Helgoland

Have you ever wondered whether your reality is the same as someone else’s—or whether the world exists independent of your observation? In Helgoland, theoretical physicist Carlo Rovelli confronts this unsettling question by rethinking quantum physics not as a description of isolated things, but as a web of relations. The book begins from the most puzzling discoveries of twentieth-century science—those mysterious quantum leaps, superpositions, and entanglements—and gradually unfolds into a philosophical meditation on the nature of existence itself.

Rovelli argues that the heart of quantum theory lies not in hidden particles, parallel worlds, or elusive waves, but in the realization that objects exist only through their interactions. Reality is not a static collection of substances—it’s a tapestry of relationships between things. When an electron “is,” it only is with respect to something that interacts with it. When you measure a photon or look at a cat in Schrödinger’s thought experiment, that interaction itself creates the event. This relational vision overturns centuries of metaphysical thinking that imagined matter as a set of objects with intrinsic properties.

Quantum Puzzles and Human Perspective

The story begins with the young Werner Heisenberg’s retreat to the windswept island of Helgoland in 1925, where he discovered matrix mechanics—the foundation of quantum theory. Heisenberg’s insight was radical: stop trying to describe what electrons do when we aren’t looking. Instead, describe only what we can observe. Rovelli recounts how this thought revolutionized physics and how later figures, from Bohr to Born and Schrödinger, struggled to interpret it. Einstein objected—“God does not play dice”—but Bohr replied, “Stop telling God what to do.” Nature, Rovelli writes, resists our human craving for certainty; it demands that we listen rather than instruct.

From Things to Relations

As the book unfolds, Rovelli expands the insight that measurement defines properties: not just in the laboratory, but throughout the cosmos. In quantum mechanics, you cannot isolate an object’s state from the others it interacts with—it exists only in context. He develops this idea into a relational philosophy, asserting that the universe is a network of interactions. Entanglement, contextuality, and superposition, all those hauntingly strange physics notions, become natural once we abandon the idea of a world made of standalone substances. “No interaction, no property,” he summarizes. A cat or a photon becomes real through the very web of correlations that tie it to others.

Beyond Physics: Mind, Meaning, and Ethics

Unlike most science writers, Rovelli doesn’t stop at physics. He asks what this vision means for our minds, our politics, and our understanding of meaning. He connects quantum relationality with Ernst Mach’s empiricism, Alexander Bogdanov’s socialist philosophy of “organization,” and the Buddhist philosopher Nāgārjuna’s doctrine of śūnyatā—emptiness, the idea that nothing exists independently. Rovelli suggests that consciousness and thought may also be part of this web. There is no “I” outside reality; the self is a node in the same dynamic network. The recognition that we exist through relations, he argues, should inspire collaboration and humility rather than competition and arrogance.

Why These Ideas Matter

This radical vision matters because it restores wonder and subtlety to our picture of the world. Rovelli’s relational quantum mechanics teaches that knowledge is never absolute—it is always perspective-bound, like every observation in the universe. Facts are relative to the systems that interact. Just as Einstein’s relativity redefined space and time, Rovelli’s relational quantum mechanics redefines existence itself. The world is not built of atoms or things, but of events—living threads of interaction weaving a cosmic web. We are not detached observers but participants in the dance of nature. By the book’s end, you may feel what Rovelli calls the “lightness of being” in a world where solidity melts into interconnection.

In the chapters that follow, you’ll explore how superposition challenges the idea of certainty, how entanglement reveals a dance between three partners, how contextuality bridges science and philosophy, and finally, how this relational worldview reshapes our understanding of mind and meaning. As Rovelli writes, “We are such stuff as dreams are made on.” But those dreams, he insists, are relational—and they are real.

Rovelli opens the story at its most human: a young physicist, Werner Heisenberg, in desperate solitude on the harsh island of Helgoland. Afflicted by allergies and sleeplessness, Heisenberg seeks not rest but clarity. His goal is to understand the strange behavior of electrons; why they jump between orbits instead of moving smoothly. This summer in 1925 brings his breakthrough—the birth of quantum mechanics. Rovelli’s vivid narration grounds science in emotion and struggle, reminding you that revolutions in understanding often arise from moments of isolation and doubt.

Heisenberg’s Radical Leap

Heisenberg’s leap was unprecedented. He decided to describe only quantities that can actually be observed rather than hypothetical entities moving behind the scenes. No trajectories for electrons, no invisible orbits; only measurable effects like the light emitted when an electron jumps. From this astonishing act of restraint emerged a new mathematical structure built from tables, or “matrices,” representing transitions between atomic states. It was the moment when the old mechanical world gave way to a new grammar of nature.

