Category Archives: Art

Bootstrapping to quantum gravity


“If … there were no solid bodies in nature there would be no geometry.”

A while ago, I discussed the mystery of why matter should be the source of gravity. To date, this remains simply an empirical fact. The deep insight of general relativity – that gravity is the geometry of space and time – only provides us with a modern twist: why should matter dictate the geometry of space-time?

There is a possible answer, but it requires us to understand space-time in a different way: as an abstraction that is derived from the properties of matter itself. Under this interpretation, it is perfectly natural that matter should affect space-time geometry, because space-time is not simply a stage against which matter dances, but is fundamentally dependent on matter for its existence. I will elaborate on this idea and explain how it leads to a new avenue of approach to quantum gravity.

First consider what we mean when we talk about space and time. We can judge how far away a train is by listening to the tracks, or gauge how deep a well is by dropping a stone in and waiting to hear the echo. We can tell a mountain is far away just by looking at it, and that the cat is nearby by tripping over it. In all these examples, an interaction is necessary between myself and the object, sometimes through an intermediary (the light reflected off the mountain into my eyes) and sometimes not (tripping over the cat). Things can also be far away in time. I obviously cannot interact with people who lived in the past (unless I have a time machine), or people who have yet to be born, even if they stood (or will stand) exactly where I am standing now. I cannot easily talk to my father when he was my age, but I can almost do it, just by talking to him now and asking him to remember his past self. When we say that something is far away in either space or time, what we really mean is that it is hard to interact with, and this difficulty of interaction has certain universal qualities that we give the names `distance’ and `time’.
It is worth mentioning here, as an aside, that in a certain sense, the properties of `time’ can be reduced to properties of `distance’ alone. Consider, for instance, that most of our interactions can be reduced to measurements of distances of things from us, at a given time. To know the time, I invariably look at the distance the minute hand has traversed along its cycle on the face of my watch. Our clocks are just systems with `internal’ distances, and it is the varying correspondence of these `clock distances’ with the distances of other things that we call the `time’. Indeed, Julian Barbour has developed this idea into a whole research program in which dynamics is fundamentally spatial, called Shape Dynamics.

Sigmund Freud Museum, Wien – Peter Kogler

So, if distance and time is just a way of describing certain properties of matter, what is the thing we call space-time?

We now arrive at a crucial point that has been stressed by philosopher Harvey Brown: the rigid rods and clocks with which we claim to measure space-time do not really measure it, in the traditional sense of the word `measure’. A measurement implies an interaction, and to measure space-time would be to grant space-time the same status as a physical body that can be interacted with. (To be sure, this is exactly how many people do wish to interpret space-time; see for instance space-time substantivalism and ontological structural realism).

Brown writes:
“One of Bell’s professed aims in his 1976 paper on `How to teach relativity’ was to fend off `premature philosophizing about space and time’. He hoped to achieve this by demonstrating with an appropriate model that a moving rod contracts, and a moving clock dilates, because of how it is made up and not because of the nature of its spatio-temporal environment. Bell was surely right. Indeed, if it is the structure of the background spacetime that accounts for the phenomenon, by what mechanism is the rod or clock informed as to what this structure is? How does this material object get to know which type of space-time — Galilean or Minkowskian, say — it is immersed in?” [1]

I claim that rods and clocks do not measure space-time, they embody space-time. Space-time is an idealized description of how material rods and clocks interact with other matter. This distinction is important because it has implications for quantum gravity. If we adopt the more popular view that space-time is an independently existing ontological construct, it stands to reason that, like other classical fields, we should attempt to directly quantise the space-time field. This is the approach adopted in Loop Quantum Gravity and extolled by Rovelli:

“Physical reality is now described as a complex interacting ensemble of entities (fields), the location of which is only meaningful with respect to one another. The relation among dynamical entities of being contiguous … is the foundation of the space-time structure. Among these various entities, there is one, the gravitational field, which interacts with every other one and thus determines the relative motion of the individual components of every object we want to use as rod or clock. Because of that, it admits a metrical interpretation.” [2]

One of the advantages of this point of view is that it dissolves some seemingly paradoxical features of general relativity, such as the fact that geometry can exist without (non-gravitational) matter, or the fact that geometry can carry energy and momentum. Since gravity is a field in its own right, it doesn’t depend on the other fields for its existence, nor is there any problem with it being able to carry energy. On the other hand, this point of view tempts us into framing quantum gravity as the mathematical problem of quantising the gravitational field. This, I think, is misguided.

I propose instead to return to a more Machian viewpoint, according to which space-time is contingent on (and not independent of) the existence of matter. Now the description of quantum space-time should follow, in principle, from an appropriate description of quantum matter, i.e. of quantum rods and clocks. From this perspective, the challenge of quantum gravity is to rebuild space-time from the ground up — to carry out Einstein’s revolution a second time over, but using quantum material as the building blocks.

Ernst Mach vs. Max Ernst. Get it right, folks.

My view about space-time can be seen as a kind of `pulling oneself up by one’s bootstraps’, or a Wittgenstein’s ladder (in which one climbs to the top of a ladder and then throws the ladder away). It works like this:
Step 1: define the properties of space-time according to the behaviour of rods and clocks.
Step 2: look for universal patterns or symmetries among these rods and clocks.
Step 3: take the ideal form of this symmetry and promote it to an independently existing object called `space-time’.
Step 4: Having liberated space-time from the material objects from which it was conceived, use it as the independent standard against which to compare rods and clocks.

