"We shall never explain by means of particles, whatever these may be, the simple properties of matter... The materiality of the atom dissolves more and more under the eyes of the physicist. We have no reason, for instance, for representing the atom to ourselves as a solid, rather than as a liquid or gaseous."
French philosopher Henri Bergson wrote this in 1896, arguing against the popular but as yet unfounded physical theory of atoms. In hindsight, his view would appear vindicated by science. As German philosopher of physics Brigitte Falkenburg put it in 2007:
“The 20th century history of the particle concept is a story of disillusion ... It turned out that in the subatomic domain there are no particles in the classical sense. . . . [A] generalized concept of quantum particles is not tenable either. Particles are experimental phenomena rather than fundamental entities.”
Nevertheless, within a decade of Bergson’s publication of Matter and Memory, atomism was declared a scientific reality. New experimental phenomena like x-rays, radioactivity, electrons, and canal rays, altered the prevailing ideas of matter and energy in physics. The attempts to explain these phenomena coherently, which became Albert Einstein's means of entry onto the scene, would drastically alter the direction of physics in the 20th century, paving the way for an entirely new metaphysics of the universe.
In the same period, the relationship between philosophy and science also became deeply antagonistic, leading to a disciplinary split that has prevailed for a century, a professionalized bifurcation between increasingly specialized discourses.
Metaphysics, as the classical language between physics and philosophy, came to be abandoned on both sides. In philosophy of science, metaphysics was regarded as antithetical to properly empirical science. But much like atomism in physics, this line in the sand has turned out to be illusory.
Today, particle physics and cosmology operate at the very limits of the knowable, and limits is precisely what metaphysics is about—the implicit and explicit conditions that enframe the knowable.
As Martin Heidegger once put it, physics itself is not a possible object of a physical experiment, and similarly, limits cannot themselves be subject to testing. Herein lies the essential conundrum that haunts today's cosmological physics.
And as I discuss in my book, something began to go awry at the turn of the 20th century.
What was practically at stake for physics at the end of the 1800s was finding a way past its own limitations. The threshold for resolution under an optical light microscope had been reached and to render an atomic level of hypothetical matter constituents visible to the human eye would require at least one hundred times this level of magnification. (In this sense, their problem was analogous to today's attempts in physics at mathematical unification, such as string theory, that require for validation experimental machines far beyond what can be realistically built.)
When this leap was finally made, it was not directly through technological advancement but rather due to a slow metaphysical revolution in physics and mathematics that had yielded a new logic called probabilistic reasoning.
If that sounds complicated for experimental proof, it’s only the simplified half of it. For what emerged as a physical particle, I argue, was and still is a distinctly two-faced construction. Today, despite the great magnifying leap of electron microscopy into a probabilistic quantum universe, it still remains inadequate for imaging at an atomic level. For a century, atoms have been known and taught as the building blocks of the universe, but to this day, nobody has ever seen an atom in any empirical sense. How could this be?
In brief, the 20th century particle concept is a strange metaphysical beast, mutually constituted by, on the one hand, the quantum—the limit condition of light phenomena—and on the other hand by the atom—the limit condition of matter. Both derive from the same probabilistic operation, and their independent reality status is implied by their mutual conceptual unity.
Since the 1950s, every time a new particle accelerator operates at new energy levels, new kinds of particle images occur. This is because a particle must exist for an experiment to work, and to show this particle, an experiment is necessary. This fundamental circularity has characterized the development of quantum physics from its inception, and it has been extended into the field of cosmology, which has become increasingly reliant on the theories and methods of particle physics.
The crux of the invention of the particle is that it allowed physicists an entirely new range of operation, new modes of action, new forms of research.
In Matter and Memory, Bergson had postulated as axiomatic that “all division of matter into independent bodies with absolutely determined outlines is an artificial division.” But despite his popular attempts at dialogue between philosophy and physics, Bergson's view was soon cast aside on both sides of the emerging divide.
In physics, any attempted distinction between real and artificial would soon become hopelessly futile. In philosophy, the key modern distinction between ontology and epistemology, being and knowing, would in turn become incapable of making sense of the development of physics.
