Materialism began as an imaginative vision about the nature of reality and the true natures and properties of things. While others speculated about the existence of gods, souls and spirits, and imagined the material world was ultimately composed of water, or fire or some combination of elements, the ancient and early modern materialist thinkers envisaged a world in which the phenomena we observe, and life itself, are produced by matter in motion in three-dimensional space, and nothing more. This vision, in the form of the mechanical philosophy, formed the intellectual foundation for the transformation of natural philosophy into natural science. The matter in question was thought of as tiny particles, like motes of dust that are too small to see. However, the idea that the motions of matter could be explained in terms of action by contact, that is, one piece of matter moving another by directly pushing it, did not suffice. As discussed in Chapter 3, Newton’s Principia of 1687, the founding theory of modern mathematical physics, posited a universal gravitational force acting between all bodies instantaneously at a distance (Newton, 2016). This seemed to many of his critics as mysterious as witchcraft, but, as Newton said in reply, that is not so because it has a precise mathematical form from which can be derived exact predictions. In due course his most diehard mechanist opponents succumbed to the empirical success of the laws of classical mechanics he formulated.
Materialism has always faced the challenge of explaining how matter in motion could give rise to ideas and sensations. However, it was not materialism’s failure to account for life or mind that caused its radical revision. Ironically, it was the success of the science it did so much to inspire that undermined materialism. Materialism was made obsolete by developments in the area that materialists most admire, and for which they believed they were providing philosophical foundations, namely physics. In the centuries following Newton the study of matter in physics transformed our concept of matter. Our best current accounts are incomplete but are far removed from our concept of everyday material objects. This chapter explains briefly why the materialism of the ancients and early modern philosophers is no longer plausible.
Newton’s great achievement was to unify the physics of the heavens and the physics of the world we see around us, but he certainly did not bequeath his successors a Theory of Everything. The idea of particles of matter subject to contact with other particles, and, subject to the laws of gravitation, was only going to get physics so far. Classical mechanics could be adapted to deal with fluids and continuous solids as well as rigid bodies like planets, but it was of next to no use in dealing with electricity, heat, light, magnetism and chemistry. Ontological issues were at the heart of science’s endeavours to give an account of these phenomena. Exotic forms of matter, or semi-material stuff, or specifically non-material stuff were posited throughout the seventeenth and eighteenth centuries to provide the required explanatory accounts. To mention two: phlogiston was postulated in the 1660s as a bizarre fire-like substance that is present in combustible bodies and that could help explain combustion. Caloric was postulated in the effort to explain heat and was envisaged as a fluid that flows from hotter bodies to colder ones. Both these theories were eventually abandoned, the former in the eighteenth century, when Lavoisier found his classification of the chemical elements, and the latter in the nineteenth century, and physics eventually came to Francis Bacon’s conclusion that heat is not a stuff but associated with the motions of matter.
The story of the historical development of the scientific account of the nature of light is much more complicated, and one in which materialism has an uncertain place. In the simplest terms, there was a contrast between wave theories and particle theories. Newton proposed a particle theory of light, but light has many properties that are better described in terms of waves, and if there is a wave, there is also medium that is vibrating. In the early nineteenth century the optical ether was introduced by Fresnel to support transverse waves of light. Meanwhile Faraday was unlocking the connection between electricity and magnetism and was the first to use the term field. Traditional materialism may not have much to say about waves, and is certainly challenged by the concept of the field that is somehow a medium but not quite material. When Maxwell introduced his electromagnetic field theory, the solid ether became something less substantial that obeys some very complicated equations and defies understanding in terms of ordinary matter. It permeates all of space and supports the wavelike propagation of light, and other waves, at a finite velocity. Magnetism is not understood as acting instantaneously at a distance, but at the same finite velocity as light and propagated by way of the field.
So traditional materialism can be seen to have mixed fortunes in the progress of science in the two centuries following Newton. Materialists had no single account of what kinds of substance make up the natural world. Nonetheless, the hope remained that all of physics and ultimately all of science could somehow be reduced to the behaviour of matter. Materialism had two great further successes. First, the kinetic theory of gases, according to which pressure, heat and temperature were the manifestations of atomic motions and collisions, led to substantial new mathematical physics and became the basis of our current understanding. Second, the triumph of atomism at the turn of the twentieth century turned it from a metaphysical theory into an experimental and practical science that unified chemistry and physics. Towards the end of the nineteenth century, many physicists believed they had come to the end of the road of discovery. The leading scientist Lord Kelvin is purported to have declared, around 1900, that ‘There is nothing new to be discovered in physics now. All that remains is more and more precise measurement’. At this point, around 200 years after Newton’s Principia, materialism, as an ontological theory, could stand quite confident in its foundational role for physics. It had been obliged to incorporate some new concepts, such as gravitation and field, but it did not feel as though these radically undermined materialism. There were still ‘atoms’, and there was no recognition of non-material substances in scientific theory.
