The Schrödinger you probably didn’t know

It’s about everything but cats

Ulrich Mohrhoff
Aug 15 · 14 min read

In an essay written during the last year of his life, Erwin Schrödinger expressed his astonishment at the fact that despite “the absolute hermetic separation of my sphere of consciousness” from everyone else’s, there is “a far-reaching structural similarity between certain parts of our experiences, the parts which we call external; it can be expressed in the brief statement that we all live in the same world.”

Erwin Schrödinger
Erwin Schrödinger
Erwin Schrödinger

If I see you looking at a flower, I infer that you perceive a flower, but I am not aware of what the flower looks like to you. Your “sphere of consciousness” is hermetically sealed off from mine, as is mine from yours. Yet we often agree that we are perceiving or experiencing the same thing. How so? The obvious explanation is that (as far as the two of us are concerned) there are three worlds: a real world plus the world you perceive plus the world I perceive. There is a real flower that causes the both of us to perceive a flower. This, Schrödinger insisted, “is not to give an explanation at all; it is simply to state the matter in different words. In fact, it means laying a completely useless burden on the understanding.”

The standard scientific account of perception begins by positing the mind-independent existence of a real world “out there.” Objects in this world are believed to emit light or sound waves, which are believed to stimulate peripheral nerve endings (retinas or ear drums). The stimulated nerves are believed to send signals to the brain, where neural processes are believed to give rise to perceptual experience.

A neuroscientist explains the explanatory gap. Drawing by Jolyon Troscianko (jolyon.co.uk). Used with permission.

The trouble with this account is not simply that no one has any idea how objective brain processes could give rise to subjective experiences. The trouble is that no one has any idea how we could have information about what happens or exists in the real world “out there.” While the standard scientific account of perception begins by invoking events in that world, it leads to the conclusion that we have access only to our experiences, and that there is no way we could know anything about what happens or exists in that world.

If you are unconvinced, imagine a neuroscientist, Alice, who observes a specific combination of neural processes in Bob’s brain whenever she sees that Bob is looking at a green apple. Something in her experience of Bob’s brain correlates with something in her experience of what is in front of Bob. If Bob tells her that he, too, perceives a green apple, it confirms the existence of a green apple in a world about which Alice and Bob can agree. What it does not confirm is the existence of an object or the occurrence of an event or a series of events that causes Alice and Bob to each perceive an apple.

So: when I say “this is a green apple,” I do not state the correspondence between a real apple and my perception of an apple. While my judgment that this is a green apple goes beyond what is immediately given to me, it does not reach beyond what is given to me. It boils down to the claim that this thing is of much the same color, shape, and consistency as the things I previously judged to be green apples, or the claim that this particular experience is of the same kind as experiences I previously referred to as “green apples.” It states the correspondence between “green apple experienced here and now” and “green apple experienced there and then.”


To Schrödinger, the far-reaching similarity between our experiences of an external world was “not rationally comprehensible. In order to grasp it we are reduced to two irrational, mystical hypotheses.” We have seen what he thought of the hypothesis which posits a mind-independent reality that is reflected in our minds. For Schrödinger, to say “that the becoming of the world is reflected in a conscious mind is but a cliché, a phrase, a metaphor that has become familiar to us. The world is given but once. Nothing is reflected.” So what was the other hypothesis — the one he endorsed? It was that

“we are all really only various aspects of the One.”

Who or what is this “One”? It is a consciousness or a conscious self. And there is only one consciousness or conscious self. The multiplicity of minds, Schrödinger maintained, “is only apparent, in truth there is only one mind. This is the doctrine of the Upanishads. And not only of the Upanishads.” (The Upanishads are ancient Sanskrit texts which contain many of the central concepts and ideas of Indian philosophy.) If “to Western thought this doctrine has little appeal,” Schrödinger went on, it is because our science “is based on objectivation, whereby it has cut itself off from an adequate understanding of the subject of cognizance, of the mind.”