Seen in this light, the idea of judging a rod or a clock by its ability to measure space or time is a convenient illusion: in fact we are testing real rods and clocks against what is essentially an embodiment of their own Platonic ideals, which are in turn conceived as the forms which give the laws of physics their most elegant expression. A pertinent example, much used by Julian Barbour, is Ephemeris time and the notion of a `good clock’. First, by using material bodies like pendulums and planets to serve as clocks, we find that the motions of material bodies approximately conform to Newton’s laws of mechanics and gravitation. We then make a metaphysical leap and declare the laws to be exactly true, and the inaccuracies to be due to imperfections in the clocks used to collect the data. This leads to the definition of the `Ephemeris time’, the time relative to which the planetary motions conform most closely to Newton’s laws, and a `good clock’ is then defined to be a clock whose time is closest to Ephemeris time.

The same thing happens in making the leap to special relativity. Einstein observed that, in light of Maxwell’s theory of electromagnetism, the empirical law of the relativity of motion seemed to have only a limited validity in nature. That is, assuming no changes to the behaviour of rods and clocks used to make measurements, it would not be possible to establish the law of the relativity of motion for electrodynamic bodies. Einstein made a metaphysical leap: he decided to upgrade this law to the universal Principle of Relativity, and to interpret its apparent inapplicability to electromagnetism as the failure of the rods and clocks used to test its validity. By constructing new rods and clocks that incorporated electromagnetism in the form of hypothetical light beams bouncing between mirrors, Einstein rebuilt space-time so as to give the laws of physics a more elegant form, in which the Relativity Principle is valid in the same regime as Maxwell’s equations.

Ladder for Booker T. Washington – Martin Puryear

By now, you can guess how I will interpret the step to general relativity. Empirical observations seem to suggest a (local) equivalence between a uniformly accelerated lab and a stationary lab in a gravitational field. However, as long as we consider `ideal’ clocks to conform to flat Minkowski space-time, we have to regard the time-dilated clocks of a gravitationally affected observer as being faulty. The empirical fact that observers stationary in a gravitational field cannot distinguish themselves (locally) from uniformly accelerated observers then seems accidental; there appears no reason why an observer could not locally detect the presence of gravity by comparing his normal clock to an `ideal clock’ that is somehow protected from gravity. On the other hand, if we raise this empirical indistinguishability to a matter of principle – the Einstein Equivalence Principle – we must conclude that time dilation should be incorporated into the very definition of an `ideal’ clock, and similarly with the gravitational effects on rods. Once the ideal rods and clocks are updated to include gravitational effects as part of their constitution (and not an interfering external force) they give rise to a geometry that is curved. Most magically of all, if we choose the simplest way to couple this geometry to matter (the Einstein Field Equations), we find that there is no need for a gravitational force at all: bodies follow the paths dictated by gravity simply because these are now the inertial paths followed by freely moving bodies in the curved space-time. Thus, gravity can be entirely replaced by geometry of space-time.

As we can see from the above examples, each revolution in our idea of space-time was achieved by reconsidering the nature of rods and clocks, so as to make the laws of physics take a more elegant form by incorporating some new physical principle (eg. the Relativity and Equivalence principles). What is remarkable is that this method does not require us to go all the way back to the fundamental properties of matter, prior to space-time, and derive everything again from scratch (the constructive theory approach). Instead, we can start from a previously existing conception of space-time and then upgrade it by modifying its primary elements (rods and clocks) to incorporate some new principle as part of physical law (the principle theory approach). The question is, will quantum gravity let us get away with the same trick?

I’m betting that it will. The challenge is to identify the empirical principle (or principles) that embody quantum mechanics, and upgrade them to universal principles by incorporating them into the very conception of the rods and clocks out of which general relativistic space-time is made. The result will be, hopefully, a picture of quantum geometry that retains a clear operational interpretation. Perhaps even Percy Bridgman, who dismissed the Planck length as being of “no significance whatever” [3] due to its empirical inaccessibility, would approve.

Boots with laces – Van Gogh

[1] Brown, Physical Relativity, p8.
[2] Rovelli, `Halfway through the woods: contemporary research on space and time’, in The Cosmos of Science, p194.
[3] Bridgman, Dimensional Analysis, p101.

Science, psychoanalyzed

“The problem for us is not, are our desires satisfied or not? The problem is, how do we know what we desire?”

-Slavoj Žižek

The most fundamental dramatic tension is the tension between the divided self. We have all on occasion experienced an internal dialogue like the following: `I ate the cookie despite myself. I knew it was wrong, but I couldn’t help myself. Afterwards, I hated myself’. On one hand, this dialogue makes sense to us and its meaning seems clear; on the other hand, it makes no sense without a division of the self. Who is the myself against whose wishes I eat the cookie? Who is the I that could not help myself? Who, afterwards, is hated, and who is the hater? To admit that the self can be both the subject and object of an action is equivalent to admitting that the self is divided.

Let us therefore deliver ourselves into the hands of Freud, who will lead us down a rabbit-hole of self-discovery. Who are these characters, the id, ego and superego? The id is the instinctive, reactive, animalistic part of the mind. It expresses emotion without reflection, it is wordless, mute, free of morals, shame or self-consciousness. The superego is the embodiment of laws and limitations. When the child learns that it is separate from the world, confined to a small, weak body and cannot have everything it wants – when it learns that it is at the mercy of beings far more powerful who dictate its life – it internalises these limitations and laws by creating the superego. The superego tells us what we are not allowed to do, where we cannot go, and what is forbidden by physical, moral or societal laws.


