18 July 2014

Buddhism and the Observer Effect in Quantum Mechanics

This essay is a follow up to one I wrote in 2010 called Erwin Schrödinger Didn't Have a Cat. It might be worth refreshing your memory of that one first. Plus I've continued to add notes since writing the original article.  The subject of Buddhism and quantum mechanics keeps coming up. Quantum mechanics seems to draw Buddhists like moths to a flame. Of particular interest seems to be the observer effect that Schrödinger used to critique the Copenhagen interpretation. Google "Buddhism Quantum Mechanics and the Observer Effect" and you'll get a raft of webpages talking about how observers interact with the physical world.  They say things like:
"Basically, what quantum theory says is that fundamental particles are empty of inherent existence and exist in an undefined state of potentialities. They have no inherent existence from their own side and do not become 'real' until a mind interacts with them and gives them meaning. Whenever and wherever there is no mind there is no meaning and no reality. This is a similar conclusion to the Mahayana Buddhist teachings on sunyata." Buddhism and Quantum Physics.
This is not quantum mechanics or Buddhism either. It's Idealism combined with the strong form of the anthropic principle. It's very misleading. Buddhism is talking about mental events and quantum mechanics about subatomic particles. At best the relationship is metaphorical, because subatomic particles don't behave like mental states and vice versa! In this blog post I will explore what the observer effect is and why it has very little or nothing to do with consciousness and also why it does not support Idealism.

I have to confess there is a great deal that I don't understand about quantum mechanics, not least of which is the maths involved. No one likes to admit they are ignorant, but I know that I don't understand this stuff to any great degree. I know that most of the Buddhists writing about it don't understand it either. I just wish they'd admit it.


Mass of the electron

In this essay I'll focus on the electron. Electrons have reasonably well defined properties and are all, so far as we can tell, identical. For example electrons have mass of approximately 9.10938291 × 10-31 kilograms. This is literally an unimaginably small number. As far as the human imagination is concerned this is zero. Protons have almost 2,000 times more mass than electrons and that's still an unimaginably small amount. Clearly there is some measurement uncertainty in this figure, we can only measure it as accurately as our experimental design and measurement device allow, but it's precise to an extremely fine degree. Similarly, electrons have an electric charge of approximately −1.602×10−19 coulombs, or a billionth of a billionth of the current that comes out of your wall socket.

Most relevant to our topic, an electron has an intrinsic angular momentum of either +½ or -½. Electrons seem to behave as though they spin on their axis, though in fact there is no classical phenomenon which the "spin" of an electron is exactly like. Seen from above the angular momentum of a clockwise spinning top points up, and for an anticlockwise spin it points down. So conventionally we speak of spin up and spin down.

Classical objects (roughly speaking, objects perceptible by our unaided senses) obey the classical laws of physics. A spinning top is a classical object. As it spins it has momentum: it will keep moving unless a force acts on it. Since it experiences friction as it spins it gradually and smoothly slows down, shedding kinetic energy as heat and sound. Even the solar system is gradually slowing down, the rotation of the earth is gradually slowing down. However, an electron just 'spins'. Always. Without ever slowing down. I presume that even at absolute zero, an electron has spin.  Additionally, though a spinning top tends to orient itself, the axis of spin need not be in any particular direction, and can even wobble around. So the 'spin' of an electron here is a metaphor for an incomprehensible underlying reality.

Curiously if you rotate an electron with spin ½ through 360° then you would expect that the angular momentum would be the same, but it is in fact -½. To get back to spin ½ we have to rotate the electron through a total of 720°. Again there is no physical analogy that can explain this, no real process to compare it to. And this is partly why the great genius Paul Dirac said: "The fundamental laws of nature control a substratum of which we cannot form a mental picture without introducing irrelevancies." (Principles of Quantum Mechanics. 4th Ed. 1958).

If a spinning top had an electrical charge it would generate a magnetic field. This is more or less how an electric engine or generator works. Moving electric charges produce magnetic fields and moving magnetic fields induce electric currents. Electrons, having an electric charge do produce a magnetic field as they 'spin'. However looking at the electron as a classical spinning object with electric charge causes some problems. It turns out that in order to generate the measured magnetic field an object the size of an electron, considered as a classical object, would have to spin so fast that a point on its surface would be going several times faster than the speed of light. And the answer to the problem in fact turns out to be that the electron does not seem to have a size. This is deeply counter-intuitive. To have mass but no size suggests infinite density. I'm not even sure how the physicists deal with this problem.

