The Spark

the Voice of
The Communist League of Revolutionary Workers–Internationalist

“The emancipation of the working class will only be achieved by the working class itself.”
— Karl Marx

The Development of the Sciences and the Foundations of Communist Ideas

Jan 23, 2015

The following text is the translation of a presentation given at the Leon Trotsky Circle by the French revolutionary group, Lutte Ouvrière, in Paris, France on January 23, 2015.

Society has been mired in crisis for more than 40 years. The consequences have not just been economic. There has also been a general decline of society. This has reinforced all sorts of reactionary ideas, including superstitions, mysticism, religious beliefs, and obscurantism in all its forms.

This creates a fertile breeding ground for reactionary and anti-working class political parties to develop and grow in strength. In France, we have seen demonstrations by the far right against marriage equality, with priests marching while wearing the cloth and combat boots, prepared to fight with their fists. In North Africa and the Middle East, Islamic fundamentalist parties are trying to impose their own laws. In Israel, the growing weight of far-right religious organizations is the price that society is paying for its policy of oppressing the Palestinians and permanent conflict with the Arab populations. One could also mention the Christian fundamentalists in the United States, the Hindu far right in India, or the wide variety of religious militias in Africa, etc. There is no region in the world, no country that has escaped this retrogression.

Even in a country like France, which has been marked by a history of anticlerical struggles and by a strong tradition of atheism, there has been a rise in religiosity for many years. It seems that the Catholic Church has been able to attract new followers. Judaism and Islam are both reinforcing their positions. And new mystical doctrines linked to Protestant, Hindu, Buddhist, or other tendencies are developing. What all of these faiths, institutionalized or not, have in common is that they convey conceptions of nature, of life, and of society that date from another era. And they all tend to challenge the scientific discoveries, like the evolution of species, that contradict their dogmas.

This ideological regression of society also expresses itself in a more subtle manner, in the way that idealist philosophical conceptions are becoming fashionable. Beyond their diversity, these conceptions all deny in some way or another the existence of a reality independent of what can be observed. They also champion the idea that there is something inherent to nature that limits the possible extent of scientific understanding. Even if they do not proclaim their religious character, these conceptions leave the door open to mysticism and obscurantism.

There are popular scientific magazines, including some that pretend to be serious journals, that regularly take it upon themselves to transmit these notions. For example, the magazine La Recherche recently ran an edition with the headline: “Reality Does Not Exist.” The idea that the goal of science should be to understand this reality and that the goal of a popular scientific magazine should be to inform the general public of the progress of this understanding does not seem to bother the editors, who are more concerned with inventing sensationalist headlines than with combatting obscurantism.

These questions may seem far removed from the struggles of the working class. But they are not. The working class can only carry out the decisive struggle against capitalism if it frees itself from all superstitions, at least if its most conscious militants do so, and if this struggle rests on a rational and objective understanding of society, with a scientific knowledge of its internal dynamics and their functioning. We must combat all of these superstitions with another conception of the world and of the history of human societies, of their past and, of course, of their future.

The communist ideas of Marx and Engels, which they themselves called “scientific socialism,” were based on materialist and dialectic conceptions of nature and the history of societies. These conceptions were rooted on the one hand in the materialist philosophers of the 17th and 18th centuries, who, in Europe, had systematized the first non-religious interpretation of nature and society, and on the other hand in the German philosopher Hegel of the early 19th century, who had developed a vision of the world based on dialectics. Dialectics refers to a recognition that nature, society, and history are in a permanent and necessary state of transformation, that not only do these evolve, but that their evolution is the product of periodic upheavals, which are themselves the fruit of the internal contradictions in all reality. Marx and Engels’ fusion of materialism and dialectics gave birth to dialectical materialism.

Since the emergence of these conceptions a little more than a century and a half ago, science has made considerable progress in every field. Many discoveries have reinforced these concepts. Our intention here is to review what dialectical materialism is and the ways in which new scientific discoveries have enriched it, and therefore to understand the modern foundations of our revolutionary communist ideas.

The Materialist Conception of Nature

Matter and its Properties

The First Development of Sciences Prepares the Way for Materialism

The sciences first flourished during the transition between the Middle Ages and modern times. During the Middle Ages, there were no conscious materialists. A materialist current had already existed in ancient Greece, even if it was always in the minority. But in order for this philosophical conception of the world to truly emerge in its modern form, it needed a basis in solidly established scientific discoveries. During this preliminary phase in ancient Greece, which lasted about 200 years, the first scientific advances made their way in a society dominated by religious ideas.

The first laws concerning the movement of the planets around the Sun and motion of falling bodies on the Earth’s surface were elaborated from the middle of the 16th century to the end of the 17th century. It took more than 100 years and the contributions of intellectuals all across Europe to accomplish this – from Nicolaus Copernicus in Poland who published his work De revolutionibus orbium coelestium in 1543 to Isaac Newton in England with his celebrated book Philosophiae naturalis principia mathematica written in 1686, as well as Tycho Brahe in Denmark, Johannes Kepler in Germany, and Galileo Galilei in Italy.

Just as we stand in the tradition of the earliest struggles of the oppressed, such as those that the ancient Roman slaves waged under the leadership of Spartacus, we identify with these early thinkers who pushed forward our understanding of the world and who, even if they did not directly contribute to the emergence of materialist conceptions, at least helped bring about their consolidation. They were fighters, and, in their own fields, they were also revolutionaries. Their major scientific advances were the fruit of struggles, and not only in the realm of ideas. The tribunal of the Inquisition of the Catholic Church placed Galileo Galilei under house arrest for having defended the idea that the Earth revolved around the Sun. And before him, the Inquisition condemned another of these thinkers, Giordano Bruno, to be burnt at the stake.

The tradition of all dead generations weighs like a nightmare on the brains of the living,” Marx would later write. And in fact, these scientists had the intellectual and moral courage to reject this dead weight, to resist conforming to traditions. They had the audacity to confront the society of their time in order to open a new path forward, and, in their own way, to make a leap into the unknown. Incidentally, it is only because in every period there have been women and men capable of making this leap into the unknown that humanity has made progress. Whether or not their names have been written down in history, it is the struggles of all these people with which we identify ourselves.

These scientists discovered the basis of our current view of the solar system. Galileo, pointing towards the sky a magnifying lens that instrument makers had just developed, found irrefutable proof for the rotation of the planets around the Sun. Furthermore, by observing the planet Jupiter, he saw four small astronomical objects, its moons, rotating around Jupiter. This was a huge revelation, the proof that celestial bodies could rotate around other celestial bodies besides the Earth.

In England, Isaac Newton synthesized all of these developments in a new theory that constituted a milestone in the history of knowledge. He imagined the movement of a cannonball shot from the Earth’s surface with enough force to never touch the ground and to rotate around the entire planet. By comparing this movement to that of the Moon around the Earth, he elaborated the law of universal gravitation, which explained the movement of celestial bodies … as well as that of cannonballs. Newton developed the basic laws of motion1, whose formulas we still rely on when sending satellites into space, in order to predict the trajectory of the Rosetta probe over the course of over 10 years and to allow it to deposit a module onto a comet at a distance of over 300 million miles from the Earth.

1 Mechanics is the science of motion and of the equilibrium of physical bodies.

In order to pay homage to all of his predecessors, Newton borrowed a phrase from a monk of the Middle Ages, famously written in a letter to another scientist: “If I have seen further, it is by standing on the shoulders of giants.” In effect, the discoveries made by some had inspired the thought of others. But during this period, they were also the product of a society undergoing a profound transformation, following a constantly accelerating rhythm. The cities of Europe were becoming centers of increasingly intense artisanal and commercial activity.

Since the 12th century, European cities had begun to regenerate, developing an ever greater division of labor. This led to the constant creation of new professions and trades, with new specializations such as the instrument makers who provided Galileo with his lens. And more generally, a new social class born out of trade and commerce was beginning its rise: the bourgeoisie. This class would undertake the conquest of the world, inspiring a thirst for geographical discovery as never before. From Marco Polo at the end of the 13th century to Christopher Columbus at the end of the 15th century, all of these merchants and sailors who set foot in the Far East, in sub-Saharan Africa, and in the Americas opened up gigantic new horizons to humanity. The revolutionaries of the sciences inserted themselves within this powerful course of continual upheavals of society. All of these “giants,” to use Newton’s expression, were therefore themselves lifted up because the whole society was on the rise.

Newton’s vision of the universe posed a new question: if the planets revolve around the Sun and the Moon revolves around the Earth, what is at the origin of all of these movements? Where did the initial impulse setting the Moon and the planets in orbit come from? Newton continued to believe that God was at the origin of this.

It fell to a German philosopher, Immanuel Kant, to arrive at the first intuition of a scientific explanation of this problem, towards the end of the 18th century. And it was a French astronomer and mathematician, Pierre-Simon Laplace, who gave it a precise formulation. Kant’s original idea was to imagine that the Sun and the planets had not always existed as they did in the present. He imagined that a cloud of gas, which he called a primitive nebula, was at the origin of their formation.

Several decades later, Laplace showed that Newton’s law of universal gravitation, when applied to the gas cloud that Kant imagined, was able to explain not only the formation of the Sun, but also that of the planets and their rotation around the Sun.

An anecdote is associated with this discovery. Just after the French Revolution, at the moment when Napoleon Bonaparte had become an important figure, Laplace presented him with the results of his work. Bonaparte remarked to him that, unlike Newton, he said nothing about God. And Laplace responded to him: “I had no need of that hypothesis.”

From Mechanistic Materialism to Marx and Engels’ Dialectical Materialism

God had become a hypothesis, a hypothesis that scientists could do without. And not only scientists, because it was from this way of reasoning that the first modern materialist conceptions emerged. Starting in the 18th century, French philosophers like Denis Diderot and Julien Offray de La Mettrie would elaborate the first totally non-religious conceptions of nature since the ancient world.

At the center of materialism is the idea that the world, the universe, nature, and all that surrounds us and includes us has an objective reality outside of our own consciousness, independent of whatever we do or do not observe. Even if we perceive this reality with our senses, which allow us to see, hear, and touch, this reality exists separate from ourselves. It is not the product of our thoughts.

