“And if time didn’t exist?” is the title of the book by physicist Carlo Rovelli posing a question which could seem first of all to be very strange, absurd even. Every day we see, experience the passage of time. Clocks, alarms, omnipresent watches count off the seconds. For example, the frustration one feels when you miss the train by arriving too late; children that grow up or the wrinkles in the corner of the eye. Everything, absolutely everything seems to justify beyond any possible doubt the implacable existence of time and its effects.
Really? For those who travel little the earth doesn’t seem flat, decorated with swellings and depressions as it is. The idea of a round earth with an “underneath” where people walk “upside-down” without “falling off”, isn’t that also contrary to intuition? And to say that this earth goes around the Sun whereas we see each and every day the Sun “rise” in the east and “set” in the west?
The history of science has confirmed what the Greek philosophers had already understood more than 2,500 years ago: our senses can be mistaken; it is necessary to go beyond the immediate impressionable sensations to get to the truth. So perhaps the hypothesis of Carlo Rovelli is worth some serious consideration. For what reasons does this scientist affirm that time is fundamentally an illusion?
The illusion of the passage of time
Since Einstein humanity has known that there is a snag in the ticking of our clocks: time is relative. It doesn’t pass at the same rate everywhere. The more the speed of movement is greater or gravity stronger, the more the passage of time slows down. Interstellar, Christopher Nolan’s very successful 2014 film, correctly put this scientific discovery at the centre of its story: the protagonists age differently depending if they are on Earth, or if they travel through space, or if they stay on this or that planet provided with a different gravity. The hero, a cosmonaut sent into space at the beginning of the film, returns at the end of the adventure to find his daughter who remained on earth a very old woman, while he had only aged a few months. If this example is a case of science fiction, it is nevertheless accurate, and the relative nature of time has been experimentally verified. For example, if two atomic clocks (the most precise at the present time) are started simultaneously with one remaining on the ground and the other on a flight 10km above the earth and its gravity, then the readings show two different results: the one at a distance would have “lived” less long by some nanoseconds than the one on the ground.
Time is thus not a regular ticking, fixed and implacable. But Carlo Rovelli goes further by advancing the hypothesis that time doesn’t really exist: “...we never measure time itself. We always measure the variable physics A, B, C ... (oscillations, pulsations, and many other things), and we always compare one variable with another. But it is useful to imagine that there exists a variable t, the real time that we can never measure, but which is found behind everything (...) Rather than any resort to an abstract and absolute ‘time’, which was a thing invented by Newton, one can describe each variable in relation to the state of other variables (...) Just like space, time becomes a relational idea. It only expresses a relation to the different states of things”. And thus: “Space and usual time quite simply disappear from the framework of basic physics, in the same way that the notion of the ‘centre of the universe’ disappears with the scientific image of the world” (pp.100 to 103). Time does not fundamentally exist but comes from an illusion due to our knowledge or to our limited perception of the Universe: “... time is an effect of our ignorance of the details of the world. If we understood perfectly all the details of the world, we would not have the sensation of the passage of time” (pp. 104-105).
In other words, the universe is made up of constant, permanent interactions of an infinite complexity of cause and effect. A modifies B which modifies C in its turn but also perhaps A itself, etc. Thus the universe is in movement, ceaselessly modifying itself, and these are the changes and interactions that we perceive. Alone, our existence unfolds with few fundamental variables, always on Earth or near to it and at extremely modest speeds compared to the speed of light, with all these interactions appearing to us as dictated by a physical component of the universe that man calls “time”. At our level the swing of the pendulum is imperturbable; we never see the difference of some nanoseconds which could happen here or there on Earth according to the speed of our movement or our altitude. Newton himself integrated this notion of “time” as a fundamental component of his physics. Only what Carlo Rovelli says is that when we observe the swing of a pendulum we have the illusion of the passing of “seconds” whereas we are only measuring a concatenation of interactions within the mechanism of the clock. And that is why modern physics can do without the notion of “time” within its equations: “... instead of predicting the position of a falling object ‘at the end of five seconds’, we can predict its fall after ‘five oscillations of the clock’. The difference is weak in practice, but great from a conceptual point of view because this approach frees us from all constraints on possible forms of space-time” (p. 115).
It’s neither in the competence of the author of this article nor the role of a revolutionary organisation as the ICC to validate or invalidate a hypothesis during the course of a debate in the scientific world. On the other hand, beyond the necessary interest for the advancement of thought in general, the method and the scientific approach which underpins these advances are also a foundation that needs to be assimilated in order to try to understand the world and society. Does time exist? We can’t settle that, but the approach of Carlo Rovelli is a source of inspiration for reflection. Because there appears a treasure much greater than the result of his research and that is the road that it’s necessary to take: thought in movement.