The Revolution That Changed Everything

Within months, joined by Max Born and Pascual Jordan, Heisenberg formed a theory that worked spectacularly. It predicted atomic spectra, explained Bohr’s mysterious quantum leaps, and described energy as discrete. Their equations became the foundation of modern physics—so powerful that Einstein himself described them as “witchery.” Dirac later refined the mathematics, Pauli tested it, and Schrödinger offered a competing vision based on waves. But Heisenberg’s matrix mechanics remained the conceptual core: it taught us that the world resists direct description. What exists are interactions, not isolated things.

From Scientific Discovery to Existential Wonder

Rovelli’s account of Helgoland is poetic as well as intellectual. He imagines Heisenberg staring at the sunrise after his realization, feeling the dizziness of unveiling nature’s “strangely beautiful interior.” That image mirrors what every thinker faces when confronting mystery: an abyss where certainty dissolves. Rovelli uses this episode to invite readers into that abyss. Quantum theory, he insists, has not merely improved our measurements—it has demolished our comfortable metaphysics. The world is no longer simple; we must learn to inhabit complexity with curiosity rather than fear.

(Contextually, Rovelli’s narrative echoes Thomas Kuhn’s idea of paradigm shifts: scientific progress as revolution rather than accumulation. Helgoland stands as a turning point where the map of reality was redrawn—showing that science’s true power lies not in mastering the world, but in learning how to listen when the world contradicts us.)

One of the strangest discoveries in quantum physics—and the one that haunted Rovelli as a student—is the principle of superposition. A particle can be in two states at once, like Schrödinger’s cat that is both awake and asleep until you look. Rovelli recounts his encounter with this phenomenon not in theory but in practice: in Anton Zeilinger’s laboratory in Innsbruck, watching photons behaving like waves and particles simultaneously.

The Puzzle of Observation

When Rovelli blocked one path of light with his hand, the photons rearranged their outcomes. Simply observing—or deciding to measure—altered reality. The act of looking changed what happened. Schrödinger dramatized this paradox through his cat experiment, showing that observation and reality are intertwined. Superposition is not about mystery for mystery’s sake; it reveals that the world does not have fixed states waiting for us to see them. States are actualized only in relation to something else.

Competing Interpretations

Rovelli explores several grand attempts to make sense of superposition: the Many Worlds hypothesis (every observation creates a new universe), Bohm’s Hidden Variables (unseen deterministic rules beneath chaos), and Physical Collapse theories (waves collapse spontaneously). Each seeks to save our intuition that something must be real, definite, or objective. Yet experiments refute these add-ons. As Rovelli emphasizes, reality at the quantum scale is undefined until it interacts.

Accepting Indeterminacy

Rather than patch quantum theory with metaphysical scaffolding, Rovelli invites us to accept indeterminacy as inherent. He aligns partly with QBism, which interprets the quantum wave as information about what we know—but then goes further: information itself is physical, and the world is woven of informational relations. For Rovelli, recognizing superposition is an act of humility. You learn to let go of the childish illusion that nature must conform to human categories. Instead, you discover a rare freedom—the freedom that comes from embracing the shimmering uncertainty that is the universe’s true rhythm.

(The comparison with Richard Feynman’s famous dictum “Nobody understands quantum mechanics” underscores Rovelli’s point: understanding is not possessing certainty; it is learning how to coexist with mystery.)

The centerpiece of Rovelli’s argument is his relational interpretation of quantum mechanics. He contends that reality consists not of things, but of interactions between things. A tree, a cat, a star, a photon—all of them exist only by affecting others. If something never interacts, it might as well not exist. This transforms how you see the world: rather than a stage full of objects waiting to be described, reality becomes a dynamic conversation among participants.

From Observer to Participant

In older physics, the “observer” was human—someone in a lab measuring outcomes. Rovelli extends the idea: every physical system observes every other. A photon interacting with a detector is like a person seeing an apple. “Observation” is no longer about consciousness; it’s simply physical interaction. Heisenberg’s discovery on Helgoland now applies universally: properties emerge from interactions, not from solitary existence.

No Interaction, No Property

Rovelli sharpens Bohr’s insight that the apparatus is part of the phenomenon. Extend this idea, and you reach a frontier conclusion: any object’s properties—its position, momentum, color—only exist during interaction. An electron doesn’t have a trajectory when unobserved; it has potentialities for relationships. To ask what it “is” apart from those relations is meaningless. Reality is the web, not the nodes.

Facts Are Relative

In Rovelli’s retelling of Schrödinger’s cat, the cat knows whether it’s asleep or awake; the observer outside does not. Both descriptions are valid—but relative to different systems. Facts are not universal truths floating in the cosmos; they are relational events between systems. This radical idea replaces determinism with a mosaic of perspectives, each forming its own local reality that maintains coherence through information exchange. Science, then, is not a repository of immutable truth—it is an evolving dialogue among perspectives.