It is our thoughts that are the products of this reality: not only because they are reflections of it, but also because their source, our brain, is a material object. Thought is a property of matter, or more precisely of this specific organization of matter, a complex organism that is the product of a biological evolution that took hundreds of millions of years, but an organization of matter and nothing else.

This conception might seem obvious to us today. But as long as humans have sought to explain the world that surrounded them, their thought appeared to them to be something profoundly different from the rest of nature. They were incapable of understanding and even of imagining that matter could create thoughts. They did not even have a scientific conception of matter itself. This is why the earliest visions of the world all associated living beings, humans, animals, and finally the surrounding world with a soul of some kind. For our prehistoric ancestors, and for the immense majority of those who lived during the ancient world and the Middle Ages, the “soul” was something separate from matter, even from that which made up their own bodies. The human body may have been mortal, but the soul was immortal because it was immaterial.

In order to base any conception of nature on a vision of a material world existing independent of our thought, and of which our thought was but one of its products, it was first of all necessary for the sciences to develop. There also needed to be a systematic reflection about their results.

The materialism that these 18th-century philosophers elaborated was termed “mechanistic.” The only science that had reached a certain degree of development by that time was mechanics, and they had a tendency to understand reality only through the model of mechanics, a bit like saying that everything could be understood as if it were a machine, including human beings. La Mettrie’s most well-known work was called Man a Machine. This was another fundamental limit to their materialism: they did not conceive reality as a process in perpetual transformation. These thinkers were dependent on the limited understanding of the time. They could not elevate themselves beyond the point that they had already reached.

In order to progress, materialism needed to take account of evolution, both that of nature and that of human societies. There was nothing obvious about comprehending evolution. In many ways, nature seems unchanging: the seasons follow regularly one after the other, while the life cycles of animals and humans reproduce themselves as if it has always been this way and always will be. Human society could also seem unchanging, with kings succeeding kings and the oppressed always staying oppressed. Trades and professions even used to be passed down from father to son, generation after generation.

The political and social upheavals of the French Revolution and the assault on the feudal order all across Europe brought the idea of evolution into fashion. The German philosopher Hegel lived during this European social upheaval, which fascinated and inspired him. Hegel was a philosopher for whom the sources of any change were to be found in the inherent contradictions within whatever was in the process of changing. Evolution takes place under the effect of these contradictions, gradually at times, rapidly at others. The contradiction is resolved by the victory of one side over the other. This does not result in a stable situation, but gives birth to a new reality that is also full of contradictions, which gives rise to a new evolution, towards a greater degree of development.

Hegel was an idealist in the philosophical sense of the term. For him, the real world, whether physical or social, found its realization in the world of the Idea with a capital I. He did not conceive of this in a fixed way, but as an evolving process moved by explosive contradictions.

Hegel’s philosophical conceptions of a world in perpetual transformation achieved a certain success among young radical German intellectuals at the beginning of the 19th century. This was true most of all among those who were revolted at the political, social, and economic backwardness of their country, which remained on the sidelines of the progress they saw taking place in England and France. Marx and Engels were part of this group. Defining themselves as Left Young Hegelians, they were also deeply marked by the conceptions of French materialists. And their own philosophical and political evolution, which pushed them towards the most comprehensive social struggle and therefore towards communism, led them to attempt to combine these two points of view.

Seizing on Hegel’s dialectic, they stood it back “on its feet,” as Marx said, meaning that they gave it a materialist foundation in order to apply it to the study of natural and social phenomena. As Marx wrote, “the movement of thought is nothing more than the reflection of real movement, transported and transposed to the mind of man.” Armed with their dialectical materialist point of view, they developed their conception of communism based on the real movement of society.

By integrating the dialectic, materialism went beyond the limits of the mechanistic materialism of the eighteenth century. It made it necessary to study natural and social phenomena in their dynamics and contradictions, all while remaining conscious of the never-ending evolution of the scientific concepts themselves.

The Development of the Natural Sciences since Marx

The nineteenth century was a period of considerable growth for many fields of the natural and social sciences. The evolution of species that Darwin established, the newly-discovered history of the earliest human societies, and other discoveries would constantly inspire Marx and Engels’ reflections.

Since this period, science has not stopped making advances, and it would be impossible to make a list of the major discoveries of the past 150 years. To illustrate the way in which scientific conceptions have progressed and how this progress reinforces the materialist and dialectical conception of nature, we will use the example of two fundamental fields: that of matter and the history of its organization as contemporary physics conceives it, and that of biology and the evolution of living organisms.

The History of the Universe and the Organization of Matter

At the beginning of the twentieth century, it was known that matter was made up of atoms corresponding to each of the elements discovered in the field of chemistry, classified and forming the basis of all known chemical combinations: hydrogen, carbon, oxygen, lead, uranium, and many others. Chemistry had established, for example, that a water molecule consists of two hydrogen atoms and an oxygen atom, and that combustible gas molecules like butane are simply made up of carbon and hydrogen atoms.

Advances in the field of optics and electromagnetism have allowed us to develop ever more powerful microscopes to observe matter, first optical and then electronic. Among other devices, large particle accelerators allow us to study matter at an even more detailed level by smashing it into ever smaller pieces. And we are understanding better and better how matter behaves in the realm of the “infinitely small.”

In the late 1960s, physicists established a very simple model according to which all known chemical elements were made up of three basic building blocks, or three types of elementary particles: two particles called “up quarks” and “down quarks,” and another, the electron, whose role in electric phenomena had already been known for some time.

In this way, two up quarks and one down quark form the nucleus of the simplest atom, hydrogen, which only requires an electron to orbit around it to form a complete hydrogen atom. And matter is formed through successive combinations of atoms. Nuclei are made up of quarks, atoms are made up of nuclei and electrons, and molecules are made up of atoms. These molecules can be very simple, like water molecules, or extremely complex, like the molecules of living organisms made up of several billion atoms.

To understand how such a wide range of forms of matter can emerge out of so few basic elements, one can make an analogy with the alphabet. Our alphabet has 26 letters. We have a way of pronouncing each letter A, B, C, D, etc, but when these letters are arranged in a certain way, they can form a word that we pronounce differently from sounding out each of the letters that make it up. As for the meaning of this word, it is not related to the letters themselves, but to how they are arranged. Here is an example. With the letters H, O, R, S, and E, one can write the word “HORSE.” But with the same letters placed in another order, one can write “SHORE,” a word that has nothing to do with the first one. And we can take this further: one can write sentences in which the meaning of the same word can change, since it is how the words within the same sentence relate to each other that give each word its definitive meaning. We have written all of our literature using the same 26 letters. In the same way, all of the diversity of matter is formed from the three elementary particles that we have mentioned.

In order to understand the history of this complex organization of matter, we must make a detour into the field of astronomy.

Thanks to the construction of more and more powerful telescopes, the U.S. astronomer Edwin Hubble proved in the 1920s that the universe is composed of a vast number of galaxies containing billions of stars like our sun. Several years later, Hubble made a discovery that would revolutionize the field of astronomy: he noted that these galaxies all seemed to grow farther apart from each other, a little like how the molecules of an exploding gas behave. He had just discovered the expansion of the universe. The idea of an unchanging universe had collapsed. It turned out that the universe itself had its own history.

For several decades, astrophysicists advanced hypotheses about what this history could be, taking into account what they understood about the structure of matter. And in the middle of the 1960s, they came up with a model that they named the Big Bang theory.

Supposing that more than ten billion years ago, the universe was no more than an immense soup of elementary particles, including the quarks and electrons that we have mentioned, and making another hypotheses that this soup was expanding, it is possible to use the known laws of matter to explain how this soup of elementary particles would gradually transform itself. It expands and cools, which results in an ever more complex organization of matter, forming the first nuclei, then the first atoms, and then the stars, which create heavy elements within them. This theory takes into account the evolution of the universe, from a very simple primitive state to the current structure of the universe with its stars, its planets, and all the chemical elements known to us.

For the moment, there is not yet a satisfactory explanation for the cause of the expansion of the universe. Obviously, this allows certain people to see the hand of a god behind this. But there is nothing new about religious prejudices taking refuge in the spaces where science has not yet shed light.

This is all the more ridiculous given that this history of the universe and the organization of matter is a major blow against mysticism. The Big Bang theory shows that the universe, as complex as it is today, was in an extremely simple state billions of years ago: a soup of elementary particles, governed by laws that have been established by science, leaving no place for nonsense about the soul or the divine. There are an astounding number of steps between this soup of elementary particles and the complex organization of matter from which we human beings are made. Many of these are waiting to be fully understood, but they are a part of the same universe and the same matter.

The Evolution of Species and Genetics

The systematic study of the functioning and evolution of living beings truly began more than two hundred years ago.

In the second half of the eighteenth century, naturalists set about identifying, classifying, and naming all known species of animals and plants. The large majority of these scientists believed species to be unchanging, even if they based their classifications on the similarities between the different species. The religious conception of Creation still dominated. Fossils of unknown species had already been discovered, but most people’s opinion was that these were proof of species wiped out in the flood described in the Bible.

Proceeding from the similarities between the species found in fossils and living species, a French naturalist, Jean-Baptiste Lamarck, came up with the idea of the transformation of species, right in the middle of the French Revolution. The mechanism that he proposed for this transformation was an adaptation of species to changes in their environment. According to Lamarck, for example, giraffes’ necks grew longer to allow them to reach the high branches of trees in the African savannah. But there was no proof to support his hypothesis.

In 1831, a 22-year-old English naturalist, Charles Darwin, set off on a scientific voyage around the world that would last for five years. Like others before him, he discovered new animal and plant species and sent their specimens to England.

When his ship passed through the Galápagos Islands in the Pacific, he was surprised by the exceptional specialization in the anatomy of certain birds, the finches. The beaks of the finches differed slightly from island to island. Each type of beak was adapted to a certain way of eating: a thin beak in order to reach worms deep in their holes, or a stronger beak in order to break apart seeds, etc., and this depended on the environment of each island.

On his return to England, Darwin tried to interpret his observations. One day in 1837, he drew a diagram of a tree with branches representing different species descended from a common ancestor in his little notebook, writing “I think” just above it. Darwin had just conceived of the evolution of species. But he still had to explain what law this evolution was based on.

