The Instrument Inside the Question

I. Where Darwin left the question

Darwin’s horrid doubt asked whether a mind that came out of nature could trust what it concluded about nature. He asked it in a letter, late in his life, and did not follow it into the instrument itself. Within twenty years of his death, physics walked straight into that question. It did not arrive by philosophy. It arrived by measurement, because the experiments stopped giving answers the old way of thinking could carry.

Five people stood at that door. Planck opened it reluctantly, and Einstein, who helped hold it open, could not follow where it led. Heisenberg, Bohr and Schrödinger went further than their training allowed, and each paid for it in a different way.

II. Planck — the reluctant door

Max Planck did not want the quantum. In 1900 he introduced energy in discrete packets to make the blackbody formula fit the measurements, and he later called the step “an act of desperation.” He spent years trying to fold it back into classical physics. Planck introduced quantum as discrete packets to make it fit. It has now become closer to discrete clouds, or more probable places where these might be found. A whole science became named after something which got nailed down into parts — when the whole point is more about a rippling shape in space-time.

He also left the most honest sentence we have about how ideas actually change: “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.” That is the problem this book is written against. If correction must wait for funerals, the method has handed its verdict to time instead of to the thinker.

Yet Planck is not a villain here. He opened a door his own training told him should stay shut, and he told the truth about how slowly minds follow. This led to a new direction in thinking, which means he was not wrong entirely, but headed in the right direction. That is the standing question working at the scale of one life: not are we perfect, but are we headed in the right direction.

III. Heisenberg — the observer named

“What we observe is not nature itself, but nature exposed to our method of questioning,” Heisenberg wrote in Physics and Philosophy. Here Darwin’s doubt returns, with the instrument now inside the sentence. Nature need not be unreal for our access to it to be shaped by the questions we ask. The method of questioning cannot be left outside the account of what we observe. Neither can the training that teaches us which questions to ask—and which possibilities to overlook.

Heisenberg’s search took him outside the boundaries of his specialty. During his visit to India in 1929, he met Rabindranath Tagore. Much later, Fritjof Capra reported a conversation in which Heisenberg remarked that quantum theory would not look ridiculous to people who had read Vedanta. Was he looking for an operator, an operative pattern, or a philosophical language for something the science had brought dimly into view? We cannot settle that from these encounters. But we can recognize the reaching: a physicist looking beyond the familiar boundaries of his discipline for ways to think about what he had encountered within it.

Schrödinger also pursued philosophical and religious questions. It is not unexpected that these pioneers would look toward traditions concerned with unity, opposition, and the relation between the observer and the observed. Perhaps they hoped to find in philosophy an observation they saw in the science dimly. Just maybe they were not yet able to look in the right places. More has been made of their searching by those seeking the same answers in modern times than is likely warranted. Their interest gives us something to contemplate, not permission to turn an encounter into a settled conviction or a philosophical affinity into scientific evidence.

For me, the great things handed down by Heisenberg were his uncertainty principle, his entry into the quantum universe, and the questions opened by matrix mechanics about the inherent nature of what we observe. Complementary pairs became part of that unfolding quantum understanding. But running through all of it was the very thought that we could be asking the wrong questions or looking through the wrong lens. That possibility changes the work. We must examine not only the answer that comes back, but the habits of thought through which we asked for it.

IV. Bohr — complementarity, with care

Niels Bohr named the problem outright: some descriptions of the same thing cannot be held at once, and yet both are needed. Complementarity is the right next step after Heisenberg, and also the first warning. It can become a comfortable abstraction, a word that ends a question instead of opening one. It earns its place only where it changes what a thinker does — holding two accounts in tension instead of forcing one to win. Even the line most often quoted for him, that physics concerns not how nature is but what we can say about nature, comes to us through his assistant’s recollection rather than his own pen, and it should be read with that care.

Bohr carried the duality onto his own coat of arms. Knighted in 1947, he chose the yin-yang figure with the motto Contraria sunt complementa — opposites are complements. Today we have much more insight into the interplay of geomagnetics and positive-negative than he did in his time. The charged two-layer membrane, where the field gathers at sharp deformations, and the altermagnet, whose bulk cancels to zero while its information survives in the modes, are instances of that interplay his century could not yet measure. The seam his reaching left is still open.

Niels Bohr is also the quantum pioneer who plays a role in my introduction to intellectual ping pong — the back-and-forth in which two minds keep returning the question rather than letting either one keep the last word.

