flow systems with configurations that changed from one era to the next. In other cubicles of academia, I did not see the therme and the dynamis. Furthermore, I did not see drawings of movement and flow configuration (design) and I concluded that in the absence of these foundational notions the discussion is not really about thermodynamics.
I asked myself, what is the cause of this separation that obstructs academic communication? After all, the ‘thermodynamics power for the people’ came from mechanical engineering, not from some other cubicle.
Figure 1. The evolution and spreading of thermodynamics during the past two centuries [47,51].
The answer that needed two decades to take shape in my mind is that, contrary to nature, the concepts of form, configuration and purpose (directionality) were not in the thermodynamics doctrine of the 1850s. This meant two things: the thermodynamics of the physicists et al. is the correct one, and the thermodynamics of engineers is correct only up to a point, beyond which it is complemented by arbitrary and local (ad hoc) acts of common sense called thermal design, efficiency, effectiveness, yield, objective, purpose, function, thermodynamic optimization, self-optimization, self-organization, entropy generation minimization, exergy destruction minimization, thermo-economics, sustainability, animal design, cost, improvement, return on investment and so on. All the ad hoc notions were evident but disconnected, and not recognized as missing in physics.
How was I to bring configuration and purpose together into the thermodynamics mainstream? This step was easy coming from the art of making drawings, in which I was trained. If you flip fast (like a fan) the pages of the engineering book you see movies of evolving configurations: one movie of heat engines, one movie of refrigeration machines, another of turbines and so on. Many different movies, but only one plot. The various movie tapes run in a single direction, which is known as evolution, directionality, time and future.
Figures 1 and 2 are posters for the movie of the evolution of thermodynamics. The cliff between the possible and the impossible designs (figure 2) is sharp, unforgiving. Only innovations can move this cliff into the domain of previously inaccessible designs (cf. figures 7–17). The image in figure 2 is itself an evolutionary design, which began in 1988 [52] and 2004 [7] and continued in several publications reviewed in [50].
Figure 2. The evolution of the second law efficiencies of steam power plants [47]. The points on the crest of the mountain define the domain of possible designs. Note the logarithmic scale on the ordinate, and the second-law efficiency ceiling, ηII = 1, which no design can surpass. At every point in time, the crest divides the designs into two realms, the possible and the impossible. In every era, in a vertical cut through the mountain of the possible, the more efficient flow designs are few and the less efficient are many. This is ‘hierarchy’, the organization that unites all flow architectures in nature, biological, non-biological, sociological and, as in this figure, technological. The population of designs in any other domain of flow system with freedom to morph, from running animals to flowing rivers and the global air traffic, is the same separation between two subdomains, the possible and the impossible. The higher performance belongs to the few designs that are near the demarcation line between the possible and the impossible.
Evolution means change after change in a direction discernible to the human mind. To be able to change, the system must have physical features of freedom. No freedom means no change, no evolution, no time and no future [47,50]. Freedom, like flow architecture, is physics. Freedom can be measured in two ways: by counting the number of features that are free to change in the flow architecture (i.e. the number of ‘degrees of freedom’), and by changing the number of degrees of freedom and measuring the corresponding changes in the flow access (i.e. the performance) associated with the architecture (the design).
The universal principle of evolution became clear, and so was the new stream added to the flow and coverage of thermodynamics (figure 1). In the months immediately after June 1996, I published this principle in three journal articles and one textbook [1–4]. I illustrated the principle by formulating for the first time the volume-to-point flow access problem and predicting the evolution of its hierarchical architecture (figure 3). The rationale that I published then is still valid today—here is an excerpt from [2]:
Figure 3. Flows that connect discrete points with areas or volumes are just one class of evolutionary designs in nature. This class is recognized as arborescent, hierarchical, architectures (other classes are pictured in figure 5). In the upper-left corner is how the point-volume problem was proposed in 1996. The rectangular area (grey) generates heat uniformly, and the generated heat current is evacuated through a high-conductivity blade (white). The freedom in the configuration is in the shape of the rectangle. The configuration evolves towards providing greater access to what flows, namely, the heat current. Easy access is represented by an area that does not overheat, such as the middle shape in the column of three rectangles. Difficult access characterizes configurations in which the area overheats (note the prevalence of red). Solutions to more recent versions of the problem are illustrated in the lower-right of the figure. The complications resulted from the greater number of degrees of freedom in morphing the configuration.