The use of selection to make species evolve was something already well known to livestock breeders. They had known for millennia that by selecting the individuals within a given species with some trait that interested them, making them reproduce with each other, and carrying this out for several generations, they would favor the transmission of this trait to the descendants of the chosen animals. This was how they created different breeds within the same species. Many breeds of dogs and horses are the product of this selection by humans. But how did the selection of species work in nature?

It was a reactionary Anglican pastor, Thomas Malthus, who had put forward the theory of the “struggle for survival” between humans that would inspire Darwin. His reflections led him to the conviction that the evolution of species was the result of selection of the most well-adapted individuals to a given environment, or those who had traits most likely to ensure survival and reproduction.

It took Darwin more than 20 years to make his ideas public, since he knew that he would have to confront the pressure of the Church. In 1859, he published a book called On the Origin of Species by Means of Natural Selection. In the introduction, he wrote: “I can entertain no doubt, after the most deliberate study and dispassionate judgment of which I am capable, that the view which most naturalists entertain, and which I formerly entertained—namely, that each species has been independently created—is erroneous. I am fully convinced that species are not immutable; but that those belonging to what are called the same genera are lineal descendants of some other and generally extinct species, in the same manner as the acknowledged varieties of any one species are the descendants of that species. Furthermore, I am convinced that Natural Selection has been the main but not exclusive means of modification.”

In the middle of the nineteenth century, society was in a ferment of activity. The industrial revolution had spread from Great Britain to the rest of Europe, definitively undermining the economic and social bases of the old aristocracies. And revolts and social revolutions were shaking kingdoms and empires all over Europe. This was the context in which Darwin carried out his fight.

Darwin set off a real revolution in the realm of ideas. He and his defenders waged a determined battle against the conceptions of the past, starting with those disseminated by the Church, which also exercised a certain pressure among the naturalists. But Darwin’s discovery remained, and just like during the times of Galileo and Newton, this brilliant new vision of nature was irresistible. It was bound to take hold, and it certainly did!

Since Darwin, advances in biology and chemistry have illuminated much more about the mechanism of evolution, including at the molecular level.

It was already known at the beginning of the nineteenth century that every living organism is composed of a wide range of cells: those that make up our skin, our bones, our brain, our liver, etc. Since the middle of the 20th century, we have known that all of the cells of the same individual contain a single molecule called DNA (deoxyribonucleic acid). This molecule, which is unique to each individual (as crime shows remind us) is the chemical basis of what we call genes, as well as the source of a considerable amount of information that allows for the expression of these genes.

The development of a living organism, such as a human being for example, begins with a single cell that divides again and again. This produces lines of cells that specialize, creating the diversity of cells that make up the organism in question. All of the biological information about the developing organism can be found in the DNA molecule. This molecule therefore carries a considerable quantity of information within it.

As with the organization of matter, a very simple “alphabet” is at the root. The entire DNA molecule can be broken down into sequences of only four simple molecules called nucleotides. These four nucleotides – adenine, guanine, thymine, and cytosine – are represented by their first letter A, G, T, and C. These nucleotides alone code all of the information contained in DNA, which is the key to all chemical processes allowing the single cell, called the egg, to transform into a complete organism through cellular division and then specialization.

An individual inherits the sequence of its DNA molecules from its parents. But like any molecule, its composition can undergo modifications. It is these changes that, when they affect reproductive cells – the ovum or the sperm – are the source of biological changes in species. A modification in DNA does not necessarily have a negative impact on the individual about to be born, since it could be a handicap or make the individual better adapted to its environment. Natural selection then operates through the pressures of the environment, causing the species to evolve in the direction of a better adaptation to its surroundings, as was the case for the finches of the Galápagos Islands. It is therefore the DNA molecule that is the chemical basis for both heredity and evolution.

However, the genes we inherit from our parents do not determine everything. We are all much more than the gene sequence that they have left to us. The environment does not only intervene at the level of natural selection, but also in the biological development of the individual, directly influencing the expression of genes at the level of the chemical mechanisms that decode them and translate them into observable biological traits. These mechanisms are called epigenetic, since they determine gene expression. For example, twins that are homozygous, meaning they have exactly the same genes because they issue from the same egg, are very similar at birth. But throughout the course of their lives, they become more and more different. This can be seen with our eyes, but specialists can also measure it at a cellular level. During the process of cellular division that results in the birth of twins, numerous chemical processes can modify the DNA molecule at the time of its replication. But an organism also adapts differently during its entire life, by means of these epigenetic mechanisms under the influence of the environment.

These mechanisms can have a major effect on the development of an individual. All of the bees in a hive have the same genetic inheritance at birth. But just one among them becomes the only fertile bee of the hive, since it is fed differently than the others, with royal jelly. It then takes on the role of reproduction, of the “queen,” as beekeepers call it.

For several years, it has been established that this environmental influence on epigenetic mechanisms can be transmitted from one generation to the next. This was observed in mice, for example: even without the gene responsible for fur color being modified, the appearance of white marks on the tail is controlled by an epigenetic mechanism, acquired by a mouse during the course of its life and which it can transmit to its descendants.

From the first single-cell organisms appearing in ocean water more than 3.8 billion years ago, to the current diversity of the animal and plant world, the advances of biology have led to a more and more unified vision of living beings. This vision is based on an ever more precise understanding of the functioning of living beings and the mechanisms of evolution that tie together all of the members of this worldwide genealogical tree.

On the Evolution of Scientific Laws

The sciences have allowed us to make progress in our understanding of nature and in our control over it. It is thanks to scientific laws that we can make airplanes fly, that we can provide the entire Paris metro region with electricity for a day with 66 pounds of uranium, and that we can communicate between one side of the planet and the other as if we were side by side.

All of this is very far from benefitting the immense majority of the population. And although billions of human beings have a portable phone today, these same people might not have access to a roof or drinking water. But the problem here is not the control over nature that science allows, but the absence of humanity’s control over its own social organization.

There still remains an infinite amount of unexplained phenomena. Each discovery that causes the limits of knowledge to retreat opens at the same time a new field for the exploration of nature. But all of the knowledge that we have acquired shows just what the human mind and the creative activity of humanity are capable of, and it also allows one to imagine that we are still only at the dawn of a spectacular adventure: that of humanity finally freed from all oppression.

The history of the sciences and their progress shows that all of the laws that we elaborate can evolve and sometimes are revolutionized. Scientific laws are models that the human mind constructs to understand nature. None of them can be treated as an eternal truth. This does not mean that science is only concerned with constructing and demolishing its own theories. If a new theory may sometimes undermine a preexisting law or theory, this always results in a higher level of understanding. The new theory can assimilate past results and place them in a new, wider, and more productive perspective.

Einstein revolutionized the understanding of the universe inherited from Newton with his theories of relativity. In order to correctly understand the overall history of the universe, only Einstein’s theory provided a clear view. However, in order to launch probes or satellites into space, Newton’s theories are used because they are close enough to Einstein’s theories and are much simpler to apply.

Scientific laws are nothing like absolute, unchanging laws that are revealed to human beings because they already exist in the realm of thought, where humanity has only to go and find them. Scientific laws are the result of the social and collective labor of humanity, and they are elaborated in reaction to the problems and prevailing ideas of a given time period. A few of the many hypotheses put forward to solve a problem end up giving birth to a new law, because they are successful in modeling objective reality and making understandable that which had previously seemed obscure or disorderly. And this allows us to act on this reality which we understand more clearly.

The Battle over Determinism in the Sciences

Scientific progress has demystified many phenomena that had seemed to be determined by chance. In the natural sciences, this concept of chance is none other than the expression of our own ignorance. A scientific law does not change reality, but it gives us a new understanding of it and transforms chance into necessity in our minds and in our lives. In other words, scientific laws explain the workings of reality, the causes of the phenomena we observe, and their necessary consequences.

Our distant ancestors viewed earthquakes as the product of fate, chance, or the will of a god, terms which ultimately express the absence of a rational explanation of these phenomena. Today, geology has revealed how shifts in the Earth’s crust necessarily result in earthquakes. From the earliest human beings to modern-day geologists, the reality of earthquakes has not changed. But our knowledge has allowed us to move from a situation where fatalistic submission to the forces of nature was all that was possible to one where humanity, at least in the rich countries, has greater and greater ability to predict these geological shifts and to protect itself from them.

Despite the progress of the sciences, some people still defend the idea of an inherent degree of chance present in nature. Determinism is opposed to this conception. This notion, which is inseparable from materialism, assumes that it is possible to find the causes of any phenomenon and that there is fundamentally no such thing as chance, only our ignorance of these causes. Determinism is a sort of “declaration of faith” in the sciences which is justified by discoveries themselves. It is at the heart of the scientific process, since it is necessary to make the assumption that the same causes result in the same effects in order to try to figure out the laws behind them. To renounce the determinist assumption means to at some level renounce the search for the laws that allow us to discover order in an apparent disorder. In other words, it means renouncing any attempt to understand the world.

A French mathematician, René Thom, who did not identify with materialism and at times even put forward idealist conceptions, was nevertheless a determined opponent of the propagandists of chance. He was able to summarize determinism with a saying, which is in fact materialist: “Scientific determinism is not a given but a conquest. And in this matter, the zealots of chance are apostles of desertion.”

It sometimes happens that scientists express idealist points of view while pretending to base themselves on one discovery or another. There are those already mentioned who wished to place God at the origin of the Big Bang, but this way of thinking can also be more subtle.

For example, why was the Big Bang powerful enough to cool down the soup of elementary particles, diluting it and enabling the organization of matter, but not powerful enough to blow apart all of the elementary particles, preventing them from taking shape in the form of atoms and then stars and galaxies? Certain astrophysicists respond to this question with what they call the “anthropic principle” (from the word anthropos, which means “human” in Greek). This principle can be summarized in the following manner: the universe has its current layout because if this was not the case, humanity would not exist, and nobody would be there to observe it. But what may seem to be a common-sense remark is in fact only an idealist evasion or a “desertion,” to use René Thom’s term. Or else this sort of response is the only kind that can be given, and, in this case, we should hang up science in the closet, at least as far as this problem is concerned. Otherwise, it is completely possible that sooner or later, scientific progress will give a response to this problem, and, if this happens, this “anthropic principle” has done nothing more than give our ignorance another name. Instead of contributing towards the solution to this problem, it will have actually hindered its formation and opened the door to mysticism.