The fundamental tension between superego and id demands a mediator to decide whether to go with the desires of the id or follow the rules of the superego. This mediator, haplessly caught between the two, is our hero, ourselves: the ego. When the ego obeys the superego, the id is suppressed and frustrated, while the ego becomes more powerful and more strict in its demands. When the ego obeys the id instead, the satisfaction is short-lived, for the id knows only the present moment, and is hungry again no sooner it is fed. Meanwhile, the superego brings its vengeance on the ego for the transgression, afflicting it with guilt and feelings of inferiority. The id expresses our desires and fears, the superego expresses our judgements, and the ego determines how we respond in our actions. Before reading the end of this paragraph, take a moment to re-read the dialogue about the cookie and try to name the actors and the victims. Did you do it? The id wanted to eat the cookie, the superego knew it was wrong, and the ego ate it. The superego was helpless to stop the ego, but afterwards, it hated the ego, and punished it with feelings of guilt. Now it makes sense.


Humans have a curious obsession with the number three. There are three wise men, the holy trinity, the `third eye’ of Hinduism. Dramatic tension between fictional characters also frequently relies on combinations of three. It is an entertaining exercise (but not always fruitful) to identify the roles of id, ego and superego in famous triplets from mythology and fiction. Here is a puzzle for you. In Brisbane, I used to frequent a coffee house called Three Monkeys. Inside, they had amassed a collection of depictions and statuettes of the `Three Wise Monkeys’, a mystical image originating from Japan in which the first monkey has covered its eyes, the second its ears, and the last one its mouth. The image is typically associated with the maxim: see no evil, hear no evil, speak no evil, thought to originate from a similar passage in the Chinese Analects of Confucius. The puzzle is this: if the monkeys were to represent the different aspects of the divided self, which monkey is the id, which is the ego and which is the superego? Or does the comparison simply fail? My own answer is given at the end of this essay.


Tension is by nature unsustainable. It must eventually resolve itself in one of three ways: destruction, reconciliation, or transformation into a new kind of tension (which just means the destruction of some things and the reconciliation of others). Destruction can occur when the division between the id and superego is too extreme, tearing apart the ego with opposing forces. Since the ego exists only to mediate the conflict between the other two, a reconciliation of the id with the superego automatically conciliates the ego as well. This represents a dissolution of the ego, meaning a loss of the distinction between the self and the external world: the attainment of Nirvana in the eastern philosophies. In reality, however, most of us experience only a very small and partial conciliation of this type, a sort of secret collaboration between the superego and the id. This secret collaboration is at the core of science, so let us examine it in more detail.

The easiest way to appreciate the perverse but necessary collaboration between superego and id is to look at stories and films. There, the characters are nicely separated into roles that often reflect the roles of our divided selves. Take Batman and the Joker as depicted in Christopher Nolan’s film, The Dark Knight. The Joker is obviously a candidate for the id:

The Dark Knight
“Do I really look like a guy with a plan? You know what I am? I’m a dog chasing cars. I wouldn’t know what to do with one if I caught it. You know, I just… do things.”

Batman, although a vigilante, is a good fit for the superego: he is the true enforcer of law, both the judge and the executioner. In fact it is the police force, embodied by Commissioner Gordon, that best represents the ego in its unenviable position, caught between the two rogue elements. Given these roles, we finally understand this brilliant exchange:
Batman: Then why do you want to kill me?
Joker: I don’t want to kill you! What would I do without you? Go back to ripping off mob dealers? No, no, NO! No. You… you complete me.
You could not ask for a more perfect exposition of the mutual dependence of the superego and the id.

Sometimes the bond is more subtle. Consider one of fiction’s greatest characters: Sherlock Holmes. Not coincidentally, Holmes is a poster boy for scientists, with his strict adherence to a method based on evidence, reasoning and deduction. Quite obviously, he is a manifestation of the superego, leaving Watson to carry the banner of the ego. He wears it well enough, constantly being lectured and berated by Holmes, occasionally skeptical and rebellious but always respectful of Holmes’ superior judgement. Where, then, could the id be hiding? Therein lies a profound mystery, worthy of Holmes himself! One is tempted to point at Moriarty, the great enemy of Holmes – but the shoe does not fit. In Moriarty one finds exactly the kind of characteristics more typical of the superego: self-confidence verging on megalomania, mercilessness, a strict adherence to methodology. He is more like Holmes’s evil twin – the vindictive, cruel side of the superego – than the impulsive and chaotic id.


My own theory is that Holmes is a much more subtle character than he first appears. Who is the Holmes that we find, lost in a wordless reverie, playing the violin? Who is the Holmes that disguises himself to play a prank on poor Watson – the Holmes who, indeed, delights in upsetting Watson with eccentric and erratic behaviour? Who is the Holmes that goes missing for days, only to be found curled up in a den of iniquity, his eyes clouded with Opium? I contend that Holmes has an instinctive, intuitive and sensitive side that embodies the id, working in harmony with his superego aspect. Indeed, the seedy side of Holmes – his indulgent, drug-taking, reckless aspect – is somehow essential to completing the portrait of his genius. We would not find him so credible, so impressive, so almost mystical in his virtuosity if it were not for this dark side.

