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Sunday, 26 May 2013

Spooky Action at a Distance

I don’t think I’ve ever seen a popular account of quantum entanglement that failed to mention Einstein’s “spooky action at a distance” quote. That’s not surprising, because quantum mechanics is a notoriously difficult subject to communicate to the non-specialist. It needs all the memorable sound-bites it can get... especially ones that a layperson can relate to. If you saw an experiment in which an electron in one location seemed to know what another electron somewhere else was doing, then the word “spooky” might well spring to mind.

Part of the appeal of the quote is that “spooky” is a colloquial word, rarely encountered in serious writing. It’s quite a recent coinage, as you can see from the Google Ngram chart below. “Spooky” was virtually unknown before the 20th century, and its usage only really took off in the 1970s and 80s. When Einstein used it in a letter to Max Born in 1947, the word was still quite novel (you can view the original context here – it’s on page 158 of the original, on the left-hand-side of page 90 of the scanned PDF).
There’s a catch, however. Einstein’s letter is translated from German, and what he originally wrote was not “spooky action at a distance” but “spukhafte Fernwirkung”. The Ngram stats for spukhafte (or spukhaft) are different from spooky – the word was at the peak of its popularity around 1947, and its usage has declined since then. This led me to wonder if “spukhaft” might have a slightly different meaning from “spooky”.

Spooky comes from “spook”, which is an informal, rather playful term for ghost. The German word Spuk also means ghost, but as you can see from the chart it’s been around longer. The word occurs in the first scene of Wagner’s Der Fliegende Holländer (mentioned a few weeks ago in Fortean Opera)... a gloomy Gothic tragedy, which isn’t the sort of place you’d expect to find a childishly jolly term like “spook”. The Norwegian sailors, on hearing eerie voices emanating from the Dutchman’s ship, say: “Welcher Sang! Ist es Spuk? Wie mich’s graust!”... which is rendered in the English version as “What a song! Are they ghosts? I’m filled with fear!”

If “Spuk” simply means ghost, with no cosy Halloween or Scooby-Doo overtones, that makes me wonder if “spukhaft” is better translated as “ghostly” rather than “spooky”. If so, it would place a somewhat different emphasis on the Einstein quote. If you say something is “spooky”, that’s not so much a description of the phenomenon itself, as your reaction to it – something is “spooky” if it makes you uneasy because you can’t explain it. On the other hand, if something is described as “ghostly”, that’s saying something about the phenomenon itself. It’s being labelled as supernatural, non-physical and possibly even irrational. For a scientist to refer to something in these terms is tantamount to saying it’s not real.

The closest idiomatic phrase I can think of would be “mystical action at a distance” rather than “spooky action at a distance”. If Einstein objected to “mystical action at a distance”, he wasn’t the first one. As I’ve mentioned before, this was the reason Galileo heaped ridicule on Kepler for his suggestion that the Moon was responsible for the Earth’s tides (see Galileo wasn’t always right...). Soon after Galileo’s time, Newton explained the tides—and the motion of the Moon and planets—as consequences of the gravitational inverse square law. On the face of it, this was nothing more or less than “action at a distance”, and many people objected to Newton’s theory on the metaphysical grounds that action at a distance was illogical and therefore impossible. Numerous mechanical explanations of gravitation were put forward to try to get around the need for action at a distance.

My understanding of the German language is only marginally better than non-existent, so I really don’t know what Einstein meant by spukhafte Fernwirkung. He might have meant “spooky action at a distance” in the sense that English-speakers would understand the term – i.e. that he found the concept unsettling, if not downright scary, because it was seemingly supernatural. But I’m not convinced the emotive overtone of the word “spooky” was intended at all. He may just have been saying “I don’t believe in it, because I don’t believe in the supernatural”.

Ultimately, it doesn’t matter what Einstein meant. “Spooky action at a distance”, as the phrase is commonly understood, is a perfect description of quantum entanglement. Wittingly or unwittingly, Einstein gave quantum physics one of its most accessible memes, right up there with Schrodinger’s Cat, the Many-Worlds Interpretation and the God Particle.


Ross said...

In his book ENTANGLED MINDS: EXTRASENSORY EXPERIENCES IN A QUANTUM REALITY, parapsychologist Dean Radin quotes Albert Einstein as writing, "I cannot seriously believe in [the quantum theory] because it cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance." (Radin cites THE BORN-EINSTEIN LETTERS: FRIENDSHIP, POLITICS AND PHYSICS IN UNCERTAIN TIMES as the source of this quote.) It is obvious that Einstein here used the word "spooky" to express disbelief in quantum entanglement.
Radin goes on to write, "The repeated [experimental] confirmation of quantum theory, and of the concept of entanglement, would have genuinely shocked Einstein. As physicist Daniel Greenberger put it, 'Einstein said that if quantum mechanics is correct then the world would be crazy. Einstein was right--the world is crazy.'"

Andrew May said...

Thanks for the added info. That's essentially what I was getting at. Einstein was using the word "spukhafte" to say "I don't believe in this phenomenon" not "this is a spooky phenomenon"... although the latter turns out to be a more valid observation.

Carl Aserio said...

Thank you gentlemen for your attempt to read in between the lines of this important Einstein comment, now in 2017 , we are at a 70-year distance from the 1947 Born addressed characterization.
The phenomena doesn't go away, even with lots of inquiring work done , and
perhaps now gravitational wave measurements will lead to greater insight of black holes etal..
With quantum entanglement being apparently faster than light,
obviously we are missing something...
I wonder if you can comment on any new insights in this direction which you can point me towards?
Thank you again for your time.
Sincerely yours,

Carl Aserio said...

Thank you Mr.May for reading in between the lines of this famous Einstein- to -Born quote.
I wonder can you direct me to any ideas about the relationship of quantum entanglement and black holes, on the apparent contradiction that the needed faster than speed of light entanglement represents.
Do black holes structure shed any 'light' on quantum entanglement?
Thank you.

Andrew May said...

Hi Carl - thanks for your comments. Your questions are all very sensible, but I'm not up-to-date enough on the science to answer them!