The role of observation in events has been a staple of quantum physics for decades and is closely associated with "the Copenhagen interpretation". On closer inspection, it turns out that everyone connected with Bohr's lab in Copenhagen had a slightly different view on how to interpret the Schrödinger equation. Worse, those who go back and look at Bohr's publications nowadays tend to confess that they cannot tell what Bohr's view was. For example, Adam Becker speaking to Sean Carroll (time index 21:21; emphasis added):
I don't think that there is any single Copenhagen interpretation. And while Niels Bohr and Max Born and Pauli, and Heisenberg and the others may have each had their own individual positions. I don't think that you can combine all of those to make something coherent...
...Speaking of people being mad at me, this is something that some people are mad at me for, they say, "But you said the Niels Bohr had this position?" I'm like, "No, I didn't, I didn't say that Niels Bohr had any position. I don't know what position he had and neither does anybody else."
So we should be cautious about claims made for "the Copenhagen interpretation", which seem to imply a consensus that never existed at Bohr's lab in Copenhagen.
That said, the idea that observation causes the wavefunction to collapse is still a staple of quantum physics. Despite playing a central role in quantum physics, "observation" is seldom precisely defined in scientific terms, or when it is defined, it doesn't involve any actual observation (I'll come back to this). The situation was made considerably worse when (Nobel laureate) Eugene Wigner speculated that it is "consciousness" that collapses the wave function. "Consciousness" is even less well-defined than "observation". While most academic physicists instantly rejected the role of consciousness in events, outside of physics it became a popular element of science folklore and New Ageism.
The idea that "observation" or "consciousness" are involved in "collapsing the wave function" is also an attachment point for Buddhists who wish to bolster their shaky faith by aligning it with science. The result of such legitimisation strategies is rather pathetic hand waving. Many Buddhists want reality to be reductive and idealist: they want "mind" to be the fundamental substance of the universe. This would align with some modern interpretations of traditional Buddhist beliefs about mind. But the idea is also to find some rational justification for Buddhist superstitions like karma and rebirth. As I showed at length in my book Karma and Rebirth Reconsidered, it simply does not work.
In this essay, I will show that it is trivially impossible for observation to play any role in causation at any level. I'm going to start by defining observation with respect to a person and exploring the implications of this, particularly with respect to Schrödinger's cat. I will also consider the post hoc rationalisation of observation qua "interaction" (sans any actual observation).
What is "An Observation"?
We may say that an observer, Alice, observes a process P giving rise to an event E, with an outcome O, when they become aware of P, E and O. It is possible to be aware of each part individually, but in order to understand and explain what has happened, we really need to have some idea of what processes were involved, what kinds of events it engendered, and the specific outcomes of those events.
It's instructive to ask, "How does Alice become aware of external events?" Information from the process, event, and/or outcome of interest first has to reach her in some form. The fastest way that this can happen is for light from the process, event, and/or outcome to reach Alice's eyes. It always takes a finite amount of time for the light to reach her eye.
But light reaching Alice's eye alone does not create awareness. Rather, cells in the eye convert the energy of light into electrochemical energy (a nerve impulse). That pulse of energy travels along the optic nerve to the brain and is incorporated into our virtual world model and then, finally, presented to the first person perspective. Only then we become aware of it. And this part also takes a finite amount of time. Indeed, this part takes a lot more time than the light travelling.
Therefore, the time at which Alice becomes aware of P, E, and O, is some appreciable amount of time after E happens and O is already fixed. There is no alternative definition of "observation" that avoids this limitation, since information cannot travel faster than the speed of light and the brain is always involved. The only other possibilities are, if anything, slower. Therefore:
Alice can only observe processes, events, and outcomes after the fact.
If observation is always after the fact, then observation can never play any causal role in the sequence of events because causes must precede effects, in all frames of reference. Therefore:
Observation can play no causal role
in processes, events, or outcomes.
This means that there is no way that "observation" (or "consciousness") can cause the collapse the wavefunction. Rather, the collapse of the wavefunction has to occur first, then the light from that event has to travel to Alice's eye. There is no way around this physical limitation in our universe. And given the nature of wavefunctions—the outputs if which are vectors in a complex plane—this can hardly be surprising.
Observation is never instantaneous let alone precognitive. And this means that all talk of observation causing "wavefunctions to collapse" is trivially false.
We could simply leave it at that, but it will be instructive to re-examine the best known application of "observation".
Schrödinger's cat
Schrödinger's cat is only ever alive or dead. It is never both alive and dead. This was the point that Schrödinger attempted to make. Aristotle's law of noncontradiction applies: an object cannot both exist and not exist at the same time. We cannot prove this axiom from first principles, but if we don't accept it as an axiom, it renders all communication pointless. No matter what true statement I may state, anyone can assert that the opposite is also true.
Schrödinger proposed his thought experiment as a reductio ad absurdum argument against Bohr and the others in Copenhagen. He was trying to show that belief in quantum superpositions leads to absurd, illogical consequences. He was right, in my opinion, but he did not win the argument (and nor will I).