It is also pertinent at this point to mention the success of materialism in another crucial science – biology. There is a tradition reaching back to ancient times that tries to account for the apparently profound difference between living and non-living things. Vitalism is the name given to the tradition that postulates something non-physical to be found in, and only in, living things. It had its adherents well into the twentieth century but has fallen out of mainstream biology completely now. This will be referred to again in the discussion of the formulation of one kind of contemporary physicalism in Chapter 6.
The statement attributed to Lord Kelvin was, of course, profoundly mistaken. Very soon the discovery of radioactivity and the rise of quantum theory soon led to the radical transformation of our understanding of the nature of the atoms themselves. Far from being the indivisible building blocks of antiquity, they turned out to be compound entities whose behaviour and properties were beyond visualisation. Matter in the sense of extended stuff that takes up space like the familiar solid objects we see around us is, according to physics, not ultimately solid at all but mostly empty space. Matter is composed of atoms that are in turn composed of a nucleus and orbiting electrons. If an atom were the size of a football pitch the nucleus would be the size of the centre spot and the orbiting electrons on the touchline much smaller than that. But much worse than that was to follow in the twentieth century. With the discovery of sub-atomic particles, materialism still could feel there was a way of hanging on – still little things at the heart of everything. In the next section it will be shown that contemporary conceptions of the very small are incompatible with traditional materialism in any form.
In summary, then – having been the major intellectual stimulus to the scientific revolution, materialism gained its major triumph and readily abandoned its own speculative theories about lightning, volcanoes and other natural phenomena, safe in the belief that it had become the foundational philosophy of science, in both its ontological and epistemological aspects. But it didn’t quite work out like that.
While materialist epistemology is the scientific method, developed and honed over the centuries, the application of that method of investigation has discovered a world of the very small of extraordinary complexity and strangeness, and thereby has condemned ontological materialism as a positive theory of what exists to the catalogue of false theories.
At its simplest, classical materialism imagined reality as a three-dimensional space, perhaps finite, perhaps infinite. Movement in time was an aspect of this reality, more or less imperfectly understood. Within the space were indivisible atoms, of varying kinds, and the void. All observable phenomena were ultimately composed of atoms.
Physics does not have a generally accepted theory of reality to contradict this, but there are general trends in twentieth-century physics that strongly suggest classical materialism doesn’t really stand a chance. Rovelli (2014) offers an outline of current perspectives in physics that demonstrate this claim.
As mentioned above, advances in the nineteenth century introduced into physics the crucial concept of the field. There was, then, a need for something more than atoms and the void in order to provide a satisfactory description of reality. The electromagnetic field occupied space and could be described mathematically. Einstein took the concept of a field a vital step further. Recalling the struggle with the nature of gravitation discussed in Chapter 3 above, Einstein solved this problem not by identifying a gravitational field existing in space in the same manner as the electromagnetic field. He identified the gravitational field as space itself. Space is not a void with things existing in it. Space is not a void at all. Space is an entity that ‘undulates, flexes, curves, twists’ (Rovelli, 2014, p. 6). Space curves where there is matter. From these insights
… the magical richness of the theory opens up into a phantasmagorical succession of predictions that resemble the delirious ravings of a madman, but which have all turned out to be true.
(p. 7)
Rovelli here is referring to, amongst other things, the fact that light doesn’t move in straight lines but, rather, deviates; that time ‘curves’ as well – ‘if a man who has lived at sea level meets up with his twin who has lived in the mountains, he will find that his twin is slightly older than him’; that when a large star burns up all its hydrogen it collapses in on itself and ‘plummets into an actual hole … the famous “black holes”’; that space is expanding, and that there was a beginning of the universe in which everything, including space and time, were compressed into an unimaginably small volume – the Big Bang.
Rovelli turns from the very large to the very small. He also moves from the extraordinary world of Einstein’s General Theory of Relativity to the seemingly incomprehensible world of quantum mechanics. Another famous physicist remarked that if you are not baffled by quantum mechanics then you haven’t understood what it is saying. From this it follows that the notion of clarification around this area of physics is itself compromised. But what is clear is that there is no comfort for the traditional materialist. This is because in quantum mechanics the very core ontological notion of objective existence is withheld from elementary particles.
Rovelli introduces a patchwork of ideas; Einstein showed light is made up of particles of light – photons. Einstein himself then struggles with the new path taken by the new theory. Neils Bohr
understood that the energy of electrons in atoms can only take certain values, like the energy of light, and crucially that electrons can only ‘jump’ between one atomic orbit and another with fixed energies, emitting or absorbing a photon when they jump.