The superego and id can indeed collaborate, but it is usually only in a secretive, almost illicit way as though neither can admit that it depends on the other. The superego turns a blind eye, allowing the id to run wild, and then acts surprised and disappointed when it discovers the transgression. Then ensues what is in essence a sadomasochistic mock-punishment, since the id secretly enjoys the flogging, and the superego knows it, but plays along. In short, the union between superego and id is possible through the hypocritical self-awareness of both parties that they depend on each other to exist. They throw themselves into their respective roles with even more gusto, maintaining as it were a secret conspiracy against the ego, keeping up the tension but with a knowing cynicism.

We now begin to see the first inklings of the mad scientist. The quintessential mad scientist is Dr. Jekyll and Mr. Hyde, whose two faces represent unmistakably a perverse union of superego and id; other examples in fiction abound. The mad scientist is in fact the manifestation in an individual character of the public’s view of scientific activity in general. Since (as Kuhn tells us) science is a human activity, its attributes can be traced to attributes of the human mind. In other words, science as an institution can be psychoanalyzed.
Science is defined on one hand by its rationality, its strict adherence to method, zero tolerance for transgression of its rules, and a claim to superiority in its judgements and conclusions about the world. On the other hand, science is a powerful vehicle for the realisation of our (human) fantasies: what technology is not born from the dream of a science-fiction nerd? Technology is transgressive in the same way that dreams are transgressive: there is no taboo in science, no political correctness, no boundaries. At its purest, science and technology is obscene, disturbing and visionary all at once. Medicine is born of the desire to be immortal, chemistry is born of our desire to have power over the substances and forces of the world, to make gold and riches from lead; physics is born of our desire to fly through the sky like a bird, to be invisible, telepathic, omnipotent. Biology promises us the power to make animals and other organisms serve our needs, and psychology offers us power over each other. Science, with all of its adherence to evidence, logic and deduction, remains silent on matters of its purpose, has nothing to suggest about the ends to which it should be used. There lies hidden the id of science: an amoral, primitive, instinctive drive of humanity, just like the indignant infant trying to come to terms with the world. Without an effective intermediary in the form of public discussion and deliberation over scientific advances, science risks becoming a Sherlock without a Watson, that is, a Dr. Jekyll and Mr. Hyde.

Of course, just as it does in the individual’s psyche, the scientific id also plays a beneficial role: it supplies the creative drive and aesthetic sensibility without which science would be impossible. This is why we cannot divorce the id from the superego in science without destroying science altogether. Eliminate the id from Science, and you are left with a stagnant dogma; eliminate the superego, the methodology and tools of rational inquiry, and you are left with mysticism and superstition. The philosophy of science does an injustice to the true mechanism of scientific progress by focusing too much on the methodology – how to evaluate evidence and test hypotheses – and neglecting to address the aesthetic side of science.

Rick and Morty
“Sometimes science is more art than science. A lot of people don’t get that.”

How do we generate hypotheses? Where do ideas come from? Scientists themselves often don’t acknowledge the role that instinct and intuition plays in proposing new theories – we tend to downplay it, or insist that science progresses without any creative input. If that were really true, computer programs could do science in the foreseeable future. But most of us consider the revolution of the machines to still be far away, for the simple reason that we don’t yet know how to teach computers to be creative and to select `good’ hypotheses from the vast pool of logically possible hypotheses. This is (so far) a uniquely human ability, which has everything to do with gut feelings, impulsive thoughts and secret desires. The philosophy of science would perhaps benefit greatly from a more careful examination of this hidden aspect of scientific progress.

My answer to the three monkey’s question is this: The monkey who cannot speak is the id, because the id is voiceless. That leaves the blind monkey and the deaf monkey. It boils down to a matter of opinion here, but the argument that appeals to me most is this one: the superego has a closer relationship with the id than the ego does. Since the blind monkey can neither see nor hear the id (because the id can’t talk), but the deaf monkey can at least see the id, it stands to reason that the deaf monkey is the superego and the blind monkey is the ego.


Wigner has no friends in space

The title phrase of this post is taken from an article by Seth Lloyd that appeared on today’s arXiv, entitled “Analysis of a work of quantum art“. Lloyd was talking about an artwork in collaboration with artist Diemut Strebe, called `Wigner’s friends‘ in which a pair of telescopes are separated, one remaining on Earth and the other going to the International Space Station. According to Lloyd, Strebe motivates the work by appealing to the concepts of quantum superposition and entanglement, referring to physicist Eugene Wigner’s famous thought experiment in which one experimenter, Wigner’s friend, finds herself in a superposition prior to Wigner’s measurement. In Strebe’s scenario, both telescopes are aimed at interstellar space, and it is the viewers of the exhibition that are held responsible for collapsing the superposition of the orbiting telescope by observing the image on the ground-based telescope. The idea is that, since there is nobody looking at the orbiting telescope, the image on its CCD array initially exists in a quantum superposition of all possible artworks; hence Wigner has no friends in space. Before I discuss this intriguing work, let me first start a new art movement.

I was doing my PhD at the University of Queensland when my friend Aggie (also a PhD at that time) came to me with an intriguing problem. She needed to integrate a function over a certain region of three-dimensional space. This region could be obtained by slicing corners off a cube in a certain way, but Aggie was finding it impossible to visualize what the resulting shape would look like. Even after doing a 3D plot in Mathematica, she felt that there was something missing from the flattened projections that one had to click-and-drag to rotate. She wanted to know if I’d ever seen this shape before, and if I could maybe draw it for her or make one out of paper and glue (Weirdly, I have always had an undeserved reputation for drawing and origami). I did my best with paper and sticky-tape, but it didn’t quite come out right, so I gave up. In the end, she went and bought some plasticine and made a cube, then cut off the corners until she got the shape she wanted. Now that she could hold it in her hands, she finally felt that she understood just what she was dealing with. She went back to her computer to perform the integration.