In their own field of study, scientists can only act as materialists. Only scientific reasoning allows us to discover new laws of nature. But this does not automatically make all scientists conscious materialists. Scientists are also immersed in the prejudices that run through our society. And if they may seem better equipped intellectually to resist certain prejudices, it must be remembered that this is not the case for all of them – far from it.

Understanding the Workings of the Human Brain and Human Thought

After these ideas about the organization of matter and the evolution of species, we must also discuss a field of natural sciences that has become a base of materialist conceptions: that of the biology of the brain, neurobiology. Scientific developments in this field have resulted in even more advanced explanations of the nature of thought, explanations that are tools in the struggle against all sorts of prejudices about the soul or idealist conceptions about the origin of ideas.

The Human Brain: Thinking Matter

The study of the brain’s biology is a recent science, linked to the development of modern hospitals and public hygiene in the second half of the nineteenth century.

A French doctor, Paul Broca, who was studying people diagnosed with aphasia – meaning that they could no longer speak but could understand what they heard and had no problem with the muscles of their mouths – came up with the hypothesis that a part of their brain was defective. Once these patients died, their autopsies allowed Broca to identify a region in the left frontal lobe of the brain linked to language, since this same area was damaged in all of the patients. About ten years later, the German neurologist Carl Wernicke attributed language comprehension to another region located in the rear of the cranium. The race had begun to locate the brain’s functions.

Knowledge of the links between the brain and the rest of the organism progressed at the same time. The nervous system was systematically studied. Next was the discovery of neural signaling, the electric impulses capable of propagating through the organism’s nerves and causing muscles to contract.

By the end of the nineteenth century, what emerged was the conception of a brain with regions specifically associated with the organism’s functions by means of a nervous system extending throughout the body, with all of this forming a kind of single rigid structure called the “reticular,” similar to a network of electric cables.

However, the first observations of brain matter through a microscope instead revealed filamentous but independent structures, the brain cells that biologists would call neurons. After heated debates between supporters and opponents of the reticular theory, a new vision of the brain became established, far removed from that of a rigid network of cables.

The brain is made up of a large number of specific cells connected together, called neurons. A human brain contains around 100 billion neurons, with each one having on average about 10,000 connections with other neurons. This means that there are a total of about one trillion connections that are made and unmade throughout the course of an individual’s life, playing a fundamental role in our ability to learn.

With the discovery of neurons, neurobiology posed again the problem of the transmission of neural signals. How could the electric impulse propagate if the cerebral structure was so divided? Within the neuron, the neural signal is propagated like an electric impulse. But how does this happen between neurons?

At the beginning of the twentieth century, advances in chemistry and the development of instruments capable of measuring at ever greater detail allowed us to understand the chemical mechanisms that facilitated transmissions between neurons. Scientists discovered molecules that pass from the end of one neuron to another. We call these molecules neurotransmitters or chemical messengers. Whether it takes places through chemical transmission between neurons or through the propagation of an electric signal within the neuron, all of our brain’s activity is reduced to electrochemical processes.

The discovery of neurotransmitters has allowed us to take one more step towards the understanding of the functioning of the nervous system and particularly of the brain. It was also a revolution in pharmacology. Medicines were invented that interfered with these mechanisms of transmission between neurons. These medicines were used to numb certain regions of the body or affect the functioning of the brain.

In the middle of the twentieth century, a Canadian neurosurgeon, Wilder Penfield, studied neural signals in the cortex – the surface of the outer layer of the brain – among patients suffering from epilepsy. By opening the cranium, he was able to map out the regions in the brain that control all of the sensory and motor organs of the human body. He was able to link a region of the cortex with each of these parts of the body. He showed that the size of these regions of the brain is proportional not to the size of the corresponding part of the body, but to its level of sensitivity. Accordingly, the important regions of the cortex deal with the face (especially the mouth and the inside of the throat) or with the hands (especially the thumb), while the entire rest of the body corresponds to much smaller regions.

One of the most spectacular applications of these discoveries was related to what is called neuroprosthetics. Implanting electrodes capable of picking up the neural signals running through the motor regions of the cortex into a patient can allow patients to use their thoughts to control an artificial limb, such as a jointed arm. This is possible because all thought is manifested through neural impulses in the brain. Several years ago, a young quadriplegic man whose brain had been connected to a computer was able, with training was able to move a cursor on a screen with almost as much ease as someone with their hand on a mouse pad. He was also able to manipulate a jointed arm to pick up an object and set it in the hand of the doctor who was caring for him. And very recently, a U.S. team of researchers partially restored vision to a person who had been blind for about 30 years by installing an optoelectronic prosthesis (a device for transforming light into electric signals) within their left eye connected to an optic nerve.

With the identification of the regions of the brain specialized for certain tasks and the knowledge of how information is transferred between these different regions, neurobiologists have been able to begin to understand how the brain is organized. It has become clear that just to produce a simple thought, to understand a sentence, to observe an image, or to pronounce a word, a considerable number of regions must be activated and linked to each other. The act of observing an object and saying the word associated with that object requires the use of the eye, its sensors, and the optic nerve, as well as several areas of the brain that process the information sent by the optic nerve. One of these identifies the “objects” within an image, another separates what is moving from what is remaining still, and yet another is able to restore an overall coherence to all of these analyses. And the association between the identified object and a word comes from a link with the language areas of the brain.

One part of the brain located near the front, the prefrontal cortex, plays an essential role. It is in constant contact with all of the regions of the brain and even with the entire organism, since the nervous system extends all throughout the body. This region of the brain, which is not dedicated to any precise function of the organism, is clearly the source of rational thought. All of the mammals have a prefrontal cortex. We have this in common with monkeys, dogs, and rats. But it is remarkable to see that the relative size of this part of the brain gradually increased with the evolution of vertebrates and that it is distinctly larger in monkeys than in dogs, and even larger in humans: the prefrontal cortex represents 7% of the total cortex in dogs, 17% in chimpanzees, and 29% in humans.

Near the end of the twentieth century, neurobiology had made considerable progress in the exploration of the brain. However, an essential question remained unanswered. The networks connecting neurons were considered fixed. But how then could learning take place, something that was so fundamental for the human species? At the beginning of the 1980s, a revolution took place in neurobiology: the discovery of “neuroplasticity.” Scientists discovered that the links between neurons could be made and unmade and that the brain could create connections between different regions of the cortex or eliminate them.

This is what takes place, for example, when a blind person learns to read Braille with their fingertips. During the learning process, they have the impression that the end of their index finger is becoming more sensitive. In reality, the regions of the brain linked with touch in the index finger are developing. In the same way, if hearing is more developed in blind people, it is because this sense occupies a larger region of their cortexes as it takes on a more important part in their lives.

This neuroplasticity is the biological condition for learning and the acquisition of knowledge. And in the old debate over what is innate and what is acquired, this notion confirms the materialist conception of the origin of human thought.

The Innate and the Acquired

The first English philosophers to draw closer to materialism, near the end of the seventeenth century, had already put forward the idea that thoughts originate in our senses and that there were no innate ideas, not even that of God. One of them, Locke, used the expression “blank slate” to characterize the mind of a newborn baby.

The first modern materialists, such as Diderot and La Mettrie, were inspired by the stories they heard about people who were blind or deaf from birth and about their way of imagining the world. For them, these particular cases allowed them to reflect on how each human’s brain worked.

In his work entitled Letter on the Blind, Diderot related the story of a man who was born blind and became a professor of mathematics at the University of Cambridge in England. He related the words that this man spoke to the priest who had come to receive his deathbed confession and who praised nature’s miracles to him:

“‘Ah, sir,’ replied the blind philosopher, ‘don’t talk to me of this magnificent spectacle, which it has never been my lot to enjoy! I have been condemned to spend my life in darkness, and you cite wonders quite out of my understanding, and which are only evidence for you and for those who see as you do. If you want to make me believe in God you must make me touch Him.’”

After having recounted that the priest suggested that he touch himself so that the blind man might see the divine realization in himself, Diderot returns to the declarations of the blind man:

“‘I must repeat it, all that does not appear so admirable to me as to you. But even if the animal mechanism were as perfect as you maintain, and I dare say it is (for you are a worthy man and would scorn to impose on me), what relation is there between such mechanism and a supremely intelligent being? If it fills you with astonishment, that is perhaps because you are accustomed to treat as miraculous everything which strikes you as beyond your own powers. I have been myself so often an object of admiration to you, that I have not a very high idea of your idea of the miraculous. I have had visits from people from all parts of England who could not conceive of how I could work at geometry: you must allow such folk not to have been very exact in their notions of the possibility of things. We think a certain phenomenon beyond human power and we cry out at once: ‘Tis the handiwork of a god’; our vanity will stick at nothing less. Why can we not season our talk with a little less pride and a little more philosophy? If nature offers us a knotty problem, let us leave it for what it is without calling in to cut it, the hand of a being who immediately becomes a fresh knot and harder to untie than the first. Ask an Indian how the earth hangs suspended in midair, and he will tell you that it is carried on the back of an elephant; and what carries the elephant? A tortoise. And the tortoise? You pity the Indian, and one might say to yourself as to him: ‘My good friend Mr. Holmes, confess your ignorance, and drop the elephant and the tortoise.’”

On the basis of this kind of example, Diderot, La Mettrie, and the other materialists of the time concluded that the thoughts of human beings were the product of interactions between people. La Mettrie expressed this in the following way: “The greatest source of men’s ideas is their contact with one another.

Today, the developments of neurobiology give a scientific foundation to these philosophical positions. During the formation of the fetus, it is the individual’s genes that are responsible for the biological organization of the brain. And our genes are the product of evolution. During the course of millions of years of evolution, the cortex has developed to the point of having to be folded in order to fit inside the cranium. If one were to unfold the human cortex, one would see that it has a surface of about two square meters.

The general organization of the brain, encoded by our genes, is therefore innate. But this innate organization is something that our species, homo sapiens, has obtained and has inherited from the many species that make up our ancestry over millions of years of evolution. Genes can be encoded for very elaborate behaviors, including in animals. With animal behavior, the innate, encoded by genetic inheritance, plays an essential role. For example, a squid always has the same reflex when it encounters a predator: it retreats, shakes its tentacles, and shoots out ink to blind its enemy and to hide itself. Such a behavior, an inheritance of evolution, is programmed into the squid’s brain from birth.

