Detail from Starry Night (1893) by Edvard Munch. Courtesy the Getty Centre, Los Angeles
The ancient philosophy of monism and the physics of quantum entanglement agree: all that exists is one unified whole
‘From all things One and from One all things,’ wrote the Greek philosopher Heraclitus some 2,500 years ago. He was describing monism, the ancient idea that all is one – that, fundamentally, everything we see or experience is an aspect of one unified whole. Heraclitus wasn’t the first, nor the last, to advocate the idea. The ancient Egyptians believed in an all-encompassing but elusive unity symbolised by the goddess Isis, often portrayed with a veil and worshipped as ‘all that has been and is and shall be’ and the ‘mother and father of all things’.
This worldview also follows in straightforward fashion from the findings of quantum mechanics (QM), the uncanny physics of subatomic particles that departs from the classical physics of Isaac Newton and experience in the everyday world. QM, which holds that all matter and energy exist as interchangeable waves and particles, has delivered computers, smartphones, nuclear energy, laser scanners and arguably the best-confirmed theory in the entirety of science. We need the mathematics underlying QM to make sense of matter, space and time. Two processes of quantum physics lead directly to the notion of an interconnected universe and a monistic foundation to nature overall: ‘entanglement’, nature’s way of integrating parts into a whole, and the topic of the 2022 Nobel Prize in Physics; and ‘decoherence’, caused by the loss of quantum information, and the reason why we experience so little quantum weirdness in our daily lives.
Yet, despite the throughline in philosophy and physics, the majority of Western thinkers and scientists have long rejected the idea that reality is literally unified, or nature and the Universe a system of one. From judges in the Inquisition (1184-1834) to quantum physicists today, the thought that a single system underlies everything has been too odd to believe. In fact, though philosophers have been proposing monism for thousands of years, and QM is, after all, an experimental science, Western culture has regularly lashed out against the concept and punished those promoting the idea.
t wasn’t always that way. In ancient times, the concept of monism held more weight in the popular mind. Philosophers in the school of Pythagoras (c570-490 BCE), renowned for his alleged discovery of the geometrical relation among the three sides of a right triangle, identified the number one as the centre of the Universe. Heraclitus’ contemporary Parmenides (c520-460 BCE) believed in reality as a timeless ‘one, that is and that is not not to be’. And Plato, arguably the most influential philosopher ever, is said to have taught monism as a secret doctrine at his academy, to be disseminated only orally. Indeed, monism later evolved into a trademark of his school, and Neoplatonists such as Plotinus (c205-270 CE) wrote about ‘the one’ that is ‘all things’ and ‘being’s generator’. Around the same time, mystery cults popular in late antiquity advocated a hidden unity behind the many gods of the Greco-Roman polytheistic pantheon, and understood the different deities as representations of the various facets of a single, unified reality.
Later on, philosophical ideas derived from Plato’s monistic instincts competed with Christianity to become the dominant worldview of the Roman Empire. Christianity prevailed.
Even then, Christianity adopted Platonic ideas by identifying the monistic ‘One’ with God. But Christianity drew also on dualistic philosophies such as Manichaeism, which advocated a world caught in an epic struggle between good and evil. This is how concepts such as God and devil, heaven and hell, or angels and demons received their prominent role among Christian beliefs. At the same time, the monistic influences were pushed into an otherworldly beyond. The Christian God was understood as different from the natural world that he governs from outside.
A student who claimed that ‘God, the world, and nature, are but one thing’ was hanged for blasphemy
With the Christian Church rising to political power and the fall of the Roman Empire, much of antiquity’s culture and philosophy got lost, and monism got suppressed as a heresy. If ‘all is One’, God gets conflated with the world, and medieval theology understood that as atheism or a devaluation of God.
When in 855 John Scotus Eriugena, a medieval philosopher at the court of the Frankish emperor Charles the Bald, described God as an ‘indivisible unity’ holding together ‘all things’, he got condemned and his books forbidden. Sure, these monistic ideas inspired philosophers, but theologians saw them as an intrusion into the realm of religion. By the 13th century, a group of scholars in Paris had resorted to the stance that there exists a double truth: that what is right in natural philosophy may be wrong at the same time in theology, and vice versa.
These conflicts framed the relationship between religion and the developing sciences. After Nicolaus Copernicus advocated a heliocentric model of the planetary system in 1543, proposing that Earth and planets revolved around the Sun, instead of the Universe around Earth, his book was suspended by the Inquisition in 1616; for more than 200 years, it was allowed to be published only in editions that stressed it presented just a mathematical model but no statement about reality. That same year, Galileo Galilei was warned by the cardinal Robert Bellarmine, an inquisitor and one of the judges who had condemned Giordano Bruno to be burnt at the stake, to teach the heliocentric model not as truth but only as a hypothesis.
