When reality is not out there: Making sense of quantum weirdness

Reading | Quantum Physics

Prof. Arash E. Zaghi, PhD, PE, SE | 2025-11-21

Why the idea of a world “out there” feels so obvious

From the moment we open our eyes in the morning, the world feels like something already there. The alarm clock was there before we woke up. The mug in the kitchen was waiting on the counter. The tree outside the window stood there through the night. Our personal experiences come and go, but the stage on which they happen seems solid, continuous, and independent of us.

That feeling is not a mistake in any trivial sense. Our nervous system is trained from infancy to expect a stable outside world. By a few months of age, babies already behave as if objects keep existing when hidden, a skill psychologists call “object permanence” [1].

Later in life, the brain refines this into a powerful predictive machine that constantly guesses what comes next and corrects its errors. Theories in neuroscience describe this as the brain’s drive to reduce “prediction error” or “free energy” [2,3].

This strategy is extremely useful. It keeps us alive. It lets us cross the street, recognize a friend, and trust that the floor will still be under our feet when we take the next step. So it is no surprise that the idea of a ready-made external world feels like common sense.

The question I want to explore is more radical. When we set aside common sense and look carefully at how nature behaves in precise experiments and in the mathematics of quantum theory, is it still accurate to say that there is a single physical reality “out there,” existing in the same definite way for everyone, independent of any perspective?

My claim, based on recent work in quantum foundations, is that the answer is no. There is no universal, context-free story of “what is really happening” behind all appearances. Reality does not exist as a fixed inventory of objects with pre-given properties. It is better understood as a web of relations that only become definite within particular perspectives, inside a single field of awareness [4,5].

This sounds like a direct clash with our most intimate experience. That is why it deserves to be unpacked slowly and with care.

 

What the quantum experiments really say

Most readers will have heard of the famous double-slit experiment. Richard Feynman went so far as to say that it contains the essential mystery of quantum mechanics [6].

The basic setup is simple. You fire tiny particles, like electrons, at a screen with two narrow openings, then record where they land on a detector behind the slits. When you send the electrons one by one, you see individual dots. Over time, those dots form an interference pattern of bright and dark bands, as if each electron somehow behaved like a wave that went through both slits at once and then interfered with itself.

Now you modify the apparatus so that you can tell which slit each electron went through. You do not have to hit it with a hammer. Even a very gentle “which-way” detector is enough. Once you do this, the interference pattern disappears. The electrons now arrive in two broad clumps, one behind each slit, as if they were ordinary particles that chose a route. Remove the which-way information and the interference returns [2,7].

The result is not a curiosity from old textbooks. It has been filmed and measured in exquisite detail, electron by electron [7].

What does this really tell us?

If there were a single, context-independent story about what each electron “really does,” we would expect to be able to describe it like this: each electron has a definite path at all times, and our detectors simply reveal that path. But the double-slit experiment refuses that description. When we ask “which slit?” the world answers with one kind of pattern. When we do not ask, it answers with a different pattern. There is no way to keep all the answers together inside one classical narrative about pre-existing paths.

Physicists call this dependence on the questions we ask a dependence on measurement context. A “context” is simply a precise set of compatible questions we arrange to ask at once.

This is not limited to the double-slit experiment. Consider the spin of an electron, which can be tested along different directions. If we measure spin “up or down” along the vertical axis, we can repeat the test and get stable, predictable results. If we then rotate our apparatus and test along a horizontal axis, we again get stable answers for that new question. But we cannot have both sets of stable answers at once. Choosing one test disturbs the answers to the other. The properties we talk about are not simply labels already written on the electron. They crystallize as definite only within the context we choose.

Over the last decades, this intuition has become mathematically sharp. Contextuality theorems show that, for a wide class of quantum experiments, there is no way to assign pre-existing values to all possible measurements that agree with what we actually observe. Any attempt to do so leads to contradictions [4].

More recently, extended “Wigner’s friend” experiments have pushed this point even further. They suggest that it is not only the properties of particles that resist a single global description, but even the “facts” recorded by different observers. Consistency between all perspectives cannot always be maintained if we insist that every observed event has an absolute, observer-independent status [8,9].

Taken together, these results deliver a clear message. The world does not behave as if there were a universal God’s-eye ledger that lists, once and for all, the outcomes of all possible measurements. The idea of a perspective-free, fully classical story is simply not compatible with quantum phenomena.

 

A simple principle hidden inside the quantum rules

So far, this might sound like familiar quantum weirdness. Many interpretations accept the strange behavior but treat the mathematical rules, especially the rule for probabilities, as mysterious givens.

Those probabilities are encoded in Born’s rule. It tells you how to turn the abstract quantum state into concrete chances for different outcomes once you choose a measurement. The rule has been spectacularly successful, yet in most formulations of quantum theory it arrives with little explanation. It is simply postulated.