Is the electron (or the atom, or the light quantum) ontologically real or an epistemological construct? While this question can be fodder for endless academic debates, the problem is fundamentally misconstrued.
The modern particle concept is neither epistemological or ontological, it is theoretically and experimentally operational.
The particle is the condition of possibility for physicists to act upon and into matter in such a way as to extend their research beyond the limit of optical instruments.
As Falkenburg describes it, “the only decisive proof of particles is apparently to make them and to use them as tools in other experiments.” Even as the technological means of extension fail to reveal their certain existence, and in fact ultimately point to the opposite conclusion, particles remain a necessary condition for research, and therefore physicists must act as if they exist.
In this sense, I argue particles should be understood as metaphysical inventions rather than ontological beings or epistemological constructs. Bergson would likely have agreed.
However, Bergson never foresaw the drastic turn of physics happening during his own rise to fame. In 1922, Bergson and Einstein met for a public debate. Both of them were intellectual celebrities in their own right and both belonged to a last generation of metaphysicians, trained to conceive of their work in the vein of seventeenth-century natural philosophy.
As science historian Jimena Canales recounts, the theme of the debate was the meaning of time and relativity, but a deeper and more controversial subtext soon surfaced:
Who can most authoritatively determine metaphysical questions—physicists or philosophers?
During the debate, Bergson argued that philosophy still played a crucial role in understanding the nature of time. But Einstein was not willing to cede ground and posited a full metaphysical reversal. Bergson had claimed in Matter and Memory that the abstract physical conception of time failed to account for its durational reality. Now Einstein countered that the absolute reality of physical time is in fact different from what he called the “time of philosophers,” which is “nothing more than mental constructs, logical entities.” Mathematical physics, Einstein argued, actually has the firmer grasp on reality, while it is philosophers who deal with artificial conceptual constructs.
In effect, Einstein declared metaphysical independence from physics. And the widespread view in aftermath was that Einstein had won the debate because Bergson failed to recognize the independent reality of physical time.
As Gilles Deleuze would later put it, Bergson’s intervention “led to so much misunderstanding because it was thought that Bergson was seeking to refute or correct Einstein, while in fact he wanted . . . to give the theory of relativity the metaphysics it lacked.” Bergson always pleaded for a complementary role for philosophy, but his modest proposal was squarely rebuffed.
The encounter between Bergson and Einstein marks not only the waning of Bergson’s influence in his own time but, more profoundly, the historical passing of philosophy into increasing irrelevance in matters of science, and its loss of influence over metaphysics.
New philosophical currents, most notably phenomenology, arose with the aim of recovering some sense of the lost “life-world” toward which Bergson had gestured. In turn, they faced ever starker opposition from the positivist movements that sought to abolish metaphysics from philosophy of science altogether.
By the time a young Martin Heidegger waded into the bitterly fraught scene in Europe, the vicissitudes of Bergsonism had revealed the incipient resentment of modern mass popularity by mercilessly turning the French philosopher from cause célèbre to cliché. As Whitehead once remarked, “a system of philosophy is never refuted; it is only abandoned”—and Bergson’s fate during the world war decades illustrates it all too well.
Heidegger, who easily dismissed Bergson as irrelevant to his own philosophy, would write more on the development of physics than most continental philosophers, but he would always speak from the other side of a widening chasm. Thus the German philosopher could bemoan technological advances and its metaphysical implications, but he could never address his criticism in terms that scientists could understand.
And so he too could be dismissed as irrelevant by the real practitioners of metaphysics in the twentieth century: theoretical physicists and cosmologists.
The physics that emerged in the wake of Einstein became an independent force, unshackled not only from philosophy but also from its own metaphysical foundations.
It reached into the future as it disengaged with its past, forging a new macro-cosmology from inventions in micro-physics. In the new metaphysical order, physics would venture far beyond the limits of the given, make discontinuity its new metaphysical foundation, and discontinue its own metaphysical tradition.
It is against this historical backdrop we must understand the emergence of Big Bang theory as the current cosmological paradigm.
This is an edited excerpt from Chapter 3 of Metaphysical Experiments. For references and footnotes, please see the book's notes and bibliography.