Einstein vs. Bergson

An Enduring Quarrel on Time

Alessandra Campo, Simone Gozzano, Alessandra Campo, Simone Gozzano

• Éditeur: De Gruyter
• Année: 2021
• ISBN:
  9783110753721
• Édition: 1
• Sujet: Philosophy
• Sous-sujet: Philosophers

This book brings together papers from a conference that took place in the city of L'Aquila, 4–6 April 2019, to commemorate the 10 th anniversary of the earthquake that struck on 6 April 2009. Philosophers and scientists from diverse fields of research debated the problem that, on 6 April 1922, divided Einstein and Bergson: the nature of time.

For Einstein, scientific time is the only time that matters and the only time we can rely on. Bergson, however, believes that scientific time is derived by abstraction, even in the sense of extraction, from a more fundamental time. The plurality of times envisaged by the theory of Relativity does not, for him, contradict the philosophical intuition of the existence of a single time. But how do things stand today? What can we say about the relationship between the quantitative and qualitative dimensions of time in the light of contemporary science? What do quantum mechanics, biology and neuroscience teach us about the nature of time?

The essays collected here take up the question that pitted Einstein against Bergson, science against philosophy, in an attempt to reverse the outcome of their monologue in two voices, with a multilogue in several voices.

Part One Some Preliminary Questions

Who Is Entitled to Talk about Time? Philosophers or Physicists?

Étienne Klein

Abstract

Speeches, theses, theories, systems claiming to have captured the nature of time proliferate. They sometimes complement each other, other times compete or contradict each other. Therefore, to whom should we give any credit? And according to what criteria? We are trying here to put philosophical systems and physical theories against each other.

1 Introduction

We have to be honest: we reflect on time without really knowing what it is we are thinking about: is time a substance? Is it a fluid? Is it an illusion? Or a social construct? There are many common sayings that suggest it is a physical being, while others imply the opposite, for example that it is a product of our consciousness, or a simple word that we use to say this or that aspect of natural processes. Who can actually say, with any certainty at all, whether time accommodates events or is in fact created by them? And who can say that they know enough, with enough certainty, to explain what clocks are really telling us when we say they are telling the time? We all feel entitled to answer these questions, but we generally end up with a muddle: each of us knows at least one person saying that time stops when everything stops changing, another person saying that time still passes when nothing happens, and yet another saying that it only passes in our consciousness, whereas another one says that nowadays time truly accelerates, or even does not exist. The least we can say is that there is no harmony of viewpoints on time: telling it is never the same thing as talking about it, and still less as understanding it. So, fundamentally, what is time really like? Is it how we think we perceive or experience it? How it is represented by physicists? How it is thought of by philosophers?

Fig. 1: Le Théâtre de Chronos, Marie-Christine Rabier (image published with permission from the author).

A priori, it is to philosophers that we need to turn, since the question of time has been and continues to be one of their main preoccupations. Haven't many of them come up with clever, coherent systems for thinking about it more clearly? Indeed, they have (Aristotle, Saint Augustine, Leibniz, Kant, Husserl, Bergson, Heidegger, to name but a few). But nevertheless, anyone whose only resort on the subject of time his philosophy will come up against two problems. The first is a common problem due to the very essence of philosophy: it is the fact that not all philosophers agree with one another; in their discourse, time is sometimes the principle of change, sometimes it is a static arena filled with what has already happened waiting for what is going to happen; sometimes it is seen as a purely physical being or, alternatively, as an invention of the imagination or a product of certain cultures, or even as an illusion. So there are choices to be made. But on the basis of what criteria? The elegance of the proposed system? Its appeal? Its rigour? Its plausibility? Who came up with this system? The second difficulty, which is related to the first one, is the fact that philosophy itself is divided on the question of time, in the sense that it places the different doctrines in two very distinct categories.

In one category (Aristotle, Leibniz, Russell, Carnap etc.), time has to be thought of as a simple order of anteriority or posteriority, with no reference to the present moment or to the consciousness of any observer, or even to the mere presence of an observer: the only thing that exists, in this category, is temporal relationships between events; time therefore appears to be an order of succession in which sequences of events are objective, definitive and independent of us. For instance, if one says ‘Newton was born before Einstein’, this sentence is true now and will remain to be true at any other moment. What I mean is that its truth does not depend on the moment when it is said. In the other category (Augustine, Kant, Bergson, Husserl, Heidegger), time is a passage: the passage of a particular moment, the transit of the present to the past and the future to the present. Because this movement can only be described if there is a subject present to perceive it, time appears to be not just a chronological order, but an endless dynamic motion, the driver of which is linked to subjectivity. In this case, the truth of a sentence will depend on the moment where it is said. For instance, if one says ‘the weather is beautiful’, it is true now but can become false tomorrow. Now, the question is: towards which of these two schools of thought should rational thought lean?