Science is supposed to be objective. To achieve objectivity, Schrödinger explained, “we step with our own person back into the part of an onlooker who does not belong to the world, which by this very procedure becomes an objective world.” Because this objective world does not contain the part of ourselves which has stepped back to become an onlooker, it does not contain our minds. What happens if we forget that the objective world is but a part of our experiences, the part from which we have stepped back? What happens is that we feel compelled to re-insert our minds: “I so to speak put my own sentient self (which had constructed this world as a mental product) back into it — with the pandemonium of disastrous logical consequences” that ensue from this error. One of them is “our fruitless quest for the place where mind acts on matter or vice-versa.”

What we are up against here is what Edmund Husserl has called “the paradox of human subjectivity” — being at once a subject for which the world exists and an object that exists in the world. The simplest solution of this paradox is to deny it. Those who do so end up by denying either consciousness or the world. In this day and age, denying the world is no longer in fashion, so we deny consciousness in one way or another: by faulty analogies, by defining it as something that just isn’t consciousness, or by treating it as an illusion, forgetting that in order to have illusions one has to be conscious.


For Schrödinger, the objective world was not a world that exists independently of our thoughts and perceptions. It was that part of our experiences which is amenable to objectivation, to being regarded as a reality about which we can think as if it existed by itself. Niels Bohr, whose views are often portrayed as antithetical to Schrödinger’s, heartily agreed: “in our description of nature the purpose is not to disclose the real essence of the phenomena but only to track down, so far as it is possible, relations between the manifold aspects of our experience.” Yet today science has the reputation of being engaged in figuring out how things really are, and not a few physicists claim — especially on TV, in press releases, and in grant applications — that they are about to discover just that. They certainly have their nerve.

The general theoretical framework of contemporary physics — quantum mechanics — is a probability calculus. It is a theory that serves to assign probabilities to the possible outcomes of future measurements on the basis of the actual outcomes of past measurements. This poses a formidable problem: what justifies the exalted status of measurements in our fundamental physical theory? Unsurprisingly, there has been no dearth of attempts to sweep this problem under the rug. Avoiding the obvious solution has turned into a growth industry. Denying it seems de rigueur, even as the denials become increasingly strained and the obvious solution increasingly hard to avoid.

Niels Bohr
Niels Bohr
Niels Bohr

Measurements owe their exalted status to being the interface between two kinds of reality: a reality that is accessible to us through direct sensory experience, and a reality that is not directly experienced by us. Nearly a century ago, in 1922, Niels Bohr wrote to his philosophical mentor Harald Høffding what he thought of the difficulties physicists were facing at the time: they are “of such a kind that they hardly allow us to hope, within the world of atoms, to implement a description in space and time of the kind corresponding to our usual sensory images.’’ In 1925 and 1926, Erwin Schrödinger and Werner Heisenberg hit on their respective formulations of quantum mechanics, and by 1929 Bohr’s insights had gelled into what remains the most astute understanding of quantum mechanics to date. (Of this, the several existing versions of the so-called Copenhagen interpretation are more or less grotesque caricatures).

To David Mermin, “Niels Bohr was either one of the great visionary figures of all time, or merely the only person courageous enough to confront head on, whether or not successfully, the most imponderable mystery we have yet unearthed.” These are Bohr’s principal conclusions:

  • While the properties of objects that are directly accessible to sensory experience can be thought of as existing independently of measurements, the properties of quantum systems are amenable to objectivation only when they are measured.
  • The function of measurements in quantum mechanics is twofold: while they serve to indicate the properties that quantum systems do possess, in the first place they are needed to realize (make real) the properties that quantum systems can possess.

Take, for instance, the property of position. To model an ideal position measurement, we imagine an array of detectors monitoring distinct regions of space. (Real measurements are more messy than ideal ones, but their proper messiness is not part of the problem that concerns us here.) The result of an ideal position measurement is that the detector monitoring a particular region clicks, indicating the presence of something (a particle, say) in this region. The particle’s presence in this region, however, is not the cause of the click. Rather, it is because of the click that a particle is present in this region.

