Coherence, decoherence and the observer of the state wave

The state wave is a probability wave

The state wave in quantum physics is the solution of the Schrödinger equation, it is thus a mathematical object. This mathematical object predicts the probability of an object, to which that state wave relates, to be found at a given time and location when doing a measurement. Because it is a wave, its medium, whatever that is, should be coherent. The coherence of this state wave plays an important role in quantum physics. When a measurement takes place, the state wave ends abruptly and the object is observed. The end of that wave is often called the decoherence of the state wave. An understanding of what is meant by coherence and decoherence is therefore important for a better understanding of quantum physics.

A coherent phenomenon

In order to exhibit wave behavior, a form of cohesion of the medium is required plus a force that strives for the middle position. In water, this cohesion results from the direct physical connection and attraction of the water molecules. It is gravity that returns the medium to the middle position, the rest position of the water surface. Gravity thus ensures the return to the middle position of the wave. The physical connection, the coherence, of the water molecules ensures that the movement is propagated in the medium.

Surface wave in a liquid. The liquid particles perform a circular movement. So there is no liquid transported by the wave in the direction of the wave.

With a sound wave in air, the air pressure is the force that strives for the middle position. This ambient pressure ensures a return to the middle position. In the middle position, the pressure is therefore equal to the ambient pressure. The coherence of the medium transporting sound waves in air stems from the continuous collision of air molecules, through which they constantly exchange their energy. A sound wave is therefore a coherent phenomenon. This means that the air provides coherence, just like with a liquid.

No air molecules are transported in a sound wave, only areas of high and low pressure. Switching on the sound system does not lower the pressure in the room by transporting air molecules out of the room.

With electromagnetic waves, EM waves, such as light, the coherence is ensured by the fact that a changing magnetic field also causes a changing electric field. And vice versa. These changes are therefore closely related and evoke each other. The force that makes the EM wave return to the middle position is a bit more difficult. Electric and magnetic fields tend to extinguish gradually when there is no electrical or magnetic charge nearby. Only their mutual dynamics keep them moving. The force to the middle position is therefore a result of the tendency of an oscillating field to lose its energy. This is again a result of the tendency of an electric or magnetic field to spread in space at the speed of light in all directions, so that the local strength must quickly decrease. That an electric or magnetic field spreads in space in this way is a fundamental but also an unexplained phenomenon. We still don’t even know what it is. We only know very well how it behaves.

EM wave. The electric (E) and the magnetic (B) field forces are perpendicular to each other. The change in electric field strength causes a change in magnetic field strength .. and vice versa. This only functions well if the wave moves at the speed of light.

The quantum state wave and the observer

The quantum physical state wave is somewhat more difficult. As far as we can judge and know, it is a wave of potential, of possible observations, in which the probabilities of position and movement, more exactly the probabilities of showing these properties when measured, alternate. This is thus a wave of potential. Potential is clearly immaterial. The object – before its measurement – is not. Position and movement do conflict with each other. If the position changes then that is clearly movement. As soon as there is movement, the position becomes more variable, so it becomes more uncertain. But as soon as the position is more certain, the movement decreases.

In short, standstill is the absence of movement, movement is the absence of standstill. That is therefore also a form of coherence between these two phenomena, position and movement, in which wanting to know position and/or movement is the driving force. In this wanting to know, we immediately, hopefully, recognize the observer’s influence on his observation, which is just having an experience, and perhaps understand a bit more of the non-material nature of the state wave.

Yin and Yang. Standstill is the absence of movement, movement is the absence of standstill

Loss of coherence?

So, can you still speak of a collapse? Can something that is not material, so is not really there in the sense that we are assigning to the idea of materiality, collapse? We never see such a sudden loss of cohesion in all the waves that we can observe unless we take very special measures. Such as the sudden removal of the medium in which the wave propagates. There is then no longer any sound propagating in that vacuum. In an analogous way would a measurement then suddenly annihilate the medium in which the state wave propagates. The appearance of the measured object from nothing is even more mysterious.

Citing decoherence as a cause of the loss of coherence that is the end of the state wave is a tautological trick. Using the description of the event, the name we give it, as a logical explanation is a tautology. It rains because it rains. The wave disappears because the wave disappears. Decoherence is just a label and very probably a misnomer.

An immaterial wave of potential

Now back to the, in my opinion most likely, cause of the transition from the state wave, that wave of potential, to the observed object. This, the transition from potential into realization, happens in our experience, which is the becoming aware of what is observed. It is here that we see the influence of the observer. This is not to say that the awareness of the act of observing something, inexorable means that the observed objects then materially concrete exist. Just think of what we observe in our dreams.

Why are we convinced that the quantum state wave exists when we cannot observe it? That’s because of all these double-slit experiments, the result of which can only be explained as the result of a wave phenomenon. The overwhelming evidence of it.

I have said already a lot about the influence of the observer on what is observed elsewhere. That is something that Einstein saw very early on already as a consequence of quantum mechanics and he did not like it at all. So, he used the predicted effect, the observation of the slit influencing the outcome of the experiment, which is the dissappearance of the fringes, therefore as an argument for his deep suspicion that quantum mechanics could not be a complete theory. Complete in the sense that its predictions were in all circumstances correct. But he was proved right in a way by various experiments that indeed demonstrated the observer effect he had predicted. Quantum mechanics was therefore right in its predictions. Too bad for Einstein.

I refer those who still have doubts about the reality of the observer effect to this fascinating interview with Professor Donald Hoffman below who makes a very convincing argument for the case of primary consciousness. He aasumes a network of a multitude of conscious agents. For an article by him on this, just google for ‘Objects of Consciousness’ or click here for the pdf.

Yin and Yang

Observation causes the manifestation, 
manifestation causes the observation.

The first part is the message of quantum physics, the second part is so obvious that we tend not to see the connection. But there is a straight connection between the two. Both seem opposites and implicate and initiate each other. It’s very much like the Yin-Yang symbol for simultaneous unity and duality. Yin and Yang are not real opposites but complementary and shape reality, just as observation and manifestation do.

We experience the events in the world as something that happens to us, but the truth is deeper, we are the author of our own story. But we are so absorbed in our story that we have forgotten our authorship.

The experience of a thought is the thinking of that thought. Do you see the obvious parallel to the observer effect? Think about that. Isn’t everything we experience a thought?

Which means that the moment you really control your thoughts, you have your own story also in hand. That is essentially what you are looking to achieve with meditation.

Hence our fascination with stories, such as in a book, a film, a play. We are the storyteller and the listener at the same time. Even dreams are actually stories that we create ourselves without realizing that we create them. The moment we realize that we dream, that it is ourselves who are creating the dream, we dream lucidly.

Isn’t the transition in dying something like it? In the communications about life after death that come to us through mediums and shamans, life after death is very similar to a transition from an ordinary to a lucid dream.

The Realities of Heaven: Fifty Spirits Describe Your Future Home.
by Miles Allen.

Asking for the meaning of existence is asking about the meaning of listening to stories, of the meaning of creating stories, of going to the cinema, of visiting a stage performance, of listening to music, of reading or writing a book. Of gathering wisdom.

This is the deeper message of quantum physics. Things, matter, are stories that we tell. That’s all folks.

The One

The ultimate ground of the world.

Some physicists are beginning to realize that quantum physics has much more to say about the world than that quantum mechanics is an unparalleled successful predictor of physical phenomena. The book ‘The One‘ by Heinrich Päs, professor of theoretical physics at TU Dortmund, is a very good example of this changing attitude. He concludes that quantum physics can only be fully understood if we accept the existence of a quantum universe – already ages ago described by many philosophers as The One – as the ground of the world we observe.

According to Päs, this quantum universe is the – immaterial yet real – version of Everett’s multiverse, but metaphysical instead of physically material. Päs states that the image presented to the public of endlessly splitting material universes is wrong, brought into the world by opponents of Everett’s idea. All these possible universes exist certainly, however as state waves that together, by their respective superpositions, form one single state wave, where all their oscillations cancel each other out. This composite superpositioned state wave of all possible universes together is The One, the unmoving immaterial ground of everything, where space, time and matter do not exist any more, not even as thought, but from which all observed diversity sprouts. This is the Tao of Lao Tze, here anew presented as an ultimate quantum metaphysical reality..

So what’s Everett’s idea, precisely?

To answer that, we first need to look at the greatest mystery that quantum physics confronts us with, the quantum collapse. The end of the – unlimited in space and time expanded (non-local) – immaterial state wave that, according to the accepted quantum physics interpretation, represents the probability to find the material particle at measurement when, precisely at that act of measurement, that wave ends abruptly. This end of that state wave is however not predicted by the mathematics describing the state wave, the Schrödinger equation. How the act of measurement triggers this abrupt transition of immaterial probabilities into matter is still not explained satisfactorily. The most commonly accepted explanation given is decoherence, which is actually not an explanation but only a verbal description of what seems to occur. Which is that a coherent phenomenon – the wave – suddenly loses its coherence as a connected whole, whereupon only one element of it – the in our measurement found particle – remains and becomes matter.

The attributed name – decoherence – doesn’t really explain how it works. However, Päs explains decoherence as an effect caused by the necessarily limited perspective of the observer on the composite quantum wave of the universe, that one single unmoving state wave in which the state waves of all possible universes are summarized, superpositioned in the language of the physicist. His explanation how a limited perspective of the observer hides the full unmoving universal state wave and presents us only one of its myriad components, does unfortunately not go into more detail.

