Physicist Brian Cox, who is a professor at the University of Manchester and a well-known BBC science presenter, caused a sensation when he was trying to explain Pauli Exclusion Principle in layman's terms on TV.
Here is the segment in the show:
And here is the relevant quote from the segment:
"...but this shift in the configuration of the electrons inside the diamond has consequences, because the sum total of all the electrons in the Universe must respect Pauli. Therefore, every electron around every atom in the Universe must be shifting as I heat the diamond up, to make sure that none of them end up in the same energy level. When I heat this diamond up, all the electrons across the Universe instantly but imperceptibly change their energy levels. So everything is connected to everything else."
Apparently this statement caused quite a stir on the net, especially on Twitter where Prof. Cox was greeted with a flurry of criticisms from physicists and non-physicists alike.
Recently, physicists Ed Copeland and Tony Padilla on the YouTube channel "Sixty Symbols" weighed in on the discussion and here are their views:
In summary, they felt that Prof. Cox should have used the term "quantum state" rather than "energy level", since two electrons CAN have the same energy level.
Prof. Padilla mentioned the example of helium, where two electrons do occupy the same energy level but don't violate Pauli Exclusion Principle because they have different angular momentum.
But both of them felt that there was nothing controversial in what Prof. Cox said; Prof. Padilla thought that the spirit of what he said is OK, while Prof. Copeland enjoyed the TV lecture and expressed surprise that it provoked such a reaction.
He thought that some people might have interpreted the "everything is connected" part as applicable to the connection of human consciousness, which is not what Prof. Cox meant at all.
Here at Fresh Brainz, we are NOT SURPRISED that this statement could have sparked such a heated debate.
In fact, I see three key parts in what Prof. Cox said that have the potential to generate controversy.
And here they are, in order of increasing intensity:
1. Energy Level
As mentioned earlier, two electrons can share the same energy level but not the same quantum state.
This simply means that no two electrons can have the same four quantum numbers.
Energy level is one of the quantum numbers, but there are three more: angular momentum, projection of angular momentum, and spin.
Prof. Copeland observed that people who notice this technical inaccuracy tend to be physicists.
He defended it by noting that Prof. Cox was speaking to a TV audience who might find the idea of "energy level" novel enough, let alone the concept of "quantum state".
Since these physicists don't consider this a major inaccuracy, I'll have to take their word for it.
Nevertheless, I should mention that the choice of words is important, especially when there are different meanings of the same word in academia and everyday use.
This can't be helped because it is the regular language users, and not scientists, who determine the common meanings of terms, unless it is a new term invented specifically for the science, eg. "quantum state".
2. Everything Is Connected
I can almost hear the groans from science educators and communicators.
Although Prof. Copeland didn't think there was anything untoward about this assertion, Prof. Cox himself saw it coming:
"This statement received some criticism in scientific circles. Not because it’s wrong, because it isn’t; without this behavior, we wouldn’t be able to explain the bonds that hold molecules together. The problem is that it sounds like woo woo, and quantum theory attracts woo-woo merde-merchants like the pronouncements of New Age mystics attract flies – metaphorically speaking.
For the record, the reason that everything being connected to everything else does not allow us to be, (selects randomly from a pit of drivel), at one with the Universal consciousness, is that the subtle interconnectedness in quantum theory cannot be used to transmit information. Quantum theory, in other words, describes a counterintuitive world, but not a mystical one."
Unfortunately, in popular culture, statements like "everything is connected" are already strongly associated with New Age mysticism.
Supporters of such beliefs immediately interprete it as the "connection" between consciousness, or something like that.
I think they feel that their views are validated when a well-known particle physicist actually said it!
From what I see, much of the negativity on the net is directed against this phrase, and I empathize with Prof. Cox.
Let me explain what I think is going on.
As part of the training, scientists have to give presentations, sometimes to people outside the field who may not understand the significance of their research.
The style of presentation called "zoom-in, zoom-out" is a useful strategy to keep the attention of your audience.
Start with a broad overview, zoom into the technical details, and then finally zoom out again to discuss the wider implications of your work.
Prof. Cox is doing exactly that; by widening the scope to that of the entire Universe, he is trying his best to capture the attention and hopefully the imagination of his audience.
Moreover he is trying to impress on his audience the power of quantum mechanics, which as Prof. Copeland explained, can describe all of the particles with just one wavefunction.