"It is this ‘evolution’, the history of new (better) designs that replace older ones, that measures the passing of time and brings time into thermodynamics. See the history of heat engines and power plants: these evolve to persist in time because they do so along with us. They are an integral part, the modern part, of our own development.
Similar observations hold for the networks seen in river basins and deltas. The overall size (a surface) is fixed, and the total flow rate is dictated by rainfall. On the ground, the water has the option to seep (as a sheet) over or through the wet soil, in the direction of the lowest point of the collection area. Instead, the river basin develops its own network of ‘high-conductivity paths', rivers, tributaries, creeks and rivulets, to collect the rainwater from the seepage that comes from the smallest (elemental) scale.
The river basin problem turned inside out is the river delta. The water flow rate is constrained, enters a finite geographical area through one point, distributes itself through a network of low-resistance channels and finally seeps, with high flow resistance, into the ground. This final stage occurs over areas (stagnant pools) defined by the length of the smallest channels. Superimposed on this ‘point to finite area flow’, there is the related architecture that distributes … a fraction of the original stream to the coastal portion of the perimeter of the delta area. Lightning is a phenomenon like the river basin … and so on.
The commonality of these phenomena is much too obvious to be overlooked. It was noted in the past (e.g. figure 4) and most recently (empirically) in fractal geometry, where it was visualized (simulated) based on repeated fracturing (algorithms) that had to be assumed and then truncated arbitrarily. The origin of such algorithms was left to the explanation that the broken pieces (…) are the fruits of a process of self-optimization and self-organization. The present paper places a purely deterministic (predictive) approach behind the word ‘self’ and empowers the thinker to predict (to see with the eyes of the mind) the fractal algorithm that should be employed to generate a machine drawing that resembles a lung, not a delta.
Figure 4. The delta and the lung serve as icon for the principle of all evolution (constructal law), as it unites the biological with the geophysical, social and technological systems that have configurations and flow and morph with freedom (after [38]). Note that hierarchies (tree-shaped flows) are just one class of freely evolving flow architectures that make up the design of nature (more classes are shown in figure 5).
If we limit the discussion to examples of biological systems (lungs, circulatory systems, nervous systems, trees, roots, leaves), it is acceptable to end with the conclusion that such phenomena are common because they are the result of a long running process of ‘natural selection’. The tendency of biological systems to become optimized … was abandoned to the notion that it is imprinted in the genetic code of the organism.
If this is so, then what genetic code might be responsible for the development of equivalent structures in such non-living systems as rivers and lightning'? What genetic code is responsible for a man-made network…? Indeed. whose genetic code is responsible for the societal ‘trees’ that connect us, for all the electronic circuits, telephone lines, air lines, assembly lines, alleys, streets, highways and elevator shafts in multistory buildings'?
There is no difference between the living and the non-living when it comes to their behaviour when faced with the opportunity to find a more direct route (…) for example, the opportunity of getting from here to there in an easier manner. If living systems can be viewed as engines in competition for better thermodynamic performance, then physical systems too can be viewed as living entities in competition for survival.
This analogy is purely empirical: we have a very large body of case by-case observations indicating that certain designs (bio and non-bio) evolve and persist in time, while others do not. Now we know the physical feature that sets each surviving design apart, but we have no theoretical basis on which to predict that the design that persists in time is the one that has this feature. This body of empirical evidence forms the basis for a new law of nature that can be summarized as follows:
For a finite-size system to persist in time (to live), it must evolve (with freedom) in such a way that it provides easier access to the imposed (global) currents that flow through it."
The constructal was restated in mathematical terms in 2004 [7,8]. This law brings life and time explicitly into thermodynamics and creates a new bridge between physics and biology.’ In 2012 [38], I inserted the word freedom in ‘to evolve with freedom’, even though the original ‘to evolve’ implied the presence of freedom to change. Freedom is not an objective: it is a set of physical features (properties) that endow the flow system with the ability to change and evolve in the direction towards its sustainability.
Important to note are the words ‘finite-size system’, which rule out the infinitesimal, the zero size, the point. The infinitesimal (the point) does not have freedom, flow, configuration, organization and evolution. The finite size does.