The role left to learned behavior is determined by the brain’s possibilities of adaptation. Very weak in invertebrates like the squid, but much stronger in mammals, the importance of learned behavior varies a great deal between species. The large size and plasticity of the human brain form the biological basis of our formidable capacity for learning. At the moment an individual is born, only 10% of the future connections between its neurons have been made. The remaining 90% are made during childhood and adolescence and continue to change throughout one’s life. This is the material foundation of neuroplasticity.

Today, thanks to medical imaging, it is possible to follow the variations in rushes of blood within the brain. We can see precisely which regions are activated in an infant and at what moment. This is how scientists have been able to study the formation of a baby’s brain, and then that of a child, during their gradual learning process. Starting at birth, the brain adapts and becomes used to what the child sees, hears, and touches. Connections are made between neurons as a function of the child’s environment. Its brain becomes specialized, such as in how it analyzes the characteristic sounds of its native language. Even before producing a single word, the baby’s brain prepares itself to speak for months by listening to others.

In this way, we know that after the age of six months, babies can already tell the difference between the sound in English associated with the letter R and that associated with the letter L. But Japanese babies, since their language does not differentiate the two sounds, do not develop the ability to distinguish them. Similarly, the brain of an individual whose native language is English cannot tell the difference between the two kinds of sounds in Hindi associated with the letter D. The examples could go on and on.

Little by little, the baby’s brain develops and specializes under the influence of interactions with its physical, familial, and social environment. The social and cultural environment plays an essential role in the formation of the human brain. And this makes it at least as much a product of society as of biology.

The Human Brain is Also a Product of Society

To use a phrase of a Soviet neurobiologist, Alexander Luria, our brain – or, more precisely, our prefrontal cortex – is our “organ of civilization.” Thanks to this, the human species has been able to evolve culturally and not just biologically. In return, our prefrontal cortices form in relation to our cultural and social context.

Our distant ancestors began to speak more than two million years ago. Homo habilis is probably the oldest pre-human to have used spoken language. Along with the evolution of the human species, of its brain size, of its ability to make tools and to modify its own environment, the human being has also evolved in its language and its thinking.

This is because we think with the aid of language. In the end, to think is to silently talk to oneself. And as language is the product of the collective life of human beings in constant evolution, the ideas that arise or resonate in our brains are also the product of our mutual interactions, of the society in which we live. In order to understand what ideas are, one must understand what society is and how it develops.

The Materialist Conception of the Evolution of Societies

We have mentioned the natural sciences, but what can we say about society? What laws can we extract about the social organization of human beings? And how have the discoveries about humanity’s past strengthened a scientific understanding of societies and of their evolution?

In this field more than others, idealist, superstitious, and even religious conceptions still carry a great deal of weight. At many levels, these are even the dominant ideas. This is especially true given that materialist conceptions of the history of human societies have been linked with Marxism from an early date, and, as such, have been attacked by the dominant ideology.

Free Will and the Laws of the Evolution of Societies

In examining the history of human societies, the wide range of situations is striking. There have been societies in which people lived entirely on hunting and gathering; great empires of antiquity in Egypt and Mesopotamia; societies based on slavery in Greece and Rome; feudal societies of the Middle Ages; great kingdoms; and in the course of the past few centuries, the global development of capitalism. And this is just a rough and limited list that is more or less centered around Europe.

The history of humanity presents us with a considerable number of different social formations that may be hard to understand when compared with the society in which we are living. For example, the idea of slavery is revolting to us. But slavery marked the entire Mediterranean basin during the centuries of ancient Greece and Rome. Even later it was fundamentally linked with modern Europe during the period of the abominable trade in millions of slaves that the European powers captured in Africa to grow cotton in their American colonies, among other things.

On the other hand, certain societies that ethnologists have studied may seem unbelievable to all those who think that oppression, inequality, and private property are inevitable. The San people (also known as Bushmen or Basarwa) of southern Africa systematically share the meat from animals they hunt. The person who made the arrow is the one who does the sharing, and this is not necessarily the person who shot the arrow, since the arrows circulate among different hunters.

All of these societies are nonetheless made up of the same human species, since there is no fundamental biological difference between the San, people living in slavery-based societies, including both masters and slaves, and ourselves.

In the same way, there is no biological difference between us and the women and men who painted on the cave walls at Lascaux in France, Altamira in Spain, and many other places 15,000, 20,000 or 30,000 years ago. We are the same biological species. We know this from having studied fossils. Biology has definitively demonstrated the impossibility of defining human races, whether past homo sapiens or today. Although each one of us is unique, ties of kinship bind together all of the Earth’s inhabitants to one degree or another.

The tremendous diversity of all of these societies, both past and present, might seem to derive from chance. However, the usefulness of the scientific method is to try to discover laws exactly where chance would seem to govern.

Human beings have consciousness and act as a function of their own thoughts, but many of the consequences of their actions and decisions are beyond them. They make individual choices for a variety of motives. The direction in which society evolves is simply the result of all of these choices, of all of these actions that are not coordinated except in rare occasions. Even when they are, the result is often quite different from what was hoped or expected.

This is because individuals act with only a relative degree of consciousness, if only because they only know and understand one part of the society in which they live. Despite their free will, their choices actually are the result of multiple factors and social pressures of which they are generally not clearly conscious.

To use the expression of one of the Russian popularizers of Marxism from the end of the nineteenth century, Georgi Plekhanov, “human activity is itself defined as being not free, but necessary, that is, as being in conformity with a law, and therefore capable of becoming an object of scientific study.

The attempt to determine these laws does not mean that human beings cannot control their destiny. On the contrary, by becoming conscious of the mechanisms by which societies evolve, one can try to consciously act within the society in which one lives. Having knowledge of the laws of gravity has never allowed us to free ourselves from gravity, and people fall to the ground no less often than before the discoveries of Galileo, Newton, and Einstein. But the discovery of these laws has allowed us to fly airplanes and then to send human beings into space and onto the Moon.

The Forces of Production: The Foundation of All Social Organization

Unlike other animal species, even those whose existence is governed by collective organization, humans have transformed their environment in a more or less fundamental way depending on the society in question. This is less the case for hunter-gatherers, distinctly more for farmers, and considerably more for modern capitalist society with the rise of large-scale industry. In modern capitalism, practically everything that surrounds us is actually the product of human labor, even what is sometimes incorrectly called “natural.” And to complete the picture, all of this is now the result of a series of operations set in motion by the transformative activity of a large part of humanity!

The life and the survival of human beings has always been directly linked to their capacity to harness and transform nature in order to produce what they needed to feed themselves, to protect themselves from the elements, to house and clothe themselves, and to respond to many other more complex needs engendered by the development of society itself. These include the need to move from place to place, to exchange objects and ideas, to transmit knowledge, to care for the sick and injured, etc. Each society has responded to these problems, or at least to the most essential of them, as a function of its means. These means are mainly determined by the level of technical advancement, the knowledge, and the skills of each human group at a given moment.

Societies of hunter-gatherers generally have a very low level of technological development. Certainly, if one becomes lost in the outback of southern Africa, it would be much better to find oneself in the company of a San who knows the local flora and fauna, who knows how to make their way and find what is needed to survive in an environment that appears desert-like and empty to us, than to be stranded alone with a nuclear physicist. But the very weak capacity of these primitive societies to transform the natural world around them often threatens their survival. They are forced to confront regular periods of famine. We know only the societies of this type that have survived, since many others have disappeared. In general, among hunter-gatherers, there is very little surplus, or in any case very little durable surplus that would allow the society to accumulate and therefore to evolve.

For millions of years, our distant ancestors were content to achieve subsistence from collecting the remains of small animals, from scavenging carcasses, and later from hunting. We have discovered the traces left by these humans: skeletons, tools, and even paintings from a more recent period. All throughout this evolution, over considerable stretches of time, archaeologists have been able to trace the outlines of a very slow but fundamental technical progress.

The tools they have discovered provide evidence for this evolution of technical abilities. Humans worked stone, which is the only material that remains from the oldest periods, with growing effectiveness. Specialists have estimated that human beings who lived 2.5 million years ago were able to make 4-inch-long sharp edges from 2.2 pounds of material. Two million years later, or 500,000 years ago, our ancestors were able to make 16-inch-long sharp edges from this same amount of material, or four times as much. And 40,000 years ago, it was 6.5 feet.And 10,000 years later, it was more than 20 feet!

This increasing ability to carve greater sizes of stone reflects many changes. First of all, it reflects changes linked to biological evolution, since the brain size of our ancestors increased considerably. Going from Homo habilis to Homo erectus to Homo sapiens, brain size almost doubled. During these 2.5 million years, humanity spread to all of the world’s continents, while adapting itself to extremely diverse environments. For a long time, humanity had been restricted to small groups on the African continent living from gathering and scavenging carcasses. But it was able to survive in colder latitudes by diversifying its tools and activities. The most notable of these changes was the mastery of fire, which has been in use for 500,000 years, as well as the practice of hunting, which developed with the use of ancient throwing weapons 400,000 years ago.

During the past tens of thousands of years, our use of tools has gradually become more diversified and specialized. The eye of a needle made from wood or reindeer bone allowed humans to make clothing, for example, as well as dugout canoes, harpoons, or spear-throwing devices….

The period of adaptation to climate changes that occurred 13,000 years before our own era was even more impressive. In less than 5,000 years, from 7,000 B.C.E. to 2,000 B.C.E., the use of the bow and arrow, the fishing net, the hunting trap, the practice of navigation, and, in certain regions, the creation of ceramics for cooking and food preservation, all spread. This was also the period in which the dog, which had been domesticated for some time already, was first used for hunting. Finally, two of the most exceptional discoveries in the history of humanity arrived: agriculture and livestock raising.

We can therefore see that while humanity’s progress was slow in developing the earliest techniques, the rhythm of this progress has only accelerated. Each discovery has opened up new possibilities for humanity to improve its mastery over the environment, and each one has allowed for the progress of what can be called the primitive productive forces of humanity.

Along with this technological evolution, other traces that these societies have left behind provide evidence of the advances in consciousness that these women and men had about themselves and the world that surrounded them.