The difficulty here is to choose a statement that has impact so that the audience can have a "take-home message" that is easy to remember.
It might be technically more accurate to say that the electrons in the heated up diamond will affect the quantum state of all other electrons in the Universe, but such a statement clearly lacks the impact of "everything is connected"!
3. Instantly But Imperceptibly
Although many criticisms target the "everything is connected" part, personally I find the part "...all the electrons across the Universe instantly but imperceptibly change..." more contentious, especially the latter bit about "imperceptible change" which I will talk about later.
a. But first, I'll briefly mention the former bit - "instantly".
Dr. Copeland insisted that by "instantly" Dr. Cox didn't mean to say that Einsteinian causality has been violated.
Other people are not so sure.
In an online discussion between physicist Tom Swanson and Prof. Cox, there are people who sought clarification about this.
For example twistor59:
"However in the present discussion we’re talking about a correlation, not just of a spin direction which could give either up or down when you measure it, but in energy levels – energies can be measured, and if my excitation of an electron in London can cause an instantaneous change in an electron energy in the Klingon system, wouldn’t that mean that information can be transmitted instantaneously in principle?"
"So for example, if you start with such a stationary state and “wiggle” one subsystem, the full system does not have to instantaneously adjust itself so that it stays in a definite energy state. The story is more complicated, and certainly is causal: if an electron 5 lightyears away wiggles, all the electrons in my body will certainly adjust, but not until at least 5 years from now. This is not much different from what happens in classical physics, where we interact in small ways with faraway objects (nor should it be different, physics is classical on those scales)."
Since I'm not an expert in this area, I'll leave it at that.
b. What disturbs me more is the latter part about "imperceptible change".
In that same discussion forum, commenter "The Jab" described it this way (in a very colourful language!):
"As to the validity of his claims, it is indeed true in a trivial way. If QM is correct, and if his model is accurate, then it is true that if he shakes the crystal all electrons in the universe will adjust to it. But there is nothing novel to it. Newton’s theory of gravitation could make exactly the same claim: if Newton flicked a booger in one direction and not another, all planets in the solar system would readjust to it (instantaneously, by the way). As for the claim, it was indeed correct at the time of Newton, and nobody would dispute it then (with the risk of getting some nasty letters from Newton himself). The question is of relevancy for the effect."
JG noted that:
"I think everyone would agree that Cox’s jiggling is not there for all practical purposes, I mean we’re talking about shifts of probability in the many googolplexth decimal place. It’s irrelevant to science in the same way the poincare recurrence theorem is irrelevant to statistical mechanics (maybe even much less relevant)."
And stringph added:
"Hmmm, I would hope that an experimental physicist would place a little more emphasis on what could either in principle or in practice ever be measured.
The difference between physics and pure mathematical or metaphysical speculation is precisely in this point. Asking yourself whether the ‘connections’ have measurable consequences is a great way of clarifying whether they represent any physical reality."
I think these commenters hit an important point in this entire discussion, which is the main reason why this TV lecture makes me feel uncomfortable.
Let me illustrate this with an imaginary scenario.
Suppose I am a counsellor, and my goal is to encourage you to feel good about yourself.
I could say inspirational things like...
"One tiny drop of water will make waves across an ocean."
"If you jump for the sky, you will move the Earth."
"Even a candle in the dark will light up the whole Universe."
And these are not merely metaphors - they are also technically correct, like The Jab's flying booger example.
Backed up by actual (classical macroscale) physics!
But the problem is, I neglected to tell you just how much change has been produced, and whether that change is even measurable.
In other words, these are "imperceptible changes".
Without knowing the size of the effect, the audience would walk away feeling encouraged and empowered; I have inspired them to feel better about themselves using metaphors that are given weight because they are based on technically correct physics.
Since that is my goal as a counsellor, I have succeeded.
However, if I was a science communicator, I did not succeed in conveying an accurate representation of the truth to the audience.
It is not inspirational that everything is connected to everything else... if the connections are practically undetectable.
Would you like to know more?
Critique of Prof. Cox's TV lecture:
- Everything is Connected (by Sean Carroll)
The reason why everyday objects don't pop in and out of existence:
- Quantum Decoherence
More about Quantum Mechanics:
- Power and Strangeness of the Quantum (Public Lecture by Serge Haroche)
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