A metaphor he offers as an explanation is that of a completely flat ocean surface that, observed from an overall perspective, shows no movement, but which in that motionlessness may as well be the result of an endless conjoining of an enormous number of waves, that together completely cancel each other out. Waves can cancel each other out, which is what we call destructive interference. This is applied in noise reduction headphones. From a much more restricted perspective then, the area of that ocean that we are able to observe becomes something that appears to be separated from the rest. I don’t understand fully how a perspective change will present to us the world of distinct objects, but it’s an interesting image and it can at least serve as a useful metaphor for a rough explanation of the idea. If you accept his idea, the decoherence of the state wave, happening on measurement, is not that the state wave does disappear into thin air on observation, but that it is just no longer observable from the limited perspective of the observer. The observer observes then only a small part of the full quantum universe. It’s still there, in its immaterial way, but we can’t ‘see’ it.

Everything becomes an observer

Which raises the questions of what an observer actually is, and – related – if an observer is really necessary for evoking the quantum collapse. Everett’s idea to do away with the observer and the quantum collapse is that every possibility exists in the state wave where ‘existence’ does not mean a material existence, but nevertheless a real existence. With this, the definition of what is real is changed in an important way. Accept this for the moment. According to Everett’s proposal, in the double-slit experiment with a single object shot at the slits, both possibilities exist in a real way – the object goes through the left slit and it goes also through the right slit – but both in their own separate immaterial realities. In each of these two realities exists an immaterial observer, who observes the only one outcome within his reality. Every observer is after all only able to observe the reality in which he exists. This eliminates the apparent necessity of a physically enigmatic influence of the observer on the state wave, triggering the quantum collapse of that wave, simply because there is no collapse at all. Instead, however, there are now two completely identical observers.

I hope that you will understand that Everett’s proposal does not impose any special immaterial requirements on the observer, such as perceptive awareness, a camera will suffice. The underlying condition for his idea is clearly that consciousness is an emergent property of the immaterial but nevertheless real brain of the observer. Both observers in both universes are (immaterially) identical to each other and therefore have an identical emergent consciousness, with their also identical emergent memories. The only difference is their observation at the time of the experiment. There splits their universe, with them in it, in two.

Wat is real, really?

Multiverse interpretation of Schrödinger’s living ánd dead cat.

This example of ‘bifurcating’ observers in their universes has been kept simple for reasons of explanation here, way simpler than in any practical real double-slit experiment. In practice, there are many, almost innumerable, possibilities in such an experiment where the observed object can manifest itself everywhere at any of the interference fringes on the back screen, and each possibility therefore means a split universe, each including a copy of the observer. I hope you see that the number of universes and observer copies can get quite substantial if not improbably gargantuan. Therefore, Päs stresses that all these possible universes are not material, even if they are real. The definition of what is real therefore needs to be adjusted. But in such an extended interpretion of reality, an illusion, even a dream, is also something real, although I think Päs does not want to stretch it that far.

Emergent consciousness as condition for the multiverse

Only by considering consciousness as an emergent property of the physical brain, this way of interpreting quantum physics is defensible, it is definitely a prerequisite for Everett’s idea, and this assumption is also stated repeatedly in Päs’s book: ‘Of course, as long as we stick to the reasonable hypothesis that our consciousness is confined within our brains, …’. After shortly considering the idea of primary consciousness as a possible cause of the quantum collapse like, for example, John von Neumann did – Päs joins the almost unanimous opinion of neurologists (Tononi et al.) that consciousness is an emergent product of the brain. He forgets that neurology is an ultimately reductionistic branch of science while he argues elsewhere in his book strongly against reductionism in physics.

Monism – not a new idea – to the rescue of physics?

The idea of the existence of an ultimate source of reality that is The One, that knows no separation, that contains no separate elements, that knows no time and space, is called monism. Päs spends an extensive and indeed fascinating chapter of his book on the history of monism. It is a view on reality – also known under the more common denominator Platonism – that can already be found in Greek antiquity with proponents like Thales, Plato, Parmenides, Pythagoras, and Philolaus. Later on, monism as an opponent of the monotheistic but dual presentation of the world that the Christian church steadfast portrays, repeatedly pops up in historical figures such as Giordano Bruno, Kepler, Copernicus, Meister Eckhart, John Scotius Eriugena, and much later on in time, Spinoza and Kierkegaard.

According to Päs, the strong reactionary suppression of the Catholic church of these clearly monistic ideas, through torture, pyre, excommunication and social exclusion, is the root cause of the fact that the notion of an immaterial ground of our reality is not very popular at the moment, certainly not among most physicists, although I do notice a growing change in attitude. Bohr and Heisenberg also played an important role in this suppression, with their idea of complementarity, by classifying the deeper reality of the state wave as not relevant to physical theories. They classified thus the contradictions, between for example particle and wave, as fundamental to nature, and thus not susceptible to further investigation. There is just no underlying reality to investigate. Case closed. Shut up and calculate.

According to Päs, this is the reason that physics, with its highly reductionistic approach, is currently in crisis. The investigation into the foundations of matter has so far been sought in the ever smaller dimensions of matter for which the necessary energies ánd finances are correspondingly increasing . The path of reductionist approach of nature, and what could be achieved by it, seems to have come to an end. It is therefore time, according to Päs, to introduce monism as a grounding principle in physics. Quantum physics and the quantum universe show us the way.

Entanglement as the ultimate creator of unity and universal love

According to Päs, entanglement is by far the most important factor in the quantum universe. It ensures a connection of everything with everything and confirms thus the unity of The One. Individual properties of the parts do cease to exist in favor of strongly interrelated properties. Interestingly, he quotes Neoplatonist John Scotus Eriugena in: ‘Just as entanglement unites the universe in quantum cosmology, for Eriugena it is “the pacific embrace of universal love” that “ gathers all things together into the indivisible unity which is what He Himself is, and holds them inseparably together”. Päs, apparently makes here a connection between quantum entanglement and what Eriugena calls universal love. That immediately reminds me of the NDE reports that are almost always about the overwhelming experience of universal love. This is found in almost all reports. That’s real, if only because of the amount of data.

You could protest now that you and your ex have a common history and must therefore be quantum physically entangled, but that there is no more love in your present relationship. Päs would say – I think – that your observation is of course a matter of your limited perspective.

Love is entanglement, entanglement is love.

Does Päs acknowledge the quantum physical reality of universal love? It might be different. By linking entanglement and universal love in this way, he also could reduce the latter to the first. Love would then become something that could be examined in the physicist’s laboratory as a phenomenon to which numbers could be assigned by means of measurement. He would then do the same that physicists have done with the actually incomprehensible mystique of forces at a distance, as we experience it with gravity, electricity and magnetism; reducing it to a field that can be measured and described mathematically and thus reduce the phenomenon to something that belongs to the material universe. Reïfication by reduction.

How could they know?

An important question then is, of course, how the ancient philosophers had already stumbled on this principle of the very substance of our reality without having the technical tools available to science today. The ancient Greeks had little more at their disposal than their own senses and their sharp minds. Päs just briefly goes into this and assumes that early and primitive humanity was capable of a more direct observation of The One than modern man, and that these insights were handed down from generation to generation. Which is very close to the assumption of the general validity of mystical lore.

Summary and comments

At the end of this book review, it is good to briefly summarize Päs’ ideas, supplemented with my summarized comments:

  1. The perceived reality is an illusion and originates in the quantum universe. Certainly a remarkable statement by a physicist.
  2. The multiverse is the quantum universe and it is not material. It’s one. That too is remarkable.
  3. In the apparent split of the universe, the physical observer and his mind also split into several observer copies, each observing a single outcome. The quantum collapse is therefore the impression that every observer copy has because each one observes necessarily only a single result of the many possible outcomes. That means that an underlying assumption has to be made, that the mind is a product of the physical brain. That assumption is essential in this multiverse explanation of the quantum collapse. Accepting this, the large number of experiences of people leaving their body at the threat of an imminent physical demise, often verified by third parties, while being able to perceive and report the circumstances near their body correctly (the NDE), are either completely ignored or declared as illusion.
  4. In this assumption, the observer is therefore just a physical object, so that actually every physical object becomes an observer. Which is also the conclusion that, among others, Carlo Rovelli, Sean Carrol and Thomas Hertog convey. Why certain objects, such as lenses, mirrors and even reflective crystals, are exempt from being observers is not clear to me.
  5. But since, according to Päs, physical reality is an illusion, we as observer have an illusion that observes the world and thus creates also reciprocally the illusion of the observer. Whoever wants to believe something contorted like that, is fooling himself, as far as I’m concerned.
  6. The quantum collapse is caused by decoherence which is, according to Päs, an effect of the observer’s limited perspective. The deeper mechanism of decoherence, and how it is triggered, remains unexplained.
  7. Given the interference that the state wave always shows us when it travels through the double slit, all those universes must be able to interfere with each other. That can only be true if all those universes are themselves indeed non-material state waves. Then they can indeed interfere with each other, because they are waves. In this way, they are not material and therefore do not contain any material observer copies. How a non-material state wave can then produce emergent consciousness is pure speculation.
  8. As Päs describes the quantum universe, he is already very close to the idea of the universal mind from which all reality comes, which is a description precisely matching those reported by many near-death experiences. He’s clearly switching his own perspective and he is almost there.

