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# Quantum Mechanics: The Drifts of Today's Physics
- URL: https://www.421.news/en/current-quantum-mechanics/
- Published: 2026-11-14T11:02:06.000Z
- Updated: 2026-11-14T11:26:40.000Z
- Description: Quantum physics isn't incomprehensible; it's the victim of a century-old dogma. Why we need to let go of classical physics.
- Author: Raimundo Fernández Mouján
- Tags: tech, #en

In the [first](https://www.421.news/en/what-is-quantum-physics-origin-heisenberg-en/) and [second](https://www.421.news/en/quantica-en/) installments of this series on quantum physics, we traced the emergence and history of this peculiar theory, from Max Planck's quantum of action, through the first mathematical formalism proposed by Werner Heisenberg, all the way to the formation of so-called “standard” quantum mechanics in the 1930s. This last “standard” formulation, developed under the decisive influence of Niels Bohr and given its definitive shape mainly through the work of Paul Dirac and John von Neumann, has since become the version taught in universities all over the world. But along the way we stopped to talk not only about the great insights from which quantum theory emerged, but also about the great problems involved in understanding it. Before moving on, let's go back to those problems for a moment.

![](https://storage.ghost.io/c/2b/7f/2b7f69fc-a243-4d2f-ae8e-db8312c6653a/content/images/2026/10/image-asset.jpeg)

The famous Solvay Conference, which brought together the most important physicists of the era.

The success that classical theories (Newtonian mechanics and electromagnetism, thermodynamics and classical statistical mechanics) had enjoyed for several centuries was such that, in physicists' minds, their concepts seemed to be the only guarantors of understanding. In the first decades of the twentieth century, and mostly under Niels Bohr's guidance, the tendency was to somehow apply those concepts to the new quantum mechanics, as if that were the only way to reach an understanding of the physical reality expressed in this strange theory. That application, however, no matter how far the concepts were stretched, never stopped being problematic, and the contradictions that kept cropping up between the classical picture and the mathematical formalism of quantum theory seemed to doom that alliance, which nevertheless, against all odds, has managed to hold up to this day. A good moment to recall the warning of Einstein, a critic of that “standard” interpretation:

> Concepts that have proven useful in ordering things easily acquire such authority over us that we forget their earthly origins and accept them as unalterable givens. Thus they come to be stamped as "necessities of thought," "a priori givens," etc. The road of scientific progress is frequently blocked for long periods by such errors.

As we saw, the price we paid for holding on to that picture was undoubtedly a steep one: clinging to an illusion of understanding, to a semblance of familiarity, we talk about “particles” and “probabilities” that nobody knows what they are, and to prop up those impossible referents we add phenomena that have never been observed (and that have nothing to do with the mathematical formulation of quantum theory), like the famous “collapse” of the wave function. We even ended up accepting relativism as legitimate within physics for the first time, embracing the incompatibility of different perspectives on the *same* physical state. And so we're left with a fantasy of understanding that only holds up as long as we refuse to dig into its assumptions, and that conceals the loss of the referent, the sacrifice of objectivity, and even calls into question the very possibility of a physical theory connecting with the real.

## “Shut up and calculate!”

Faced with its many inconsistencies (both formal and conceptual) and the nonsense of its narrative of unrepresentable particles, never-observed collapses and states *relative* to experimental setups and reference frames, the question that arises about the standard formulation is this: how is it possible that a theory so full of holes, and about which nobody knows what it's actually talking about, has survived without major changes from its formulation almost 100 years ago to the present day? Part of the answer can be found in the testimonies of physicists who studied after World War II, when the US became the epicenter of scientific knowledge. 

> How is it possible that a theory so full of holes, and about which nobody knows what it's actually talking about, has survived without major changes from its formulation almost 100 years ago to the present day?

Combined with logical positivism, American pragmatism developed into its most extreme form: instrumentalism. According to it, scientific theories should be understood solely as “instruments” capable of predicting future observations. Asking whether a theory is “true” is meaningless; the only thing that matters is whether it's empirically adequate—that is, whether it works. And so, in the end, theories cut all ties with the real (and physicists lost all interest in it). In physics, this pragmatic attitude was reinforced both by the standard formulation of quantum mechanics and by the pursuit of technical-military goals like the [Manhattan Project](https://www.421.news/en/protect-and-survive-nuclear-apocalipsis-en/). 