3. Thermodynamics discipline
Thermodynamics is a discipline, i.e. a body of knowledge with precise words, principles and usefulness [55]; the words are few, and each word has one meaning. The thermodynamics concept of ‘system’ denotes a region in space that the observer selects for analysis, description, communication and discussion. The observed being of the system is called ‘state’. The state is a collection of quantities called ‘properties’; a few are measurable, others are derived from measurable properties.
The change that occurs in the state of the system is called ‘process’. The selected system exists surrounded by the rest of nature, which is called ‘environment’. The imaginary surface that delineates the system and distinguishes it from the environment is called ‘boundary’. The boundary is not a system because it has no volume and no mass. The name of the system indicates the type of flows that cross its boundary, in this order of decreasing generality: open, or flow system (mass, work, heat currents), closed system (work, heat currents), and isolated system (no currents whatsoever).
A law, or principle, is a brief statement that accounts for a distinct phenomenon. A distinct phenomenon is the name for observations of nature that repeat themselves the same way innumerable times. A law is distinct from other laws. A law cannot be derived from other laws.
The first law accounts for common phenomena such as in the ‘what goes up must come down’, which after the merger of mechanics with caloric theory 200 years ago are covered by the principle of conservation of energy. As a balance (an equation), the first law serves as definition for the system property called ‘energy change’ [44].
The second law accounts for all phenomena of one-way flow (from high to low), which are taught as irreversibility, dissipation, entropy generation, exergy destruction and so on [45,47]. In the limit of reversible changes (or reversible processes) undergone by a system, the second law is a balance (an equation) that serves as definition for the system property called ‘entropy change’.
The constructal law accounts for the phenomenon of flow configuration occurrence and evolution throughout nature. This phenomenon is distinct from the phenomena covered by the first law and the second law. Before the constructal law (1996), thermodynamics was concerned with systems as black boxes in which anything and everything could fit.
3.1.. Nature is not black boxes
Nature impresses all observers with moving, flowing and morphing architectures. The ‘live’ configurations impress us with directionality. Change after change happens constantly in a direction that is perceptible to human senses and minds. The evolutionary direction is towards configurations (designs) that flow and morph to provide greater access, incessantly. Human perceptions (observers and observations) are part of the physics [50].
The observed phenomenon is the natural and endless occurrence of form (configuration, change, evolution), which is why the constructal law is the law of physics that empowers us to predict evolutionary designs. Abstract notions proposed ad hoc, such as maximum power, minimum entropy generation and maximum entropy generation, are not observable phenomena, and to proclaim each of them is not a principle.
Evolution is the word for change after change in a direction that is discernible and is called the forward arrow of time [56]. The universal phenomenon of evolution (configuration, form, design, morphing) was missing from the thermodynamics doctrine. It was introduced in 1996 as the constructal law of design evolution in nature as physics (cf. §2).
The constructal law guides many theoretical and practical advances (more than 11 000 titles so far on Google Scholar) that proclaim the universality of the physics of evolution, and of the physics of life. Advances are reviewed regularly in peer-reviewed articles, books, popular science and 12 international Constructal Law Conferences [16,57].
4. The two cultures
Evolutionary design with freedom is now the physics of life everywhere, or the science of live form—the science that in nature the evolving animate systems are happening hand in glove with the evolving inanimate systems. This science brings us to the much freer conversation and education (known as ‘natural sciences’) that was before the ‘grand schism’: biology, geophysics, sociology, technology and many cubicles inside the university, scientific language, publishing and academic clubs.
The polymaths who made and lit the fire of science—da Vinci, Galilei, Newton, Réaumur, Count Rumford, Thomas Young—have vanished. They have not been replaced. Instead, the science of nature is in the hands of epigones: multiple (20+) co-authors, multiple tiny details, multiple obscure sources, multiple government initiatives and multiple gratuitous citations driven by nationalism [58,59]. Science is being transformed into a doctrine of ‘truth from above’ that stifles free questioning and the fearless pursuit of truth.
In the constructal framework, the two cultures (sciences and humanities) are a unitary culture [5,38,43,47,50]. The engines that came from human ingenuity (Savery, Newcomen, Watt) were minuscule additions to the engines of nature: the atmospheric and oceanic circulation, animal metabolism and locomotion, magma convection, and natural (free) convection in every building and glass of hot tea [60]. The wheels and spokes of carts and bicycles are tiny additions to the ‘wheels’ that carry animal mass on the globe: the legs of runners, wings of fliers, and undulating bodies of swimmers and crawlers. Animals and human beings, organs and assemblies of organs, animal niche construction and city living, are parts of one nature that constantly changes, turns over the dirt and relocates it, and renews the world.