In short: A fascinating, instructive and in general honest book of the quest of a quantum physicist for the meaning and future of quantum physics and a much needed beginning of a farewell to the there-is-only-matter paradigm.

The Observer and his Measuring Device

The classical view on observation and measurement.

In classical physics, the human observer does not play a creative role in what is observed. Everything is observed from the so-called 3rd person perspective. In all physics experiments, any influence of the measurement on what is measured should be avoided as far as possible, although some small effect is unavoidable. For example, consider the radar detection of a vehicle’s speed. The radar photon will bounce back from the vehicle and thus have a tiny influence on the speed of the vehicle. But that effect is so small that we can safely ignore it in practice. Protesting the traffic control fine on account of this effect will be in vain. The electricity meter also uses a very small amount of energy by its measurement. But protesting the energy bill on that account will also be in vain, I am afraid.

Observation in quantum physics

However, in quantum physics – a branch of physics that has succesfully taken over the fundamental role of its parent, classical physics – this is not the case. The way we measure is of crucial influence on the behavior of that which we are measuring. There is nowadays no doubt about that effect. Is it the influence of the measuring instrument or of the experimenter? After 120 years of quantum physics success, the discussion about exactly what a measurement is is still not definitely decided. Measurement causes the so-called quantum collapse, the end of the immaterial state wave and the emergence of the material particle. John von Neumann – one of the first quantum physicists – already stated emphatically that the observed object and the measuring instrument are not physically connected in some way and thus cannot cause the quantum collapse.

Two waves meet without collapsing each other

This was the way he reasoned; both – instrument and measured object – are ultimately composed of fundamental particles that, when not measured, will behave like an immaterial wave of probabilities, which is their state wave. Both state waves will meet each other when doing the measurement, but will not collapse, just as two meeting waves will run unimpeded through each other without eliminating in some way the other wave. On meeting they excite their medium by summing their movements and after that they just roll on, unaffected. According to von Neumann, there is therefore no reason to assign a special influencing role to the physical measuring instrument with regard to the end of the state wave. His insight was dismissed by later phycisists, as the influence of the observer (and his consciousness) was not considered as something objectively measurable and was therefore preferred to be left out of physics. What made it even worse is that the state wave is a wave that we can formally describe, calculate and predict with physics – that is, with numbers and symbols – but that the state wave itself is not materially observable. It does not even exist in a material sense. It is a wave of probabilities and these are numbers, symbols, mathematical constructions of the mind.

Is then everything an observer?

As soon as you make a measurement, however, the immaterial wave ceases to exist and we find only one of the many possibilities, the particle, which is decidedly not a wave. This behavior is also expressed in the Copenhagen interpretation of Bohr and Heisenberg. Gradually, the insight of von Neumann, Bohr and Heisenberg – mainly because of some recent advanced quantum physical experiments such as the delayed choice experiments – has been confirmed in such a way that the observer, who is seemingly physically realising that which is observed, can no longer be ignored and is acknowledged as an essential element in the fundamental understanding of nature, which is of course something what physics aspires to. This inspired Carlo Rovelli – among others – to declare that literally every object acts as an observer of any other object in order to materialize each other. So, according to his idea, each particle only exists materially in relation to another particle. My question is then, of course, how to imagine such a process, where both particles – while not yet existing materially – are able to relate to each other and then become material as a result. In my opinion, the order of events here is wrong. Cosmologist and quantum physicist Thomas Hertog describes in ‘The origin of Time’ something similar; all things become observers causing the quantum wave to collapse and therefore matter to appear. But things are made of matter which has to collapse itself first? So – to ask the real question – what exactly do we mean by an observer and what role does it actually play?

What is an observer according to quantum physics?

Alternative realities Wigner’s friend experiment 2019

In many quantum physical experiments – especially those seeking to investigate the observer effect – have until now been carried out by an instrument acting as observer. The question is whether this is the right perspective. In an complex experiment pictured in the above figure – it was based on Eugene Wigners thought experiment with two observers – Wigners idea was indeed implemented, albeit with instruments acting as observers. In such an experiment, part of the experiment is carried out within a closed environment. One of the so-called observers is residing within that closed environment and thus observes directly the result of ‘his’ experiment. The state wave is then considered to collapse by that observer observing the experiment and has by that observation collapsed into an observed particle.

But outside this closed environment there is a second observer for which the content of that closed environment – the larger box with the experiment and the first observer in it – is still an uncollapsed state wave as long as the second observer has not yet observed the contents of the larger box. Only when that second observer can observe the contents of the larger box will for ‘him’ the state wave end, making the measurement of the particle becoming a fact. As far as the second observer is concerned it is then that the particle becomes manifested with its physical properties. Who of these observers is now the person who triggers the materialisation of the measured particle with its properties?

The figurines inside and outside the boxes, representing the observers, are physical measuring instruments and lack therefore any consciousness that could interpret their observation. So, is an interpretating consciousness really necessary here? The experimenters apparently do not think so. Anyhow, the outcome of the experiment implicated surprisingly that we could start to doubt the existence of an objective material world in which consensus rules, in which a fact is simply a fact, regardless of who did observe it.

Is consciousness really needed? Is interpretation necessary?

Can a physical instrument observe its environment and then interpret its observation? I would like to draw attention here to something that I do not think a physical instrument can do, however advanced it may be, namely interpretation, giving meaning to perception. That’s the core of the case here. What is interpretation? Can a physical instrument do that? The experimenters think so, which fits their materialistic image of the world in which man, and any organism, is only a complex machine. Something that can – in principle – be described as the result of its parts. The observers brain is according to them merely an advanced computer, coincidentally created in the evolutionary process of survival of the most suitable biological machines. The mind, emerging from the brain, can therefore be replaced by an advanced but non-biological machine such as ChatGPT, an AI. Interpretation by the mind is – in that vision – not different from a calculation. So, the question is; is there any difference between an organic living observer and an observing instrument? And what is the difference? In trying to answer this question, we have to simplify the discussion and look at the essential differences between a simple ‘acting’ measuring instrument – a central heating thermostat – and an organic observer.

Can a physical instrument be an observer?

What is the difference between the central heating thermostat and the biological entity that depends on its central heating thermostat for a pleasant ambient temperature? Is there a fundamental difference, fundamental in the physical sense? The thermostat ‘senses’ the ambient temperature, determines if it deviates from the optimal value, and then activates or deactivates the central heating boiler. Is that interpretation? Is that a measurement? These seem to me to be essential questions, although I suspect that they cannot be answered with a 100% waterproof answer. But I will try.

What causes the state wave to collapse?

We could therefore ask the following question. How is it possible that a physical instrument, which itself is not observed and thus is in a state wave, will cause the state wave to collapse or reduce? (The “collapse of the wave function” is also known as the “reduction of the wave packet). Consider the central heating thermostat. It does its job, even if no one is present because you have forgotten to lower the ambient temperature for a few days of absence. When you return home after a few days of absence you will notice that the house is warm, that the thermostat is still set on higher temperatures, so you must conclude that during your absence the boiler has been burning fuel for nothing. That conclusion – fuel burned for nothing – is interpretation. This unconscious thermostat was not able to understand that, otherwise it would have chosen to lower the desired ambient temperature. Can you still say that this unconscious thermostat is an observer? If so, did the thermostat collapse the state wave that contains your unobserved central heating boiler, all the radiators and the air in your home into a materiality? Every time it measured the temperature? How?

Real observers are interpreters

I think indeed that a real observer should be able to interpret his observations. Interpretation is assigning a meaning to an observation. That’s not what an instrument does. I have to tell the thermostat first, by programming it, which is a pleasant temperature. It cannot do that by itself because such an instrument has no knowledge of ‘pleasant’. Now you might argue that an advanced AI like ChatGPT could do it. But to do that, ChatGPT should first search through a huge database with data on what are pleasant temperatures for human beings. And how is ChatGPT’s database fed with these data? Indeed. By human beings who have recorded what they experience as a pleasant temperature. Had they not done so, ChatGPT would not be able to produce an answer on the question of what a pleasant temperature is. You might get an answer on the question of what ambient temperature a biological human being needs. But that’s not what is meant by pleasant. Pleasant is not a numerical expressible experience. Always, and without exception, the question of the meaning of an observation, its interpretation, has to be traced back to an observation by a conscious being. A being that was able to consciously interpret his perception as pleasant or unpleasant, red or green, hard or soft, wet or dry, beautiful or ugly. These experiences are certainly not numbers. I hope you will realize that, without living people, the ‘pleasantness’ of a temperature wouldn’t make any sense. The thermostat has no inkling of ‘pleasantness’. Of course it can be programmed to produce pleasant temperatures, but that always takes someone to think what that means and to translate it subsequently into the numbers a machine can process.

Conscious interpretation is always the final act of an experiment

The fact that a conscious interpreter is ultimately required, in my view, applies without exception to any experiment. Even for a run of the enormous Large Hadron Collider in Geneva. Ultimately, the result is always observed by a conscious being that assigns meaning to it. We may eventually get informed of the meaning by a publication, but it is usually not mentioned in the publication that there was always a person involved in the interpretation of the results. That is so obvious that it does not need to be mentioned explicitly. This means that an essential element of the experiment is never mentioned in reports. The observation was X, and that means Y. And that last part of it — and that means Y — that’s what it’s all about. That’s the interpretation of a person and therefore the actual experience of the world. That conclusion creates in the Copenhagen Interpretation by observation also all the previous events in the experiment as someting that did happen. As in previous example about the central heating, the history of the unwanted fuel consumption during your absence has become a fact after and because of your observation. That fact is then, after the quantum collapse brought on by your observation on returning home – unfortunately – no longer an immaterial probability distribution. It became what we call a fact. That’s something for which there can exist consensus.