V. Schrödinger — the physicist who asked about life

In What Is Life? (1944), Erwin Schrödinger asked how a living thing keeps its order, and answered that it feeds on “negative entropy,” order drawn from its surroundings. In a note added to the book, he conceded to physicists that free energy would have been the more proper term. He sharpened his own wording in print, and that is the direction of the change made visible. Life does not defy entropy; it defies it only in a limited machine sense, holding local order paid for by entropy exported to its surroundings.

He crossed from physics into biology — the stretch Darwin could not make in the other direction. His reading of the Upanishads shaped the closing pages of that book and his later My View of the World, and here the caution already given for Heisenberg applies with equal force: the looking is documented, while the industry later built on it often outruns the documents.

His cat makes the same point from another side. Schrödinger built it in 1935 as an absurdity, a criticism of taking the formalism at face value at everyday scale, and it is now often taught as though it were the strangeness itself. Teaching it backwards is a small, exact example of a training that hands students the conclusion instead of the question. Erwin Schrödinger is the man behind my website on quantum comedy, a website which bases its own source of ironic humor on the absurdity of a cat — a cat which could be considered both alive and dead, or neither, or either one, all at the same time. The joke works because he meant it as one.

VI. Einstein — the tragic one

It was the mathematics of Einstein that played the most important role in my childhood, as his theories were the most in the public eye. Because of the importance his work was given in the development of the atomic bomb, this is what impressed young children who might someday write about science.

Einstein made the quantum possible with his 1905 light-quantum paper, and then could not accept where it went. “I, at any rate, am convinced that He does not throw dice,” he wrote to Max Born in 1926. I am not certain Einstein ever asked which God he meant — and whether that God might throw the dice which invented an atomic bomb. He spent his last decades on a unified field theory, increasingly apart from the field he had helped begin.

This is the tragedy of Darwin in another register: not wrong thinking, but magnificent thinking that reached a place it could not stretch past. His objection also carried something real. The 1935 paper with Podolsky and Rosen became the seed of entanglement research and, through Bell, of the experiments showing that the order is non-local. His refusal was fruitful. The lesson is not that he failed. It is that even the greatest mind needs the parallel streams that correct it, and that the correction can come out of the objection itself.

VII. The detour — who gets to answer for a choice?

What happened to the question of free will when physics could no longer give us the old clockwork universe?

I neglected to mention that my best high school teacher was a Frenchman who taught Camus, in whose class I argued in writing against existentialism. I was 14.

That encounter belongs here, before the question disappears into a specialty. A teacher can be the best teacher without giving a student a philosophy she adopts. Being taught a thinker and arguing against the thinking are not opposites. My disagreement belongs in the account as much as the teaching does. The argument I wrote at fourteen must not be supplied for me now, as though a later vocabulary could tell us exactly what the younger mind was refusing. What stands is the encounter: Camus was taught, existentialism was argued against, and I was already doing the work in writing.

The question reaches across physics and philosophy because both concern a person living in a world that is not theirs to arrange at will. But they do not ask it in the same form. A physical theory asks what determines an outcome, what can be predicted, and what probabilities the measurements support. A philosophy of freedom asks what it means for a person to choose and to answer for the choice. The detour begins when an answer to the first is made to do the work of the second.

The old mechanical picture tempted us toward one conclusion: if every motion follows from what came before, then the human being must be another motion, and freedom an appearance. The arrival of quantum probabilities tempted us toward the reverse: if the outcome is not fixed in that way, then perhaps the human being has been set free. Neither movement reaches the person making a decision. An unpredictable event is not, by being unpredictable, an intention. A probability does not tell us what a person understood, whom the decision affected, or why one course was taken rather than another. Nor does predictability alone tell us whether the person was coerced or acted from reasons they could examine.

This is the detour I want to bring into view. It is not that physics was wrong to examine causality. It is that the human question can be postponed indefinitely while we wait for a physical answer to arrive already furnished with an account of judgment. We move from the clock to the dice and still have not asked what it means to learn how to choose.

Jean-Paul Sartre, the French philosopher who made existentialism a public argument in the middle of the twentieth century, put the responsibility back upon the human being. In his 1945 lecture, published as Existentialism Is a Humanism in 1946, the human does not arrive with a finished purpose that excuses what they become. Existence comes before essence: we live, act, and make ourselves through what we do. His freedom is not a promise that circumstances will obey us. It is a burden of choosing within circumstances, without making those circumstances a complete excuse for the choice.

There is something here the book cannot dismiss merely because I argued against existentialism. Responsibility cannot be passed to a ready-made account of what a human being is supposed to be. Yet naming responsibility does not by itself teach a person how to bear it. A declaration of freedom is not the experience through which judgment develops. What has the person been taught to notice? What have they been taught to leave out? What does a choice cost when it is made from a narrowed mind, and who else pays? The question is not finished when the verdict returns to the individual. It has only reached the place where the work must be done.