  • The concepts available to physicists owe their meanings to the spatiotemporal character of human perceptual consciousness. (Energy and momentum, for example, derive their meanings from what physicists call the symmetry properties of space and time.)
  • These concepts cannot be applied to atoms and subatomic particles, inasmuch as these things are not accessible to direct sensory experience.
  • The properties of atoms and subatomic particles are only indirectly accessible to sensory experience, via instruments that are directly accessible to sensory experience.
  • Measurements, therefore, serve as the interface between a reality that is accessible to us through direct sensory experience, and a reality that is not directly experienced by us.

So: Science deals with that intersection of our experiences which is amenable to objectivation. This includes things that are experienced directly, as well as things that are experienced only indirectly, with the help of measuring instruments. It does not include the subject (which is not a property of objects), and it includes neither the origin of our experiences nor what is responsible for the “far-reaching structural similarity between certain parts of our experiences” that so astonished Schrödinger.


This bring us back to Schrödinger’s preferred explanation of this far-reaching structural similarity, which was that “we are all really only various aspects of the One.” In defense of this “irrational, mystical” hypothesis, he maintained that

our present way of thinking does need to be amended, perhaps by a bit of blood-transfusion from Eastern thought. That will not be easy, we must beware of blunders — blood-transfusion always needs great precaution to prevent clotting. We do not wish to lose the logical precision that our scientific thought has reached, and that is unparalleled anywhere at any epoch.

The One that Schrödinger has in mind is the ultimate subject, from which we are separated by a veil of self-oblivion. The same veil also prevents us from perceiving the ultimate object, as well as its identity with the ultimate subject. According to the Upanishads, the world is a manifestation of the One by the One to the One. In relation to the world, the One is the substance that constitutes it as well as the consciousness that contains it. As substance, it has unlimited power to determine itself, to take on qualities. As consciousness, it has unlimited power to give itself content. But it also has the power to limit itself, to be less than omnipotent and less than omniscient.

If at bottom we are all various aspects of the One (without being aware of it, except by a genuinely mystical experience that is hard to come by), we have to conceive of at least two poises of consciousness, one in which the One manifests the world to itself perspectivally, as if experienced by a multitude of subjects from a multitude of locations within the world, and one (the original poise) in which the One manifests the world to itself aperspectivally, as if experienced from no particular location or from everywhere at once.

On Schrödinger’s hypothesis, the reason why my experiences (of an external world) agree with yours is that we do, in fact, experience the same world, albeit from different vantage points. But this world does not exist out of relation to any consciousness whatsoever. It always exists in relation to some poise of consciousness, and the reason why we experience the same world is that the world we experience is the world that the One has manifested (or is perpetually manifesting) to itself.

According to the Upanishads, all knowledge, all experience, is based on the identity of the ultimate subject with the ultimate object. It knows its objects because it is one with them, for it is one with the substance that constitutes them. If the ultimate subject adopts the localized standpoints of its objects, this knowledge by identity takes the form of a direct knowledge. Each knows the others directly, without the mediation of mental or neural representations. But if the ultimate subject identifies itself with each object to the apparent exclusion of all others, this direct knowledge gets replaced by a representative knowledge: it becomes a direct knowledge only of some of the object’s own attributes — in our own case, a direct knowledge of patterns of electrochemical pulses in a brain.

This brings us to one of the unsolved mysteries associated with the existence of consciousness in an apparently material world — or the existence in consciousness of an apparently material world: how it is that we perceive external objects instead of their neural representations in us? The Upanishadic solution to this riddle is that representative knowledge is supported and made possible by an underlying direct knowledge, which in turn is supported and made possible by a knowledge by identity, which belongs to the ultimate subject.