![](https://storage.ghost.io/c/2b/7f/2b7f69fc-a243-4d2f-ae8e-db8312c6653a/content/images/2026/10/atomic-bomb.jpg)

It's in this context that David Mermin recalls his experience as a student in the 1950s:

> \[I have\] vivid memories of the responses my conceptual inquiries elicited from my professors (whom I regarded as agents of Copenhagen) when I learned quantum mechanics as a graduate student at Harvard, barely 30 years after the birth of the subject. "You'll never get a PhD if you let yourself be distracted by such frivolities," they advised me again and again, "so get back to serious business and produce some results." "Shut up," in other words, "and calculate."

Lee Smolin, one of the founders of quantum gravity, has similar memories of his student years: 

> When I studied physics in the 1970s, it was almost as if we were being taught to look down on people who thought about foundational problems. When we asked about the foundational issues in quantum theory, we were told that no one fully understood them but that studying them was no longer part of science. The job was to take quantum mechanics as given and apply it to new problems. The spirit was pragmatic; "shut up and calculate" was the mantra. People who couldn't get past their doubts about the meaning of quantum theory were regarded as losers who couldn't do the work.

In this way, by purging reflection on the theoretical foundations of quantum theory from physicists' job description, instrumentalism helped cement the essentials of that standard version of the theory, with its language and its assumptions, as a taken-for-granted starting point no longer worth examining critically.

> Asking whether a theory is “true” is meaningless; the only thing that matters is whether it's empirically adequate—that is, whether it works.

In a recent [interview](https://preposterousuniverse.com/podcast/2019/03/04/episode-36-david-albert-on-quantum-measurement-and-the-problems-with-many-worlds/?ref=421.news), David Albert, a physicist turned philosopher of quantum mechanics, recalled the abuse he suffered in the eighties when he dared to read a book by the philosopher David Hume and express interest in the foundational problems of quantum theory. “This was in the Physics department at Rockefeller. In short order, proceedings were started to kick me out of the PhD program.” Albert continues: “So those were difficult times, (…) worrying about issues like that was deeply unpopular. I was allowed to stay in the program on the condition that I work on a thesis topic assigned by the department, rather than one I chose, and the one they assigned me was clearly one that was considered good for building my character.” Albert's doctoral thesis, designed to “build his character,” was an extremely technical problem that “required an enormous amount of calculation”—a problem meant to finally teach the young student to *shut up and calculate*.

## The “interpretations” of quantum mechanics: a map of madness

The triumph of standard quantum mechanics, along with the instrumentalist orthodoxy that followed it, had, among other things, managed to bury for many years a notion that Schrödinger had at the time called the most characteristic trait of quantum physics, and that has come roaring back in recent decades: entanglement. Today's technological race around quantum information processing, expressed in developments like quantum [computing](https://www.421.news/en/quantum-computers-qubits/), [teleportation](https://www.421.news/en/quantum-teleportation-en/) and cryptography, rests above all on this particular phenomenon. But it's often forgotten that entanglement is a notion that actually emerged as a kind of critique, a reductio ad absurdum of quantum mechanics—or rather, of the standard version of the theory. 

First Einstein, in the famous paper known as *EPR*, and then Schrödinger, seemed in 1935 to expose absurd consequences of thinking about physical reality in terms of the standard interpretation. If the “collapse” of quantum superpositions introduced by Dirac was taken seriously, there seemed to be an impossible action at a distance between “particles” (a “spooky action at a distance,” in Einstein's famous phrase) capable of creating the physical reality of one of them by observing the other. But Bohr's response came swiftly, and with it he sought to show that Einstein's realism (which based its reasoning on the need for “elements of physical reality”) no longer made sense, and that the comparison between observations that revealed this strange interaction was no longer possible in the new physics, which placed the observer (and the choice of experimental setup) at the center. His response was taken by the physics community as the definitive victory of the Danish physicist (and his complementarity approach) over an old, senile Einstein, who supposedly had failed to grasp the quantum revolution unfolding before him. The young notion of entanglement was thus buried alive and soon forgotten. 