At the time, it did not occur to me to ask “Is it art?” While its form was elegant, it was there to serve a practical purpose, namely to help Aggie (who probably did not once suspect that she was doing Art) in her calculation by condensing certain abstract ideas into a concrete form.

Soft Cube
© Malcolm Wright

Disclaimer: Before continuing, please note that I reject the idea that there can be a universal definition of Art. I further reject the (often claimed) corollary that therefore anything and everything can be Art. Instead, I posit that there are many different Arts, and just like living species, they are continually springing into existence, evolving into new forms, and going extinct. Just as a discussion about “what is a species” can lead to interminable and never-ending arguments, I posit that it is much better and more constructive to discuss “what is a lion”? Here, I am going to talk about, and attempt to define, something that might be called Science-Art, Technologism, Scientism, or something like that. Let’s go with `Zappism’, because it reminds me of things that supposedly go `zap’, but really don’t, like lasers.

So what is Zappism? Let me give some examples of what it is and what it is not. Every now and then, there are Art in Science exhibitions where academic researchers submit images of pretty things that they encountered in the course of their research. I include in this category colourful images of fractals, decorated graphs of pretty mathematical functions, astrophysical images of planets and stars and things, and basically anything where a scientist was just mucking around and noticed something beautiful and then made it into a graphic. For this stuff I would suggest the name “Scientific Found Art”, but it is not Zappism.

© Jonathan McCabe. An example of scientific found art.

Aggie’s shape might seem at first to fit the bill of found art, but there is a crucial difference: were the shape not pretty, it still would have served its purpose, which was to explore, in material form, scientific ideas that would otherwise have been elusive and abstract. A computer simulation of a fractal does not serve this purpose unless one also comes to understand the fractal better as a consequence of the simulation, and I’m not convinced this is true any more than one can understand a sentence better by writing it out in binary and then colouring it in.

Zappism is the art of using some kind of medium — be it painting, film, music, literature or something else — and using it to transform some ethereal and ungraspable Platonisms of science into things the human mind can more readily play with. Sometimes something is lost in translation, like adding unscientific `zap’ sounds to lasers, but this is acceptable as long as the core idea is translated — in the case of lasers, the idea that light can be focused into beams that can burn through things.

Many episodes of Star Trek exhibit Zappism. In the episode `Tuvix‘, the transporter merges two crew members into a single person, an incident that is explicitly explained by appealing to the way the transporter recombines matter. Similarly, Cronenberg’s film The Fly is classic Zappism, as is Spielberg’s Jurassic Park. Indeed, almost any science fiction that uses science in an active way almost can’t help but be Zappist. Science fiction can still fail to be Zappist if it uses the science as a kind of gloss or sugar-coating, instead of engaging with the science as a main ingredient. Star Wars is not really Zappist because it is not concerned with the mechanisms of the technology invoked. Luke and Darth might as well be using swords and riding on flying horses for all the story cares, making it is more like Science Fantasy (Why do lightsabers simply stop at a convenient sword-length?)

A science fiction movie can always ignore inconvenient facts, like conservation of momentum, or how there is no sound in space. These annoying truths are often seen as getting in the way of good action and drama. The truth is the opposite: it takes a creative leap of genius to see how to use these facts to the advantage of dramatic effects. The recent film Coherence does a brilliant job of using the idea of Schrodinger’s Cat to create a tense and frightening scenario. When film, art and storytelling are able to incorporate physical law in a natural and graspable way, we are one step closer to connecting the public to cutting-edge science.

Screen Shot 2015-01-08 at 9.57.10 PM
Actress Emily Baldoni grapples with Schrödinger’s equation in Coherence.

On the non-cinematic side, Koen Vanmechelen’s breeding program for cosmopolitan chickens, Maguire and collaborator’s epic project `Dr. Brainlove‘, and Theo Jansen’s Strandbeest could all be called examples of Zappism. But perhaps the most revealing examples are those that do not explicitly use physical technology for the scientific motive, but instead use abstract ideas. For these I cite Dali’s Persistence of Memory (and its Disintegration) with their roots in Relativity theory and Quantum Mechanics; the book Flatland by Edwin Abbott; Alice in Wonderland by Carroll; Gödel, Escher, Bach: An Eternal Golden Braid by Hofstadter, and similar books that bring abstract scientific or mathematical ideas into an imaginable form. A truly great work of Zappism was the invention of the Rubik’s Cube, by the Hungarian sculptor and mathematician Erno Rubik. Rubik conceived the cube as a solution to a more abstract structural design problem of how to rotate the parts of a cube in all three dimensions while keeping the parts connected.

Returning now to Strebe’s artwork `Wigner’s friends’, it should be remarked that the artwork is not a scientific experiment and there is no actual demonstration of quantum coherence between the telescopes. However, Seth Lloyd for some reason seems intent on defending the idea that maybe, just maybe, there is some tiny smidgen of possibility that there is something quantum going on in the experiment. I understand his enthusiasm: I also think it is a very cool artwork, and somehow the whole point of the artwork is its reference to quantum mechanics. But in order to plausibly say that something quantum was really going on in Strebe’s artwork, Lloyd is forced to invoke the Many Worlds interpretation, which to me is tantamount to begging the question — under that assumption isn’t my cheese sandwich also in a quantum superposition?