What then is the role of a recording measuring instrument?

We have spoken enough of the observer for this moment and will now focus on the other question. What is a measuring instrument in this context? The requirement seems to be that it should be able to register. This means that a certain class of passive measuring instruments won’t qualify. Think of the yardstick, for example, which does not itself make a registration of length. It is a completely passive measuring instrument in contrast to an advanced central heating thermostat that remembers the indoor temperature pattern to anticipate the next moment of starting or stopping the boiler. So, registering ability seems at first glance a valid criterion, measuring plus recording. So, is a voltmeter connected to a recorder an observer or not? Is a photon detector connected to a coincidence detector in an advanced double-slit experiment an observer or not?

In order to answer that question, try therefore to think about how a recording measuring instrument might affect – by some yet unknown physical process – the registered object in its wave state and, above all, why another very similar instrument would not do so. Take, for example, a solid length of iron rod. That rod doesn’t seem a recording instrument, until you realize that the rod expands or shrinks according to its temperature. So, the rod measures the temperature by its length. If the rod is long enough and cleverly connected to a marker pen and a moving roll of paper, this would record the temperature evolution history. The change in the length of the rod provides the information on the temperature evolution. In this way you can consider the rod with marker and paper as a recording measuring instrument. Because we are able to use the rod in an ingenious way, as a registering instrument that we considered from another point of view as passive, it would thereby become an observer who would cause the quantum wave to collapse. I hope you see the inconsistency.

So you will not easily identify any arbitrary iron rod as an observing measuring instrument. If you start thinking about measuring instruments in this way, then the idea of an instrument as an observer becomes inconsistent and therefore highly questionable. Whether an instrument registers, or not, would then be not determined by its physical properties but by the way in which we employ it, and this is of course a case of human reflection. Ultimately, therefore, we must begin to acknowledge that even with an instrument that measures and records the result, the real observation – the observation that makes the quantum collapse happen – happens only if the result is observed finally by a conscious observer. If we accept that as an explanation then we may have an acceptable, useful, and consistent criterion for the definition of a measurement and also for the triggering of the quantum collapse, which is the material manifestation of the world.


So in the end we have to acknowledge that a conscious observer is needed for a real measurement, no exceptions. The measuring instrument is then nothing but an extension of our senses – which are also physical measuring instruments – and cannot be the cause for the quantum collapse, evoking the appearance of matter in our world. That has a profound meaning for our experience of the world. We are essential in the (hi)story. We are an essential part of the world, of the universe. By observing the world and thus experiencing the world consciously we create it.

Einstein’s insight ánd blind spot

Einstein’s opposition to the quantum state wave interpretation of Bohr

Despite his contribution to quantum physics with his explanation of the photoelectric effect with Planck’s quantum, Einstein strongly opposed the quantum mechanics interpretation of Bohr, Heisenberg, Pauli, Born and von Neumann. According to Einstein, despite the successes achieved, the theory still lacked a few essential parts. Einstein was a materialistic thinker who still thought completely in the spirit of classical physics with real hard particles with mass, speed and energy. In his view, photons were real permanently existing particles with an energy and momentum that depended directly on their frequency, although the philosophical question still remains what the frequency of such a particle actually means. On the opposite side, Bohr’s group advocated the idea that there existed only a non-material state wave before measurement which only changed into a material particle upon measurement.

Einstein was an excellent inventor of thought experiments (gedanken experimenten), which is also the way he developed his theory of relativity. He therefore devised a number of thought experiments with which he hoped to convince Bohr and his colleagues that their quantum theory was still far from complete. In his first quantum thought experiment, which he presented on a Solway conference in 1927, he wondered what would happen if you knew which slit a photon passed through in a double-slit experiment. According to him, quantum theory, as it was at the time, predicted two contradictory outcomes, namely an interference pattern on the screen behind the double slit and at the same time no interference pattern.

Gedanken experiment with recoiling slit and photons

Light can give a push

Einstein’s reasoning went like this:

  • A photon has a momentum. Momentum is a physical quantity that indicates the thrust a particle can deliver on collision. A photon’s momentum is proportional to its frequency. Although the photon has no rest mass and always moves at the speed of light, it can still push an object it hits. Watch the YouTube video above if you want to know more about that.
  • We fire single photons – monochromatic, so all will have the same frequency, energy and wavelength – with a photon gun on a double slit. But those photons have to pass first a movable slit of which we can measure its up and down movement. After the movable slit, the photons must travel up or down to pass through the upper respectively the lower slit of the double slit. We measure the recoil of that movable slit brought on by the hit of each passing photon. The photon has then a speed and a direction that is influenced by the recoiling slit, which classically means that the slit must also recoil in turn. Action equals reaction and is oppositely directed. We measure – in principle, it’s a thought experiment – the recoil movement of the single slit.
Einstein’s Recoiling Slit Thought Experiment – Version 1. There is no interference. Each photon travels through only one slit because we can know its path from the recoiling slit.
  • Behind the recoiling slit the normal double slit and screen are positioned. The recoiling slit shown in the figure is a drawing which was actually made by Bohr in finding an answer to Einstein’s challenge. He even drew the nuts and bolts with which the slit holder should be fastened to the support of the whole set-up and also a pointer and a scale that would indicate the recoil.
  • From the recoil of the movable slit we know which slit the photon passed. As the slit recoils downwards, the photon must travel upwards and thus pass through the upper slit. If the slit recoils upwards, the photon must travel the lower path and thus go through the lower slit.
  • In this way we know which slit the photon passed through. According to quantum theory, the state wave of the photon will now only extend from that slit. However, from the other slit there will now no state wave be extending. There is therefore no possibility of double slit interference, so we will not see any interference pattern on the screen. The result of shooting a large number of equal energetic photons will now look like a single spread-out spot on the screen with the greatest intensity in the center behind the double slits.
  • So far excellent reasoning by Einstein and nothing to argue really against.
  • However, you can also think of the photon gun together with that single slit, Einstein says, as a single device, a composite source of photons, so that the experiment now becomes an ordinary double slit experiment where we fire photons at a double slit.
Mechanically the same recoiling slit experiment – just envisioned differently. The recoiling slit is now considered as a part of the photon gun. We don’t know which path the photon takes. We now will see interference.

With this alternative design of the experiment, which is actually exactly mechanically the same, but only envisioned in another way in terms of components, we will now expect interference. The reason for this is that it shouldn’t matter how the photon source is composed of its parts. It only matters that the photons all have the same frequency.

A disturbing contradiction for quantum physics

With the same set-up, only arranged differently in mind, we therefore expect both interference and no interference. Quantum theory predicts two conflicting outcomes and that means there is something wrong with it, it is probably not complete.

After probably a night of worrying, Bohr more or less found an answer to Einstein’s challenge. The photon that passes through the recoiling slit and changes its direction there, loses necessarily some of its momentum. That momentum had been transfered to the recoiling slit. This is perfectly consistent with the law of conservation of momentum. That loss of momentum due to the interaction with the recoiling slit, means that the photon loses also some of its energy and frequency . The frequencies of all the photons are now no longer equal, which disrupts the interference pattern because the locations of maximum and minimum probability differ now per photon. The interference pattern weakens, and can even turn into a spread-out spot.

A real recoiling slit experiment

In my eyes a somewhat weak defense from Bohr and still almost completely in a classical physics way reasoned. But that was in 1927, quantum theory was still in full development and the technology was not yet there to really carry out the experiment. But by 2014, the technology had advanced far enough that Einstein’s thought experiment could actually be performed. I describe that experiment in detail in my book, chapter 5.

The double slit has been replaced by the two atoms of an oxygen molecule. Which oxygen atom has been hit by the photon is measured by the captured electron that flies away from the hit atom. It is investigated whether the interference pattern depends on whether or not it is possible to determine which atom has been hit by the photon.

Schematic representation of the principle of the experiment. From the publication ‘Einstein–Bohr recoiling double-slit gedanken experiment performed at the molecular level‘. Click on the figure for the full article on IOPScience.

The outcome of the experiment is that the interference stays away as soon as we can know which oxygen atom was hit by the photon. The article is rather technical, but the ‘Abstract’ does indeed describe the effect on the interference of information being available or unavailable. “This wave-like behavior and corresponding interference is absent if ‘which-slit’ information exists.” However, explicit reference is also made to the momentum transfer of the photon to the recoiling slit as argued by Bohr in his answer to Einstein. So Bohr was proved right and Einstein was wrong. But that’s a bit short sighted in my opinion. I do want to pay attention to something that Einstein saw excellently, after which both he and Bohr were apparently blind to what was really going on.

Einstein & Bohr’s blind spots.

What Einstein and Bohr both missed was that there is an essential but hidden difference between the two ways in which we envision the “double slit with moving slit experiment”. You may have noticed it already, but it took me quite a while before I saw it.