Three decades later, however, secretly returning to the forbidden work of Einstein and Schrödinger, the Irish physicist John Bell rediscovered a set of inequalities that opened the door to a testable formulation of the problem. But his research, published in an obscure journal, was completely ignored by the physics community until, a decade later, a young student named John Clauser stumbled across Bell's paper by sheer chance. Heedless of the instrumentalist climate that had outlawed this kind of foundational research, Clauser set out to find out whether quantum mechanics did or did not violate the inequalities Bell had laid out. Doing these experiments, however, would make it very hard for him to land a permanent position in academia. Alain Aspect (who did have a solid academic post) would continue the tests with his group in France, finally confirming in the early eighties the violation of Bell's inequalities, the existence of quantum entanglement, and the impossibility of capturing the correlations predicted by quantum theory in terms of classical probability.

From that point on, two fields developed that are key to understanding the current situation. On one hand, there emerged the line of research grouped under “Foundations of Quantum Mechanics,” which, within physics and from its instrumentalist standpoint, seeks to technically exploit the new quantum correlations revealed by entanglement. Note, by the way, that today's big technological developments in quantum information processing were held back for half a century by the very “understanding” of the theory that, broadly speaking, we still take for granted today. The technologies under development don't prove the success of the Bohrian view of quantum mechanics—quite the opposite: they prove the dangers of its dogmatism.

On the other hand, the situation would encourage a revival of debates about what the theory refers to, about its connection with the real, opening an apparent crack in the instrumentalist orthodoxy. These new conceptual ventures, however, would end up boxed in within the field of “Philosophy of Quantum Mechanics” and, instead of leading to a questioning of the standard picture assumed by physicists, and thus making it possible to rethink the theory, they were reduced to, so to speak, *making up little stories*. Ever since, philosophers of physics (and a few retired physicists) have devoted themselves to proposing “interpretations” that would supposedly tell us what the world is like according to quantum mechanics. As if, in physics, conceptual ventures were (ignoring Einstein's and Heisenberg's methodological warnings) mere narratives that can be *tacked on* to already complete theories, rather than a strictly fundamental component of any physical theory. But the problem is also that, cut off from quantum theory like this, all these stories lack something that would make them necessary, or that would let us decide which one is the “right” one. And so interpretations have multiplied in recent decades with no real criteria or constraints, some with more marketing success (like “many worlds”) and others with less. 

![](https://storage.ghost.io/c/2b/7f/2b7f69fc-a243-4d2f-ae8e-db8312c6653a/content/images/2026/10/MV5BN2YxZGRjMzYtZjE1ZC00MDI0LThjZmQtZTZmMzVmMmQ2NzBmXkEyXkFqcGc@._V1_.jpg)

David Mermin summed up this curious landscape not long ago: 

> Quantum theory is the most useful and powerful theory physicists have ever devised. And yet today, almost 90 years after it was formulated, disagreement over what the theory means is stronger than ever. New interpretations pop up every day. None of them ever goes away.

But it was a Spanish physicist, Adán Cabello, who best captured this ridiculous situation when he called the sea of quantum “interpretations” multiplying for no reason a veritable “[map of madness](https://arxiv.org/abs/1509.04711?ref=421.news).”

## The Scientist and the Conspiracy Theorist

So we end up in a situation where, on one side, we have an instrumentalist practice devoted to churning out algorithmic models but incapable of rethinking the theory, and therefore of investigating the nature of the problems that, among other things, derail or complicate that very instrumental practice. A pragmatism that often believes itself free of theoretical contamination, but that in reality is constantly hindered and limited by the theoretical assumptions that shape its activity, assumptions it no longer even recognizes. Faced with this, the tendency is to flee forward, throwing more and more data, and more and more dollars, at the problems. 

![](https://storage.ghost.io/c/2b/7f/2b7f69fc-a243-4d2f-ae8e-db8312c6653a/content/images/2026/11/PHOTO-2026-06-19-10-44-49.jpg)

On the other side, we have the criterion-free production of more or less fantastical narratives, with better or worse marketing, but with no real theoretical role and no conditions that systematically connect them to the theory they supposedly represent. And in the middle, the only thing that's clear, the one thing we can all agree on, is that Richard Feynman's words when he said that “nobody understands quantum mechanics” still hold completely true.