I don’t see why all this is necessary: when Dali painted the Disintegration of the Persistence of Memory, nobody was scrambling to argue that his oil paint was in a quantum superposition on the canvas. It would be just as absurd as insisting that Da Vinci’s portrait of the Mona Lisa actually contained a real person. There is a sense in which the artistic representation of a person is bound to physics — it is constrained to some extent by the way physical masses compose in three dimensional space — but the art of correct representation is not to be confused with the real thing. Even Mondrian, whose works were famously highly abstract, insisted that he was bound to the true representation of Nature as he saw it [1]. To me, Strebe’s artwork is a representation of quantum mechanics, put into a physical and graspable form, and that is what makes it Zappism. But is it good Zappism? That depends on whether the audience feels any closer to understanding quantum mechanics after the experience.

[1] “The masses generally find my work rather vague. I construct lines and color combinations on a flat surface, in order to express general beauty with the utmost awareness. Nature (or that which I see) inspires me . . . but I want to come as close as possible to the truth…” Source:

Searching for an invisible reality

Imagine that I am showing you a cube, and the face I am showing you is red. Now suppose I rotate it so the face is no longer visible. Do you think it is still red? Of course you do. And if I put a ball inside a box, do you still think the ball exists, even when you can’t see it? When did we get such faith in the existence of things that we can’t see? Probably from the age of around a few months old, according to research on developmental psychology. Babies younger than a few months appear unable to deduce the continued existence of an object hidden from sight, even if they observe the object while it is being hidden; babies lack a sense of “object permanence“. As we get older, we learn to believe in the existence of things that we can’t directly see. True, we don’t all believe in God, but most of us believe that our feet are still there after we put our shoes on.


In fact, scientific progress has gradually been acclimatising us to the real existence of things that we can’t directly see. It is all too easy to forget that, before Einstein blew our minds with general relativity, he first had to get humanity on board with a more basic idea: atoms. That’s right, the idea that things were made up of atoms was still quite controversial at the time that Einstein published his groundbreaking work on Brownian motion, supporting the idea that things are made of tiny particles. Forgetting this contribution of Einstein is a bit like thanking your math teacher for teaching you advanced calculus, while forgetting to mention that moments earlier he rescued you from the jungle, gave you a bath and taught you how to read and write.

“Don’t mention it!”

Atoms, along with germs, the electromagnetic field, and extra-marital affairs are just one of those things that we accept as being real, even though we typically can’t see them without the aid of microscopes or private investigators. This trained and inbuilt tendency to believe in the persistence of objects and properties even when we can’t see them partially explains why quantum mechanics has been causing generations of theoretical physicists to have mental breakdowns and revert to childhood. You see, quantum mechanics tells us that the properties of some objects just don’t seem to exist until you look at them.

To explain what I mean, imagine that cube again. Suppose that we label the edges of the cube from one to eight, and we play this little game: you tell me which edge of the cube you want to look at, and I show you that edge of the cube, with its two adjacent faces. Now, imagine that no matter which edge you choose to look at, you always see one face that is red and the other face blue. While this might not be surprising to a small baby, it might occur to you after a moment’s thought that there is no possible way to paint a normal cube with two colours such that every edge connects faces of different colours. It is an impossible cube!

The only way an adult could make sense of this phenomenon would be to try and imagine the faces of the cube changing colour when they are not being observed, perhaps using some kind of hidden mechanism. But to an infant that is not bounded by silly ideas of object permanence, there is nothing particularly strange about this cube. It doesn’t make sense to the child to ask what the colour is of parts of the cube that they cannot see. They don’t exist.

Of course, while it makes a cute picture (the wisdom of children and all that), we should not pretend that the child’s lack of object permanence represents actual wisdom. It is no help to anyone to subscribe to a philosophy that physical properties pop in and out of existence willy-nilly, without any rules connecting them. Indeed, it is rather fortunate that we do believe in the reality of things not visible to the eye, or else sanitation and modern medicine might not have arisen (then again, nor would the atom bomb). But it is interesting that the path of wisdom seems to lead us into a world that looks more like a child’s wonderland than the dull realm of the senses. The cube I just described is not just a loose analogy, but can in fact be simulated using real quantum particles, like electrons, in the laboratory. Measuring which way the electron spins in a magnetic field is just like observing the colours on the faces of the impossible cube.

How do we then progress to a `childlike wisdom’ in this confusing universe of impossible electrons, without completely reverting back to childhood? Perhaps the trick is to remember that properties do not belong to objects, but to the relationships between objects. In order to measure the colour of the cube, we must shine light on it and collect the reflected light. This exchange of light crosses the boundary between the observer and the system — it connects us to the cube in an intimate way. Perhaps the nature of this connection is such that we cannot say what the colours of the cube’s faces are without also saying whether the observer is bound to it from one angle, or another angle, by the light.

This trick, of shifting our attention from properties of objects to properties of relations, is exactly what happens in relativity. There, we cannot ask how fast a car is moving, but only how fast it is moving relative to our own car, or to the road, or to some other object or observer. Nor can we ask what time it is — it is different times for different observers, and we can only measure time as a relative property of a system to a particular clock. This latter observation inspired Salvador Dali to paint `The Persistence of Memory’, his famous painting of the melting clocks:

The Persistence of Memory

According to Dali, someone once asked him why his clocks were limp, to which he replied:
“Limp or hard — that is not important. The important thing is that they keep the right time.”