For more than 100,000 years, human beings have mourned their dead with rituals for which archaeologists have found evidence from the discoveries of their earliest grave sites. It was at least 30,000 years ago that they first expressed their artistic sense with frescoes, cave paintings that offer a glimpse into the richness of their spiritual life. Recent research has undermined the idea that these paintings were the exclusive work of men. By studying the negative handprints from several caves in southwestern Europe, a team of researchers affirmed that three-quarters of these prints were from women, since the anatomy of the hands enabled them to determine the age and sex of the painter. A large number of small statues dating from the same period were also found across several sites, and many of these are the female figurines made from terra cotta or stone that archaeologists have called Venus figurines.

Today, it is impossible to say precisely how the first hominids and the first humans lived, or how these small, scattered groups were organized during the very long period known as the Paleolithic. But the nearly unanimous opinion among prehistoric archaeologists is that their way of life resembled that of the hunter-gatherer societies known to us today, since their modes of survival are so similar. All of these societies are believed to have been very egalitarian, with no serious distinction between their members except for that between men and women, due to the ability to bear children, or between young and old, for obvious reasons.

Many prehistoric archaeologists have used the phrase “primitive communism” when referring to this phase in the history of humanity. They do not do this because they see some lost paradise in these societies of hunter-gatherers, nor because they idealize what they know of and can imagine about the relations between their members. Once again, in these societies of relative scarcity, life was often very unstable. The term “primitive communism” only illustrates that at a very primitive degree of development of productive forces, human societies could only be organized in a very egalitarian way, most of all because the survival of each of their members depended directly on the survival of the group.

Later, humanity gave rise to many other social organizations, all of them characterized by differentiation and social inequalities. The diversity and above all the evolution of these societies can only be understood by proceeding from the degree of development of the productive forces in each of these social organizations.

The Neolithic Revolution and the Appearance of Social Classes

The earliest populations to have mastered agriculture and livestock raising were found between 10,000 and 7,000 B.C.E. in the Middle East, in the region called the Fertile Crescent. This is where one of the largest changes in the history of humanity took place. The boundaries of this geographic area have shifted with new archaeological discoveries. Today, archaeologists believe this area began in the Valley of Jordan in Palestine and it stretched as far to the southeast as modern-day Turkey and north from the plains of the Tigris and Euphrates rivers up to the feet of the Zagros, an Iranian mountain chain.

Independent of this, agriculture and livestock raising appeared later in other locations: in Southeast Asia between 8,000 and 5,000 B.C.E., in the northeast of modern-day China between 8,000 and 6,500 B.C.E., in South America between 7,000 and 3,000 B.C.E., in what today is Mexico between 7,000 and 4,500 B.C.E., and in Sub-Saharan Africa between 3,000 and 1,000 B.C.E. Starting in these locations, over the course of several millennia, agriculture spread out across almost the entire planet. In Europe, which was already populated with hunter-gatherers from previous migrations out of Africa, agriculture arrived with populations coming from the Middle East. It reached the western limits of Europe around 5,400 B.C.E. in modern-day Portugal, around 4,800 B.C.E. in the modern-day Brittany region of France, and around 4,000 B.C.E. in modern-day England.

We know that certain populations had broken with the nomadic way of life before the appearance of agriculture and livestock raising. This is the case for the Jomon people on the western coast of Japan, who are believed to have become sedentary around 7,000 B.C.E. These populations lived from the resources of the forest and from fishing, which guaranteed for them a certain level of abundance. They also discovered pottery, whereas in the Middle East this only appeared after the invention of agriculture. It is also probable that the transition to agriculture was the result of certain nomadic populations of hunter-gatherers, the Natufians in the Middle East, with the habit of periodically installing themselves close to areas with a greater abundance of natural produce and where wild herds of animals also passed regularly.

By selecting the plants that had the most food and were the easiest to pick, these populations unconsciously carried out biological selection. In the Middle East, these included cereals (wheat, barley, and rye), as well as lentils, chickpeas, and flax. The same phenomenon of domestication and selection surely took place among the most docile of the wild animals. This is how the first artificial selection of species by humans happened, with these hunter-gatherers unconsciously acting as the first farmers and herders.

Even though for some groups of people settlement came before agriculture and even caused it to take place, it was actually the conscious adoption of agriculture and animal herding and then the spread of this mode of subsistence that caused almost all of humanity to settle into permanent communities.

In the same period, the new technology of stone polishing developed. This gave the name to a new stage in history: the Neolithic, or the New Stone Age (or even the Age of Polished Stone). Polishing a stone axe noticeably increased its resistance to blows by eliminating its fragile parts. A range of tools that could be used in woodworking was created. Equipped with stone axes, the earliest agricultural populations were able to conquer new lands for agriculture. Cutting down forests enabled livestock grazing.

The earliest agriculture in forested regions was made possible by the technique called slash-and-burn. This consisted of carving out a clearing in the forest by cutting down the most fragile trees, without even destroying the stumps. Once the foliage, branches, and dead trunks had dried out, they were burned in place so that the nutrients in the ashes could fertilize the earth.

After two or three years of cultivation, humans left the land so that the forest could regrow, which restored its natural fertility after several decades. This technique of letting woodlands lie fallow was so successful that it led to significant demographic growth among Neolithic populations, to the point that it pushed against the limits of this system. It is believed that the clearing of the land during this period played a role in the deforestation of the Mediterranean region and in the desertification of certain warm subtropical regions in the Middle East with low levels of rainfall.

These advances served as a starting point for more efficient kinds of cultivation, such as the use of irrigation, rice growing, or the perfection of crop rotation systems, depending on the region.

This ability to overcome obstacles and to push against the limits set by nature, this flexibility and creativity that humanity demonstrated at the dawn of civilization, was also a consequence of the increase in the number of human beings. The greater regularity and supply of food, along with the more settled lifestyle resulted in an important growth in women’s fertility. It has been estimated that the global population, which consisted of several million individuals in earlier periods, reached about 50 million in the Neolithic Age.

This meant a spectacular growth of productive forces. These social transformations were so important that an Australian archaeologist of the interwar period, V. Gordon Childe, used the expression “Neolithic Revolution” to characterize the breakthrough.

The existence of human beings changed radically when they no longer had to constantly change the place where they lived or to migrate with the seasons. The ability to settle in a relatively permanent way allowed them to store food in anticipation of destructive events or poor harvests. This also allowed them to accumulate tools, and therefore to have a wider variation of instruments of labor, which were better adapted and more effective. As opposed to this, certain tribes of nomadic hunter-gatherers carry only one simple tool with multiple uses. For example, the Aborigines of Australia’s central desert region have a tool that they use to launch projectiles, but with a shape that allows them to also use it as a container or as a small tool to carve wood. With permanent settlement, the diversification of tools increased considerably.

Agriculture and animal husbandry originated in many locations in different regions in the world. This shows that these discoveries did not always take place in the same order. The Neolithic Revolution consisted of a group of inventions and transformations. They each had an effect on the others – such as the use of polished stone, pottery, permanent settlement, and food storage. Those brought about the systems of agriculture and the raising of animals. This fundamental qualitative change meant a radical shift in the mode of production.

The Neolithic Revolution was a product of humanity’s technical development, and it profoundly changed humanity itself, not biologically but socially.

The development of human labor productivity brought about an increase in population. With it for the first time in the history of humanity, what Marx called the social surplus product appeared on a large and lasting scale. From this point on, labor allowed humanity not only to assure the subsistence of all members of society but also to accumulate in the general sense of the term: to accumulate food, but also to accumulate social wealth in a more subtle way, allowing certain members of society to fully or partially devote themselves to activities other than those required in producing food.

The appearance of the earliest artisans of various specializations, as well as that of the earliest intellectual laborers, was proof of a permanent and institutionalized division of labor.

This fundamental transformation definitively marked all human societies. The division of labor was the foundation of future progress, since it allowed for specialization, the advance of knowledge and skills, and their transmission from one generation to the next. A considerable part of the formidable growth of productive forces was ultimately contained in this division of labor and in the change of mentality that it implied, or in other words, the skills of each individual organized at the level of the entire society. This division of labor brought about the earliest urbanization, the first major division between city and countryside. Civilization would be born out of what can be called the “urban revolution.”

Within this framework and on this basis, private property in the means of production was first imposed, starting with the land. Social inequalities took root. The exploitation of humans by other humans was established. Society was divided into social classes. The productive forces first needed to reach a level of development that would allow for the creation of an economic surplus that was sufficiently regular and guaranteed for an advanced division of labor and social classes to take hold, with exploiters and exploited.

Private property in the means of production and exploitation thrust humanity into the era of class societies, with all this meant in terms of oppression and institutionalized violence. However, considering the degree of development of productive forces, this “evil,” if one can use that language, was unavoidable if human societies were to continue to progress.

This is what can be seen, for example, in the history of ancient Egypt. Six thousand years ago, on the banks of the Nile, humans adapted their agriculture to the rise and fall of the river and to the fertile deposits of silt that it left behind. Archaeologists have discovered the remains of these peoples’ first villages. In the beginning, agriculture only took place on the outskirts of the areas liable to flooding, cultivated just after the water returned to its normal levels. In the second phase, ancient Egyptians constructed simple dykes to create basins containing floodwater after the banks retreated. This allowed them to retain water in order to irrigate and fertilize the areas under cultivation. In the third phase, they built a series of retention basins connected to one another, starting at the riverbanks and stretching farther and farther into the desert. After this, they created a different network of retention basins that lay parallel to the riverbanks instead of trailing off into the desert, in order to assure that the water would flow uniformly into the basins. Finally, they built large protective dykes along the length of the Nile and large canals that connected the retention basins together, from the upper valley of the Nile to its delta. The stages of this hydraulic architecture, which played out over almost 1,000 years, allowed for the distribution of water and silt all along the Nile valley.