This argument is broadly misunderstood outside of academic physics. This is because Schrödinger's criticism was taken up by physicists as an exemplification of the very effect it was intended to debunk. "Yes," cried the fans of Copenhagen type explanations, "this idea of both-alive-and-dead at the same time is exactly what we mean. Thanks." And so we got stuck with the idea that the cat is both alive and dead at the same time (which is nonsense). Poor old Schrödinger, he hated this idea (and didn't like cats) and now it is indelibly associated with him.
The general set up of the Schrödinger's cat thought experiment is that a cat is placed in a box. Inside the box, a random event may occur. If it occurs, the event triggers the death of the cat via a nefarious contraption. Once the cat is in the box, Alice doesn't know whether the cat is alive or dead. The cat is a metaphor for subatomic particles. We are supposed to believe that they adopt a physical superposition of states: say, "spin up" and "spin down", or "position x" and "position y" at the same time before we measure them, then at the point of measurement, they randomly adopt one or the other of the superposed states.
Here's the thing. The cat goes into the box alive. If the event happens, the cat dies. If it doesn't happen the cat lives. And Alice doesn't know which until she opens the box. The uncertainty here is not metaphysical, it's epistemic. It's not that a cat can even be in a state of both-alive-and-dead, it cannot; it's only that we don't know whether it is alive or dead. So this is a bad analogy.
Moreover, even when Alice opens the box, the light from the cat still takes some time to reach her eyes. Observation always trails behind events, it cannot anticipate or participate in events. Apart from reflected light, nothing is coming out from Alice that could participate in the sequence of events happening outside her body, let alone change the outcome.
Also, the cat has eyes and a brain. It is itself an "observer".
Epistemic uncertainty cannot be mapped back to metaphysical uncertainty without doing violence to reason. A statement, "I don't know whether the cat is alive or dead," cannot be taken to imply that the cat is both alive and dead. This is definitely a category error for cats. Schrödinger's view was that it is also a category error for electrons and photons. And again, I agree with Schrödinger (and Einstein).
In that case, why do physics textbooks still insist on the nonsensical both-alive-and-dead scenario? It seems to be related to a built-in feature of the mathematics of spherical standing waves, which are at the heart of Schrödinger's equation (and many other features of modern science). The mathematics of standing waves was developed in the 18th century (i.e. it is thoroughly classical). Below, I quote from the Mathworld article on Laplace's equation (for a spherical standing wave) by Eric Weisstein (2025. Emphasis added)
A function psi which satisfies Laplace's equation is said to be harmonic. A solution to Laplace's equation has the property that the average value over a spherical surface is equal to the value at the center of the sphere (Gauss's harmonic function theorem). Solutions have no local maxima or minima. Because Laplace's equation is linear, the superposition of any two solutions is also a solution.
The last sentence of this passage is similar to a frequently encountered claim in quantum physics. That is to say, the fact that solutions for individual quantum states can be added together and produce another valid solution for the wave equation. This is made out to be a special feature of quantum mechanics that defines the superposition of "particles".
Superposition of waves is nothing remarkable or "weird". Any time two water waves meet, for example, they superpose.
In this image, two wave fronts travel towards the viewer obliquely from the left and right at the same time (the appear to meet almost at right angles). The two waves create an interference pattern (the cross in the foreground) where the two waves are superposed. Waves routinely superpose. And this is known as the superposition principle.
The superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually."
The Penguin Dictionary of Physics.
For this type of linear function, we can define superposition precisely: f(x) + f(y) = f(x+y)
In mathematical terms, each actual wave can be thought of as a solution to a wave equation. The sum of the waves must also be a solution because of the situation we see in the image, i.e. two waves physically adding together where they overlap, while at the same time retaining their identity.
I've now identified three universal properties of spherical standing waves that are frequently presented as special features of quantum physics:
- quantisation of energy
- harmonics = higher energy states (aka orbitals)
- superposition (of waves)
These structural properties of standing waves are not "secret", but they are almost always left out of narrative accounts of quantum physics. And yet, these are important intuitions to bring to bear when applying wave mechanics to describing real systems.
Something else to keep in mind is that "quantisation" is an ad hoc assumption in quantum physics. It's postulated to be a fundamental feature of all quantum fields. The only problem is that all of the physical fields we know of—which is to say the fields we can actually measure—are smooth and continuous across spacetime: including gravitational fields and electromagnetic fields. Scientists have imagined discontinuous or quantized fields, but they have never actually seen one.
Moreover, as far as I know, the only physical mechanism in our universe that is known to quantize energy, create harmonics, and allow for superposition is the standing wave. The logical deduction from these facts is that it is the standing wave structure of the atom that quantizes the energy of electrons and photons and creates electron orbitals.
Quantization is a structural property of atoms, not a substantial property of fields. (Or more conventionally and less precisely, quantization is an emergent property, not a fundamental property).
Also, as I have already explained, the coexistence of probabilities always occurs before any event, and those probabilities always collapse at the point when an event has a definite outcome. There is nothing "weird" about this; it's not a "problem". What is weird, is the idea that hypostatizing and reifying probabilities leads to some meaningful metaphysics. It has not, and it will not.