If the clocks are all melting, how are we to know which one keeps the right time? Dali’s enigmatic and characteristically flippant answer makes sense if we allow the clocks to all be right, relative to their separate conditions of melting. If we could un-melt one clock and re-melt it into the same shape as another, we should expect their times to match — similarly, relativistic observers need not keep the same time, but should they transform themselves into the same frame of reference, their clocks must tick together. The `right’ time is defined by the condition that all the different times agree with each other under the right circumstances, namely, when the observers coincide.

The same insight is still waiting to happen in quantum mechanics. Somehow, deep down, we all know that the properties we should be talking about are not the ever-shifting colours of the faces of the cube, the spins of the electrons, nor the abstract wave-functions we write down, which seem to jump around as we measure them from one angle to the next. What we seek is a hidden structure that lies behind the consistent relationships between observers and objects. What is it that makes the outcome of one measurement always match up with the outcome of another, far away in space and time? When two observers measure different parts of the same ever-shifting and melting system, they must still agree on the probabilities of certain events when they come together again later on. Maybe, if we can see quantum systems through a child’s eyes, we will have a chance of glimpsing the overarching structure that keeps the relations between objects marching in lock-step, even as the individual properties of objects themselves dissolve away. But for the moment we are still mesmerised by those spinning faces of the cube, frustratingly unable to see past them, wondering if they are still really there every time they flicker in and out of our view.

The Disintegration of the Persistence of Memory
The Disintegration of the Persistence of Memory

Death to Powerpoint!

There is one thing that has always baffled me about academia, and theoretical physics in particular. Here we have a community of people whose work — indeed, whose very careers — depend on their ability to communicate complex ideas to each other and to the broader public in order to secure funding for their projects. To be an effective working physicist, you basically have to do three things: publish papers, go to conferences, and give presentations. LOTS of presentations. In principle, this should be easy; we are usually talking to a receptive audience of our peers or educated outsiders, we presumably know the subject matter backwards and many of us have had years of experience giving public talks. So can someone please tell me why the heck so many physicists are still so bad at it?

Now before you start trying to guess if I am ranting about anyone in particular, let me set your mind at ease — I am talking about everybody, probably including you, and certainly including myself (well, up to a point). I except only those few speakers in physics who really know how to engage their audience and deliver an effective presentation (if you know any examples, please post names or links in the comments, I want to catalog these guys like rare insects). But instead of complaining about it, I am going to try and perpetuate a solution. There is an enemy in our midst: slide shows. We are crippling our communication skills by our unspoken subservience to the idea that a presentation that doesn’t contain at least 15 slides with graphs and equations does not qualify as legitimate science.

The Far Side

Let me set the record straight: the point of a presentation is not to convince people that you are a big important scientist who knows what he is doing. We already know that, and if you are in fact just an imposter, probably we already know that too. Away with pretenses, with insecurities that force you to obfusticate the truth. The truth is: you are stupid, but you are trying your best to do science. Your audience is also stupid, but they are trying their best to understand you. We are a bunch of dumb, ignorant smelly humans groping desperately for a single grain of the truth, and we will never get that truth so long as we dress ourselves up like geniuses who know it all. Let’s just be open about it. Those people in your talk, who look so sharp and attentive and nod their heads sagely when you speak, but ask no questions — you can be sure they have no damn clue what is going on. And you, the speaker, are not there to toot your trumpet or parade up and down showing everyone how magnanimously you performed real calculations or did real experiments with things of importance — you are there to communicate ideas, and nothing else. Humble yourself before your audience, invite them to eviscerate you (figuratively), put everything at stake for the truth and they will joint you instead of attacking you. They might then be willing to ask you the REAL questions — instead of those pretend questions we all know are designed to show everyone else how smart they are because they already know the answer to them*

*(I am guilty of this, but I balance it out by asking an equal number of really dumb questions).

I don’t want questions from people who have understood my talk perfectly and are merely demonstrating this fact to everyone else in the room: I want dumb questions, obvious questions, offensive questions, real questions that strike at the root of what is going on. Life is too short to beat around the bush, let’s just cut to the chase and do some damn physics! You don’t know what that symbol means? Ask me! If I’m wrong I’m wrong, if your question is dumb, it’s dumb, but I’ll answer it anyway and we can move on like adults.

Today I trialed a new experiment of mine: I call it the “One Slide Wonder”. I gave a one hour presentation based on one slide. I think it was a partial success, but needs refinement. For anyone who wants to get on board with this idea, the rules are as follows:

1. Thou shalt make thine presentation with only a single slide.

2. The slide shalt contain things that stimulate discussions and invite questions, or serve as handy references, but NOT detailed proofs or lengthy explanations. These will come from your mouth and chalk-hand.

3. The time spent talking about the slide shalt not exceed the time that could reasonably be allotted to a single slide, certainly not more than 10-15 minutes.

4. After this time, thou shalt invite questions, and the discussion subsists thereupon for the duration of the session or until such a time as it wraps up in a natural way.