The physics principle of design evolution grasps the animate and the inanimate with one hand, except that in this union the ‘inanimate’ systems are not ‘dead’. The river basins and deltas, like the snowflakes and the mud cracks, are incessantly morphing to provide easier access to what flows through them and away from them (figure 5). A swarm of bees swells and opens channels (chimneys) in its interior to liberate the generated heat currents, to regulate the temperature, and to sustain the life of the individual and the group. For the same reason, in a human settlement people reach unwittingly a consensus on where to beat a path, and where to build a street and a fork in the road.
Figure 5. Several classes of evolutionary flow architectures united by the physics principle of all evolution: hierarchies (rivers, lungs), cross-sections of blood vessels and river channels, swarms of honeybees, mud cracks, snowflakes, droplet impact transition (splat versus splash), turbulence, animal locomotion and steam chimneys in boiling rice. Additional classes of distinct evolutionary flow architectures are in figures 7–16.
As a phenomenon of all physics, evolution underpins a more powerful and longer lasting system of human knowledge. It brings into view the science of form: the flow configuration that changes in the presence of freedom, and the effect of the change on the immediate environment. With freedom to change and to join, the flow system becomes a conglomerate (a construct) that moves more easily: animal, river, turbulent jet, vehicle, inhabited building, city and government. Everything evolves with freedom, the construct and its organs.
The physics of evolution adds to thermodynamics a new tributary, evolution, next to mechanics and caloric theory (figure 1). Here are some examples selected from the work with my collaborators. The growing content of the new science is about the power to predict the evolution of shape, structure [5], rhythm [3], locomotion (running, swimming, flying) [12,23], athletics [61–64], social dynamics [16,38,43], human perceptions [38,43,50], surface scraping and cleaning [5], surface renewal for heat transfer [60], turbulent flow and the expiry of laminar flow [60], snowflakes [4,5,65,66], mud cracks [67], natural self-lubrication [20], hair insulation on animals [68,69], metabolic scaling that is predicted not described [70], breathing, heart beating, ejaculating, and periodic power generation and refrigeration [3–5], economies of scale [47,71], wealth and money [72], economic crises [73], social organization [74], university rankings [75], hierarchy of celestial bodies [76,77], turbulence structure [60,78], vascular design [5,79–82], the S-curve history of spreading and collecting, including viruses [43,82–85], lifespan [86,87], climate [88,89], sustainability [90], complexity [91], and vehicles and transportation [92–101]. In particular, the stubbornness (rigidity) of university rankings [75] is a clear example of the natural formation and persistence of hierarchies in human dynamics (cf. ch. 1 in [16]).
5. What life is
Nothing moves unless it is pushed. The pushing comes from power. The power comes from engines (natural and artificial) that consume an energy source (food, fuel, solar, wind, geothermal). The power is destroyed (dissipated) irreversibly through movement, as the system gets the environment out of the way.
Nature has two distinct parts, two designs flowing and morphing (evolving) hand in glove: ‘engines’ that produce power, and ‘brakes’ that dissipate the power (figure 6). Contrary to repeating Schrödinger's view, life is not ‘free energy’. Free energy is an abstract quantity of a ‘simple system’ (defined by Gibbs, cf. [44], ch. 4), which is a system in a state of perfect uniformity (equilibrium), which includes its boundary and immediate environment. Consequently, free energy does not push anything. To be ‘live’ the system must contain or be in touch with at least two different entities, a region (e.g. hot or fast) and a region that is different than the rest of the environment (e.g. cold, or slow), and a flow architecture that has the features and the effect of an engine, namely force and displacement, work, and per unit time, power. The overlooked phenomenon was the natural occurrence and evolution of flow architectures that resemble engines. Nature invented the engine (cf. [60], ch. 4).
