From the perspective of the twenty-first century it may seem strange to devote an entire book to the central figures discussed here. The physicist, Albert Einstein, quite rightly remains a cultural icon, renowned the world over for his revolutionary work in physics. The philosopher, on the other hand, Henry Bergson, is unlikely to be familiar to many of the general readers for which this book is written. This was not, of course, always the case, as is evidenced by the fact that both men were Nobel Prize Laureates, albeit in very different fields; Einstein received the Prize for physics in 1922 and Bergson for literature in 1927. In this book Jimena Canales successfully analysis just how important and influential both figures were in the first half of the twentieth-century as well as why Bergson’s fame subsequently dwindled whereas Einstein’s remained solid. However, the book also shows why, regardless of his current status, many of Bergson’s views are still just as important as those of Einstein.
The ‘debate that changed our understanding of time’, and the context in which it arose, is largely set out in Part One of the book and began at a meeting that occurred in Paris on 6th April 1922. It was hosted by the Société Française de Philosophie and Einstein had travelled from Germany especially for the event. In the audience were both physicists and philosophers who had been invited to hear Einstein speak about his general theory of relativity. The meeting was as much politically as intellectually motivated, for at that time there was great tension between France and Germany. He was thus invited to France ‘with the express purpose that his visit would serve to restore relations between German and French scholars’ (17). In many respects, as the book shows, this intended purpose was not achieved. The meeting took place only three years after Arthur Eddington had sailed to the island of Principe to measure the position of stars during a total solar eclipse, the result of which lent great weight to the truth of Einstein’s theory and made him a legend overnight. All facets of the theory were discussed but one particular aspect, its concept of time, was to cause great controversy and it is the ensuing debate on this topic that forms the core of this book.
In the audience that day was the famous French philosopher, Henry Bergson, who did not actually intend to speak. Like many other intellectuals of the day he fully understood the revolutionary nature of the scientific aspects of the theory of relativity and was astounded by the experimental results that lent it such strong support. However, Bergson did have a problem with Einstein’s conception of time, one that he considered was narrowly concerned with clocks and measurements. He thought that this conception was unnecessary for the science and was rather a dangerous ‘metaphysics’. When Einstein proclaimed that ‘there remains only a psychological time that differs from the physicist’s’ and ‘the time of the philosophers does not exist’ Bergson could remain silent no longer (5). Much of the remainder of the meeting centred upon this aspect of Einstein’s theory and whether ‘the time of the philosophers’ really does exist.
For Bergson this dualism regarding time was an inadequate description of reality, for although there was the time measured by clocks, and the time as experienced, these could not be separated as easily as Einstein proclaimed. As Canales notes, ‘Bergson’s perspective on time measurement could not be more different from Einstein’s. The philosopher was convinced about the importance of the unquantifiable aspects of time, whereas the physicist was equally convinced of the opposite’ (252). Bergson developed this view in his book Duration and Simultaneity published later that year.
In terms of the debate, most physics thought Einstein had won and that ‘rationality’ had triumphed over ‘intuition’. However, many others took Bergson’s view much more seriously as evidenced by what occurred at Einstein’s Nobel Prize ceremony, which occurred later that same year. Although it was by far the greater achievement, Einstein was not actually presented with the Prize for his work on relativity but rather for that on the photoelectric effect. One of the reasons given for this was that relativity ‘pertains essentially to epistemology and has therefore been the subject of lively debate in philosophical circles. It will be no secret that the famous philosopher Bergson in Paris has challenged this theory.’ So Einstein failed to secure the prize on the merits of his work on relativity not because of any scientific shortfall but because of the alleged ‘metaphysics’ coupled to it. Subsequently, however, Bergson’s view was discredited by most scientists because of what appeared to be a total lack of understanding of relativity. Bergson claimed that the central message of his book Duration and Simultaneity was to ‘explicitly prove that there is no difference, in what concerns Time, between a system in motion and a system in uniform translation’ (25). This is fundamentally at odds with the theory of relativity and can be empirically proven to be false. Bergson did, however, subsequently state that he did accept the effects of time dilation but claimed that this had no effect on his conception of time.
In Part Two of the book Canales takes us beyond the actual meeting that occurred in Paris and introduces us to the lives and ideas of many of the significant scientists and philosophers of the age who became embroiled in the debate. Amongst them are Paul Langevin, Henri Poincaré, Hendrik Lortentz, Albert Michelson, Ernst Cassirer, Martin Heidegger, Hans Reichenbach, Rudolph Carnap, Jean Becquerel, Arthur Eddington and Bertrand Russell. Some of these supported Bergson whilst others Einstein and in a few cases neither. For each of these Canales provides biographical information, explains how they were associated with Einstein and Bergson, and how their views influenced the debate concerning the nature of time. The sheer number of figures that are introduced is testament to how important this debate became as well as to the breadth of this study. In addition Canales examines how the Catholic Church as an institution reacted to this debate as well how Einstein and Bergson dealt with the emergence of the new science of quantum mechanics, many proponents of which felt that it somewhat rescued Bergson’s conception of time.
Part Three ‘focuses on the debate by taking us beyond the men, asking instead what drove them to fall into such a stark impasse in the first place’ (242). Canales takes us on a journey through the development of technologies that occurred during the twentieth-century and explores the effect these ‘things’ had on the two conceptions of time, noting ‘what do we find when we look even more carefully behind the scenes of the debate? We stumble upon certain things that drove ‘adversaries’ into absolutely opposite positions’ (241). The ‘things’ that she considers include clocks, the telegraph, the telephone and radio communications, cinematographic cameras and film, atoms and molecules. In each case she explains at length the effect they had on Einstein and Bergson and their theories of time. She claims that ‘Einstein and Bergson disagreed about the meaning, use, and importance of all of these things’ and ‘they played a central role in the twentieth-century divisions often associated with Bergson and Einstein’ (241).
In the final part, Canales examines the last comments that the physicist and the philosopher made about each other. We find that, whilst Bergson did not deny his genius, he considered Einstein to be a relentless self-promoter. Canales presents some fascinating comments Einstein made about himself, and also describes aspects of his behaviour which suggest that there was some truth in this. Bergson’s last thoughts on Einstein’s conception of time, in his book La Pensée et le mouvant, show that he held firm to his own view when he writes ‘with regard to Time attached to Space, to a fourth dimension of Space-Time, it has no existence . . . other than on paper’ (335). Furthermore, ‘the reality of [Einstein’s] Space-Time is purely mathematical, and one cannot transform it into a metaphysical reality, or into ‘reality’ tout court, without giving to this word a new meaning’ (335). Einstein, who outlived Bergson by over a decade, similarly held steadfast to his view of time up until the day he died. Writing to a friend shortly before he died he said ‘you cannot get used to the idea that subjective time with its own ‘now’ should not have any objective meaning. See Bergson!’ (338).
In this book Canales shows that the apparent difference between ‘the time of the universe’ discovered by Einstein, and ‘the time of our lives’ associated with Bergson, had a major impact on the views of subsequent scientists, humanists, and philosophers that is still felt to the present day. She cleverly demonstrates why this is the case whilst at the same time providing interesting biographical background of the main characters as well as presenting it in the context of the social and political upheavals that raged across the world during the first half of the twentieth-century. Her writing style and composition makes the book an enjoyable read and her clear exposition renders some difficult concepts in physics and philosophy easily accessible. The book will be of great interest to both the specialist and the general reader.