To some people, this might seem terrifying: what if nobody has any questions? What if I present my one slide, everyone coughs in awkward silence, and I have still 45 minutes to fill? Do I have to dance a jig or sing aloud for them? It is just like my childhood nightmares! To those who fear this scenario, I say: be brave. You know why talks always run overtime? Because the audience is bursting with questions and they keep interrupting the speaker to clarify things. This is usually treated like a nuisance and the audience is told to “continue the discussion in question time”, except there isn’t any question time because there were too many fucking slides.

So let’s give them what they want: a single slide that we can all discuss to our heart’s content. You bet it can take an hour. Use your power as the speaker to guide the topic of discussion to what you want to talk about. Use the blackboard. Get covered in chalk, give the chalk to the audience, get interactive, encourage excitement — above all, destroy the facade of endless slides and break through to the human beings who are sitting there trying to talk back to you. If you want to be sure to incite discussion, just write some deliberately provocative statement on your slide and then stand there and wait. No living physicist can resist the combined fear of an awkward silence, coupled to the desire to challenge your claim that the many-worlds interpretation can be tested. And finally, in the absolute worst case scenario, nobody has any questions after your one slide and then you just say “Thank you” and take a seat, and you will go down in history as having given the most concise talk ever.PhD Comics

Art and science, united by chickens.

When I saw that Anton Zeilinger of the Vienna quantum physics department was hosting a talk by the artist Koen Vanmechelen on the topic of chickens, I dropped everything and ran there in great excitement.

“It has finally happened,” I said to myself, “the great Zeilinger has finally lost his marbles!”

I was wrong, though: it was one of the most interesting talks of the year so far. Vanmechelen began his talk with a stylish photograph of a chicken. He said:

“To you, this might look like just a chicken. But to me, this is a work of art.”


It seemed absurd — here was a room full of physicists, being told that a chicken was art. But as Vanmechelen elaborated on his work, I saw that his work was not simply about chickens, in the same way that Rembrandt’s art was not simply about paint. In Vanmechelen’s words “It is not about the chicken, it is about humans!” Chickens are merely the medium through which Vanmechelen has chosen to express himself. Humans have such precise control over chickens, we breed them for specific purposes, we use them like components in a factory; no wonder Vanmechelen calls the chicken `high-tech’. So why not also use chickens as an artistic medium? Vanmechelen also enjoys working with glass, a seemingly unrelated medium, except that it allows him a similar level of self-expression and self discovery:

“I like the transparency of glass. You cannot see a window until it is broken. It is the same with people — it is through scars that we come to know ourselves.”

For Vanmechelen, part of his motivation to work with chickens comes from the strange and often profound experiences that this line of work leads him to. One notorious example was his idea to rescue a rooster that had lost one of its spurs. Perhaps to reinstate some of the glory afforded the chicken by its dinosaur heritage, Vanmechelen had surgeons give the rooster a proud new pair of golden spurs.

Shortly afterwards, Vanmechelen was taken to court in Belgium by animal rights activists. It seemed that, by the letter of the law, it was illegal to give chickens prosthetic implants. Vanmechelen defended his work and pointed out that he was helping the rooster, which would have otherwise been an outcast in chicken society, and the activists finally agreed with him. But the judge was adamant: there was still the matter of the law to be settled. Struck by the absurdity of the case, Vanmechelen asked: if prosthetic augmentation was not allowed, then what precisely was it legal to do to a live chicken? The judge unfolded an official document and read from a list. Legally, one could burn its beak, scorch its wings, cut its legs, and more in a similar vein. Needless to say, Vanmechelen did not have to face prison, but the incident stayed with him.

“I am not a scientist, I am not an activist, I am an artist. I do not pass judgement, I simply comment on what I see.”

He called the animal rights activists afterwards. He said to them, “I have done my job as an artist. Now you can do your job as an activist: change the law”.

Vanmechelen’s major work has much less to do with chickens and much more to do with people. The Cosmopolitan Chicken Project is an exercise in fertility. Travelling around the world, Vanmechelen collects chickens that have been selectively bred to suit their country of origin, and creates cross-breeds. He notes that each country has developed a breed of chicken that represents the nation; as an extreme example, the French Poulet de Bresse has a red crest, white body and blue-tinged legs, matching the country’s flag.

Image credit: the internets.
Poulet de Bresse

“When you put an animal in a frame, you halt its evolution,” he explains. “The chickens become infertile through too much inbreeding. Cross-breeding restores life and fertility to the species. It is the same for humans.”

Duality is also a major theme in Vanmechelen’s work: every organism needs another organism to survive. Humans have not simply enslaved chickens — we are in turn enslaved by them. There are over 24 billion chickens in the world today, about three and a half per person. Historically, we have taken them everywhere with us, to such an extent that researchers at the University of Nottingham can even trace the movements of humans through the genomes of chickens.

This duality can be seen directly in the theory of coding and information. Take two messages of the same length and combine them by swapping every second letter between the two. Suppose we separate the resulting scrambled halves and give them to different people. It doesn’t matter how many times you copy one half, you will never recover the message — you will stagnate from inbreeding the same information. But if you get together with someone who has different information that comes from the other half, you can combine your halves to discover the hidden message that was there all along.

By the end of Vanmechelen’s talk, I finally understood why Professor Zeilinger had invited him here, to a physics department, to talk about art. In isolation, every discipline stagnates and becomes inbred. I rarely go to see talks by scientists, but I always find talks by artists stimulating. Why is that? Perhaps the reason is not that scientists are dull, but simply that I am one of them. Sometimes, to unlock the riches of your own discipline, you need to introduce random mutations from the outside. So bring on the artists!