Figure 6. Nature is dynamic. It is a conglomerate of embedded and intertwined flow systems with configurations that morph with freedom in time. The movement is driven by power from systems configured and functioning as ‘engines’ (in blue). The movement is steadied by the dissipation of power as the mover gets the environment out of its way. The dissipation occurs in systems configured and functioning as ‘brakes’ (in green). The evolutionary direction is towards ‘engine and brake’ configurations that facilitate movement, relocation and organization on Earth. Figure 7. Evolution is observable in our lifetime. Each of us is a ‘human and machine’ specimen, where ‘machine’ means ‘artefact’, an add-on in general, the niche. The machine part evolves much faster than the body of the naked adult animal, say, from one millennium to the next. Figure 8. Movement spreads as a chain reaction on a territory when power savings (money) accompany the generation and use of power at discrete centres, which borrow power from (and return power to) each other. The movement driven by each centre covers a local area, around the centre [50]. Figure 9. Economies of scale is a natural evolutionary phenomenon, predictable from the principle underlying all evolution. In this figure the phenomenon is illustrated as the effect of size (power) on the efficiency (η) of steam turbine power plants during their entire history. The most efficient are at the points that mark the crest of the mountain of designs (the mountain is shaded). The crest rises at a decreasing rate: this indicates diminishing returns from innovations that are being added to a mature technology. Diminishing returns is another natural evolutionary phenomenon predictable from the principle underlying all evolution [48]. Note: The efficiency η is the ratio of the power output divided by the rate of heat input to the steam that circulates through the power plant. This ratio is also known as the first law efficiency. Figure 10. The city serves as icon for how humanity moves on Earth [43]. Human movement is from area to point, and from point to area, river basins and deltas intertwined and superimposed in space and time. The city is a thumbnail of the flow of our lives. Figure 11. Hierarchy in how animals and humans fly on the globe: qualitative distribution of population sizes versus body sizes [47]. Figure 12. Wealth is proportional to fuel used, which means physical movement on Earth. (a) All the countries line up on the diagonal and migrate upward from year to year. (b) When plotted as fuel used versus economic freedom, the predicted migration of the same data is the prediction of a future with incessantly more wealth, more human movement on Earth (more fuel consumption) and more freedom. Figure 13. (a and b) Bigger entities that move more easily are always those that invade entities characterized by less movement (e.g. floods, invaders on horseback, transatlantic migration, mechanized infantry, drones). Figure 14. The accumulated share of income (ε) held by the fraction of the population (β) [48]. Figure 15. A single innovation is a local design change that eases the flow and attracts more flow (wealth) to the place of innovation [48]. In this example, the innovation is the opening of one valve between two nodes in the flow design with 2 × 2 grid. The result is a more equal distribution of flow (wealth) over the whole area. Figure 16. Ideas flow from high to low: from those who create them, to those who need and use them. Over the entire population, one innovation empowers and facilitates everyone's movement (i.e. life) [50]. Figure 17. Innovation, education and freedom empower an underdeveloped group to migrate vertically across the ‘peloton’ of figure 12a. Vertical migration means advancement (freedom, ideas, flow connectivity, life, wealth) without the increase in fuel consumption and environmental impact that accompany the usual migration along the diagonal [101].
The engine flow configuration (design, architecture) must exist. The engine system must receive an ‘inflow’ (mass, fluid stream, radiation flux, fuel, food) that differs from the environment. The inflow contains an energy portion (called exergy, availability, heating value, etc.), the size of which is measured relative to the state of the environment in which the movement takes place. To set the engine in motion, the ‘inflow’ must be different than the environment.
The engine design is half of the design of nature. The other half is the interface system-environment, the ‘brake’ in which the energy inflow is dissipated into heat rejected to the surroundings. Together, the two parts create movement on Earth, and the reshaping of the Earth's crust. Movement is life as physics, bio and non-bio. Movement is change in the environment. Life is movement and impact on the environment.
6. Human beings are part of nature
Human life makes clear the engine and brake design of nature. Even better, the human design allows each of us to witness evolution in our lifetime. To be able to witness evolution is a huge advantage for the thinker—a crystal ball—because the popular view holds that evolution cannot be witnessed in our lifetime because it needed millions of years to generate the forms that are on display today.
We can certainly witness evolution if we look at ourselves, from year to year, decade to decade, and generation after generation. Clear are the pages of the history book. The beginning of the homo, the naked man with bare hands, is pictured at the start of the timeline in figure 7. To extend the life, power, movement and access of his naked body the prehistorical homo attached to himself artefacts: tools, fire, language, wheel, money and domesticated animals. In this procession, old artefacts were joined by new artefacts. This natural phenomenon continues to this day because it is nature itself, called evolution.
