The One: How an Ancient Idea Holds the Future of Physics

by Heinrich Päs

“the ‘many worlds’ idea again is a left-over of classical conceptions,” in obvious contradiction of Everett’s original intent, as Lévy-Leblond finds. “To me, the deep meaning of Everett’s ideas is not the coexistence of many worlds, but on the contrary, the existence of a single quantum

“The physical ‘reality’ is assumed to be the wave function of the whole universe itself”72—and what he had explained in his long thesis: “It is meaningless to ask about the absolute state of a subsystem—one can only ask the state relative to a given state of the remainder of the system.”

fundamental reality isn’t only a single universe but a single unique entity comprising matter, space, and time as well as all potentially possible events and situations.

Decoherence acts as the agent protecting our daily-life experience from too much quantum weirdness, resolving the conundrum of how classical experience emerges in a quantum measurement. Whenever a quantum system is measured or coupled with its environment, entanglement causes the quantum system, the observer, and the rest of the universe to become interwoven with each other. Consequently, from the perspective of the local observer, who can’t oversee the entire universe, information is dispersed into her unknown environment.

Among the most striking consequences of decoherence is that matter, understood as solid stuff made out of particles, may turn out to be an illusion.

The basic idea behind this notion is that matter—or, more specifically, particles—is not fundamental; it is “emergent,” as philosophers describe the nature of concepts that are useful for practical purposes but do not exist on a closer look, such as, for example, “temperature,” which boils down to the average energy of atoms or molecules from a microscopic perspective.

Particles’ appear localised in space not because there are particles, but because the environment continually measures position. The concept of a particle seems to be derivable from the quantum… state.”

Schrödinger believed that quanta are not fundamental but a consequence of our sloppy description of nature:

To make a long story short, decoherence allows the observer to experience things that are not really existent, as a consequence of his limited information about the whole.

we usually see less when we overlook something, decoherence perplexingly allows us to see more than what really exists.

In any of these cases, light from the light source is absorbed by the puppets or the pictures on the slide or the film roll to create the images displayed on the screen. The characters, objects, and stories we experience by watching the screen are a consequence of us not seeing all the light emitted from the lightbulb.

Just like decoherence, a colored lens, a shadow puppet, a painted slide, or a film roll seemingly creates information by actually filtering out information. In all these cases, it is our ignorance that constitutes our experience.

“The only object that can truly exist is the quantum state of the entire universe,”

“The whole point of Schrödinger’s cat example… is to show that, given a suitable coupling, any microscopic superposition can be made to generate a corresponding macroscopic one.”

What is inconsistent with the universal applicability of quantum mechanics is not our ordinary experience as such, but the common-sense way of interpreting it.”

“Physicists can use magnetic fields to induce current to flow in both directions around the ring at the same time. That doesn’t mean half go one way and half go the other; all the electrons… simultaneously stream clockwise and counterclockwise,”

“the gradual action of decoherence and thus the step-by-step transition between the quantum regime and the classical domain,”

“indeed convinced that the importance of decoherence was overlooked for the first 60 years of quantum theory precisely because entanglement was misunderstood as no more than a statistical correlation between local objects.”

It was made fairly clear that, to be frank, there was no place in physics—no jobs in physics!—for anybody who dared to question the Copenhagen position.”

This holistic, “all is One” feature of reality finally proved that properties aren’t necessarily located in specific places. They can be “nonlocal,” such as the properties of Zeh’s nuclei that can’t be found in the component nucleons.

It was this second type of nonlocality that Bell’s inequalities proved: that a property of an entangled quantum state couldn’t be reduced to the properties of its constituents simply because these constituents didn’t exist as long as the total state was considered as a whole. This finding is in perfect agreement with Zeh’s finding that quantum mechanics doesn’t support the existence of particles (i.e., localized lumps of matter).

Zeh’s finding that quantum mechanics doesn’t support the existence of particles (i.e., localized lumps of matter).

fundamental quantum reality is nonlocal, that it exists in a “nowhere land”...

Decoherence does not describe what happens to the universe during an interaction or a measurement; on the contrary, it describes how an entirely quantum mechanical universe looks to a local observer.

“From the bird perspective, [Everett’s] multiverse is simple. There is only one wave function. It evolves smoothly and deterministically over time without any kind of splitting or parallelism.

“From their frog perspective, observers perceive only a tiny fraction of this full reality. They can view their own… universe, but the process of decoherence—which mimics wave function collapse while preserving [quantum mechanics]—prevents them from seeing… parallel copies of themselves.”

“Nobody seriously believes that ‘dinosaurs’ are just a calculational device intended to tell us about fossils… And almost all of science is like this.”142 Insisting that parallel universes are “only an interpretation” instead of “a scientifically established fact” has, according to Deutsch, “the same logic as those stickers that they paste in some American biology textbooks, saying that evolution is ‘only a theory.’”

classical reality is a consequence not only of a measurement system being coupled to an environment but also of the incomplete knowledge about this environment.