Although an uncompromising and thorough thinker, Einstein did not recognize that when there was no difference in the machinery of the experiment the only remaining difference was that which we can know. In the envision in mind where the recoiling slit is not part of the photon source, we can know which slit the photon passed through. From this ‘being able to know’, Einstein realizes that it can be deduced that the state wave only comes from one slit because the photon is – as we know – only in one slit. This may seem obvious but is a deep and extremely important insight. In the alternative envision in mind where the recoiling slit is seen as part of the photon source, we are supposed no longer to be able to know the recoil; such is more or less tacitly assumed but not explicitly expressed. But it is an extremely important difference. I think that it is not so easily recognized because, mechanistically speaking, both versions are completely identical so that they should therefore behave identically. The difference in the experimental set-up exists purely in the mind. There is still a moving single slit between the primary photon source and the double slit in the envision where slit and photon gun have become a single device. Only in that case it is now tacitly assumed that we cannot observe it. In both envisions Bohr’s argument of loss of impulse would equally apply, so the difference is really only in being able or not being able to know which slit has been chosen.

So you could now perhaps conclude, as the researchers seem to do, that it is indeed the impulse transfer that would make the interference disappear, but there are several arguments against this. First, that argument also applies in the event that the researchers were unable to determine which atom was hit because the atoms stuck together. There was, of course, just as much impulse transfer there, so that can’t make a real difference. Second, this is not the only experiment where the interference disappears once we can know which path the quantum object has taken. I describe two of these experiments in my book: The Delayed Choice Experiment with Single Atoms in Australia at the University of Canberra and The Delayed Choice Experiment with Two Photon Imaging at the University of Maryland, Baltimore.

In short; to measure is to know is to realize

As soon as we can know which path the quantum object has traveled, we see that the state wave has adapted to what we can know. As soon as we can know which slit has been chosen, the state wave will only have passed through one slit. I am speaking here on purpose about the state wave and not about the particle, for the reason that we will never be able to determine the difference between ‘there was a material particle in the slit‘ and ‘the state wave passed through one slit, so the probability of passing the photon measured there was 100%‘. I prefer the latter option as it assumes less concerning the so-called quantum collapse, which only happens in that case on the screen and not in the slit, and therefore has a greater probability of being closer to the truth. Ockham’s Razor.

And last but not least; if it is indeed a question of ‘being able to know‘, then the connection with the consciousness of the observer is of course obvious.

Nobel Prize physics for demonstrating non-local quantum entanglement

It was time the Bell was heard

John Clauser, Anton Zeilinger, Alain Aspect. Nobel Prize Physics 2022.

Alain Aspect, Anton Zeilinger and John Clauser were jointly awarded the 2022 Nobel Prize for their efforts to demonstrate that quantum entanglement exists and is non-local. John Clauser was the first to demonstrate this experimentally doing a Bell test in 1972. His result – entanglement is a non-local effect – was confirmed in 1982 by Alain Aspect, but there were still loopholes that could explain his results in a classical physics way. Then – 35 years later in 2017 – Anton Zeilinger conducts a test that definitively excludes all possible loopholes.

Quantum entanglement exists and is non-local, i.e. the relationship the particles have with each other is instantaneous and does not depend on the distance from each other and thus conflicts with Einstein’s laws of relativity because such a relationship would involve instantaneous communication between the particles.

To be accurate, a test that excluded all possible loopholes was already done in 2015 by the team of Hanson and Henson in Delft. However, I heartily grant these three guys their well-deserved Nobel Prize. Non-locality was still a hotly contested idea in 1972 and this kind of research was not really very beneficial for your scientific career at that time. Non-locality raised (too) big questions about the fundamental behavior of nature then. It just couldn’t be. Clauser and Aspect were thus putting their careers at risk by just posing the question. See this quote from the Nobel Prize article on Quanta Magazine under the headline “Who performed Bell’s experiment?”.

"Initially, physicists including Richard Feynman discouraged Clauser from pursuing the experiment, arguing that quantum mechanics needed no further experimental proof."

I will briefly explain what a so-called Bell test basically means, a more extensive description can be found in my book, chapter 5, “Bell’s theorem”.

Bell’s theorem

John Stewart Bell (1928-1990) published in 1964 what is now called the Bell theorem. In principle, this theorem can be used to demonstrate experimentally whether or not local variables play a role in quantum phenomena. I won’t explain local variables here, but it means ultimately that – if local variables apply in quantum physics – particles exist permanently throughout their journey from source to detector – in the same way that we assume that arrows exist permanently throughout their trajectory from source to target, and even before that. Remember that. The experimental setup of a Bell experiment should be such that faster-than-light communication between entangled objects is excluded.

Most Bell tests have been performed with polarized light – that is, polarized pairs of photons. An EM wave consists of an electric and a magnetic field component. These oscillate perpendicular to each other and both oscillate perpendicular to the direction in which the light travels.

EM-wave. Red: magnetic component, Blue: electric component. Speed in vacuum is constant: 299,792,458 metres per second.

The direction of oscillation of the electrical component of the EM wave is called the polarization. The wave in the above figure is horizontally polarized. A polarizing filter, such as Polaroid glasses, only transmits light that oscillates – after its passage through the filter – in a direction that is determined by the orientation of the filter. If the light oscillates at an oblique angle to the orientation of the filter, light is only partially transmitted. The transmitted light oscillates only in the direction the filter has enforced. If the incident light oscillates exactly perpendicular to the direction of the filter, nothing is transmitted. Light is an EM wave, but from a quantum physics point of view, that wave consists of masses of photons that are each polarized. How we should imagine the polarization of a single photon is not clear, so we don’t do that.

Vertically polarized light can be rotated 90o to horizontally polarized light in two steps. 50% of the originally vertically polarized photons are then transmitted.

No halved photons but probabilities

Photons that are not polarized exactly in the orientation of the polarizing filter, for example hit the filter at an angle of 30o, are transmitted for 50% but are not halved. Their frequency is not affected, but the probability of passing through the filter is 50%. The probability of transmission of a single photon depends on the angle its polarization makes with the orientation of the filter. So, if they are polarized exactly perpendicular to that orientation, the probability of passing through is zero. At an angle of 45o, according to quantum mechanics, the probability that they will pass through the filter is about 71%. The photons transmitted by the filter have not changed in energy, wavelength and frequency. They certainly haven’t halved. So, it’s all about probabilities.

Bell test with polarized photons

Image of a Bell two channel experiment. A and B are the polarizers that can be rotated relative to each other.

The photons are detected by D+ or D-. The coincidences (co-occurring detections) and the angle between A and B are recorded in the coincidences detector. According to the conservation laws of physics, the polarization directions of both photons should be identical when they were created as a pair. But this joint polarization is a quantum manifestation that becomes real when one of the photons is measured and is therefore completely random. This begs the question if the measurement is done by the detector.

Spooky action at a distance?

If the left photon appears to have a certain polarization upon detection, then the right photon must have at the same time the same polarization since they were created as a pair. And that’s strange when their polarization only becomes ‘real’ upon detection, as quantum mechanics seems to imply. So, that looks on first sight like mutual communication. But as soon as you assume that you also have to ask yourself how the communication between the two manifesting photons actually works: “Hello partner, I have been measured, now you must immediately show your polarization and it should be the same as the one I am showing at the moment”. That’s Einstein’s “Spooky action at a distance”. Do you see why Clauser was discouraged from investigating this experimentally?

Either classical permanent particles or materialization by observation

The Bell experiment is therefore concerned with whether it can be determined if the polarization of the photons already existed from the moment of their creation (classical permanent particles) or if they only ‘materialize’ at the moment of their detection (non-local quantum interpretation). According to non-local quantum theory, if the two polarizers are not equally oriented with respect to each other, the correlation between the polarizations of the photon pairs – the [D-/D-] or [D+/D+] coincidences – must be greater than the correlation predicted by the local permanent particle theory.

That angle-dependent correlation between the coincidences can be predicted for both theories, classical local or non-local quantum. The genius of Bell was that he realized that differences between classical local and quantum theory occurred if the polarizers (A and B) made different angles with each other than 0o, 90o, 180o or 270o. See figure below for the predictions of the correlations as calculated in both theories. For example, the figure shows that for an angle of 158o between the two polarizers, the classical local expectation for the correlation will be 0.75 (75%), but for the non-local quantum expectation it will be 0.85 (85%).

The classical and the quantum mechanically predicted correlations between detections of the polarized photon pairs, measured at different angles between the polarizers in a Bell experiment. The blue curve corresponds to non-locality.

Locality falsified

If the measured correlation of all coincidences at that angle of 158o is greater than 75%, then local hidden variables are falsified and has it been experimentally confirmed that the polarizations of both photons only ‘materialize’ at the moment they are measured in the D+ and D- detectors. When it can be shown that mutual communication at a speed that is at most that of light is excluded, then the hypothesis that particles only exist when detected is strongly confirmed. Therefore, in a Bell experiment it is required that communication between the photons with at maximum the speed of light is excluded.

In any case, it means that very high demands are made on Bell experiments. Two absolute requirements are:

  • Communication with the speed of light (or below) must be excluded; this means that the mutual distance of the detectors on the left and right must be very large or the time difference between the coinciding detections on the left and right must be very small.
  • All photons sent in the experiment should also be measured to prevent photon pairs that do not show coincidence of the same polarization from being excluded from the measurement and thus making the measured correlation appear larger.
  • All photons must come from a source that precludes their creation from being dependent on the experimenters.