Another of these unsolved mysteries is the question how patterns of electrochemical pulses in brains can give rise to (or stimulate or trigger) the experience of qualia. These qualia include not only the sensory qualities of color, sound, taste, smell, and touch but also the qualitative aspects of our experience of space and time. The extendedness of space is such an aspect. It cannot be defined in quantitative or mathematical terms. The only way to know it is to perceive it. If you are not convinced, try to explain to my friend Andy, who lives in a spaceless world, what space is like. Andy is good at math, so he understands you perfectly if you tell him that space is like the set of all triplets of real numbers. But if you believe that this gives him a sense of the expanse we call space, you are deluding yourself. We can imagine triplets of real numbers as points embedded in space; he cannot. We can interpret the difference between two numbers as the distance between two points; he cannot. At any rate, he cannot associate with the word “distance” the sense of remoteness it conveys to us.

Much the same goes for time. Time passes, and the only way to know this is to be aware of it. This is what St. Augustine meant when he wrote, “What, then, is time? If no one asks me, I know; if I wish to explain to him who asks, I know not.” That the passing of time is another quality that cannot be defined in quantitative or mathematical terms, is obvious from the fact that we cannot measure the speed at which time passes. (One second per second?)

If patterns of electrochemical pulses in brains are to trigger the experience of sensory qualities displayed in space and changing as time passes, they need to be interpreted, and this can only be done by a subject that is intrinsically acquainted with the qualitative aspects of space and time. It might be argued that to interpret these patterns is to decode information that is encoded in them. This stands to reason, and according to Schrödinger’s hypothesis this is the case, but it calls for a subject that knows the code. Alice, our neuroscientist, who observes a particular firing pattern in Bob’s brain whenever she sees that Bob is looking at a green apple, cannot help us here. This is because the correlation she observes is a correlation between two of her own perceptions — the firing pattern in Bob’s brain and the apple Bob is eyeballing — both of which are extracted from neural firing patterns in her own brain. It is not a correlation between a firing pattern in anyone’s brain and whatever it is that causes this pattern.

The following flow chart illustrates the Upanishadic solution to those two mysteries. The information provided by our brains is not sufficient to account for our experience of the external world in its full 3+1 dimensional technicolor glory. This information is supplemented by a sustained intuition originating in a subliminal consciousness, which is in possession of a direct and complete knowledge of the external world.

In the surface consciousness knowledge represents itself as a truth seen from outside, thrown on us from the object, or as a response to its touch on the sense, a perceptive reproduction of its objective actuality…. Since it is unable to observe the process of the knowledge coming from within, it has no choice but to accept what it does see, the external object, as the cause of its knowledge…. In fact, it is a hidden deeper response to the contact, a response coming from within that throws up from there an inner knowledge of the object, the object being itself part of our larger self. — Sri Aurobindo

N. Bohr, “Introductory Survey,” in Atomic Theory and the Description of Nature (Cambridge University Press, 1934)
Collected Works, Vol. 10 (Elsevier, 1999), pp. 513–514
E. Husserl, The Crisis of European Sciences and Transcendental Phenomenology (Northwestern University Press, 1970), p. 178
N.D. Mermin, Boojums All the Way Through (Cambridge University Press, 1990), p. 189
E. Schrödinger, “What is real?,” in My View of the World (Cambridge University Press, 1964)
— “The principle of objectivation” and “The arithmetic paradox,” in What Is Life? With: Mind and Matter & Autobiographical Sketches (Cambridge University Press, 1992), pp. 117–139
Sri Aurobindo, The Life Divine (Sri Aurobindo Publication Department, 2005), pp. 560–561

The distinction between perspectival and aperspectival structures of human consciousness is due to Jean Gebser, The Ever-Present Origin (Ohio University Press, 1985).

Arguably the most authentic sources of information on the philosophy of the Upanishads are Sri Aurobindo, Isha Upanishad and Kena and Other Upanishads (Sri Aurobindo Publication Department, 2003, 2001) as well as The Life Divine. The Collected Works by Sri Aurobindo are free to download at this link.

Ulrich Mohrhoff

Written by

Aurobindonian / Author of “The World According to Quantum Mechanics: Why the Laws of Physics Make Perfect Sense After All” / paypal.me/ujmPondy

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