And then there is the entire quantum universe: global, encompassing, with no external environment and thus not subject to decoherence. This latter system constitutes the only true fundamental quantum state, a conjunction of opposites accommodating everything that is physically possible.

Nevertheless, the bird’s perspective isn’t entirely inaccessible: as Zeh emphasized, although the frog is not able to fly like a bird and experience this fundamental reality, with “imagination guided by reason,” the frog is capable of developing a description of the bird perspective of quantum reality (by solving the Schrödinger equation).

probably the emergence of matter and possibly even space and time itself isn’t a real process in the fundamental quantum universe. It only describes the impression an observer located in space and time gets about this fundamental reality.

“Platonic Paradigm: The bird perspective… is physically real, and the frog perspective and all the human language we use to describe it is merely a useful approximation for describing our subjective perceptions.”146 As Zeh concludes, “Quantum theory requires quantum cosmology.”

“Quantum theory requires quantum...

IF EVERYTHING IN THE UNIVERSE IS MERGED INTO A single One by entanglement, if decoherence explains how this hidden unity unfolds into the planets, pebbles, and critters populating our universe, and if its profound, bizarre, and flat-out revolutionary implications are evident in the equations of quantum mechanics, we may have resolved the contradictions inherent in our universe, but another fundamental question still remains. Namely, how is it possible that such a revolutionary notion could have been ignored for so long?

Whereas in polytheism “the divine cannot be divorced from the world,” Assmann writes, monotheism “sets out to do just that. The divine is emancipated from its symbiotic attachment to the cosmos.”

Parmenides emphasizes that “mortals,” portrayed as “deaf and blind at once, bedazzled, undiscriminating hordes,” “know nothing” about this fundamental reality.

Parmenides provides an early comprehensive exposition of the seemingly paradoxical view that “there exists exactly one thing,”20 “ungenerated and imperishable, entire, unique, unmoved and perfect” and composed of complementary principles such as light and darkness.21

Neoplatonist Plotinus, who wrote in his magnus opus, The Enneads, “The One is all things and no one of them; the source of all things is not all things; and yet it is all things in a transcendental sense—all things, so to speak, having run back to it: or, more correctly, not all as yet are within it, they will be.”

“The One is all things and no one of them; the source of all things is not all things; and yet it is all things in a transcendental sense—all things, so to speak, having run back to it: or, more correctly, not all as yet are within it, they will be.”

“It is precisely because there is nothing within the One that all things are from it: in order that Being may be brought about, the source must be no Being but Being’s generator, in what is to be thought of as the primal act of generation.”

since an all-encompassing One embraces both things that are blue and other things that aren’t, it can’t be either entirely blue or not-blue itself. Nor can it be composed of things being blue and not-blue, since in the latter case it would be many things; it wouldn’t be “one” anymore. Plato used different characteristics, but the logic remains the same: “the one can neither be the same, nor other, either in relation to itself or other.”

“the one can neither be the same, nor other, either in relation to itself or other.”

if everything is integrated into a single concept, this concept necessarily becomes a conjunction of opposites. It defies any description in terms of concrete properties, as highlighted, for example, in the first sentences of Lao-tzu’s Tao Te Ching: “The Tao that can be spoken of is not the constant [true] Tao; The name that can be named is not the constant [true] name.”

Just replace “blue” and “not-blue” with “particle” and “wave,” and Plato’s Parmenides reads like a standard textbook introduction to quantum mechanics. As Carl Friedrich von Weizsäcker wrote, “We find… the foundation of complementarity already foretold in Plato’s Parmenides.”

Plato’s One is “transcendental” and “metaphysical.” It isn’t directly observable and lies beyond the domain of everyday physics. Yet, to Plato, metaphysics wasn’t unreal. In fact, it was more real than the observable phenomena; it was the real world rather than its shadow. Eventually, the effect of how Platonic philosophy got appropriated by Christianity pushed Plato’s monism into an otherworldly realm.

compared the ascent in Plato’s Allegory of the Cave with Moses’s journey up to God on Mount Sinai.

Dionysius’s idea of a reality projected out of God is strikingly reminiscent of the projector realities that help explain quantum mechanics. This raises the same question that John Bell posed in his criticism of the Copenhagen interpretation: “How exactly is the world to be divided into speakable apparatus… that we can talk about… and unspeakable quantum system that we can not talk about?”

Eriugena conceived the evil in the world as a lack of God. Likewise, God wouldn’t ever condemn anybody to hell: “God does not curse the things which He made, but blesses them,” Eriugena wrote.64 Thus, rather than being a physical place in space and time, hell had to be understood as a psychological condition afflicting those neglecting their connection with God.

“The beauty of the whole established universe consists of a marvellous harmony of like and unlike in which the diverse… and various species and… substances… are composed into an ineffable unity.”66 In other words, “there is a most general nature in which all things participate, which is created by the One Universal Principle” and “from this nature corporeal creatures are derived,… [like] streams which, issuing from one all-providing source,… break out… in the different forms of the individual objects of nature”

What was described as the Fall of Man and the original sin in the biblical Genesis is now understood as a metaphor for the individual separating herself out of this unity with God.