Anton Zeilinger’s experiment in 2017 fully met all these requirements. He used starlight photons.

What now? When does something exist?

Every Bell test – see the timeline on the Quanta Magazine article – has so far confirmed with increasing probative value that the quantum particles only ‘get’ their properties – such as polarization – upon detection. In other words, they do not materially exist until they are detected.

That is quite something. Especially when you consider that the quantum laws are by no means limited to the atomic domain, but also apply to objects in the order of magnitude that can be perceived with our own senses, or even much larger. There is not a single good argument why the quantum laws should not apply at the level of our daily experience. The moon only exists when it is detected. Period. Sorry, Professor Einstein.

Now you can think about this: if the polarization of a photon does not exist before detection, how is it possible that a polarization filter even works? I’ll let you ponder this question for now.

That’s why you have to ask yourself what detection and observation actually mean and what it means if you close the door of your house behind you and no one is left behind. The contents of your house do not materially exist as long as no one is detecting them. The probability that the content will materialize again on your returm, almost exactly as you left it is 99.999999999% (or even closer to 100% but never exactly). That’s reassuring to hear, of course. So, as long as we do not recognize the role of the observer, the interpretation of quantum physics remains an issue that urgently needs to be solved. That’s my opinion, and I’m certainly not alone. Many physicists are already convinced of the role of the observer in experiments, such as Carlo Rovelli almost does with his hypothesis that all properties of objects – just like velocities were already – are relative. If you’re not convinced yet, I propose that you read Bernardo Kastrup, he has some very convincing arguments showing that the permanence of matter is a wrong image of reality.

What if ..?

A good way to do science is to ask the question ‘What if .. ?’. Posing this question is usually the first step in a hypothesis. The next step in such an exercise is to investigate how many unanswered questions you find a satisfactory answer to. The phenomena and experiments that do not match the hypothesis should also be considered of course. If they don’t match, the ‘What if..?’ assumption can be rejected as impossible or improbable. Important: bias should be recognized and avoided in this regard. Together, that is what I call: ‘Research with an open mind’. So switch your bullshit detector off. It is a fast but unreliable instrument. Read if you wish ‘Thinking Fast and Slow‘ by Daniël Kahnemann.

Isaac Newton must also have followed such a what-if thought: ‘What if the heavenly bodies attract each other with a force that depends on their mutual distance?’ Quite an absurd assumption at the time, given the question of how such a force could be exerted through empty space – although we already had experience with forces at a distance such as magnetism. In fact, that force-at-distance question still hasn’t really been answered today, but Newton’s what-if question did result in the classic gravitational mechanics that were beautifully confirmed by Edmund Halley’s comet and that we still start our physics study with.

The Case against Reality

A good recent example of what-if thinking and then consecutively seeing whether there are obvious conflicts with known facts and if it provides explanations for as yet unexplained phenomena is – as far as I’m concerned – Donald Hoffman’s ‘The Case against Reality‘. What if the reality that our senses present to us is just a construction that our senses and our brains create? Hoffman is a cognitive psychologist and convincingly argues that our senses developed by Darwinian evolution where the appearance of the most suitable version of an organism for survival – read also sense here – always offered the best chances for becoming inheritable .

Based on that assumption, we can say the following:

  • It is not necessary that what is presented to us by our senses corresponds 1:1 to reality, whatever reality may be. What we sense as beneficial to our survival – an apple on a tree, a slice of bread, a glass of water – is just a translation that makes us act in such a way that we survive and are able to reproduce, in this case grab the food and consume it. Think of a VR program where the actual electric digital actions in the computer are hidden and are translated for us into an image that we understand, such as a map icon. There is absolutely no need for that translation to be equal to the underlying reality, as long as our response is adequate that’s fine. So here we see no apparent conflict with our experiences.
  • Hoffman’s idea is broadly in line with the idealism of Bernardo Kastrup. According to Kastrup, everything, including our own senses and brains, is not material and does not exist in a solid state separate from us. All our observations are complex experiences that enter our consciousness through a translation (Kastrup evokes the image of a dashboard that represents the phenomena that are happening outside) and are only experienced within consciousness. Solid material reality as something that exists outside of us is an illusion. Again, there are no obvious conflicts with our experiences, although it requires that we switch our bullshit detector off.
  • The question of what consciousness – that which experiences – is has not been answered, neither by Hoffman nor by Kastrup. However, it is the ground on which their philosophy rests. That is in itself not an argument against their idea as there is no philosophy where consciousness is fundamentally or even weakly explained. Neurologists are also limited to speculating about consciousness as some hazy emergence from a complex brain like steam rising from hot water, but that’s very far from even being a provisional explanation.

All in all, we thus arrive at the what-if assumption of primary consciousness which says that all matter, and the experience of it, are products of consciousness. By primary consciousness I mean something much more extended than our daily waking consciousness, which is probably only a small part of it. The next step in this what-if exercise is whether we can with the hypothesis of primary consciousness explain phenomena that we have not been able to explain with the materialist paradigm – also often called physicalism. Then, of course, we also have to see if there are phenomena that contradict it. That’s the scientific approach.

Step 1 – Explanations of observed phenomena not explained by physicalism

What observed phenomena is the hypothesis of primary consciousness able to explain where physicalism fails utterly, I count nine here:

  1. Quantum Physics: Quantum physics seems to tell us that the information available to the observer creates the observed reality in time and space. There are excellent arguments for this. I’ve published a complete book about quantum physics, information and consciousness, also and especially for the lay reader. If reality is a construct of our consciousness – including our body and bodily senses – then it provides an explanation for the otherwise incomprehensible results of quantum physics such as objects that can be in multiple places at once and are entangled over astronomical distances, to name but a few.
  2. Relativity Dilation: Special relativity says that when we observe a relative to us moving object such as a rocket, a bullet, or an elementary particle, the rulers, or whatever may pass for them, shorten in that object to zero and time slows down to standstill as its relative velocity increases to lightspeed. This effect has been confirmed by many experiments. This dilation effect is incomprehensible if we stick to the ideas of solid permanent matter, fixed space and time. But when the consciousness of the observer creates the world – the world is within the mind – it becomes suddenly understandable. Matter, space and time acquire then the same properties as thoughts (James Jeans: ‘The stream of knowledge is heading towards a non-mechanical reality; the Universe begins to look more like a great thought than like a great machine. Mind no longer appears to be an accidental intruder into the realm of matter… we ought rather hail it as the creator and governor of the realm of matter.’
  3. Field Forces: Gravity, electromagnetic force, the strong and the weak nuclear force are all field forces. They affect matter remotely without direct contact through the use of force-transmitting objects, such as with billiard balls. If the world consists only of matter, then field forces are inherently incomprehensible, not even when we try to use the curved space-time dimensions of Einstein’s general relativity. But when consciousness creates reality, field forces become not fundamentally different from thoughts either.
  4. Dreaming: Dreaming is utterly common and incomprehensible at the same time. When dreaming we sometimes create fantastic virtual realities sometimes complete with all possible sensory impressions, seeing, hearing, feeling, tasting, smelling. You really see colors, hear sounds, touch objects. However, try evoking such a realistic experience in the waking state (without hallucinogens). Just try to evoke, with your eyes closed, the experience of seeing the color red or the picking up and feeling the size and weight of an object as a real experience. The result is never more than a faint shadow of a real experience. It always amazes me how little amazing most people find it that we can dream at all. If consciousness is indeed capable of creating vivid experiences of reality, then dreaming is no longer so different from what we do in our everyday waking world.
  5. Blindsight: Nicola Farmer has founded a school – the ICU academy – where children can learn to read, draw colored figures, and play with balls while blindfolded. Nicola also trains teachers who can teach this subsequently to children. This blindsight ability of these children has been confirmed by independent observers and recorded in a film ‘Children with real superpowers‘. Apparently our eyes are not really necessary to perceive the world visually. From the idea of primary consciousness creating the idea of matter this is understandable since what the children “see” is the creation of consciousness itself. Blindsight is also a phenomenon recognized by neurologists, but they attribute it to a different from normal visual processing neural path, ultimately still based on the signals that our eyes transmit to the brain. This cannot be the case with these blindfolded children.
  6. Psychokinesis (Pk): Pk has been confirmed in laboratory experiments, although they concern usually micro-Pk. This is nothing but the primary consciousness in immediate action.
  7. The NDE (Near-Death Experience): Since Raymond Moody’s book “Life After Life” – published originally in 1975 – worldwide interest in the NDE has exploded and large numbers of people have come forward with their NDE experience. The Near-Death Experience Research Foundation (NDERF) has collected more than 5,000 experiences on its website since 2000. It is estimated that between 3 and 5% of the world’s population has had an NDE. Primary consciousness provides an excellent explanation for such a widely reported phenomenon, since consciousness being primary means that it cannot the product of a material brain and thus – after the death of the material body – can continue to exist and perceive independently. Skeptics’ claim that the NDE is neurologically explained is – sorry – bullshit.
  8. The ADC (After-death-communication): Since the beginning of this century, the After Death Communication Research Foundation (ADCERF) has collected more than 2,000 reported experiences of contact with recently deceased loved ones and animals. Polls show that more than 50% of people report an ADC experience shortly after the death of a partner, child or beloved pet. Read “The Departed among the Living” by professor Erlendur Haraldsson. This phenomenon is also perfectly explainable from the non-material death surviving primary consciousness.
  9. Evolution: The predominant neo-Darwinian view of the origin of life and evolution — life has come into existence by blind chance and by the survival of the most suitable organism plus a few billion years of single local mutations in DNA — is on the verge of collapsing. Read “Evolution 2.0” by Perry Marshall, “Evolution: A view from the 21th Century, Fortified” by James Shapiro or “Active Biological Evolution” by Frank Laukien. All life, from viruses and single-celled organisms to “modern” animals and plants, responds to challenges from its environment by actively modifying its entire genetic machinery (not just its DNA) – humans also. Amazingly often successfully and also inheritable by the next generations. The irrepressible suspicion that an intelligent reaction to the experiences of the organism is taking place here, starts to receive more and more attention. Primary consciousness, assuming it is also intelligent (a fairly obvious assumption), offers a good explanation.