(Philosophically, this links Rovelli to Willard Quine’s naturalism and structural realism, and also to existentialist traditions insisting that knowledge arises in encounter, not observation.)

Entanglement—the eerie connection between distant particles—is for Rovelli the crown jewel of relational physics. Two photons far apart behave as if they share information instantly. How? Experiments from John Bell’s 1964 inequalities to the Chinese satellite Micius prove the reality of such correlations. Rovelli dramatizes it through an image of lovers who still sense each other from opposite sides of the Earth. But quantum logic eliminates romantic mystique: the link is not signal transmission—it’s the structure of relations themselves.

The Puzzle and Its Resolution

After decades of debate, physicists realised that neither hidden variables nor faster-than-light signals explain entanglement. The key lies in perspective. The color of a photon measured in Beijing is defined only with respect to Beijing; the one in Vienna gains reality only when its data arrives—through normal communication. Until they interact via exchanging signals, their states are undefined relative to one another. “Entanglement,” Rovelli concludes, “is not a dance for two partners—it is a dance for three.” The third participant is the system that compares them.

Reality as Correlation

Every property in nature, from the color of butterfly wings to the heat measured by a thermometer, emerges as correlation. A thermometer doesn’t record temperature—it becomes correlated with the cake’s heat. This perspective reframes entanglement as the external view of interactions themselves. The world is woven of these correlations: knots of information linking systems across distances and scales. When you grasp this, the notion of an overarching, universal “fact” dissolves. Only interconnected facts exist, each meaningful relative to others.

Consistent Perspectives

The relational web might seem chaotic—but it isn’t. Quantum theory ensures consistency: when signals are exchanged, perspectives align. If one observer saw blue wings on a butterfly, everyone will see blue once information is communicated. Inter-subjectivity arises naturally through shared interaction, grounding our collective perception of an objective world. Rovelli draws comfort from this: even in a fragmented universe, communication and collaboration repair fragmented perspectives into coherence.

(The “dance for three” idea poetically echoes Martin Buber’s “I and Thou,” presenting relation—not substance—as the locus of reality.)

In one of the book’s most philosophical turns, Rovelli connects quantum contextuality to broader human thought. He revisits the early twentieth-century debate between Lenin and Alexander Bogdanov over Ernst Mach’s empiricism—whether knowledge is fixed or relational. Mach proposed that science should describe only observable relations. Lenin insisted on material certainty. Bogdanov foresaw a culture grounded not in hierarchy but collaboration—and Rovelli sides with him. Contextuality becomes both a scientific and ethical principle.

Mach’s Legacy

Rovelli sees Mach’s anti-metaphysical stance as quantum-friendly: reality reveals itself in phenomena, not hidden substances. Knowledge evolves through interaction with experience, not by discovering eternal truths. He pays homage to Mach’s influence on Einstein and Heisenberg, noting that their revolutions began by doubting metaphysical assumptions. “Nature is richer than our metaphysical prejudices,” Rovelli writes, echoing Bohr’s reply to Einstein.

The Relational Nature of Science

Science, in Rovelli’s view, is not a Depository of Truth but a process of readjustment—a continuous conversation between models and observations. Contextuality in physics means properties depend on conditions; contextuality in philosophy means ideas depend on circumstances. Both reject permanence. Understanding grows through collaboration, like natural systems evolving together. Bogdanov’s cooperative vision of revolutionary science parallels Rovelli’s quantum collaboration: meaning and knowledge emerge through exchange.

A World of Relations, Not Substances

Here Rovelli states his boldest claim: quantum mechanics abandons the idea that the world is made of substances with attributes. Everything is relational. To exist is to interact. He likens it to Douglas Adams’s startling thought that we live on “the surface of a gas-covered planet orbiting a nuclear fireball,” yet call it normal—just a reminder of how skewed our perspective is. We must renounce arrogance and embrace the provisionality of understanding. Knowledge, he tells you, is not possession—it’s participation in the world’s relational unfolding.

(This section bridges physics with naturalism and philosophy of science, aligning Rovelli with William James and Willard Quine’s view that thinking itself is a natural process within nature.)

When confronted with the radical relationality of quantum physics, Rovelli turns eastward. Many readers asked him, “Have you read Nāgārjuna?”—the Buddhist philosopher of the second century CE who taught that nothing exists independently. In discovering Nāgārjuna’s Mūlamadhyamakakārikā (“Verses on the Middle Way”), Rovelli finds a conceptual ally for quantum theory. The resonance is stunning: both perspectives dissolve the idea of ultimate substance and celebrate interdependence.