(p. 14)
Equations were established in 1925 from which a conclusive explanation of the structure of the periodic table of elements could be derived – ‘the whole of chemistry emerges from a single equation’ (p.15). And then Rovelli introduces Werner Heisenberg:
Heisenberg imagined that electrons do not always exist. They only exist when someone or something watches them, or better, when they are interacting with someone else. They materialize in a place, with a calculable probability, when colliding with something else. The ‘quantum leaps’ from one orbit to another are the only means they have of being ‘real’: an electron is a set of jumps from one interaction to another. When nothing disturbs it, it is not in any precise place. It is not in a ‘place’ at all.
(p. 15)
Rovelli’s chapter on particles may at first sight seem to bring some hope for traditional materialism. But in fact it is more like a further nail in the coffin of the cherished philosophical theory, qua ontological theory of what exists.
Light is made of photons; things are made of atoms; an atom consists of a nucleus surrounded by electrons; the nucleus consists of protons and neutrons; these latter are made up of quarks; the force that ‘glues’ quarks inside protons and neutrons is generated by particles that physicists, with a pleasing sense of the ridiculous, call ‘gluons’:
Electrons, quarks, photons and gluons are the components of everything that sways in the space around us. They are the ‘elementary particles’ studied in particle physics. To these particles a few others are added, such as the neutrinos which swarm throughout the universe but which have little interaction with us, and the ‘Higgs bosons’ recently detected in Geneva in CERN’s Large Hadron Collider. But there are not many of these, fewer than ten types in fact. A handful of elementary ingredients that act like bricks in a gigantic Lego set, and with which the entire material reality surrounding us is constructed.
(pp. 29–30)
From the standpoint of traditional materialism, so far, so good – seemingly a more sophisticated, more filled-out version of the original story. But these are not particles as intuitively understood, not very much at all like Lego bricks:
The nature of these particles, and the way they move, is described by quantum mechanics. These particles do not have a pebble-like reality but are rather the ‘quanta’ of corresponding fields, just as photons are the ‘quanta’ of the electromagnetic field. They are elementary excitations of a moving substratum similar to the field of Faraday and Maxwell. Minuscule moving wavelets. They disappear and reappear according to the strange laws of quantum mechanics, where everything that exists is never stable, and is nothing but a jump from one interaction to another.
(p. 30)
Evidently, the particles of contemporary physics are of a qualitatively different kind from the particles – the atoms – of traditional philosophical materialism.
Atoms in the void? Forget it. Materialism, as encountered so far in this story, has been left far behind not only by the extraordinary complexity of modern physics, but also by its theoretical and mathematical sophistication. In the space of 300 years, there has been an exponential growth in scientific and technological understanding, in the course of which reality has revealed itself to be more bizarre than could possibly have been imagined.
Physics now rests on two pillars, Quantum Theory and the General Theory of Relativity. These are extraordinary achievements of the scientific enterprise, with vast explanatory power and with startling degrees of confirmatory verification. The problem is that it is not known how to combine them, or even if they can be combined. A large proportion of theoretical physics in the early years of the twenty-first century was devoted to the project of finding a consistent unified theory that incorporated the essence of both great theories.
In general terms, classical materialism was, inevitably, couched in the language and concepts of everyday life. The advances in physics in the last 150 years have exposed the ultimate inadequacy of everyday concepts to convey the discovered world of the very small and the very large. The complexities and intricacies of processes at the large and small scale cannot be accurately described with concepts of ordinary language. And this perhaps is not surprising, given that it is a language that has evolved, after all, in the context of human beings striving to live in the world of medium-sized physical objects. Our scientific image of the world is one from which mathematical representation is ineliminable. This applies to all the sciences, not just to physics.
If there is one clear lesson from the history of physics, it might be this – take nothing for granted. At this point in time physics lacks a unified theory of reality, but suppose it found one – would it then be in a position to answer the ontological question?
Physics would have an answer, but it could only claim to be the answer if the theory were shown to be, in some important sense, the final theory. This is because the history of science is a story of one conception of the world holding sway until another theory, superior in some way or other, takes its place. Unless a point is reached in the future when science can argue convincingly that it has found the Theory of Everything, any answer science gives to the ontological question will be provisional – ‘in our present conception of reality, or according to our best theories so far, so and so exists’.
This chapter recounts a sobering story for traditional materialism. However, all is not lost. If it has been necessary to lay to rest the theory, qua ontological theory of what exists – as was stated above – the implied negative claim of the theory, about what doesn’t exist, survives. What theoretical physics has not brought into the picture is anything answering to the description of the spiritual or the divine. The next chapter turns to the responses of philosophers in the materialist tradition to these developments in physics.