Step 2 – Conflicts with established observations

Are there phenomena that conflict with the hypothesis of primary consciousness? At first glance (our bullshit detector) it seems there are at least four:

  1. The experience of solidity: Reality as we experience it is solid and rather permanent. We can’t walk through a wall. If we bump ourselves, it hurts. If we fall, we get hurt. Objects left behind remain there until we – or others – relocate them. Matter does not appear out of nothing, nor does it just disappear into nothingness. That would go against the well-known and soundly affirmed conservation laws of physics.
  2. Multiple observers: When my consciousness creates the world and everything in it, a problem arises with multiple observers (read ‘Tom Poes en de Kwanten’ in the bundle ‘Trammelant en Tierelier‘ by Marten Toonder, highly recommended, however only available in Dutch).
  3. Free will: Why – assuming I have free will – can’t I create the world I want. I cannot create or make matter disappear at will. The latter can probably be doubted if you take Mary Rose Barrington’s book – JOTT – seriously.
  4. Evil: Why does Evil exist? In itself this is not a physically definable conflict but nevertheless a valid question. If consciousness creates the world why also Evil? That question is food for philosophers.

I hope you can see that in all the above points the assumption is hidden that primary consciousness is identical to the individual waking consciousness. Which is not necessarily the case. When we can drop that assumption, all of the above points fail as strongly valid conflicts that might reject the primary consciousness hypothesis.

Furthermore, the above is not intended as a plea for idealistic monism, as for instance Kastrup advocates, and which completely denies the existence of matter. Most of the points mentioned in step 1 can also be explained with the dualistic view that matter and consciousness coexist and can influence each other. Something that René Descartes assumed in his Meditations. However, the question that is not answered in his dualism is how these two intrinsically different things, matter and consciousness, can interact with each other.


As far as I’m concerned, this what-if exercise provides ample confirmation that the primary consciousness hypothesis is at least worth taking seriously. While it’s probably not the ultimate scientific theory of everything, it can explain a lot of things that are simply inexplicable from the physicalist perspective that prefers to ignore en deny an abundant amount of clear facts.

What is real? A short exercise in reality

When I’m discussing quantum physics in company of friends or presenting a course in quantum physics and consciousness, and I present the substantiated conclusion from the quantum physics experiments – especially the delayed choice experiments of John Wheeler – that we create reality by observing it, the common and very understandable reaction is often that people shy away from it because of its unimaginablity. As if it would imply that the everyday world is an illusion and therefore not ‘real‘. I answer them usually by giving them the metaphor of the rainbow, definitely not an illusion but a ‘real‘ phenomenon. But if you think that the rainbow above you is a material arc, then you are clearly wrong and suffering from an illusion.

The words “real” and “material” have become so closely linked by our upbringing that, for most people, they have taken on the same meaning. What is considered ‘real‘ is something that can be measured – so to speak – with a yardstick. If you can’t measure it, it is not ‘real‘. In this way ‘Real‘ means nowadays a permanent existence without the involvement of an observer. I wonder though: Are thoughts, dreams, fantasies not real? Are my thoughts not real as long as I have expressed them not in words, like I am doing here now?

A VR fantasy

To disconnect that engraved automatic link between the concepts ‘real‘ and ‘material‘, I propose now that you do the following simple VR imagination exercise. You don’t have to be in possession of a VR headset. A little bit of imagination will suffice.

Nursing home residents using VR headset ‘visiting’ the Rijksmuseum, Amsterdam

Imagine then that a VR headset is ready and waiting for you on the table, including a pair of wireless earbuds. You place the headset over your eyes, plug the earbuds in …. and find yourself looking out over a plain covered mostly with fresh green grass, blooming flowers and scattered here and there a bush. Above you the blue sky with some white clouds floating quietly with the wind. Birds fly, and you can hear their songs. In the far distance you see an imposing mountain towering high into the sky, a super Mount Everest. It’s upper half is covered in snow and you notice wisps of clouds streaming away from the top.

Then you turn 180 degrees. Now you do notice that you are standing firmly on the top of a ridge overlooking a sea. Down below you see a beach where the waves roll in. Now you understand where that background noise came from. A sailboat is passing far away. The crew waves to you.

Now the reality question. Where’s that mountain you saw a moment before? Has it disappeared from reality? Does it still exist? You turn back again and there is the mountain again. Did you just recreate it from nothingness? By observing it?

Creation from non-existence by observation?

I do not think so. The image of that mountain was just not displayed on the LCD screen of the VR headset when you were looking in the direction of the sea, but its source still existed. It existed in the memory of the headset’s VR software all along, ready to be displayed if you turned your head in the right direction. The image of the mountain thus constantly exists as an opportunity to be shown and thus seen.

As far as I’m concerned, that’s exactly like the quantum behavior of the reality that we experience every day. The moment I look at the table before me, it becomes real through my observing. Before I looked at it, it did exist “really” as a well-defined stable possibility wave pattern in the quantum field. The larger the object, the smaller the relative deviations of its physical properties that are allowed by the quantum probability wave distribution. That is what makes the world appear so sharp and concrete to us with our relatively coarse senses. As far as I’m concerned, the world is ‘real‘ enough to be careful when crossing a busy road.

No creation out of nothingness

So, it is not the case that by observing we create something out of empty nothingness. It is already there, but in an unmaterialized form that leaves some room for deviations from the exact outcomes as predicted by Newtonian mechanics. That’s more room than you perhaps think. It has been calculated that after 7 or 8 collisions the movement of a billiard ball has become fundamentally unpredictable because of the accumulated and exponentially increasing Heisenberg uncertainty. Thus, the deterministic mechanical predictability of the universe, á la Laplace, collapses. That’s all. We are creators, but not free to create anything we want.

Not yet anyhow.

Schrödinger’s stopwatch

A rhetorical trick

When Erwin Schrödinger presented in 1935 his thought experiment with a cat in a closed box to his colleagues, in particular Bohr and Heisenberg, to demonstrate the absurdity of the Copenhagen interpretation of quantum physics, he used a rhetorical trick. He introduced a living being in a physics experiment, a living entity that would be in a quantum superposition. Secondly, he also introduced something to which Bohr would give a name in that same year, entanglement, which is now widely accepted among physicists. But back to the cat, are you allowed to introduce an element into your physics experiment, even if it is a thought experiment, of which it is actually not known what it is in a physical sense? Because, what is life?

What is life anyway?

We recognize the difference between life and death, and we think we know it well. We recognize if life has disappeared from a previously living being, when it has passed into the state of inert dead matter. Physics is the very science that deals with dead matter, not with living beings. A living being has a number of characteristics, including homeostasis and purposefulness, but is it then really clear what these characteristics are based on, what their origin is? One of the major problems with organ donors is to determine correctly the donor’s death so that the removal of the still usable organs can begin. But we do not yet have an objective measuring instrument for life, a test that determines with 100% certainty whether a being is alive or dead. It is therefore not surprising that in his later career Schrödinger gave a series of lectures on the subject “What is life”. With these lectures he gave the starting signal for what is now called quantum biology.

A physically correct thought experiment

Thought experiments should be also physically correct, every component should be described accurately and without ambivalence. Einstein was a master at it. So in fact, Schrödinger’s thought experiment should not be regarded as a correct physical thought experiment. So let’s take that unjustly introduced live cat out and replace it with something that can be described physically very well, a thing, dead matter. For example, a clock or stopwatch that is stopped by the click of the Geiger counter.

The Schrödinger stopwatch experiment: A hermetically sealed box contains a radioactive atom known to have a 50% chance of being decayed after one hour. It also contains a Geiger counter connected to a stopwatch. Closing the box starts the stopwatch. A click of the Geiger counter will stop the stopwatch. According to the Copenhagen interpretation, it is impossible to predict when the atom will decay, which is still the prevailing opinion among physicists. As the atom decays, it produces radioactive radiation that is detected by the Geiger counter. The click of the Geiger counter stops the running stopwatch. After closing the box we  wait an hour before opening the box to observe if and when the stopwatch has stopped.

The Copenhagen interpretation tells us that the atom, the Geiger counter and the stopwatch form one joint superposition of quantum states, i.e. entanglement, when the box is closed and no measurements have been taken yet. As soon as we open the box, the quantum wave collapses and we will observe the materialized contents of the box. Now suppose that the stopwatch turns out to have been stopped after 44 minutes, so 16 minutes before the box was opened. Thus we recognize that the atom decayed 16 minutes ago. Now realize that the stopwatch materialized – became tangible matter with the hand at 44 minutes – at the moment that we opened the box. During the hour between the closing and the opening of the box, there existed no material stopwatch, neither running or stopped, but a non-material entangled state wave representing the contents of the box.