None of us is a naked human with bare hands anymore. Each single one of us is a specimen of the human and machine species, where the world machine (mihaní, Greek) is general and means any artefact [92]. Because of the machine part each of us is in permanent evolution. From left to right in figure 7, what works is kept. Today, we are so ‘evolved’ that we have access to the whole globe, through weather, commerce, foods, travel, sciences and communications. Through evolution is how the human and machine species continues to enhance its movement, access and mixing on earth [47].
Indeed, human beings are part of nature. Our natural evolution is evident in the parade of artefacts in the possession; it is evident if we imagine these human activities as high-speed movies of animal evolution. For example, we can witness evolution in athletics and team sports. By watching the Olympics, we grasp the essence of the physics of evolution, and we acquire the power to predict what will happen at future Olympics [100].
7. What money is
Money is an important artefact that was adopted by the human and machine species. With money, human life, movement and mixing (impact) on earth are incomparably more intense and spread than when money did not exist [72–75]. From the left side in figure 8, we see how one individual produces an amount of food, fuel and more artefacts. In time, the power of one individual to sustain his group becomes progressively greater (cf. figure 7). With the acquisition of boating, wheel and agriculture, some people found ways to produce more than the amounts needed for individual sustenance. The excess was then passed to a neighbour, who did two things with it: he produced enough to sustain himself, and enough excess to return the borrowed amount to the original source, and to lend the remaining excess to a new neighbour. In addition, the amount returned to the original source was given to yet another neighbour who duplicated what the first neighbour did.
Saved money is useful work (exergy) that is stored, not used. Spending the saved money to move things is instant power, available to be spent by new people to move new things.
The adoption of money and savings triggered a chain-reaction—an explosion—of human movement on the globe. The drawing made in figure 8 captures the physics of this evolving flow architecture. The chain reaction is unstoppable, and so is the use of money in all its forms, old and new. Unstoppable is also the tendency towards freedom, to remove obstacles to the flow pictured as discs and arrows in figure 8.
8. How cooperative behaviour evolved: with economies of scale and hierarchy
It is easier to move together than to move alone. This is physics in its most general form and message, from rivers on the plain to animals in the bush. It is the facts, not an opinion.
We can easily show that a stream of water that flows through two identical pipes in parallel flows more easily through one larger pipe. The volume of the larger pipe equals the sum of the volumes of the parallel pipes. The same demonstration can be made with two identical river channels in parallel, versus one large channel. There are many examples from the non-bio realm, and that is just the seed of the physics of irreversibility (§3). Flows through wider spaces are ‘liberated’ in comparison with flows through narrow spaces.
In the bio realm, the examples are numerous as well. Imagine an amount of coal that is transported on two identical barges on a river. Next, the same amount is carried by a bigger barge. The tugboat pulling the bigger barge uses less power than the tug boat pulling the two smaller barges.
The bigger flow architecture is more efficient. This is the physics of the observed phenomenon of ‘economies of scale’ and, coming from the principle underlying all evolution, it is predictable [48]. The phenomenon is observed throughout the animal realm. To carry 10 kg of animal mass on an elephant requires considerably less food than to carry 10 kg of animal mass on a dog.
Economies of scale are also the message of figure 9, which shows that the efficiencies of the most efficient power plants line up in the direction towards bigger power plants. Among moving and flowing systems, size matters and bigger is better.
If this is so, and if the tendency towards easier and greater flow access is universal, why is not everything big? The reason is that movement on Earth is not from one point to another point, scribbled as a line. On Earth, movement is between one point and an infinity of points (area, or volume). Big channels and big moving bodies cannot sweep the area and volume completely. Between the big channels, there are always smaller spaces that attract their own ‘big’ channels, except that the ‘big’ channels in the interstices are necessarily smaller than the big channels between which the interstices reside.
Hierarchy is the name for the natural flow architecture that connects a point with a surface and a volume. Hierarchy means two things, diversity of sizes, and ranking of numbers of features of the same size. Hierarchy is the coexistence of a few big movers with many small movers. Together, the many small and slow movers, and the few large and fast movers, sweep the available space more easily, efficiently, economically, and with greater staying power.
In the human realm, hierarchy is present everywhere and known as human dynamics and social organization. One example is life in the city (figure 10). The human flow is not the orthogonal grid. It is an area-point flow in the morning, and a point-area flow at the end of work hours [43]. On a much larger scale, analogous river basins and deltas of human flow are visible as aviation and maritime transportation on the globe [98]. At all imaginable scales, the natural hierarchy of movers is evident in moving bodies ranging from the smallest insects to the biggest airplanes [47] and celestial bodies [76,77] (figure 11).
