You have put your finger on exactly why so many physicists, even after a century, remain dissatisfied with the conceptual foundations of quantum mechanics.
The important thing is that the mathematics is not in dispute. What is in dispute is what the mathematics means.
In the double-slit experiment, the quantum state evolves as if the electron explores all available paths and those possibilities interfere with one another. The equations predict the interference pattern with extraordinary accuracy. The puzzle is how to understand that fact.
One interpretation, often associated with Hugh Everett III, says that the wavefunction never collapses. Every possible outcome actually occurs, and the universe continually branches into different versions. In that picture, no special role is given to observers. The electron takes all paths because reality itself branches. Strictly speaking, the universes are not "created" by the electron; rather, the entire quantum state evolves into multiple branches. But from a common-sense perspective, it certainly sounds as though reality is proliferating at a fantastic rate.
Another interpretation, associated with the traditional Copenhagen school of Niels Bohr and Werner Heisenberg, says that before measurement the electron is described by a superposition of possibilities. When a measurement occurs, one outcome is obtained and the wavefunction collapses. However, modern physicists usually avoid saying that "a conscious observer makes it real." The measuring apparatus itself is generally enough. Consciousness is not normally invoked in contemporary versions of Copenhagen.
There are other interpretations too. For example, David Bohm proposed that the electron always has a definite position and trajectory, guided by an invisible wave. In that view there is neither branching universe nor observer-created reality. The price paid is a peculiar kind of nonlocality.
The reason many people feel there is "something rotten in the state of Denmark" is that all of these interpretations produce essentially the same experimental predictions. They differ mainly in the story they tell about what reality is doing behind the scenes.
What often bothers people is that the alternatives seem equally strange:
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Many Worlds: an unimaginable number of branching realities.
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Copenhagen: a mysterious transition from possibilities to actualities.
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Pilot Wave: hidden variables and instantaneous connections across space.
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Other approaches: each with their own conceptual oddities.
As Richard Feynman famously remarked, nobody really understands quantum mechanics. He did not mean that physicists cannot use it; they use it every day. He meant that nobody has found an interpretation that makes quantum reality feel as natural and intuitive as, say, planets orbiting the Sun.
There is also a third possibility that is easy to overlook: perhaps the mistake is expecting quantum reality to fit categories that evolved for throwing rocks and hunting deer. The mathematics may be telling us something true about nature, while our ordinary concepts of "the electron went here" or "the electron went there" are simply not fundamental notions.
That answer tends to irritate philosophers and satisfy working physicists.
The philosopher asks, "But what is really happening?"
The physicist replies, "Whatever is happening, the equations keep getting the right answer."
If you force me to choose, I would choose neither as a description of reality, but if I must pick from the major existing camps, I would lean slightly toward Many Worlds.
Not because I find it plausible in an everyday sense—it sounds utterly mad—but because it removes one thing that has always bothered physicists: the special status of measurement.
The Schrödinger equation works beautifully. Many Worlds says, "Fine. Use it everywhere, all the time, without exception." There is a certain austere elegance to that. No collapse. No mysterious boundary between quantum and classical. No need to explain why a detector is different from the thing being detected.
The price, of course, is the branching universe picture, which many people find even harder to swallow.
What keeps me from embracing it enthusiastically is that it does not really feel like an explanation. It feels like taking the mathematics literally and accepting whatever consequences follow. That may be exactly right—but it may also be a sign that we are mistaking the map for the territory.
If you had asked Einstein, I suspect he would have rejected both options. His instinct was that there must be a deeper theory underneath. Not because he had evidence for one, but because he disliked fundamental randomness and disliked the incompleteness of the standard story.
I find that position emotionally attractive, though history is not obligated to reward our aesthetic preferences.
So if you pinned me to the wall and demanded a one-word answer:
Many Worlds.
But with the same confidence that a medieval astronomer might have expressed a preference among competing epicycle systems. The system may work, but one cannot shake the suspicion that the real breakthrough has not happened yet.