In my recent technical work, I asked a very simple question. Suppose you accept that reality has an underlying quantum description. Suppose you also accept that any actual experiment gives only a partial view, because each context asks only a limited set of questions. Given those two assumptions, is there a natural way to say how this underlying quantum situation appears from the point of view of a particular context?

The answer is yes, and surprisingly, it picks out Born’s rule uniquely.

Here is the idea in everyday terms.

Think of the full quantum state as a rich, high resolution scene that no single experiment can take in completely. A given measurement context is like a camera with a particular lens. It can record some aspects of that scene very sharply and is blind to others.

Now ask: among all the simplified “pictures” you could assign to this context, which one stays as faithful as possible to the full underlying scene, while respecting what the lens can actually resolve? In information theory, being faithful in this sense means losing as little information as possible. The loss can be measured by a standard quantity known as relative entropy or information distance.

Mathematically, one can prove that there is a unique best answer to this question. For each context, there is a single probability assignment that minimizes the information distance to the full quantum state. When you work through the details, this optimal assignment turns out to be exactly what Born’s rule prescribes [4,10].

In other words, the familiar quantum probabilities are not arbitrary. They express the best possible way for a particular perspective to summarize a deeper situation it can never see completely. Each context gets its own “least distorted” shadow of the underlying quantum reality.

The really striking part comes next. What happens when you try to stitch all these best local shadows together into a single classical picture that works for every possible context at once?

Here, the mathematics says something very definite. For quantum systems that show contextuality, there is an unavoidable positive gap. No single classical model can reproduce all the context-wise optimal summaries simultaneously. To force a classical global story onto the data, you must pay a nonzero price in information distance.

This “contextual divergence” is a quantitative measure of how badly the universe refuses the God’s-eye view.

 

How a shared classical world still manages to appear

If there is no single external ledger of facts, why does the world feel so stable and shared?

Part of the answer lies in the way our brains are wired, as mentioned earlier. They are prediction machines that prefer stable patterns and smooth over ambiguity. But there is also something deeper happening at the level of physics itself.

When a small quantum system interacts with its surroundings, information about some of its properties leaks out into the environment. Light bouncing off a dust grain, air molecules scattering from it, photons hitting your retina or a camera sensor: each interaction carries a little record of the grain’s position and other properties. Work by Wojciech Zurek and others has shown how this process, called decoherence, suppresses fragile quantum superpositions and singles out certain stable “pointer states” [11].

Quantum Darwinism builds on this insight. The environment does not merely destroy superpositions. It also acts as a vast communication channel that redundantly copies information about those stable states into many fragments of the world. Many different observers can then intercept different subsets of these fragments and still agree on the same classical facts, such as “the dust grain is here” [12].

Recent experiments with superconducting circuits and other platforms have directly probed this redundancy. They find multiple, independent imprints of the same system state in different parts of the environment, just as quantum Darwinism predicts [12].

Put simply, the environment continuously writes a public newsfeed of certain durable facts. Those facts are not absolute in the sense of belonging to a view from nowhere. They are stable relational patterns that many observers can access and agree on because they are copied widely. It feels as if there were an external world because we are all reading from the same emergent channel.

From this angle, “objectivity” does not mean a hidden, perspective-free realm behind experience. It means robust agreement across many overlapping perspectives inside experience. The classical world is the surface of this agreement, not the foundation below it.

 

Reality as a field of relations in awareness

So far, the story is still framed in physical language. We talk about quantum states, environments, observers, and information flows. Yet the mathematics and the experiments leave us with an important question.

If there is no God’s-eye ledger of facts, no view from nowhere, what is reality actually made of?

One influential family of views, known as relational quantum mechanics, takes a bold step. It says that the quantum state and the properties of a system are always relative to some other system. There is no absolute state, no context-independent value of an observable, no event that simply “happens,” full stop. Reality is the network of relations among systems [6].

This is already a significant move away from the idea of an external world of things. Yet it still treats “systems” as the basic ingredients. A natural next step is to ask whether even those systems might themselves be appearances within something more fundamental.

Here is the picture that I find most coherent and that aligns with both the mathematics and our direct experience. Reality is a single field of awareness. Not awareness as a property “inside” a brain, but awareness as the basic “stuff” of existence. Within this field, there are many local perspectives. Each perspective is a way the field looks at itself. Each interaction between perspectives gives rise to a relation, and it is these relations that show up as physical events.

On this view, an “observer” is not a separate subject peering at an external world. An observer is a localized pattern in awareness that has formed enough stability to carry a point of view. An “object” is another pattern with which this point of view enters into relation. The quantum rules, including Born’s rule, then describe how the field of awareness organizes these relations so that they hang together consistently.

My variational result about Born’s rule fits naturally into this picture. For each context, the field of awareness chooses the least distorted local face it can present, given the limitations of that perspective. The Born probabilities are the weights of that face. The impossibility of gluing all local faces into a single classical story reflects the simple fact that there is no place outside awareness from which such a story could be told. There is only the inside, endlessly relating to itself.