We're starting to see that a single electron does not obey the classical mechanics (aka the "laws of physics") and this is where quantum mechanics comes in. Quantum mechanics is a series of equations which describe the behaviour of sub-atomic particles, like the electron. They were the first physical laws to be derived theoretically rather than through observation, but on the whole they do describe the behaviour of sub-atomic particles (though there are still competitors waiting in the wings - see article on bouncing oil drops at the end of the essay). 

In the quantum world there are restrictions on everything: every quantity is a multiple of some constant with no in-between values (hence quantum). Transitioning between quantum states is instantaneous and discontinuous. For an electron there are just two possible spin states (i.e. two states of angular momentum): spin up and spin down. An electron can be made to flip states, but the action is instantaneous with no transition and no in-between states. Something one never observes in the macro world. 

In my description of water I noted that electrons move around an atomic nucleus in well defined orbitals or shells. In hydrogen for example the single electron occupies the s shell which is spherical. Helium has two electrons in the s shell. Now Linus Pauli discovered that if two electrons are in the same orbital then they must have opposite spin (called the Pauli Exclusion Principle). The next shell, p, can accommodate 8 electrons, but they in fact occupy four separate orbits that each accommodate 2 electrons of opposite spin.


This quality of spin is an important one because it was this quality that Schrödinger was referring to in his famous thought experiment. A consequence, an unbelievable consequence from Schrödinger's point of view, of the Copenhagen interpretation of quantum mechanics was that an electron could be either spin up or spin down and we wouldn't know which until we measured its angular momentum. Niels Bohr argued that before being measured the spin state would effectively be a super-position of both states. Schrödinger's example of the cat was intended to show that the conclusion was untenable because the idea of an object being in two states at once was ridiculous. As it happens the Copenhagen Interpretation won the argument and now advocates use Schrödinger's complaint to illustrate the point about super-position.

It's the spookiness of this metaphor that seems to attract Buddhists. They latched onto this idea of the necessity for the "observer" to break the symmetry of superposition and force the electron to take up one spin state or the other, because it looked like the Idealist end of the Yogacāra spectrum of thought in which objects are brought into existence by an observing mind. That Yogacāra is inherently Idealistic is hotly disputed by scholars, but for many Buddhists what cittamātra means is that only mind exists and as one Idealist Buddhist put it to me recently:
"I agree with Schopenhauer - objects only exist for subjects. Without a subject who brings to the picture, a sense of relatedness, some proportion, a point of view, there are no objects whatever." (Dharmawheel.net)
Tying Buddhist Idealism into Western Idealism is a popular pastime amongst Western Buddhists and Schopenhauer is a favourite exponent of this kind of thing. But just because a 19th century philosopher thought this or that about the universe tells us nothing. The fatal flaw is that this kind of Idealistic ontology has no possible supporting epistemology - there's no way to gain this knowledge about the nature of objects from a Buddhist point of view. In this view we have no way to know what happens to objects when we stop observing them, because we are not observing them! It's simply a theological position. And as I said in the post on ineffability we can easily infer that it's not true simply by comparing notes. Those who fail to compare notes come to ridiculous conclusions that are hard to shift. One of the logical consequences of this anthropocentric Idealism, a variant of the Anthropic Principle, is the the entire universe goes out of existence and then comes back into existence when we blink our eyes. And if you believe that you'll believe anything.

There's rub...