> We have an instrumentalist practice devoted to churning out algorithmic models but incapable of rethinking the theory, and therefore of investigating the nature of the problems.

The consequences of this state of affairs, caught between a pragmatic science that forgot how to think and an irresponsible production of narratives that not even their own champions really believe in, are anything but minor. If the so-called “experts,” leveraging the authority of their credentials or the supposedly extreme difficulty of their field, can so brazenly peddle tall tales about the existence of infinite universes that have never been experimentally tested, or about there actually being 11 dimensions (but they're really “teeny”!), if they can use their position to push narratives as adolescent as the [conspiracy theories](https://www.421.news/en/qanon-one-conspiracy-all-conspiracies/) multiplying across the internet, then the line between the discourse of the scientist and that of the flat-earther or the climate change denier quickly wears away, and distrust of science finds an excuse to spread through society. 

![](https://storage.ghost.io/c/2b/7f/2b7f69fc-a243-4d2f-ae8e-db8312c6653a/content/images/2026/10/hx71v22wv21h1.jpg)

On the other hand, if the same theory talks about such different things, mutually incompatible, all at once, and there's no way to decide between them, then it isn't talking about anything at all, and the reference of physics (and its relationship to reality) finally dissolves into this *map of madness*.

## The Battle Between Einstein and Bohr: Physics in Dispute

At this point we can contrast two visions of physics. On one side, a conception ultimately anchored in Bohr's work and in the centrality of classical concepts. That anchoring makes it possible to maintain an appearance of familiarity, and the guarantee of a connection to a supposed “common sense” represented precisely by the concepts of Newton's and Maxwell's physics. A vision that, resting on that starting point, now turned into an assumption, comes to think of physical theories as mere predictive devices, ultimately meant to serve technical ends (to which, if you like, and inconsequentially, “interpretations” can be added). This view of what physicists do not only pays the price of losing interest in what makes a physical theory an incredible construction that lets us think the world; it even delays or jeopardizes its own goals.

On the other side, we find a vision of physics like the one Einstein held. Or like the one on display in large parts of the work of Wolfgang Pauli, or of Heisenberg, for whom, let's recall:

> The history of physics is not only a sequence of experimental discoveries and observations, followed by their mathematical description; it is also a history of concepts. For an understanding of the phenomena the first condition is the introduction of adequate concepts. Only with the help of correct concepts can we really know what has been observed.

A vision for which understanding is the first condition, the one that allows us not only to know what we are observing but also to make meaningful predictions, and which, as Pauli reminds us, takes us back to the very origin of our scientific endeavors in [ancient Greece](https://www.421.news/en/purism-homer-odyssey-nolan-movie-en/):

> "Understanding" probably means nothing more than having whatever ideas and concepts are needed to recognize that a great many different phenomena are part of a coherent whole (…). The reduction of a colorful variety of phenomena to a general and simple principle, or, as the Greeks would have put it, the reduction of the many to the one, is precisely what we mean by "understanding." The ability to predict is often the consequence of understanding, of having the right concepts, but it is not identical to understanding.

We can say, in fact, that what a physical theory fundamentally seeks is to answer, in its own way, an ancient Greek question: what remains the same through change and regardless of perspective? A question we could also paraphrase like this: is it possible to develop knowledge of a physical becoming in constant motion? Can we find necessity, repetition, order in the physical world? 

> We can say, in fact, that what a physical theory fundamentally seeks is to answer, in its own way, an ancient Greek question: what remains the same through change and regardless of perspective?

Answering this is the difficult feat physical theories attempt to pull off. And to do so, modern mathematical physics built a set of conditions that guide researchers in developing new theories. First, the theory must contain an operationally invariant mathematical formalism. Here the emphasis has to be on *invariance*. Invariance defines, in mathematical terms, what must be considered *the same* in a physical theory, and, in that sense, its moments of unity, its units of meaning, the elements it talks about. Invariance is what allows us to go beyond ourselves and ensure that different frames of reference are talking about the same state of affairs, which therefore presents itself as independent of the observer, and whose evolution can be described as the evolution of the same thing. This is perfectly achieved, for example, in Newtonian mechanics through the Galilean transformations, that is, a set of mathematical relations that allow us to translate between different reference frames (the perspectives) and thus conceive of them as referring to the same state of affairs. And one could even say that it's not only classical physics that meets this condition, but also the relativity developed by Einstein.