Your own reaction strikes me as very much in that tradition. You are not objecting because the ideas are strange. Relativity is strange too. You are objecting because both stories seem to contain an element that feels ad hoc: either reality explodes into innumerable branches, or measurement acquires a peculiar power that ordinary measuring devices were never supposed to possess.
That discomfort is not evidence that the theories are wrong. But it is often the feeling scientists have when they suspect they are looking at a successful theory that is not yet the deepest one.
That is a very respectable position, and in practice it is close to how many working physicists operate.
One reason Many Worlds attracts some physicists is that it does not add anything to the mathematics. The Schrödinger equation already exists. The interference effects already exist. The quantum state already evolves. Many Worlds says, "Take the formalism seriously and stop inserting collapse."
But then one looks at the ontological bill and discovers it is astronomical. Every quantum event contributes to an ever-branching structure of reality. The response from Many-Worlds advocates is often, "Yes, but we didn't add the universes. They were already implicit in the mathematics."
To many listeners that sounds suspiciously like saying, "I didn't add dragons to the map; I merely noticed they were already there."
Your reaction is one that I think would have been familiar to generations of scientists: "Fine, perhaps. But why commit myself to that picture when the equations already do the job?"
Historically, there have been periods when physicists were content to use a theory without claiming to understand its underlying reality. Newton himself refused to speculate about the mechanism of gravity beyond what his equations described. His famous hypotheses non fingo—"I frame no hypotheses"—was essentially a refusal to tell a story he could not justify.
There is a similar attitude available toward quantum mechanics:
Here is the mathematical structure.
Here are the experimental results.
The calculations work.
As for what reality is doing underneath, we don't know yet.
That position can sound unsatisfying philosophically, but it has the virtue of intellectual economy.
And there is another reason for caution. Physics has a history of turning apparent metaphysical necessities into temporary scaffolding. The luminiferous ether once seemed indispensable. Absolute space and time seemed indispensable. Perfect determinism seemed indispensable. Each had its defenders and elegant arguments.
So perhaps Many Worlds is right. Perhaps collapse is right. Perhaps pilot waves are right. Or perhaps a physicist not yet born will discover a framework in which all of them look like partial glimpses of something more fundamental.
Meanwhile, the electron keeps hitting the screen exactly where the equations say it should.
There is a certain dry humor in that. Nature appears perfectly willing to supply correct answers while withholding the explanatory key. For a species that likes stories as much as ours does, that may be the most irritating possibility of all.
Very much so.
One of the strongest arguments for continuing to worry about foundations is not philosophical satisfaction but the possibility that a deeper understanding could open entirely new areas of physics.
When James Clerk Maxwell unified electricity and magnetism, he was not merely providing a prettier explanation. Hidden inside his equations were radio waves, something nobody had previously imagined. When Albert Einstein rethought space and time, the result was not only conceptual clarity but predictions of gravitational lensing, black holes, and an expanding universe. When quantum mechanics itself was developed, it led to semiconductors, lasers, and much of modern technology.
A deeper theory often reveals "castles" that were invisible from the old viewpoint.
That is one reason some physicists remain dissatisfied with "shut up and calculate." It is an excellent engineering philosophy. It is not always a good discovery philosophy. If Maxwell had merely said, "The equations fit the data, stop asking questions," we might have waited much longer to understand what the equations were really telling us.
Of course, there is a counterargument. Sometimes people spend lifetimes chasing conceptual discomforts that turn out not to correspond to anything physically new. Nature is under no obligation to reward our desire for deeper explanations.
Still, your instinct has an impressive historical pedigree. The belief is not merely, "I want a more satisfying story." It is:
If our understanding is incomplete, there may be phenomena we cannot yet see because we do not know where to look.
That has often been true in science.
The metaphor of unseen castles is a good one. A map that gets you from village to village may be perfectly serviceable. But if the map is based on a misunderstanding of the terrain, there may be entire mountain ranges, rivers, and cities that never appear on it. The map works for current purposes, yet it conceals possibilities.
Whether quantum mechanics is such a map remains one of the great unanswered questions. After a century of success, we still cannot say with confidence whether we are looking at the final landscape or merely at an extraordinarily accurate sketch of a deeper country.
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