Albert Camus belongs beside this discussion, but not as another name for Sartre’s position. The Algerian-born French writer resisted the existentialist label. In The Myth of Sisyphus, published in 1942, the absurd is the encounter between our demand for meaning and a world that does not give the answer we demand. It is a relationship, not simply a declaration that nothing matters. Camus refuses both the escape that pretends the question has been settled and the surrender that abandons living. In The Rebel, published in 1951, refusal also discloses a value: the person who says no to an intolerable condition is saying that something must not be violated. The argument moves toward solidarity and limits, rather than a permission to do anything in the name of freedom.

That difference matters. Sartre’s responsibility and Camus’s refusal do not constitute one uniform doctrine, and neither is accurately reduced to despair. The classroom name under which I encountered the dispute does not erase the distinctions within it. Nor does discovering those distinctions erase my disagreement. We can read a thinker carefully without surrendering the question to him.

The quantum pioneers had not spoken with one voice on freedom either. Their disagreement over causality was already under way before Sartre’s postwar lecture. Planck’s quantum step came in 1900; the decisive development of quantum mechanics came in the 1920s. The dates prevent a story in which quantum physics first followed Sartre and Camus and then its founders rose against them. The questions meet, but their meeting is not evidence of a direct debate.

Planck had already devoted two chapters of Where Is Science Going?, published in 1932, to causation and free will. He defended causality rather than treating the quantum as a permission to abolish it. The founder of the quantum was himself resisting an inference others wanted to make from it.

Einstein’s resistance to fundamental chance did not make him an advocate of a will outside causation. In his account of his own outlook, he denied freedom in that sense and invoked Schopenhauer’s distinction between doing what one wills and being able to will what one wills. A pioneer could therefore oppose a probabilistic account of nature and also deny the metaphysical freedom that others hoped probability would supply. Opposition to the dice was not a rescue of free will.

Schrödinger took a different route. The epilogue to What Is Life? places two claims together: the body works according to the laws of nature, and the person directly experiences directing its actions and accepting responsibility for them. He explicitly argues against making quantum indeterminacy the explanation of the body’s actions; he does not solve the problem by making the will a random quantum event. He turns instead toward a philosophical account of the self and its relation to the whole, indebted to the Upanishads. The move is important even where we do not follow his conclusion. He refused to leave the experience of agency out of the account, but his philosophical reconciliation is not an experimental result about the mechanism of choosing.

These are not pioneers enlisted to defeat Sartre or Camus. They are pioneers whose own writing prevents us from pretending that the physical revolution came with a single settled philosophy of the human being. Einstein did not find freedom in chance. Schrödinger did not abandon responsibility because he described the body physically. The disagreement remains visible, and it makes the question larger rather than finishing it.

The direction of this book is not from determinism to indeterminism as though that were the same journey as from captivity to freedom. It is toward the human capacity to examine and change the thinking through which choices are made. The shape is neither an isolated will nor a single event: the choice occurs among relationships, with a history of learning, with other lives present, and with consequences that continue after the chooser stops explaining. Thermodynamics returns us to the living activity. Considering, attending, learning, and acting require a body that spends energy. That physical expenditure does not give us a numerical moral price for a decision, and it does not tell us which decision is right. It reminds us that the work of becoming cannot be done by a declaration alone.

The universe allows for choice; the decision carries its price either way. The adult who guides a child has to understand something of that price through experience, not merely recite that the child is free. Engineered intelligence changes what can be reached, what can be tried, and what can be passed off as understanding. It does not remove the need to learn what a decision carries.

The question I bring back from that classroom is not a reconstruction of the essay I wrote at fourteen. It is the question this book can now ask: what kind of education helps a human being become able to choose, rather than merely acquire a philosophy which says that they can?

VIII. What the five show together

The door opened against the opener’s will, and minds followed slowly; Planck is measured here by his direction, not by perfection. The method of questioning turned up inside the answer, and the questioner kept looking at both ends of his life, east as well as west. Two accounts of one phenomenon could both be needed, and the danger lay in letting the word replace the work. A physicist crossed into biology, corrected his own wording in print, and built a joke that was later taught as a fact. And the magnificent mind that could not stretch far enough found its refusal bearing fruit anyway.

None of them was looking for someone in charge to settle it. When the physics community later did exactly that — “shut up and calculate” became the working habit — the questions did not go away. They were postponed.