9. Why there is wealth inequality
In society, the natural phenomenon of flow hierarchy is most familiar in the form of wealth, advancement and ranking of countries on the globe (figure 12a). The dots line up on the diagonal between annual wealth (gross domestic product or GDP) on the ordinate, and annual consumption of fuel on the abscissa. The countries at the top are few, and those at the bottom are many.
The chief conclusion from the diagonal alignment is that the hierarchy called ‘wealth’ in economics owes its evolution to the hierarchy of physical movement on Earth, which is driven by the consumed fuel and food (which also requires consumed fuel). In other words, economics is physics [32,72], and so are the natural phenomena of economic growth and periodic crises [73].
The oneness of movement and wealth is visible on the pages of history. Figure 13a captures the movement of the floods and the armies that invaded areas. Entities that move more, further and more easily, invade areas that are not moving as much. The invasion happens one way, from more movement into less movement. Have money, will travel.
Another example is in figure 13b. Human migration to the Americas happened one way, westward, across the Atlantic. It happened because of greater movement and wealth, and because of the evolutionary designs of ships in Europe (figure 7).
Another conclusion stems from figure 12b. From year to year, all the dots are racing upward because the future of all flow architectures with freedom to morph is in that direction, towards easier movement. The entire global population advances towards greater wealth and, unwittingly, towards greater movement, fuel consumption, impact on the environment and freedom. All these trends happen naturally, in full accord with the evolution of humanity and civilization, and are predictable from the constructal law.
In a particular group, say, a country, the wealth is distributed unequally. Figure 14 shows data from six countries: the distribution is more unequal in bigger countries and less advanced countries. Here is why this should be expected:
Inequality happens even in the limit when the natural hierarchical flow is destroyed and replaced with a ‘one size’ design everywhere, as during communism. To see why, consider the flows on uniform grids of channels (figure 15) because designs more egalitarian than these do not exist. The square territory is inhabited by identical elements, which are connected by identical one size channels. Each element receives the same flow input as its neighbour. The flows from the elements are discharged as one stream to one point on the map.
The ‘equals’ who are positioned close to the point are the beneficiaries. So, geography matters. And so, we have just discovered the physics that underlies the establishment of oligarchy in post-communist Russia.
10. Energy, economy, freedom, innovation
The pictorial presentation of the principle that underlies all evolution (figures 1–15) brings us to the conclusion of most interest: why the dots are migrating upward in figure 12, and what can be done to accelerate their advance.
The answer was given in money terms in figure 8, but money was just one artefact of the many that were widely embraced and then kept. The more general answer is presented in figure 15 in terms of idea creation, or innovation. Every ‘good’ idea of design change produces more movement locally, for the inventor and his immediate neighbours and followers. The phenomenon of creating and spreading greater movement through innovation continues as a chain reaction, as shown in figure 16. The similarity between figure 16 and figure 8 speaks of the universal evolutionary design that underlies all aspects of society.
Every thinker, no matter how original, is a beneficiary of ideas (from parents, teachers, books) and a creator of ideas for others. In time, every single idea generates more movement and wealth over the entire population. The enhanced movement and wealth are spreading in S-curve fashion [84,85], and are unstoppable and predictable.
Free inquiry and innovation are the history proven design for spreading wealth and mitigating inequality. Wealth hierarchy is a natural phenomenon that cannot be effaced. The power of free inquiry and new ideas is important to know, to promote and to protect [102].
The spreading of innovation events over the populated territory is a way to control inequality (figure 15). Innovation happens when one individual seizes the opportunity to open the flow channel that he or she controls. This is analogous to opening a valve or flipping a switch for the first time. The local design change attracts more flow into the liberated channel. More flow means that the innovator becomes wealthier, and the flow (or wealth) is increased over the entire territory. The entire population becomes wealthier because of a single innovation. The distribution of wealth becomes more equal than in the absence of innovation.
The power of innovation on controlling inequality is an argument for teaching and spreading freedom, education, science, technology and the audacity to question, to take risks and to be unafraid. New ideas and artefacts spread the flow to distant patches of the territory that are not flowing and not known for generating innovation. Inventions and creative thought tend to occur more in places where they have occurred many times before. This is how the advanced countries, societies and territories rose above others (figure 17). They rose naturally because of freedom and because freedom is nature.