It's difficult to say, because each one leads to conceptual difficulties. If we argue that time does not exist in itself without a subject to perceive it, then we are confronted with well documented fact, which poses a serious difficulty for this idea: in the 20th century, scientists established that the universe is at least 13.7 billion years old and that humans only appeared a mere 3 million years ago. What do these figures tell us? That during much of the what the universe has experienced or undergone, humanity, a very young species, has not been present. That most of the universe's time has clearly been spent without us. Consequently, if we argue that time is dependent on there being a subject and could not exist without one, a quasi-logical problem arises: how did time pass before we came on the scene? Many authors¹ have pointed out this paradox that is called the paradox of ancestrality: saying that time exists only within the subject or that time only has subjective reality surely makes it difficult to explain the appearance of the subject within time. If, on the contrary, we take the view that time exists and passes autonomously, independent of us, then we still need to identify and characterise what drives time, i. e., the imperceptible mechanism that makes one present moment appear and another present moment appear immediately after it, pushing it out and taking its place, before yet another present moment pushes that one into the past, taking its place in the present, and so on.

Theoretical physicists are striving to find the source of this hidden dynamic, especially at the frontiers of Quantum physics (which describes nuclear and electromagnetic forces) and the theory of General Relativity (which describes gravitation), but they have not yet properly identified it². Thus, to conclude this first part, we can say that if we decide that time depends on a subject, we face a peculiar problem, and if we decide that it does not, we face a knotty problem…

2 Questions Raised by Representing Time by a Line

These impasses refer back to a question raised by Henri Bergson in Duration and Simultaneity: How can something which is successive, he wondered, be engendered by points that are present altogether, that are juxtaposed? By what mechanism do points on a straight line through space manage dynamically to become temporal? The physicist Lee Smolin recently drew attention to this puzzle, which he sees as a major conceptual difficulty blocking the progress of theoretical physics:

A motion through space […] becomes a curve on the graph […]. In this way, time is represented as if it were another dimension of space. Motion is frozen, […]. We have to find a way to unfreeze time – to represent time without turning it into space (Smolin 2008, 257).

He is right: without even realizing it, by representing time as a line of points resembling those in space, we change, we transpose its very nature (or perhaps even, we contradict it?): ‘From the moment when you attribute the least homogeneity to duration – commented Henri Bergson – you surreptitiously introduce space’ (Bergson 1910, 104). Hence, drawing the time axis as a line with an arrow becomes an almost monstrous act: by doing this we make successive moments, which by definition cannot all be present at the same time, coexist spatially, i. e., exist together in the same present moment. Essentially, we represent moments in time in the same way as if they were points in space, which changes or indeed goes against their specific nature. In his Critique of Pure Reason, Immanuel Kant had already identified this incongruity:

We represent the succession of time by a line progressing to infinity, in which the manifold constitutes a series of only one dimension; and from the properties of this line we infer all the properties of time, with this one exception, that while the parts of the line are simultaneous, those of time are always successive (Kant 2007, 69).

The habit we have of drawing time in this way masks a massive problem: when a moment is present, where are the other moments, for example those in the future? Have they existed elsewhere since the dawn of time, merely waiting to become the present for a moment, at the moment when time moves on to them? Or are they still part of nothingness, outside of reality, and they only become fleetingly real at the moment when they are present?

3 Time and Language

Stopped in our tracks by these genuinely terrifying questions, we could take some intellectual comfort from reflecting on the fact that time is only a word, a name, the meaning of which could be found by some accurate analysis. Hence, it would be possible to conduct quasi-scientific research into what it actually means: the meaning of this word is essentially nothing more than the ways in which we use it. Therefore, we just have to ask what our sentences are attempting, somehow or other, to convey. But if we advance this hypothesis, we quickly become aware of the existence of another serious paradox: as soon as it is isolated from the words surrounding it, removed from the verbal flow in which we placed it, the word ‘time’ becomes an unfathomable mystery: is time a particular substance? Does it exist by itself? Does it depend on events? After all, it seems that when we talk about time, ‘we understand each other, and ourselves, only thanks to our rapid passage over words’ (Valéry 1954, 214). ‘Time’ may be one of our most commonly used words, but in no sense does it shed light on the reality it purports to name. Telling time, verbalising it, does not mean referring to it as itself, however clever our turns of phrase may be.

The way we think about time is also heavily dependent upon the way our existence relates to it. The temporal phenomena that we are subject to or witnesses to make us believe time looks like them or sums them up. We assign to time as many different descriptors as there are different experiences of time: so we talk about time being ‘empty’ on the basis that nothing is happening...