In 1600, Bruno, an early advocate of the Copernican model, was burned alive in Rome. Among his heresies was his monistic philosophy, affirming that ‘the whole is one’ and that ‘Nature … is none other than God in things’. In 1619, Lucilio Vanini, who had preached a religion of nature where a leaf of grass was proof of God, got his tongue cut out and was strangled at the stake, his body burned in Toulouse. And in 1697, Thomas Aikenhead, a student who claimed that ‘God, the world, and nature, are but one thing’, was hanged for blasphemy in Edinburgh.
Science in those early days often emerged as a sort of ‘soft monism’. Johannes Kepler, who discovered that Earth and the other planets revolve around the Sun in elliptical orbits, tried to understand nature in terms of harmonies and symmetries. Bruno’s influence and the ideas of monism directly inspired his efforts to develop a unified theory and find harmonic, beautiful patterns in the natural world.
The monist influence was even more apparent in the work of Newton, best known for his theory of gravity. One of Newton’s most important accomplishments was the insight that gravity acts universally on all bodies on Earth and elsewhere in the Universe. He explicitly compared this feature with the idea of an all-encompassing divinity that he adopted from the Cambridge Platonist Ralph Cudworth. ‘One and the same divinity [exercises] its powers in all bodies whatsoever,’ Newton wrote.
Michael Faraday, who proposed force fields were permeating the Universe, made significant steps toward the unification of electricity and magnetism – a monistic point of view, indeed.
Albert Einstein, who gave us such concepts as the curved universe and space-time, believed that the separation of humans from the rest of the Universe was essentially an optical delusion of consciousness.
Monism has resurfaced again and again by inspiring humanity’s greatest creations and creators across the arts. Mozart’s opera The Magic Flute (1791) included a eulogy of Isis. Beethoven kept the quote ‘I am all that is, that has been and will be, and no mortal has ever lifted my veil,’ attributed to Isis, in a frame on his desk. The Romantic poets from Goethe to Coleridge to Wordsworth describe the longing for a reconciliation of ego and the world within nature.
Despite all this, the hard line of the Church stuck: monism could influence science and inspire our greatest art, but the idea that it quite literally described nature was rejected by the overwhelming majority through the years. To the present day, we tend to believe that monism and nature, or monism and science, don’t belong together; that the hypothesis of ‘all is One’ simply isn’t proper science at all.
If anything should convince us to change our mind, it is the experimental science of quantum mechanics and its underlying mathematics. One famous feature of QM is that there is no strict separation between particles and waves. What had been considered as a particle before, for example an electron, can sometimes behave as a wave, while waves (such as, for example, light) can absorb and emit energy in discrete portions, understood as particle-like quanta. In contrast to a particle though, a wave doesn’t exist in a specific place. It stretches out over the surface of a pond or the expanse of the Universe; it is ‘non-local’, in physics lingo. A quantum object described as a wave exists in several places simultaneously – until it gets measured. In that instant, the object seems to collapse into one of its potential locations.
This leads to the weirdest aspect of QM – entanglement, a property of quantum systems made up of two or more particles. According to the quantum pioneer Erwin Schrödinger writing in 1935, entanglement is ‘the characteristic trait of quantum mechanics, the one that enforces its entire departure from classical lines of thought’.
Consider observing a wave pattern on your pond that you know results from two ripples combined, such as two stones dropped into the water. Just by looking at the water surface, you won’t be able to tell what these individual ripples were to start. For instance, the pattern could have arisen from two stones causing two equal swells in the water, or from a small stone causing a third of the swell and a larger stone creating two-thirds.
Taking this logic at face value, nothing we see really exists; there are no particles or physicists or cats or dogs
The same is true for entangled quantum systems: you may know the complete system perfectly well but at the same time know nothing about its constituents until we pin them down by experiment, measuring them. In such an experiment, the very act of measurement would destroy the original whole.
It was Schrödinger who clearly summarised what entanglement means:
The best possible knowledge of a whole does not necessarily include the best possible knowledge of all its parts, …
When two systems … enter into temporary physical interaction … and when after a time of mutual influence the systems separate again, then they can no longer be described in the same way as before.
Entanglement is QM’s way of integrating parts into a whole and, when you apply entanglement to the entire Universe, you end up with Heraclitus’ tenet ‘From all things One’. Taking this logic at face value, nothing we see around us really exists; there are no particles or physicists or cats or dogs. The only thing that truly exists is the Universe as a whole.[…]
Continue reading: Monist philosophy and quantum physics agree that all is One | Aeon Essays
is professor of theoretical physics at TU Dortmund University in Germany. He is the author of The Perfect Wave: With Neutrinos at the Boundary of Space and Time (2014) and The One: How an Ancient Idea Holds the Future of Physics(2023).