While the superposition of waves or probabilities is an everyday occurrence. The superposition of physical objects is another story. Physical objects occupy space in an exclusive way: if one object is in that location, no other physical object can also be in that location. Physical objects cannot superpose and they are never observed to be superposed. And yet, the superposition of point particles is how physicists continue to explain the electron in an atom.
The electric field has been measured and it is found to be smooth and continuous in spacetime. Just as predicted by Maxwell. Given this, simple logic and basic geometry dictates that if—
- the electrostatic field of the proton has spherical symmetry, and
- a hydrogen atom is electrostatically neutral, and
- the neutrality is assumed to be the result of the electron's electrostatic field,
—then the electron can only be in one configuration: it must be a sphere (or a close approximation of a sphere) completely surrounding the proton. This is the only way to ensure that all the field lines emerging from the proton terminate at the electron. Otherwise there are unbalanced forces - a net charge rather than neutrality. And a changing electric field dissipates energy, which electrons do not.
Unbalanced forces
Now, if the electron is both a wave and a sphere, then the electron can only be a spherical standing wave. The Bohr model of the atom was incorrect and it surprises me greatly that this problem was not identified at the time.
And if the electron is a spherical standing wave then, because these are universal features of standing waves, we expect:
- The energy of the electron in the H atom will be quantised.
- The electron will form harmonics corresponding to higher energy states and it will jump between them when it absorbs or emits photons.
- When two electron waves intersect, the sum of their amplitudes is also a solution to the wave equation.
Moreover, we can now take pictures of atoms using electron microscopes. Atoms are physical objects. In every single picture, atoms appear to be approximately spherical.
And yet mainstream quantum models do not quite treat atoms as real. Quantum physics is nowadays all about probabilities. The problem is that, as I established in an earlier essay, a probability cannot possibly balance an electrostatic field to create a neutral atom. Only a real electric field can do this. Schrödinger was right to be unconvinced by the probability interpretation, even if it works. But he was wrong about modelling a particle as a wave.
Waves are observed to superpose all the time. Solid objects are never observed to do so. The only reason we even consider superposition for "particles" is the wave-particle duality postulate, which we now know to be inaccurate. "Particles" are waves.
As I understand it, the idea that our universe consists of 17 fields in which particles are "excitations" is a widely accepted postulate. And as such, one might have expected scientists to go back over the physics predicated on wave-particle duality and recast it in terms of only waves. Having the wave equation describe a wave would be a start.
I digress. Clearly the idea that observers influence outcomes is trivially false. So now we must turn to the common fudge of removing the observer from the observation.
Interaction as Observation
One way around the problems with observation, is to redefine "observation" so that it excludes actual observations and observers. The move is to redefine "observation" to mean "some physical interaction". I'm sure I've mentioned this before because I used to think this was a good idea.
While we teach quantum physics in terms of isolated "particles" in empty, flat space, the fact is that the universe is crammed with matter and energy, especially in our part of the universe. Everything is interacting with everything that it can interact with, simultaneously in all the ways that it can interact, at every moment that it is possible to interact. Nothing in reality is ever simple.
In classical physics, we are used to being able to isolate experiments and exclude variables. This cannot ever happen at the nanoscale and below. An electron, for example, is surrounded by an electrostatic field which interacts with the fields around all other wavicles, near and far.
Electrons, for example, are all constantly pushing against each other via the electromagnetic force. If your apparatus contains electrons, their fields invariably interact with the electron you wish to study. This includes mirrors, beam-splitters, prisms, diffraction gratings, and double slits. The apparatus is not "classical", it's part of the quantum system you study. At the nanoscale and below, there are no neutral apparatus.
Therefore, the idea that interaction causes the wavefunction to "collapse" is also untenable because in the real world wavicles are always interacting. In an H atom, for example, the electron and the proton are constantly and intensely interacting via the electromagnetic force. So the electron in an H atom could never be in a superposition.
Conclusions
Observation can only occur after the fact and is limited by the speed of light (or speed of causality).
Neither "observation" nor "consciousness" can play any role in the sequence of events, let alone a causal role.
Schrödinger's cat is never both alive and dead. And observation makes no difference to this (because observation can only ever be post hoc and acausal).
It is always the case, no matter what kind of system we are talking about, that probabilities for all possibilities coexist prior to an event and collapse as the event produces a specific outcome. But this is in no way analogous to waves superposing and should not be called "superposition".
All (linear) waves can superpose. All standing waves are quantised. All standing waves have harmonics.
Defining observation so as to eliminate the observer doesn't help as much as physicists might wish.
"Observation" is irrelevant to how we formulate physics.
The wave-particle duality postulate is still built into quantum mechanics, despite being known to be false.
For the last century, quantum physicists have been trying to change reality to fit their theory. Many different kinds of reality have been proposed to account for quantum theory: Copenhagen, Many Worlds, Qbism, etc. I submit that proposing a wholly different reality to account for your theory is tantamount to insanity. The success in predicting probabilities seems to have causes physicists to abandon science. I don't get it, and I don't like it.
~~Φ~~
Bibliography
Weisstein, Eric W. (2025) "Laplace's Equation." MathWorld. https://mathworld.wolfram.com/LaplacesEquation.html