Let's take the example of special relativity, which works perfectly as an illustration. Einstein faced three conditions that, in principle, you'd want to hold all at once, but that turned out to be incompatible: the finding that the speed of light is independent of reference frames (that is, it's always the same); the Galilean transformations; and the principle of relativity, which establishes the equivalence of inertial reference frames (in them the laws of physics are the same and, consequently, experiments will yield the same results). The problem was that under Galilean transformations velocities add up, so light couldn't have the same value in every frame unless there were a privileged one, which would cancel out the equivalence between them. The “common sense” option was to cling to the Galilean transformations and, with them, to classical absolute space and time. But Einstein chose the opposite: he kept the evidence about the speed of light and, above all, the principle of relativity (which expresses the requirement that the theory not depend on the particular choice of reference frame), and replaced the classical transformations with the Lorentz transformations.

The price of preserving a consistent translation of experience across different perspectives was the relativization of the notions of absolute space and time, which had become part of physicists' “common sense” thanks to the success of classical mechanics, and which now, according to Einstein's theory, were relative and intertwined notions. The picture of space and time thus changed radically. To preserve the possibility and consistency of an objective physical theory, Einstein introduced a conceptual innovation foreign to the physics of his day. For something to remain the same across perspectives, that something had to change. Fidelity to the basic conditions of a consistent, invariant physical theory struck him, rightly, as more important than fidelity to the concepts of classical mechanics.

![](https://storage.ghost.io/c/2b/7f/2b7f69fc-a243-4d2f-ae8e-db8312c6653a/content/images/2026/11/Niels_Bohr_Albert_Einstein_by_Ehrenfest.jpg)

Niels Bohr and Albert Einstein.

Driven by Bohr, the methodology that gave rise to the standard formulation of quantum mechanics could thus be seen as a diametrically opposite path. While Einstein, in order to preserve a consistent representation across different reference frames, had replaced Newton's classical concepts with new ones, Bohr applied exactly the reverse methodology. In order to save the worldview of classical physics, quantum theory had to be understood as a “generalization” of it, thereby forcing reference to an essentially inconsistent microscopic world. The *same* quantum entities would then be conceived in incompatible terms: behaving either as elementary “particles” or as “waves.” According to Bohr, quantum objects require “complementary” (albeit incompatible) classical representations such as “wave” and “particle,” which depend explicitly on the choice of a particular experimental context, which destroys invariance and objectivity. This makes it impossible to think of anything as *the same* across perspectives, and therefore leads us to give up the great power of physics to articulate a moment of unity capable of accounting for diverse phenomena, that is, as the Greeks demanded, of showing the one in the many.

## *Back to the Future*: The Return to Heisenberg and Another Possible Path

But is another path possible? Can we do with quantum theory something similar to what Einstein did with relativity? Can we find that invariance to lean on in order to move toward a conceptual innovation? Contrary to what's commonly believed, the truth is yes: the quantum formalism is operationally invariant, and has been from the very start, ever since Werner Heisenberg's matrix formulation, which we discussed in the [first installment](https://www.421.news/en/what-is-quantum-physics-origin-heisenberg-en/). A return to Heisenberg, to the theory's first formalism, may give us the key to finding a way out of the labyrinth the standard interpretation left us in. As we saw, Heisenberg, trying to develop a consistent and closed mathematical formalism, had for a while followed the lead of Bohr and his atomic model. However, the critical reaction of Pauli and Sommerfeld led him to distance himself from the Bohrian methodology. So, instead of trying to describe the trajectories of presupposed particles, Heisenberg reframed the question in terms of properly observable quantities. And what was actually observed in the lab were intensity spectra. That's what the data tables Heisenberg tried to model mathematically describe, and they eventually (with the help of Max Born and Pascual Jordan) led him to the first mathematical formulation of quantum theory. Here's how Heisenberg himself remembers it:

> When I resumed my work in Göttingen during the summer semester of 1925 (…), I began my scientific task by trying to figure out the correct formulas for the intensities of the lines in the hydrogen spectrum (…). The attempt failed. I plunged into an impenetrable thicket of complicated mathematical formulas from which I could find no way out. Nevertheless, the attempt convinced me that there was no need to inquire into the orbits of the electrons in the atom, but that the totality of the oscillation frequencies and the quantities that determine the intensity of the lines (the amplitudes) could serve as a perfectly valid substitute.