A dynamic vision of science
From the conception of a universe in constant evolution, constituted by a series of interactions of an infinite complexity, follows a dynamic vision of science and the truth. If the universe is in movement then to understand it thought must also be in movement: “With science, I have discovered a mode of thought which first of all establishes rules to understand the world, and then became capable of modifying these same rules. This liberty in the pursuit of knowledge fascinated me. Pushed by my curiosity, and perhaps by what Frederico Cesi, a friend of Galileo and a visionary of modern science, called ‘the natural desire to know’, I find myself, almost without realizing it, immersed in problems of theoretical physics” (p. 5). Carlo Rovelli disputes the validity of a fixed vision of a science which is supposed to lay down absolute and eternal truths. On the contrary, for him, “Scientific thought is the very consciousness of our ignorance. I would even say that scientific thought is the very consciousness of our great ignorance and thus of the dynamic nature of knowledge. It is doubt and not certainty that pushes us forwards. There of course lies the profound heritage of Descartes. We must have confidence in science not because it offers certainties but because it has none” (pp. 70-71).
Carlo Rovelli thus shows us that the evolution of scientific thought is absolutely opposed to the scientific approach of the 19th century. It was believed during this period that science was in continuous evolution towards the complete knowledge of the laws of the universe. Thus in the second half of the 19th century, the majority of scientists thought that all the fundamental laws of nature had essentially been discovered. It only remained to determine some universal constants in order to make the definitive turn of the physical sciences. Hardly five years after the turn of the century two fundamental theories swept away this almost perfect edifice: the special theory of relativity (completed by that of general relativity) of Einstein, and quantum mechanics which was still more profound in terms of calling into question our understanding of the world. Carlo Rovelli shows us that the scientific method always begins by taking into account and calling into question the bases of the old theories in order to elaborate new, wider, more profound and more general ones. Advances made by the new theories allow progress. This progress leads us into a new context which itself becomes contradictory in its development. Thus quantum mechanics and general relativity have opened the possibility of better understanding the dynamics of the universe, an understanding that was inaccessible through classical physics, since the latter was only able to describe a stable and definite state. But these two great theories have not brought us to a final point in physics or to a total and definitive answer to the mysteries of the universe. Quite the contrary. New contradictions have appeared: “Quantum mechanics, which describes very well the microscopic level, has profoundly overturned what we know about matter. General relativity, which explains the force of gravity very well, has radically transformed what we know about Time and Space (...) But these two theories lead to two very different ways of describing the world, which appear incompatible. Each one of them seems to be written as if the other didn’t exist. We are in a schizophrenic situation with partial and intrinsically inconsistent explanations. To the point where we no longer know what is Space, Time and Matter (...) one way or the other it is necessary to reconcile the two theories. This mission is the central problem of quantum gravity (pp. 10 to 13). And if the theory of quantum gravitation one day attains its historic mission, thus offering humanity the possibility of understanding “the end of the life of a black hole or the first moments of the life of the Universe” (p. 11), then new questions emerge for human consciousness. And it’s really the very existence of these infinite contradictions which has led Carlo Rovelli in his passion for science, this immense and perpetual enigma: “I think that it is precisely in the discovery of the limits of the scientific representations of the world that the force of scientific thought is revealed. It’s not through experiments, neither ‘mathematics’, nor in a ‘method’. It is in scientific thought’s own capacity to always question. Doubt its own affirmations. Don’t be afraid to deny its own beliefs, even the most certain of them. The heart of science is change” (pp. 56-57).
But this relative approach of truth and science doesn’t at all mean that Carlo Rovelli falls into relativism. On the contrary: he shows what aberrations relativism leads to by taking the example of the United States where Creationism has done enormous damage. In particularly in terms of education: “These deformed visions of science consequently lead to a diminishing of its aura and irrational thought gains ground... In the United States for example (from ‘rural’ Kansas to much civilised California) teachers are not allowed to talk about evolution in schools. The laws forbidding the teaching of the results of Darwin are justified by cultural relativism: they know that science can be mistaken, and thus a scientific knowledge is no more defendable than a biblical knowledge. A candidate for the presidency of the United States, recently asked about the subject, declared that he didn’t know if human beings and the apes really had ‘common ancestors’. Does he even know if the Earth goes around the Sun or the Sun around the Earth?” (pp. 53-54).
More generally: “The scientific obsession with calling all truth into question doesn’t lead to scepticism nor nihilism, or to a radical relativism. Science is the practice of overturning absolutes, which doesn’t mean a fall into total relativism or nihilism. It is the intellectual acceptance of the fact that knowledge evolves. The fact that the truth can always be questioned doesn’t imply that one can’t be in agreement; in fact science is the very process from which one can arrive at agreement” (p. 71).