The relational and the idealist readings therefore meet. We do not have to choose between “the world is made of relations” and “the world is mental.” Relations are relations within experience. The web has no outside.

 

Living in a world that has no outside

This conclusion can be unsettling. It confronts the part of us that longs for a stable, objective ground outside the flux of experience. It may even sound like it undermines science.

I think the opposite is true.

Modern physics, especially quantum theory, is already telling us that clinging to a view from nowhere is not honest. Contextuality, Bell’s inequalities, Wigner’s friend theorems, and the information-theoretic structure behind Born’s rule, all point away from a single pre-existing world and toward a reality that only becomes definite through relations.

Taking this seriously does not mean abandoning rigor. It means listening carefully to what the math and the experiments are saying, rather than forcing them back into a picture they clearly reject.

At the same time, acknowledging that there is no physical reality “out there,” in the old sense, does not make our shared world dissolve. The table does not vanish when you realize it is a stable pattern in awareness. It still holds your coffee. The difference is that we no longer imagine a layer of dead matter sitting behind experience as its cause. We see that what we call “matter” is the way experience arranges itself when many perspectives lock into mutual agreement.

This change of view can have practical consequences. It softens the sense of alienation from the world. If there is no hard boundary between “me in here” and “world out there,” then every interaction is intimacy within a single field. It also invites humility. My personal perspective is not the whole, but it is also not cut off from the whole. It is one window among many, all belonging to the same living reality [13].

We began with a simple feeling: that there is a world out there, independent of us. We have seen that this intuition, while useful for survival, is not supported by a deeper look at nature. Quantum mechanics, read carefully, points instead to a world of relations that never converge into a view from nowhere, and to a single field of awareness in which these relations unfold.

In that sense, reality truly has no outside.

 

References

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[3] Friston, K., & Kiebel, S. (2009). Predictive coding under the free-energy principle. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1521), 1211–1221. https://doi.org/10.1098/rstb.2008.0300

[4] Zaghi, A. E. (2025). Born’s rule from contextual relative-entropy minimization. Entropy, 27(9), 898. https://doi.org/10.3390/e27090898.

[5] Rovelli, C. (1996). Relational quantum mechanics. International Journal of Theoretical Physics, 35(8), 1637–1678; and Rovelli, C. (2019, updated 2025). Relational Quantum Mechanics. In The Stanford Encyclopedia of Philosophy.Stanford Encyclopedia of Philosophy

[6] Feynman, R. P., Leighton, R. B., & Sands, M. (n.d.). The Feynman Lectures on Physics, Vol. III, Ch. 1: Quantum Behavior (New Millennium ed.). California Institute of Technology. Retrieved September 4, 2025. feynmanlectures.caltech.edu

[7] Tonomura, A., Endo, J., Matsuda, T., Kawasaki, T., & Ezawa, H. (1989). Demonstration of single-electron buildup of an interference pattern. American Journal of Physics, 57(2), 117–120. https://doi.org/10.1119/1.16104.

[8] Bong, K. W., Utreras-Alarcón, A., Ghafari, F., Liang, Y. C., Tischler, N., Cavalcanti, E. G., Pryde, G. J., & Wiseman, H. M. (2020). A strong no-go theorem on the Wigner’s friend paradox. Nature Physics, 16, 1199–1205. https://doi.org/10.1038/s41567-020-0990-x.

[9] Proietti, M., Pickston, A., Graffitti, F., Barrow, P., Kundys, D., Branciard, C., Ringbauer, M., & Fedrizzi, A. (2019). Experimental test of local observer independence. Science Advances, 5(9), eaaw9832. https://doi.org/10.1126/sciadv.aaw9832.

[10] Petz, D. (1986). Sufficient subalgebras and the relative entropy of states of a von Neumann algebra. Communications in Mathematical Physics, 105(1), 123–131. https://doi.org/10.1007/BF01212345

[11] Zurek, W. H. (2003). Decoherence, einselection, and the quantum origins of the classical. Reviews of Modern Physics, 75(3), 715–775. https://doi.org/10.1103/RevModPhys.75.715

[12] Zhu, Z., Salice, K., Touil, A., Bao, Z., Song, Z., Zhang, P., Li, H., Wang, Z., Song, C., Guo, Q., Wang, H., & Mondaini, R. (2025). Observation of quantum Darwinism and the origin of classicality with superconducting circuits. Science Advances, 11(31), eadx6857. https://doi.org/10.1126/sciadv.adx6857

[13] Zaghi, A. E. (2025, May 16). Relational Quantum Dynamics and Indra’s Net: A non-dual understanding of quantum reality. Essentia Foundation. https://www.essentiafoundation.org/relational-quantum-dynamics-and-indras-net-a-non-dual-understanding-of-quantum-reality/reading/