The observer also creates time

Behold – logically arising from the Copenhagen interpretation – the origin of time. The observer not only creates the matter that presents itself to us, but also – retroactively in time – the moment at which it happened. The observer creates the event as it unfolded in time. A stunning conclusion. No wonder the Copenhagen interpretation is not very popular among physicists. But those other hypotheses are even more unlikely.

If you are still in doubt here, I therefore refer you to the delayed choice experiments that seem also to demonstrate retrocausality – not to the one of Kim et al. of 1999, there is a flaw in its design and interpretation – but to those well designed ones that are very well explained as showing the retrocausal creation of history and time.

Einstein and the speed limit of the universe

Einstein did not support the fundamental uncertainty of quantum physics. He stubbornly maintained the idea that reality was permanent and objective and that the observer played not a significant role. Yet the observer plays quite an important role in his best-known work, the theory of relativity. Precisely if you assume that the observer makes the observed ‘true’ and thus actually creates reality, his approach to the relativity of space and time offers a surprising outcome.

Special relativity

The special theory of relativity can be followed perfectly by using nothing more complicated than Pythagoras and a dose of high school algebra. But I’m not going to do that here now. There is a lot to be found on the internet doing that. Read for example: Special relativity math2410 from Leeds University.


An extremely important premise for Einstein was that the universe should basically look the same for two observers moving relative to each other. Ultimately, that’s a symmetry argument. Symmetry has been an important criterion in the theories of physics since Emmy Noether introduced it in 1918. He combined this criterion with the insight that the observed speed of light – in a vacuum – must be the same in all circumstances. This followed from Maxwell’s equations for electromagnetic waves and was indirectly confirmed by the experiments of Michelson and Morley who sought to determine the speed at which the Earth traveled through the supposed aether by measuring differences in the speed of light going in different directions with regard to this aether. The outcome was that they could not measure differences in speed, no matter how accurate their experimental set-up was.

To ride with a light wave

In addition, Einstein had realized from an early age that you cannot overtake or even keep up with a light wave. If you could keep up with light, Maxwell’s electromagnetic wave would no longer oscillate from your moving point of view, it would look like a frozen wave. But since the wave’s propagation is both caused and sustained by its ceaselessly oscillating fields, that couldn’t be right. Light must therefore always move at exactly 300,000 km/s for every observer. This follows also undisputedly from Maxwell’s equations because these do not contain any parameter relative to the position of the observer.

Einstein riding the light wave. The wave will seem frozen from his viewpoint. This is not possible. © Paul J. van Leeuwen

Einstein now imagined two observers moving relative to each other but who should both observe the same speed of light. Imagine a light source C standing still for observer Alice. Alice sees the light of C approaching her at c = 300,000 km/s. Observer Bob whizzes at great speed towards ligt source C, say 1/10 of c. Alice now considers that the light coming from C towards Bob must therefore move at 11/10 of the speed of light for Bob. I hope you can follow Alice’s reasoning. Otherwise, try to think of two cars driving towards each other while Alice watches along the roadside. Car with driver Bob drives at 10 km/h and car C drives at 100 km/h towards Bob and Alice. Car C here stands for the light that comes towards Bob and Alice. Alice observes (with radar) that the speed of car C is 100 km/h and that Bob and car C are speeding towards each other at 110 km/h. Now suppose that Bob would also perceive the speed of the oncoming car C relative to him as 100 km/h. That could only be if Bob’s clock ticked at 10/11 the speed of Alice’s watch. And not only Bob’s clock but also Bob’s entire perception of time would have to be slowed down so that Bob actually experiences the speed of car C as 100 km/h. In that case Bob will live a little bit slower. As far as Alice is concerned, Bob is now aging more slowly than Alice.

Time slows down and space shrinks

Now back to the light that is always experienced by every observer at the same constant speed. If Bob moves relative to Alice at 1/10 the speed of light and Bob sees the light move at 300,000 km/s, then that is possible if the time for Bob slows down by 10/11. Bob doesn’t feel that way because he himself is sitting in his delayed time capsule, his car.

This simplified estimate of the slowing of Bob’s time is not 100% correct because something also happens with Bob’s yardsticks, but what matters to me is that you get an understanding of relativity reasoning. If you want to do this completely right, then, as already mentioned, some algebra and Pythagoras are involved and the time dilation, the slowing down of Bob’s time, is described with:

Time dilation T for Bob’s clock moving at speed v relative to Alice’s stationary clock. T0 is the time of Alice’s clock. The closer Bob moves to the speed of light c, the slower his clock ticks as seen from Alice’s viewpoint.

Here v is Bob’s speed, relative to Alice (or Alice’s speed relative to Bob). If you enter here 1/10 of the speed of light c for v, then Bob’s clock turns out to tick 0.5% slower than Alice’s clock. Now we apply the principle of symmetry that Einstein argued. There is no absolute speed, speed is always relative. Bob, who experiences himself as stationary, observes Alice moving away from him at 1/10 the speed of light. So Bob also sees Alice’s clock ticking slower by 0.5%. This seems a paradox, but the theory is correct and has been experimentally confirmed in countless experiments. The solution is that Bob and Alice can’t compare their clocks until they come together and for that at least one of them has to turn around which means speeding up and slowing down. This breaks the symmetry.

You can see from the above time dilation formula that the maximum speed that applies in the universe is 300,000 km/s. The term under the radical becomes negative when v becomes greater than c, which would make the time dilation imaginary. That’s too bad because it makes non-imaginary trips to even the nearest stars impossible for us.

From Alice’s point of view, Bob’s rulers also shorten in the direction of his movement. For completeness, this is the formula for the contraction of fast-moving rulers, the so-called Lorentz contraction:

Lorentz contraction of a ruler L moving with speed v relative to the observer. L0 is the lenght of the ruler when at rest relative to the observer.

It goes without saying that this sparked a lot of discussion in the first half of the 20th century. Einstein took the position that the observers of the clocks and rulers did not play a vital role in relativity effects. According to him, they could just as easily be left out of the equations. Fast-moving clocks would automatically slow down, fast-moving rulers would shorten without the need for an observer. This elasticity of space and time and of the material objects therein was, and is still difficult to grasp but has been confirmed experimentally time and again. We, the physicists, are more or less used to it now, but we do not really understand it. It’s not natural.

Einstein fighting versus the probability interpretation of quantum physics

Einstein seriously put quantum physics on the map with his explanation of the photoelectric effect, for which he received the Nobel Prize. Light consists of particles with an energy per particle according to the Planck formula (f here stands for the frequency):

Planck’s law: the energy of a quantum of radiation energy is propertional to its frequency and is inversely proportional to its wavelength

But after that he argued vigorously against quantum physics and especially its implications, to no avail. Especially against the probability interpretation of Bohr, Heisenberg and Born: that the state wave, the solution of the Schrödinger equation, represents the probability that the particle will be found at a given location and time when measured. That went against Einstein’s gut view of the world as an objectively permanent collection of material objects. Einstein’s objection is understandable if you adhere to the materialistic view of the world, because a probablity is not an objective material object. It is something that exists in our mind. A thought.

And that’s exactly my own idea of how the universe works. Everything we experience takes place in the mind. The perception of the measured particle thus becomes identical to the thought of it. The experience is then the same as its creation. That explains to me very well why the laws of physics behave according to mathematical formulas. That is something that many physicists, including Einstein, have expressed their amazement about. So the observers’ mind plays an indispensable role in the universe, it creates it. Mathematics is something of and in the mind. The mind uses apparantly mathematics in its creation of the universe.

Time and space are concepts of the mind.

That idea suddenly makes things like the slower passing of time, the shrinking yardsticks and the curved space of general relativity, much more palatable. In a dream we would really not notice these things either. There exists no real objective time outside of us that does slow down, there is no objective space outside of us that does shrink, it’s all happening in the mind of every observer.

Science Fiction?

That offers hope for the possibility of exploration of the cosmos. The maximum speed in the universe that we observe – that of light – seems to be something that the mind has imposed on itself. But as soon as we can accept that time and space is happening within the mind, the possibility opens up that we could move through the universe beyond that limitation. Traveling within the mind is not bound by the restrictions of relativity. This, I believe, is also the correct interpretation of entanglement and instantaneous action over long distances, as confirmed by all those Bell tests. Traveling through the universe by means of the mind could even be the way – one that intelligent beings existing elsewhere in this vast universe already have discovered – to travel through the cosmos despite Einstein’s speed limit. And to visit us. Experiments have already been conducted confirming that quantum tunneling shows speeds greater than that of light.

A universe like a slowly fading flare

That the universe is a creation of the mind also offers an alternative for the pending entropy death of the universe that physics has been predicting for a century and a half now. Even if that is a immeasurably distant future away, it remains a bleak prospect contradicting any sense of purpose of the world. What was that fantastic spectacle all for if that is to be the end? But if the universe is the product of the creative mind, then that is by no means an unavoidable end to everything. On the contrary.


What I want to say with this story is that there is a good chance that two apparently incompatible theories – relativity and quantum physics – can be merged together very well when we start to include the all important role of consciousness. The intelligibility of the nature of reality would only increase as a result.