The necessary confrontation of hypotheses
In order to “agree with each other”, in order for our knowledge to have a “dynamic nature”, it is imperative that hypotheses are confronted one against another, that a debate of ideas with the sole aim of advancing the truth animates all of the sciences. That’s why throughout his book, Rovelli berates the scientists who sabotage the debate, preferring to defend their own interests by not sharing their work and hypotheses, conceiving research as some sort of race towards individual fame, by being animated by the spirit of competition with all the baseness, bad faith and other dishonest procedures that that implies: “The world of science as I discovered with sadness, including at my own expense, is not at all like a fairy tale. Cases of the stolen ideas of others are permanent. Many researchers are extremely concerned to be the first to formulate ideas, leave others trailing behind them who did not manage to publish or to re-write history attributing to themselves the most important stages. That generates a climate of distrust and suspicion which makes life bitter and seriously hinders the progress of research. I know very many who refused to talk about this or that idea on which they are about to work before publishing them” (p. 44).
The approach of Carlo Rovelli is quite different. When he was a student in Italy in the 1970’s he was involved in the revolt against the injustices of this society before thinking, like a large part of his generation, that the revolution wasn’t yet on the agenda, he choose not to abdicate, not to renounce his dreams, but to invest his aspirations in the changes in science: “During my university studies at Bologna, my confusion and my conflict with the adult world joined with a common route of a great part of my generation (...) It was a time where one lived one’s dreams (...) With two of my friends, we wrote a book which talked of the Italian student rebellion at the end of the 70’s. But the dreams of revolution were rapidly smothered and order retaken from above. The world can’t be changed so easily. Mid-way through my university studies I found myself more lost than before with the bitter feeling that these dreams shared by half the planet were already evaporating (...) Join the rat race, make a career, get some money and grab some crumbs of power, all that seemed much too sad to me (...) Scientific research then came to my rescue – I saw within it a space for unlimited liberty, as well as an adventure as ancient as it was extraordinary (...) Also, at the moment when my dream of building a new world came up against hard reality, I fell in love with science (...) Science has been a compromise allowing me not to renounce my desire for change and adventure, to maintain my freedom of thought and to be who I am, while minimising the conflicts with the world around me that this implied. On the contrary, I was doing something that the world would appreciate” (pp. 2-6). According to Carlo Rovelli, the subversive spirit, the desire for change and science are thus constantly intermingled: “While I was writing my book with my friends on the student revolution (a book that the police did not like and got me the third degree in the police headquarters of Verona – ‘Tell us the names of your communist friends!’), I immersed myself more and more in the study of space and time” (p. 30): “Each step forward in my scientific understanding of the world is also a subversion. Scientific thought always has something subversive and revolutionary about it” (p. 138).
What particularly attracted Carlo Rovelli was the international and cosmopolitan dimension of the scientific “community”, sometimes showing the dream of a world association, disinterested and enriching itself through the discussion of differences. At the Imperial College, London, “I met for the first time the multi-coloured and international world of researchers of theoretical physics: youths in suit and ties mixing in the most natural way possible with researchers in bare feet and with long hair tied back with coloured bands; all the languages and physiognomies intersecting, and one could glean a type of joy of differences, in the sharing of the same respect for intelligence” (p. 34).
However, islands of paradise cannot exist in barbaric capitalism. If it reveals a profound aspiration for a really human world, united and solid, this vision is idealist, as Carlo Rovelli himself recognises in his book.
And thus to take knowledge and the truth further, he advocates open and frank debate and the healthy and disinterested confrontation of hypotheses:
- “I talk freely of my ideas which I want to spread without hiding anything, and I try to convince my students to do the same” (p. 45).
- “If there is limited scientific accuracy, polemic, even harsh polemic, it is an ingredient for the fertilisation and advancement of knowledge” (p. 128).
- “The basic rules of scientific research are simple: everyone has the right to speak. Einstein was an obscure patent office clerk when he produced his ideas which changed our vision of reality. Disagreements are welcome; they are the source of the dynamism of thought. But they are never settled by force, aggression, money, power or tradition. The sole way of prevailing is to argue, defend one’s idea in a dialogue and convince the others. Of course here I am not going to depict the concrete reality of scientific research in its human and social-economic complexity, but the ideal rules to which the practice must relate. These rules are ancient, we find them written with passion in the famous Seventh Letter of Plato, where the latter explains how to search for the truth: ‘But, after many efforts, when one by one you rub these factors against each other: names and definitions, visions and sensations, and when they are put to the test of benevolent controls and discussions which do not involve envy, the light of wisdom and intelligence immediately shines on everything, with all the intensity that human strength can bear’” (pp. 136-137)
The scientific method and capitalist society
“Galileo and Newton, Faraday and Maxwell, Heisenberg, Dirac and Einstein, to name only some of the most important examples, were nourished by philosophy and would never have accomplished the immense conceptual leaps that they made if they hadn’t also had a philosophical education.” Indeed! And Carlo Rovelli himself has an approach to science that is strongly “nourished with philosophy”. That’s why he doesn’t adopt a static vision in order to understand the world as it is (as in a snapshot) but, on the contrary, he adopts a vision in movement to understand the world in its becoming. The first approach sees things existing independently from each other, for themselves and forever; here lies one of the sources of mysticism. The second sees things in terms of contradictory relations and thus in their dynamic, their becoming, which opens the way to the dialectic.