And those intensive quantities (that is, non-binary values, which admit of degrees: not just 0 and 1 but every value in between), once freed from a supposedly necessary reduction to atomic elements, are precisely what the formalism points to as invariant, as what remains the same. The condition for capturing that invariance, then, is not to presuppose from the outset the “common sense” of classical concepts. Radically new, and of strictly fundamental importance for producing a consistent and invariant formalism for quantum mechanics, was this intuition that we can accept intensive values as basic, as (in Heisenberg's words) perfectly valid “substitutes.” 

Intensities thus appeared, in mathematical terms, as basic and sufficient, that is, not as secondary measures of a more fundamental, classical, atomistic state of affairs, one that implies a binary mode of thinking (the atomistic is what either is or isn't there: a particle in an orbit, an electron in a state). And they therefore seemed to call for a conceptual representation suited to them, one grounded in the notion of an originally intensive physical element. Because if invariance, as we said, is a basic condition for any physical theory, it is equally fundamental to find the right concepts that allow us, with that formalism, to think experience, and therefore to know what we are observing, to imagine experimental situations that push our inquiries forward, even to imagine experiments that were off-limits to the conceptualization of earlier theories. And for that, a theory whose mathematical formalism is entirely different from that of classical physics, whose invariance points toward physical elements that cannot be captured by classical concepts (such as particle and wave), obviously requires a different conceptual representation. Just as Einstein was forced to abandon the classical concepts of space and time, in quantum mechanics we need to break free of the classical conceptual apparatus when it comes to thinking about its entities. We need to clear out those presuppositions in order to be able to produce a conceptual representation that makes it possible to understand quantum mechanics, that is, to develop the concepts that, connected to the mathematical formalism, allow us to think consistently about the field of phenomena the theory tells us about.

> Just as Einstein was forced to abandon the classical concepts of space and time, in quantum mechanics we need to break free of the classical conceptual apparatus when it comes to thinking about its entities.

As we have tried to show in several [papers](https://www.nature.com/articles/s41598-025-30083-5?ref=421.news), doing this actually clears up a lot of difficulties. Taking a new (intensive) representation of quantum mechanics as a starting point, it becomes possible to conceive of a state of affairs that is independent of observers and their perspectives, recovering a genuine objective reference to quantum reality. Thus both the relativism and the discursive inconsistency of the standard formulation appear not as inevitable “lessons” of quantum mechanics, but as the consequences of a dogmatism: the need to confine all of physics, past and future, to classical language.

In any case, and beyond the specifics of our proposal, this lets us say that quantum physics, in the end, isn't really all that weird. Or maybe it is, but in a different sense than we expected. The interpretations we now see multiplying like scenarios out of over-the-top [science fiction](https://www.421.news/en/science-fiction-reading-guide/) look less like consistent physical representations than like ever more exaggerated and absurd detours to hang on to the concepts of classical physics. People would rather, for example, multiply worlds than conceive of the physical world through other concepts. It's not that weird, but it is different, because, quite simply, its concepts are different. The necessary sacrifice is another one, different from the one Bohr proposed, and probably a less costly one, though perhaps more demanding on thought. Instead of pushing classical concepts to the point of absurdity or inconsistency, what we need is to think up a new system of concepts. 

In short, quantum theory is, in methodological and structural terms, similar to other physical theories: it contains an invariant mathematical formalism that can be related to an objective conceptual representation, which in turn allows for a consistent understanding of what is observed. Methodologically and structurally similar, but conceptually different. Quantum theory is an invariant, objective, operational physical theory only if we are able to suspend the idea that we already know what the “physical world” is, to embark on a critique of notions we had taken, without thinking, as self-evident, and finally to move forward with the task of providing the right concepts for this remarkably powerful theory. A demanding task, but an essential one for contemporary thought.