Wheeler.

John Archibald Wheeler is one of the most influential physicists most people have never heard of. He was Niels Bohr’s student in the 1930s. He was Richard Feynman’s teacher in the 1940s. He coined the term “black hole” in 1967. He helped develop the American hydrogen bomb. He wrote the standard graduate textbook on general relativity. He taught at Princeton for decades. He died in 2008.

He was, by any measure, a working physicist of the highest caliber. He was not a mystic. He was not religious in any conventional sense. He was a scientist who built nuclear weapons and wrote tensor calculus textbooks.

And he spent the last decades of his career arguing that the universe requires observers, in some deep sense, to exist at all.

The position is called the participatory universe. The slogan he used for it is It from Bit — meaning that physical things (the “it”) emerge from information (the “bit”), and information requires observers to be defined.

The universe does not exist ‘out there,’ independent of us. We are inescapably involved in bringing about that which appears to be happening. We are not only observers. We are participators.

This is not poetry. Wheeler arrived at this position from working through quantum mechanics carefully. The act of measurement, in quantum theory, is not a passive thing happening to an already-existing reality. The measurement is part of what brings the measured property into being. Wheeler took this seriously and pushed it to its limit. If measurement is constitutive of reality, then observers — who do the measuring — are constitutive of reality.

Most physicists reject Wheeler’s strong reading. The standard view is that quantum measurement is a real physical process but does not require conscious observers — any physical interaction can play the role. Wheeler knew this and continued to defend his position anyway. He believed something deeper was going on, and he held the view to the end of his life.

Whether or not he was right, he was serious. The participatory universe is not crackpot. It is one of the more radical positions in serious physics, defended by one of the most respected physicists of his generation.

Erwin Schrödinger founded wave mechanics. The Schrödinger equation, which still governs quantum physics, is named after him. He shared the Nobel Prize in 1933.

Near the end of his life, in 1961, he wrote a short book called My View of the World. The book has been read by far fewer people than his more famous What Is Life? The book makes a specific claim, defended by physical reasoning, that most readers would consider startling.

Schrödinger argued that the plurality of conscious beings is illusion. That there is, in some deep sense, only one consciousness in the universe, experiencing itself many times. The eight billion humans who feel like distinct selves are, on his reading, the same self looking at the world from many different positions.

His reasoning was physical, not religious. Physics, he noted, admits no special particle that distinguishes one observer’s consciousness from another. There is no “I-particle.” If consciousness were metaphysically split across observers, there would have to be some physical fact that did the splitting. But no such fact exists. Therefore, what appears to be distinct consciousnesses must be the same consciousness, appearing from different angles.

The plurality that we perceive is only an appearance; it is not real.

Schrödinger explicitly connected this to Vedantic philosophy, the Upanishadic tradition in India that arrived at the same conclusion three thousand years earlier through different means. The Vedantic formula tat tvam asi — “thou art that” — says essentially the same thing: the apparent boundary between you and other conscious beings is illusion. The Atman (individual soul) is Brahman (universal consciousness).

Schrödinger was clear that he had arrived at this conclusion from physical reasoning, not from religious commitment. He found, working from physics, that he had to agree with a position he found in ancient Indian philosophy. The convergence surprised him.

Carl Sagan was the most effective scientific communicator of his generation. His PBS series Cosmos reached half a billion people. He was a respected astrobiologist. He worked on multiple NASA missions.

In Cosmos, in a sentence that has been quoted ever since, he distilled the lineage Wheeler and Schrödinger were working in:

We are a way for the cosmos to know itself.

The sentence sounds poetic. It is also literal.

The universe contains roughly 10⁸⁰ atoms. Almost all of them are unaware. They drift in stars and gas and rocks, obeying physics without registering that they are doing so. A vanishingly small fraction of those atoms are organized into structures complex enough to model their surroundings, including themselves. Those structures — biological brains today, possibly something else tomorrow — are how the universe, locally, becomes aware of itself.

You are made of those atoms, in that configuration. The atoms in your brain right now were forged in stellar furnaces billions of years ago, were scattered across the galaxy in supernovae, were assembled into this planet, were taken up by your mother, were arranged into the structure that is currently reading this sentence.

Sagan’s line says exactly what is happening, in plain English. The cosmos contains a configuration — you — that is currently aware of being a configuration of the cosmos. You are not separate from the cosmos looking at it. You are the cosmos, in this small place, looking at itself.

Roger Penrose is the most distinguished mathematical physicist alive who works on consciousness. He won the Nobel Prize in 2020 for his work on black holes.

Penrose argues, in The Emperor’s New Mind (1989) and Shadows of the Mind (1994), that consciousness cannot be captured by classical computation. He believes the mind is doing something that requires physics we have not yet discovered — specifically, physics involving quantum gravity at the level of microtubules inside neurons.

Most consciousness researchers reject the specific Penrose-Hameroff proposal. The mainstream view is that consciousness can be captured by classical computation, at least in principle.

But Penrose’s broader claim is harder to dismiss: that consciousness is not just an accidental byproduct of physics. That it is connected to the deep structure of the universe in ways physics has not yet articulated. That when we eventually have a unified theory of physics, it will include something about minds.

Whether or not the specific microtubule story is right, Penrose has kept the question of consciousness in physics alive at the highest level of seriousness for thirty-five years. The fact that a Nobel laureate in mathematical physics has spent his career arguing this is, by itself, evidence that the question is not silly.

What is striking is not that any one of these thinkers said what they said. What is striking is that they converged.

None of these people were communicating with each other in a coordinated way. They were independent thinkers, working in different decades, in different traditions, on different problems. They arrived at related positions because the questions, when looked at carefully, push toward certain answers.

The convergence is not proof. Many smart people have been wrong in the same direction. But it is evidence that the question is real, the answers are constrained, and the position you may be reaching for — that you, as an observer, are not incidental to the universe — has been reached, repeatedly, by people whose qualifications are above reproach.

You are not making things up. You are arriving at something that has been arrived at before, by people who knew what they were doing.

Even if Wheeler is wrong about the strong participatory claim. Even if Schrödinger is wrong about the unity of consciousness. Even if Penrose is wrong about quantum gravity in microtubules.

One thing they were collectively right about — and this part is not contested — is that observers do something the rest of the universe cannot do.

Stars do not know they are stars. Galaxies do not know they are turning. The atoms in a rock do not know they are arranged. Most of the universe is, in this specific sense, asleep. It does what it does without registering what it is doing.

You are not asleep. The pattern that is your brain, right now, is modelling the universe it is part of. It is registering its own existence. It is asking why it is here. None of the asleep universe is doing this.

That is enough — independent of whether the participatory universe is literally true, or the unity of consciousness is metaphysically real, or quantum gravity is involved in cognition — to give the observer’s role its actual weight.

You are doing the rarest activity matter performs. While you do it, the universe is, locally, knowing itself a little. When you stop doing it, that local knowing stops. Other observers continue.

That is the role. It is real. It is rare. It is yours.

Wheeler. Schrödinger. Sagan. Penrose.
They did not all agree. They did all take the question seriously.
You are not asking it alone.