Part of the problem with employing the words of science without understanding them is that one makes silly mistakes. So for example when we say the mind of the observer is involved in determining the physical state of the electron, this is simply a mistaken understanding of what is meant by "observer". No electron has ever been seen by a human being. We need to be very careful about what we mean by "observe" and "observer". As physicist Sean Carroll says re "the observer":
"It doesn't need to be a 'conscious' observer or anything else that might get Deepak Chopra excited; we just mean a macroscopic measuring apparatus. It could be a living person, but it could just as well be a video camera or even the air in a room." [Emphasis added]
Schrödinger's observer, like Schrödinger's cat, is a metaphor. Given that no one can actually see an electron and 'spin' is only a notional quality with no classical analogue, how would we go about measuring the spin-state of an electron, one way or the other? Remembering that a single electron takes up more or less no space and weighs as close to nothing as makes hardly any difference. Usually we deal with electrons in amounts like billions of trillions and in such numbers they collectively behave classically. It is possible to assemble a set up that will shoot out one electron in a known direction every so often, but they travel near the speed of light. If your detector is 1m away from the emitter then it takes about a billionth of a second to get there. And since they're all identical there's no way to find our electron afterwards. So good luck observing an electron with your senses and comprehending it in your mind!

Actually it is possible to trap individual electrons, but as I think will be clear, the interaction needed to so do, involving magnetic fields, make them useless for testing the observer effect. However, thankfully it's not very difficult to measure spin-states in practice. We just need to construct a macroscopic measuring apparatus known as the Stern-Gerlach experiment

In the Stern-Gerlach experiment a beam of electrons is passed between two magnets like those shown right (we'll ignore the shapes). The path of electrons with spin up is bent up as they pass through the magnets, electrons with spin down will bend down. So we then know the spin of the electron. We can measure the numbers that are bent each way by using an electron detector. And what we find is two very small spots - the up-spin electrons all hit the same upper spot, and the down-spin electrons all hit the same lower spot. There are never any in-between and any blur we see is due to fluctuations in the experimental set up itself, not in the electrons. At this level of sensitivity the tiny fluctuations caused by Brownian motion become noisy enough to drown out any signal. The amount by which the electron is deflected is related to it's mass and magnetic moment. 

Now assuming we can use this to measure the spin of individual electrons what is going on here? An electron leaves the emitter and travels for a billionth of a second in an indeterminate spin state before passing through the apparatus and hitting a detector. An electron detector might be a loop of wire with an ammeter on it. As the electron hits the wire a very small, but measurable current flows (this is more or less how an old-fashioned vacuum tube works). Or we use a device like a TV screen that emits light when hit by a fast-moving electron and a photo-detector to record the light. As an electron travels through the apparatus and interacts with the magnetic field, it takes one or the other spin-state and enters one or other detector. It's the interaction of the electron with the experiment, with the macroscopic measuring apparatus, that forces it to adopt one or other spin and it does so at random.

And where in all of this is the "mind of the observer"? In fact the "observer" here, the experimental apparatus, has no mind. Why do we think of a person observing things and influencing them? It's because we understand Schrödinger's metaphor (man watching box) but we have no idea what underlying reality is being described. But this is a dangerous illusion.

The mistake that almost every Buddhist makes is to assume that because they understand the metaphor of Schrödinger's cat, they understand the underlying reality. This problem pervades Buddhist thinking. In the case of quantum mechanics no one understand the underlying reality, not even the people who understand the fiendish maths that predict the behaviour of particles. The reality of the quantum world is literally unimaginable, even when the theories make accurate predictions.

In fact when scientists talk about "observing" a subatomic particle (something with unimaginably small vital statistics) they really mean causing it to interact with something in a way that can be amplified and signal to us humans, on a scale we can comprehend, that something or other has happened. So all this stuff about consciousness and the observer effect in quantum mechanics is bunk. It's based on a reified metaphor and a false analogy.

The false analogy is with the observer effect in anthropology. When an anthropologist studies a culture they cannot help but see through cultural lenses. And they also change the behaviour of the people they study by being there. Famously teenage Samoan girls told Margaret Mead a bunch of lies about their sexual habits which for them was a huge joke, but wrecked the anthropologist's reputation. (Her work was debunked by Derek Freeman after she died, though his book Margaret Mead and Samoa set off a heated debate in the field of anthropology). Another variation on this is seen in the Hawthorne Effect which describes how workers modify their behaviour in response to conditions, especially whether or not they are being observed by management.

Observing humans does
change their behaviour.