Carlo Rovelli attempts to use this same method in order to also understand human society. In talking of his youth at the beginning of the book, his revolt against the injustices of this society, and calling himself “revolutionary”, he demonstrates that he doesn’t believe in an eternal capitalism: “My adolescence was more and more a period of revolt. I didn’t recognise myself in the values expressed around me (...) The world that I saw around me was very different from that which seemed to me just and good (...) We wanted to change the world, to make it better” (pp. 2 and 3). We do not share the concrete political positions that Carlo Rovelli then advances in his book. Moreover, on this level and as he himself affirms, he tends to go down the road, not of a rigorous scientific approach, but according to his “dreams” and “fantasies” (p. 146). But that alters nothing of the importance of his research and contributions. To use the scientific method in order to understand humanity and its social organisation is certainly a lot more difficult: all reflection on science, its history and method is thus for this reason also an extremely precious treasure. Here’s what astronomer, astrophysicist and militant of the Dutch Communist Left, Anton Pannekoek (1973-1960) had to say on the subject: “Natural science is correctly considered as the field in which human thought, through a continual series of triumphs, most powerfully develops its forms of logical conceptions... On the other hand, at the other extreme, a vast field of human actions and relationships are found in which the use of tools doesn’t play an immediate part and which acts at a far distance, like profoundly unknown and invisible phenomena. Here thought and action are determined by passion and impulses, by arbitrariness and improvisation, by tradition and belief; here no logical methodology leads to the certainty of knowledge (...) the contrast which appears here, between on the one side perfection and on the other side imperfection, signifies that man controls the forces of nature or will increasingly do so, but doesn’t yet control the forces of will and passion that exist within him. When he stops advancing, perhaps even regresses, it is at the level of an evident lack of control over his own ‘nature’ (Tilney). It is clear that this is the reason that society is still so far behind science. Potentially man has mastery over nature. But he still doesn’t possess a mastery over his own nature”. And this is not the only reason for the difficulty in understanding the human soul and society; what must be added is the permanent ideological pressure exerted in order to justify the status quo of the world such as it is. Capitalism has need of science for the development of its economy and thus to encourage it in a certain measure (in a “certain measure” only because scientific research doesn’t escape the spirit born out of competition and particular interests). But the advance of thought regarding man and his social life immediately and frontally comes into conflict with the interests of this system of exploitation, particularly since this system has become decadent and obsolete with the interests of humanity demanding its disappearance. Thus the science of man is always held in check by the dominant ideology which tends to impose its own blinkers on it. This is also why humanity has need of researchers and scientists like Carlo Rovelli because they furnish us with the arms of criticism and their works constitute part of the flames of the promethean fire. This work (as his previous one) takes its part in the development of an indispensable knowledge of the history of science and philosophy and thus allows us not only to spend some worthwhile “time” but also nourishes our revolutionary reflection and critique.
Ginette (July 2015)
 And if time doesn’t exist? Editions Dunod, 2012. We’ve already published an article on the preceding book of Carlo Rovelli, Anaximandre de Milet ou la naissance de la pensee scientifique . This article was published in RI 422 and is available on the French website. A discussion in English of the book and others appears on the English website under the title Reading notes on science and marxism. Carlo Rovelli has also published a new essay: Beyond the visible: The reality of the physical world and quantum gravity, according to Odile Jacob.
 Carlo Rovelli is the principal author, along with Lee Smolin, of the theory of loop quantum gravity. This theory proposes a unification of general relativity and quantum mechanics. Behind these names, as tough as they are for beginners, is hidden the most fundamental problem in science now: how to overcome the present incompatibility between the infinitely large and the infinitely small.
 Underlined by us.
 “Dreams”, as an artistic approach and a number of other aspects of the activities of human thought, are an integral part of the sources of inspiration of those who want to change the world. But they cannot be the point of departure and the point of arrival of revolutionary consciousness; they are and can only be integrated into and come into resonance with the scientific approach. That’s when dreams become possible.