Emptiness and Interdependence

Nāgārjuna describes reality as śūnyatā—emptiness—not nihilism but recognition that everything arises in relation to something else. Clouds form castles in our minds only through the relation between perception and sky; both castles and clouds are empty of intrinsic essence. Rovelli translates this into physics: particles, fields, and forces have no independent being. Their existence is contingent upon interaction. The empty nature of things is what allows them to exist together.

Emptiness Is Empty

Nāgārjuna’s second insight strikes Rovelli as breathtaking: even emptiness itself is empty. There is no ultimate foundation, not even relational emptiness. Seeking the final substance of reality is a category mistake. This parallels Rovelli’s argument that searching for hidden variables or “real” waves in quantum mechanics is misguided—it asks for what the theory denies exists. Reality is process, not foundation; dialogue, not monolith.

Liberating Knowledge

Rovelli concludes that Nāgārjuna’s philosophy exemplifies intellectual humility. Understanding comes from embracing absence of certainty. Science thrives not on absolute truth but on curiosity and openness. Emptying our metaphysics is not despair—it’s liberation. It allows new learning, compassion, and creativity. Just as the Buddhist path uses emptiness to transcend suffering, understanding quantum emptiness helps us transcend dogma. Reality becomes a luminous web of mutual arising, beautiful precisely because it has no anchor.

(This synthesis between physics and Eastern philosophy recalls parallels explored by Fritjof Capra in The Tao of Physics—though Rovelli’s approach is more rigorous, focusing on conceptual clarity rather than mysticism.)

Rovelli ends his exploration not with equations but with introspection. What does the relational world mean for consciousness, perception, and meaning? He turns to modern neuroscience and philosophy to show that our minds are also relational systems. The brain, he explains, doesn’t merely record external data; it predicts the world and corrects itself. We expect to see a cat and only change our neural messages when what we see differs. Vision is not passive observation—it’s an active dialogue between expectation and experience.

Perception as Experiment

In striking detail, Rovelli describes how signals travel not from the eyes to the brain but largely from the brain to the eyes—a reversal that astonished neuroscientists. Like quantum theory, perception depends on discrepancies between expectation and observation. Our consciousness operates as a continual experiment, comparing predicted input with reality. Science itself mirrors vision: our theories are the brain’s anticipations corrected through observation.

Meaning as Relevant Information

Rovelli then tackles the problem of meaning. How can mere matter carry significance? He merges Claude Shannon’s information theory with Darwinian evolution. Information becomes “relative information”—the physical correlation between two systems. Meanings emerge when those correlations have survival relevance. A bacterium swims toward sugar because of a meaningful signal: chemistry tied to life. Intelligence, language, and human culture are extensions of this web of relevant information. We, too, are relational systems exchanging signals for survival and joy.

Mind as Part of Nature

Finally, Rovelli bridges physics and the mind-body problem. Consciousness, he says, poses no “hard problem” for nature because it already exists as solved in nature’s fabric. The “I” is not an immaterial ghost—it’s a process, a pattern of interactions. Subjectivity is not separate from physics; it’s its complex expression. Understanding this erases the false dualism between matter and mind. Thoughts are processes of matter relating to itself. Matter, seen rightly, is already relational and luminous enough to contain mind.

(Here Rovelli diverges sharply from dualists like David Chalmers and aligns more with naturalists and philosophers of process such as Alfred North Whitehead, grounding spirit in the same relational grammar as physics.)

Rovelli closes Helgoland with poetic reflection. Quoting Shakespeare’s The Tempest—“We are such stuff as dreams are made on”—he likens the dissolution of substantial reality to Prospero’s fading vision. Quantum physics melts the solidity of the world into shimmering air, but instead of despair, Rovelli feels lightness. To him, the relational universe is not less real—it’s more miraculous. Every interaction, every correlation is a thread of existence. You, he says, are not a solitary island; you are a ripple in the cosmic network.

Science as Dialogue

Science, for Rovelli, is humanity’s way of participating in the universe’s conversation. It grows not from certainties but from discrepancies, from learning that our expectations are wrong. Each discovery—a new star, a new theory—adds perspective, not foundation. Collaboration, he insists, is more fruitful than competition; shared knowledge enriches reality itself. The politics of cooperation mirrors the physics of interaction.

Living in the Web

Accepting the relational world changes how we live. It invites empathy, respect, and awe. We are all nodes in the same luminous web: stars and photons, trees and memories, societies and languages intertwined. Rovelli ends not with final answers but with wonder—“Can we believe this? Can reality be so?” Yes, he says, and it’s beautiful. When we relinquish the illusion of separateness, we find belonging in the dance of relations.

(Helgoland, both island and idea, becomes a metaphor for the human condition: solitary minds discovering together that isolation itself is an illusion.)