One can observe how the social and even the political history of the Egyptian kingdoms corresponds to the progress of the technical organization of this agriculture. As Marcel Mazoyer, an anthropologist and specialist in the history of agriculture, has written on this subject:

“… The important stages in the development of these hydraulic installations and the coordinated management of the floodwaters on increasingly more extensive parts of the valley coincided with stages in the development of increasingly more powerful forms of social and political organization, capable of extending their hydraulic power to corresponding territories: villages strung out along the valley and on the fringes of the delta; rudimentary city-states dominating a small section of the valley; then, toward the middle of the sixth millennium before the present era, more powerful city-states dominated an entire alluvial plain ranging between two narrow passages in the valley; large kingdoms that unified several cities and dominated several alluvial plains, then, in the second half of the sixth millennium, two kingdoms (Upper Egypt corresponding to the valley properly speaking and Lower Egypt corresponding to the delta); finally, a little more than 5,000 years ago, formation of the pharaonic state that unified these two kingdoms. After that, over the next 3,000 years, some 200 pharaohs belonging to thirty dynasties reigned more or less completely over these two kingdoms. The prosperous periods (Old Kingdom, Middle Kingdom, New Kingdom) coincided with a strong concentration of power, and the decadent periods (intermediate periods, Late Period) coincided with a weakened and broken up centralized power.

So, the Egyptian peasantry of 6,000 years ago tilled the flood plain along the banks of the Nile. They worked on parcels of land that the pharaoh owned and conceded to them. In exchange, the peasants had to fill demanding levies on their labor in order to maintain the hydraulic infrastructure and build temples, tombs and pyramids. The state required them to pay taxes in kind in order to fulfill the needs of the pharaoh, his entourage, the priesthood, and the civil and military administration, as well as to feed the state workers and artisans, as well as to build up food reserves as a hedge against the unexpected rise and fall of the riverbanks.

The case of ancient Egypt highlights a new institution in the history of humanity: the state, an institution elevated above society, established to govern the contradictions that arise from the development of social classes with opposing interests. In Egypt, a larger and larger social organization was required over the course of the development of an ever more elaborate agricultural system that extended over an ever wider zone of flood management. The unification of villages, and then of city-states, under the control of a central power was a necessity imposed by the management of the flooding of the Nile in order to distribute water across the nearly 1,000 miles of the river that lie between Aswan and the Mediterranean Sea. And the Kingdom of Upper Egypt in the South, which could control the irrigation of the northern Kingdom of Lower Egypt because it was located upriver, imposed its domination and then unified the country around 3,200 B.C.E.

Another more general reason for the emergence of the state was that the creation of large empires like that of Egypt corresponded to the level of productive forces of a time period when the productivity of human labor – mostly agricultural productivity – remained very low, since over a very long period time, the tools used by Egyptian peasants were made from stone or wood. Despite the low level of individual output, large scale production created a large enough surplus to maintain a thin layer of exploiters, as well as the laborers and artisans needed by a large population and a relatively highly developed social organization for that time period.

In ancient Egypt, this tiny minority living off the labor of the immense majority played an essential role. This was most notably the case for the caste tasked with managing irrigation based on their understanding of how the waters of the Nile behaved. At the beginning of the third millennium before the present era, through careful and detailed observations of the stars, they were the first to discover that the same constellations seemed to shift locations each night and would return to the exact same place in the sky every 365 days. They used this to invent the first exact calendar based on the stars and therefore indirectly on the Sun. They no longer had to base their calendar on the lunar months, which were constantly out of synch with the seasons, and they were able to make real predictions of natural phenomena, such as when the Nile would begin to flood.

In the third millennium B.C.E., these administrative priests also invented writing. This was the case in Egypt as it was for the Sumerian priests in Mesopotamia, who had done this before the Egyptians. And they both did it for the same reasons of governance and administration of the State and the economy, with cuneiform characters in Sumer and hieroglyphics in Egypt.

Ideologies and Socialism

Class societies, of which ancient Egypt and Sumer were the major precursors, would go on to develop according to the rhythm of the progression of productive forces and conflicts between social classes, between exploiters and exploited. As Marx and Engels summarized at the beginning of the Communist Manifesto: “The history of all hitherto existing society is the history of class struggles.

Marx expressed the link between the productive forces of a given society and what he termed the ideological superstructure in the following way:

“… In the social production of their existence, men inevitably enter into definite relations, which are independent of their will, namely relations of production appropriate to a given stage in the development of their material forces of production. The totality of these relations of production constitutes the economic structure of society, the real foundation, on which arises a legal and political superstructure and to which correspond definite forms of social consciousness. The mode of production of material life conditions the general process of social, political and intellectual life. It is not the consciousness of men that determines their existence, but their social existence that determines their consciousness.”

Not only religions, but also the idea of the nation, of democracy, of a republic, and even the idea of socialism are all ideologies that are expressions of social reality. “Ideas do not drop from the sky, and nothing comes to us in a dream,” wrote Antonio Labriola, one of the earliest Italian Marxists of the end of the nineteenth century. And if ideas have an audience and are seized upon by thousands or millions of human beings, it is because they respond to a social necessity.

Ideologies are the products of societies divided into classes. They bring together masses of individuals and set them in motion in a coordinated way, acting in turn on this social reality.

Certain ideas are revolutionary and progressive, since they bear within them the elements of society’s future, announcing and preparing its later development. Other ideas are reactionary because they express the weight of the past and place a brake on historical development, or even attempt to drive it backwards. The former are often held by the social classes demanding power, and the latter by those who already have it and are trying to hold onto it. But social reality never stops changing, and the same idea that was revolutionary in the beginning can become reactionary over the course of the evolution of class struggle.

Modern republican ideas were held by the bourgeoisie as it struggled to free itself from the power of the nobility. During the Middle Ages, the urban bourgeois republics were dominated by rich patrician families, while the common people had almost no say. The bourgeoisie felt at home within these medieval cities where it had succeeded in freeing itself from the power of the local lord. It acted as the ruling class there, and the republic with voting rights based on taxation provided it with an institutional framework adapted to its collective rule. In later struggles, this time at the level not just of a city but of a kingdom, it took centuries for the bourgeoisie to feel powerful enough to demand power. This was all the more true for power that it did not have to share. At the end of the sixteenth century, in the struggle for independence of the United Provinces, which was the precursor of the Netherlands, the bourgeoisie had to place a noble at the head of its revolt and then of its state. In England a half century later, following a short-lived republic led by Oliver Cromwell, the bourgeoisie preferred to share power with the aristocracy under the cover of the restored monarchy because the bourgeoisie was still weak.

It was only with the French Revolution of 1789, under the pressure of events and above all under the pressure of the poor and working classes in revolt, that the bourgeoisie carried its struggle through to the end and established a republic. But even in France, it took almost a century for this republic to fully develop because after it took the reins of power, the bourgeoisie was wary of mobilizations of the poor and the possibility that the lower classes could more easily express themselves in the framework of a republic. Throughout the nineteenth century, the majority of the French bourgeoisie displayed royalist attitudes, with the differences inside the bourgeoisie expressed through different royalist tendencies.

The bourgeoisie also put forward the idea of the nation. Faced with the many divided feudal states and multiple customs barriers that allowed a parasitic nobility to guarantee its income, the bourgeoisie raised the flag of national unity. This nationalism of the 18th and 19th centuries was progressive. From an economic point of view, it signified the suppression of regional particularism and the creation of a far larger and more unified national market. It was also progressive from a political point of view, since it was the battle cry used against the Old Regime. However, once the political power of the bourgeoisie was assured, nationalism became the flag of the bourgeoisie’s rule and of the oppression of peoples who fell under the domination of the bourgeois nation. With the scramble for colonies that marked the end of the 19th century and the beginning of the 20th century, nationalism became the flag of rivalries between the big imperialist powers over how the world would be divided up. Nationalism has always been an ideology of the bourgeoisie and it has evolved along with it. Starting off as progressive when the bourgeoisie swept aside the old feudal order, it has become profoundly reactionary since it now serves to mark its power over the world and to divide the proletariat against itself.

To say that these ideologies are those of the bourgeoisie does not mean that every bourgeois in every time period has defended them, nor that only the bourgeoisie can take them up. It means that they correspond to the general interests of the bourgeois class, since ideas necessarily lean on groups of individuals and classes that have common interests, since “ideas do not drop from the sky.”

Ideologies that conform to the interest of a ruling class are transmitted in many ways throughout all layers of society, even of a large part of the exploited classes. One can observe this on a daily basis in capitalist society. But this was also the case for the bourgeoisie before it came to power. It also found itself captivated by the ideas of the ruling class at the time, the nobility. One example of this is Molière’s play, The Bourgeois Gentleman, which is about a bourgeois man dreaming of becoming a nobleman!

The proletariat, born out of the industrial revolution, was a fighting class practically from the time it first appeared. Even if its struggles did not at first aim at taking control over the management of society, the proletariat at least tried to defend its immediate interests as a distinct class. The earliest struggles of the English proletariat in the first half of the 19th century can’t help but impress all those who today take the side of the working classes. Over the course of its struggles, the working class learned how to put forward its own interests and its own ideas.

Very early on, the proletariat opposed the idea of internationalism to the nationalism of the bourgeoisie. This is because capitalism pushed millions of workers across the world into poverty, uprooting proletarians from everywhere to migrate towards the factories. The working class is not a national class. It has always been made up of the exploited coming from all countries, essentially from the poorest countries and regions towards the richest centers. But one person is always poor when compared to another. And the wheel of history turns: countries from which people emigrate sometimes become countries that attract a flow of immigrants and vice versa.

Faced with republicanism, the proletariat instead put forward socialism. This was not a political form of the organization of power at a national level, but a form of organization of society and production at a global level. The workers’ movement responded to the bourgeois motto “men are born free and equal under the law” with its struggle for social equality, for the end of exploitation of people by other people, and therefore for the overthrow of the bourgeoisie, its expropriation, and the collectivization of the means of production.

However, the workers’ movement only instinctively expressed the ideas corresponding to its immediate and even its general interests. Throughout history, previous classes only fought unconsciously, or with a partial consciousness of the general historical development to which their struggle was linked. The materialist conception of history, established by Marx and Engels on the eve of the revolutionary wave that swept Europe in 1848, gave the proletariat a consciousness of the whole of the historical process in which its fight was taking place. The industrial working class emerged and carried out its first struggles, and many working-class militants welcomed the ideas of scientific socialism “like a long-awaited guest,” to use Marx’s expression. By assimilating Marxism, the workers’ movement equipped itself with a conscious political expression of the historical process, and with this it had an indispensable weapon in its fight for the establishment of a new social order.

