Fact and Fiction

Thoughts about a funny old world, and what is real, and what is not. Comments are welcome, but please keep them on topic.

Thursday, October 27, 2005

Quantum mechanics is not weird

In my two previous postings State vector collapse? and Spooky action at a distance? I have talked (ranted?) at some length about commonplace misunderstandings of quantum mechanics. I find the awe in which QM is held to be quite annoying. It is described using words like "spooky" or "weird" or "mysterious", which are used by journalists and scientists alike. Remember the parrot cartoon? Yes, this is another example that is very aptly described by that cartoon.

QM has been around since 1925. How long does it have to be around before people accept it as is? Why should anything about the universe be called "weird"? The only explanation for this behaviour is that we start with a prior prejudice that those phenomena that are directly accessible to us via our senses are representative of all phenomena in the universe. When we unearth something that is not directly accessible to our senses, we therefore register surprise if it does not fit into our "standard" intuitive understanding that serves us so well for those phenomena that are directly accessible to our senses.

One of the benefits of a scientific education is that it extends one's standard intuition into areas that were not previously accessible. QM is just one example where one's intuition needs to be built up from almost no prior intuitive understanding of QM. At first, QM will seem weird because it behaves in ways that are very dfferent from standard intuition. But once one has understood that one's standard intuition must be limited in scope, it is easy to open one's mind up to the novel features of QM, and thus to achieve an "extended" (i.e. "standard" plus the extra bits needed to incorporate QM) intuition.

Of course, there are also people who love things that don't fit into their standard intuition, because they are then things to be worshipped rather than to be understood. QM is a perfect candidate for these people, because they see QM as having a mystical favour that eludes direct comprehension. Certainly QM eludes standard intuition, but that doesn't mean that QM is mystical.

So, QM is not weird, provided that you are humble enough to acknowledge that the standard intuition (e.g. common sense) that you develop using your standard senses (e.g. eyes, ears, etc) is necessarily limited to the sorts of phenomena that they can sense. You need to use entended sensing apparatus (e.g. laboratory apparatus) in order to build an extended intuition (e.g. feeling for QM).


At 28 October 2005 at 21:01, Anonymous Dave Bacon said...

It's interesting to ask why other physics, like general relativity or QCD, don't have a reputation for weirdness that quantum theory does. I mean, does anybody ever say, "Wow! How strange is the SU(3) in QCD?" Well I certainly haven't heard that!

At 29 October 2005 at 08:24, Blogger Steve said...

For GR, I presume people aren't that excited about the bendy rubber sheets that are used in the usual popular explanations. It seems too intuitively obvious, and therefore cannot possibly be weird.

On the other hand for QCD (which is a particular type of quantum theory), I presume that not many people know about it yet. It is much more difficult to visualise intuitively because it does its tricks in its internal colour space. If people think QM is weird, then the way in which QM is used in QCD will blow their minds once they begin to realise what is going on in QCD.

Awarding Nobel prizes for asymptotic freedom was well-deserved, but unfortunately not sexy enough to excite people about QCD.


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