There is also some contamination from post-modern literary criticism which emphasised the role of the reader in the "creation" of the text and called into question the very possibility of objectivity. Amongst the influential (if indirect) contributions to this discourse was Edward Said's work on so-called Orientalism which sought to show that Western views of Asia were constructs that were often only loosely related to Asia itself and were more revealing of the prejudices of Western scholars than of Asian culture and custom. At the same time the very idea of objectivity was called into question in the sciences, though this critique consistently failed to take into account the collective nature of scientific enquiry. The metaphors of quantum mechanics were conflated with these other issues and for many poorly informed people came to represent the nature of the problem of objectivity and subjectivity.

Quantum Nonsense.

Buddhists who know a little about quantum mechanics and a little bit about litcrit or anthropology are apt to fall into error. The temptation is to think that because we understand one or two metaphors or allegories that we understand the whole field. Almost no one does. Richard Feynman, another genius, was more bold:
"I think I can safely say that nobody understands quantum mechanics." (The Character of Physical Law, 1965). 
And if he didn't understand it, then probably no one could. The map is not the territory. And we Buddhists are not even using quality topographical maps. We're mostly using the cheesy, massively oversimplified, tourist maps that are given away for free in Hotel lobbies, all covered in advertising.

Too many Buddhists see in quantum mechanics a confirmation of their Idealism: the idea that there is no reality independent of the observer. I hope I've shown that such claims have misunderstood the word "observer" in Schrödinger's complaint. The conclusion drawn from quantum theory by many Buddhists, that the world only exists as and when we perceive it, is simply wrong. Indeed one of the consequences of quantum mechanics is that there must be an observer independent reality. (See Sheldon Goldstein, Department of Mathematics, Rutgers University: Quantum Theory Without Observers; and also links below).

This problem pervades Buddhist doctrine. It is full of empty metaphors. Karma is described almost entirely of such empty metaphors for example. However unlike in physics, Buddhist metaphors are not linked to mathematical models that make accurate predictions. Karma is linked to moral theories that are intended to ensure compliance with Buddhist behavioural norms. In other words Buddhist metaphors are set to prescriptive purposes, whereas physics metaphors attempt to be descriptive. This is a fundamental different between religion and science. 

I doubt quantum-nonsense will ever go away. Too many people are desperate to consume what purveyors of quantum-nonsense are selling and not equipped to make a good judgement, or unwise in whose judgements they rely on. If our teachers are also non-scientists hungry for some quantum-nonsense too, then we are in deep trouble. Buddhists have the unfortunate habit of seeking and finding confirmation of their views everywhere they look. The most trivial or banal coincidence of wording becomes a hidden "Dharma teaching". Buddhists Tweeters endlessly repeat platitudes as though they were profound. Buddhist bloggers give over inordinate amounts of space to celebrity Buddhists as though having someone famous adopt Buddhism makes the world a better place. It's all so tedious. Next thing you know we'll be knocking on doors asking people if they have accepted the Buddha into their lives.

The fact is that science is not proving what Buddhists have known all along. It is doing the opposite. Science is tearing apart the articles of faith of Buddhism;  leaving karma, rebirth, heaven & hell, and dependent arising as a Theory of Everything, in tatters. It's only blind faith and massive bias that prevents people from seeing this. We have a lot of work to do if Buddhism is going to survive this collision with modernity. Presuming of course that we do not fall back into another dark age, and looking at nominally Buddhist countries like Tibet, Korea, Burma, Sri Lanka and Thailand that possibility seems all too likely.


Some real Quantum Physics:

Extra Notes

21 June 2015
Nature has just published a new article with an argument about why large scale objects do not exhibit quantum indeterminacy, How Gravity Kills Schrödinger's Cat (Nature, 17 June 2015). Confirming my reading of the observer affect the author says "As soon as a quantum object interacts with a stray particle or a passing field, it picks just one state, collapsing into our classical, everyday view." The "observer" is in fact any physical interaction. And fields pervade the universe! Macro-scale objects interact with the gravitational field:
"Because of gravity’s effect on space-time, Pikovski’s team realised that variance in a molecule’s position will also influence its internal energy — the vibrations of particles within the molecule, which evolve over time. If a molecule were put in a quantum superposition of two places, the correlation between position and internal energy would soon cause the duality to 'decohere' to the molecule taking just one path, they suggest."
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