11. Conclusion: predicting the future based on the physics law of evolution
The physics of evolution brings with it the freedom to question and change everything that goes on in the realm of knowledge. The spoken language does not matter, energy, entropy, economy, information, politics and social sciences. What matters is the evolving design, i.e. the future that sustains the earth, all of it, bio, geo, socio and techno.
‘Anything goes’ on the path to better, safer and longer life. The path is beaten by individuals who create science and empower future generations with more science. Figure 18 is an icon of what sustainability means in physics. The tree is a flow architecture for drawing water from the wet ground and putting it in the dry wind above [18]. When a tree is surrounded by tall trees, it sheds its lower branches and leaves, and it rises above the forest canopy. When on the edge of a parking lot, as in the photograph, the tree bends away from its neighbours, and its branches reach out and curve as if to embrace the valuable air.
Figure 18. The tree has freedom to morph and seek access to the empty and dry airspace. Its own sustainability depends on freedom to change.
People like to say that one cannot predict the future because nature is random and enormously diverse and complicated. Who would dare disagree with consensus?
Science evolves because we all want to predict the future. Science is about us, for us. We design this future to be good for us, with ourselves inserted in it. In this future, we make choices, all the time. On the other hand, no freedom to question means no change, no evolution and no scientific principle. For example, while questioning whether celestial bodies should be hierarchical in sizes and numbers (not one size) [76], and why cataracts should be periodic and beneficial for flow access [102], we showed that the constructal law can be falsified in real time, in accord with the test prescribed by Ellis & Silk [103].
Science improves with freedom, fearless questioning and new ideas. Predictions based on physics are testable, and then permanent. Predictions have policy implications that, if we are wise, we must not ignore or try to overturn. Here are a few predictions based on the physics law of evolution:
The production of power will continue to increase and, necessarily, the consumption of energy sources will increase (fuel, food, area covered by solar panels and windmills). Greater efficiency and energy conservation will not lead to reduced fuel consumption. The outcome will be the opposite. This cause and effect relation is the physics basis of sustainability, or the life instinct.
The power generated and used (destroyed) by the world's population will continue to increase because every individual and group makes decisions in the direction of achieving greater wealth. This must happen because of the approximate proportionality between annual wealth (GDP) and annual energy consumption.
The route to the status of ‘advanced country’ will continue to be paved by innovation, science, education and freedom to question, speak and act (vertically in figure 17), not through the mere consumption of fuel (diagonally in figure 17).
The movement of humanity on the globe will continue to be hierarchical, a vascular flow with few big and fast movers in big channels, in harmony with many small and slow movers in small channels, all sweeping and reshaping the Earth's surface.
Wealth will continue to be distributed hierarchically, because physical movement (fuel used) is hierarchical and proportional to wealth. City traffic will continue to flow through a few large streets and many small streets. Freight will continue to move fast and long on a few big trucks, ‘hand in glove’ with many smaller trucks that move slower on shorter distances perpendicularly to the long routes.
The vehicles themselves will evolve in a predictable manner. New models of airplanes of all sizes will look the same, with wingspans as wide as their fuselage lengths, like birds of all sizes (figure 11).
The whole globe will continue to evolve unwittingly towards freedom to change, hierarchies, transport routes, economic links, trade agreements and communications. This will continue because everybody wants to have more access, to ‘flow’ more and more easily, cheaply, safely, further, and to be wealthier.
The effect of science is power, measurable in watts. Knowledge is the allocation of more power to more individuals, and this represents our evolution–design changes that keep us alive and moving further and lasting longer in time. Hierarchy will be in all the flow architectures and forms of organization of the future. Freedom will continue to increase because freedom to change is nature.
With the principle that underlies all evolution, physics extends its coverage over phenomena that were previously out of reach: social organization, economics and human perceptions. Such phenomena are physical, facts not opinion. The entire world, which today depends on the science of useful things, will benefit greatly from a physics discipline with freedom, life, wealth, time, beauty and future.
Data accessibility
This article has no additional data.
Author's contributions
A.B.: conceptualization, formal analysis, investigation, methodology, writing—original draft, writing—review and editing.
Conflict of interest declaration
I declare I have no competing interests.
Funding
I received no funding for this study.
Acknowledgement
Prof. Bejan's work was supported by a grant from Captive Aire Systems.