This consciousness allowed the Marxist workers’ movement to also fight for bourgeois demands, such as in support of the republic, national unity and independence when these still had a progressive character. At the same time, it was able to preserve the political independence of the proletariat, remaining conscious that this was only a temporary alliance for a definite goal with a fundamental class enemy.

In this way, the Bolshevik Party in Russia took part in the struggle against tzarism alongside other social forces, including those of the bourgeoisie. It did this without compromising the position and interests of the proletariat, and it maintained the political independence of the working class. And in 1917, after having overthrown the Old Regime, the proletariat took eight months of class struggle of an exceptional political intensity to come to the point of taking power from the bourgeoisie, but only eight months and not an entire historical period.

Today, we are far from a revolutionary situation like that of Russia in 1917. For several decades, we have been living in a situation in which the workers’ movement has been in retreat on a global level. And because the working class has been politically absent from all of the recent struggles that have taken place, raising the flag of communism has meant defending ideas that are against the current.

However, if the capitalism of Marx’s time contained the economic premises for a higher level of social organization by developing collective labor and the forces of production, the objective conditions today for the socialized organization of production at a global level are more than mature. Even producing the simplest object requires the participation of workers from all over the world. With modern technology, the most spectacular construction can take place at a fantastic speed. Scientific discoveries and technological achievements are mind-boggling, from the artificial heart to the Rosetta space probe. In relation to what this scientific progress could bring to all of the inhabitants of the planet, the current barbaric organization of society is all the more revolting and unworthy of humanity.

In order to free the forces of production and to place their potential at the service of the general interests of humanity, the bourgeoisie must be expropriated. The working class is the only social class capable of doing so. It is concentrated in the companies and the large cities, which are the centers of power. And, unlike in Marx’s time, when it was only present in a handful of countries, today it is everywhere on the surface of the Earth. As Marx affirmed, the working class “has nothing to lose but its chains.” It can and must lead the rest of the oppressed in its struggle to overthrow the bourgeoisie. But this act, which will be carried out by millions of proletarians and exploited around the world, can only be the result of a conscious collective interaction.

It is for this reason that it is vital to defend and spread the ideas of scientific socialism, so that they can be personified in conscious workers, organized in revolutionary parties linked together through an international that will represent, to use Trotsky’s words, “the conscious expression of the unconscious historical process; namely, the instinctive and elemental drive of the proletariat to reconstruct society on a communist basis.”

It is not uncommon for us to hear that we are utopians. But the entire history of humanity, its scientific discoveries and its social transformations, is punctuated with upheavals and revolutions. Each time that a decisive stage approaches, the weight of the past has hung over the ideas and actions of the living. Fortunately, there have always been individuals who are conscious of the necessity to break with the past and the boldness to forge ahead, which always means making a leap into the unknown. These “utopians” made their ideas into reality, since their advances responded to the transformations that were ripening in the depths of society. If this is what it means to be utopian, then we take these criticisms as compliments.


On the Subject of Determinism and Chance in the Natural Sciences

The word chance can mean very different things. Dice thrown in the air can land in a certain position, and one might say that this is due to chance. This is because they are thrown without knowledge of their initial position, of how high they are above the ground, and of their initial movement of rotation. With sufficiently precise knowledge of all of this information, besides knowing how hard the ground is, one can use the laws of physics to determine the results of throwing the dice with no mistakes. Of course, a gust of wind could come and disturb this prediction. But even then, by knowing the precise speed and direction of the wind, one can take its effect into account and use this to make more accurate predictions. In the simple case of this toss of the dice, the role of chance is therefore due to an initial lack of information … which is fine, because games would be no fun if we were able to make the kinds of calculations suggested above.

At the beginning of the nineteenth century, the Scottish botanist Robert Brown used a microscope to observe the continuous jittery motion of pollen particles on the surface of a liquid. This motion was not understood for almost one hundred years. Nevertheless, it is now known that what seems like random motion is in fact due to the incessant collision of water molecules with the pollen particles. Each collision of a water molecule with a pollen particle results in a small movement that is predictable with the simple laws of mechanics. But the large number of collisions from many directions makes it impossible to predict this motion. In this case, “chance” results from a very large quantity of successive disruptions. Taken independently, each one of these has a predictable effect, but it is their sheer number that gives an unpredictable aspect to the totality of this phenomenon.

Chance also intervenes in the genetic transmission from parents to their children. Sexual reproduction is characterized by the fact that an individual’s genes are not the simple replica of one parent’s genes, which would be cloning, but a mixture and selection of genes from both parents. This selection of the parents’ genes takes place “by chance.” But again, behind this phenomenon, there are a large number of chemical processes that, each one taken separately, is absolutely determined, but the final result of which is unpredictable. This role of chance does not contradict the law of the evolution of species, and it is even one of its key elements. In effect, natural selection, or the effect of the environment, can operate on a multitude of individuals with varied characteristics exactly because of this diversity linked to sexual reproduction, and it selects for those who are the best adapted.

We can take another example from the field of genetics to illustrate the fact that even if phenomena can have random consequences, this does not mean that the mechanisms behind them are not determined.

It is possible to identify an individual from its genetic sequence. But when we study in detail the DNA molecules in the individual’s cells, and notably those in their neurons, it becomes clear that the DNA is not completely identical. Slight variations might give each neuron a DNA molecule that is specific to it.

This variability may appear random to us, but the mechanism behind it is known. The mechanism is what are called “jumping genes,” which are pieces of DNA capable of moving within the DNA molecule during the process of cellular division. They introduce this slight variation in the DNA from one cell to the next.

And so, even if the consequence of the phenomenon is random (for example, the genome of a given neuron is impossible to predict exactly), the mechanism behind this result (the movement of “jumping genes”) has been identified and is itself determined.

In a book in which he takes up the question of materialism again and where he evokes the “general laws of motion, both of the external world and of human thought,” Engels writes on this subject: “In nature and also up to now for the most part in human history, [the general laws of motion] assert themselves unconsciously, in the form of external necessity, in the midst of an endless series of seeming accidents.”

Determinism in science does not mean that everything is predictable, and even less that “all is written.” This is because scientific predictions are made based on laws that are models of reality, elaborated from the knowledge of this reality that humanity has achieved at a given moment. Scientific laws are not absolute: the sciences progress and their predictive capabilities progress with them.

Towards the end of the 1970s, a debate broke out over the interpretation of a theory called “chaos theory.” This debate flared up again when it reached a wider public in the 1990s. This theory, which has a basis in scientific research that was done before World War One, models what are called chaotic phenomena. In the physical sciences, this term has a very precise definition: it characterizes systems that are extremely sensitive to the slightest disturbance. A tiny disruption can result in major variations. Meteorological predictions fall into this category. This is the famous “butterfly effect” stated by the U.S. meteorologist Edward Lorenz. He illustrated his point of view in the form of a question: “Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?

During the course of these debates, certain authors, including scientists, announced that determinism itself must be called into question. A famous U.S. paleontologist, Stephen Jay Gould, extended this point of view to the theory of evolution and sought to reduce the role of Darwinism, of which he had previously been a major popularizer. He claimed that over the course of the hundreds of millions of years of history of life on Earth, catastrophes like the collision of an asteroid with the Earth had disturbed evolution to such a degree that it had little more than a secondary aspect. He concluded from this that chance was the master of evolution.

With this way of reasoning, Stephen Jay Gould arbitrarily separated these destructive catastrophes from the process of evolution itself. But without ignoring the effects of these catastrophes, why not attempt to take them into account as environmental constraints and try to understand why and how certain species were able to resist these catastrophes while others were not? His approach was the result of a philosophical choice foreign to the scientific method and to scientific argument.

As for chaos theory itself, the mathematicians and physicists who advanced it by directly studying chaotic phenomena, which exist in many other fields besides meteorology, quantified this extreme sensitivity of certain systems to initial disruptions in a very precise manner. In the logic of their theory, they never questioned determinism itself. They even formally take it into account in all of their models. And the developments in chaos theory have led to improvements in meteorological predictions by increasing the number of measurements.

Marxists have often had to combat the influence of idealist conceptions that were “in fashion” at one time or another. At the beginning of the 20th century, Lenin was forced to wage a struggle within the socialist movement, and not just in Russia, against the influence of idealist conceptions that philosophers and scientists like Avenarius and Mach argued for at the time. On this occasion, he was able to summarize the difference between materialists and idealists on the subject of causality and determinism in the following manner:

The really important epistemological question that divides the philosophical trends is not the degree of precision attained by our descriptions of causal connections, or whether these descriptions can be expressed in exact mathematical formulas, but whether the source of our knowledge of these connections is objective natural law or properties of our mind, its innate faculty of apprehending certain a priori truths, and so forth. This is what so irrevocably divides the materialists Feuerbach, Marx, and Engels from the agnostics (disciples of Hume) Avenarius and Mach.”

Finally, the field of quantum physics gave rise to a philosophical interpretation considerably marked by idealism and the notion of chance. Quantum physics was first developed at the beginning of the twentieth century to study the behavior of the tiniest components of matter, the elementary particles. Its idealist interpretation was one that physicists like Einstein fought against. The outline of this debate can be seen by taking the example of radioactivity. This field has revealed that certain chemical elements can disintegrate. The life span of these elements, which are termed radioactive, can be measured with a very high level of precision. In this way, a certain type of carbon nuclei, the nuclei of carbon-14 for example, has an average half-life of 5,734 years. Archaeologists measure the quantity of these radioactive nuclei in certain bones in order to carry out the technique of carbon dating. But these 5,734 years are an average. And while quantum physics is currently able to explain why the carbon-14 nuclei disintegrate on average over this life span, it is not able to predict exactly when a particular nucleus of carbon-14 will fully disintegrate.

This limit, which reduces what quantum mechanics is able to predict to probabilities, has led to very intense debates among physicists for decades, and these are still taking place today. The dominant philosophical interpretation postulates that nature behaves in an intrinsically and deeply probabilistic manner. What is there behind this kind of behavior that can be attributed to a level of chance intrinsic to nature? The defenders of this point of view do not respond. Other physicists investigate and propose theories with the goal of completing the current formalism of quantum physics.

Scientific debates have set off and will continue to set off a variety of philosophical interpretations. But determinism, which is inseparable from materialism, concerns material reality itself, before even the representation that we make of it ourselves. And scientific laws can model this reality and will model it even more precisely as more and more discoveries are made.