Monday, 9 March 2009

Occam's Razor

Some people object to Occam's Razor on the grounds that it dismisses more complex correct solutions. I think this is a misreading of its purpose. Einstein's famous quote on simplicity is often cited as:
Everything should be made as simple as possible, but no simpler.
The 'but no simpler' highlights why I think this view of the Razor is wrong.

Another way to state the Razor is:
Plurality should not be posited without necessity.
...which perhaps makes the point of the Razor clearer.

I can see that in some disciplines there may be problems when presented with a number of competing theories, so there may be practical problems with its *application*.

However, pragmatism dictates that scientists would never get anything done if they didn't proceed on the basis of *some* theory or other, so unless we have a better mechanism for this pragmatic selection, we are stuck with Occam. And I think people get a bit hung up with the idea that more complex ideas are *wrong* because of this; well, perhaps they're not, but we know that *all* the more complex explanations *are* wrong, apart from *one*, if the simplest explanation is wrong, so nearly all of them are right to be dismissed (subject to the 'partly-right' scenario described above).

It's plainly the case that the simpler explanation has *not* been the (fully) correct explanation in the past, eg Newtonian gravity cf Einsteinian gravity. But for scientists to accept Newtonian gravity and work on with that assumption is surely achieving more than not applying Occam's; for example, by assuming the more complex 'explanation' that god is effecting the attraction between objects (and there are an infinite number of more complex explanations; which do you choose?). The simpler explanation allows Einstein to move incrementally to GR, which I think one would have to agree doesn't flow easily from the 'god' hypothesis.

Its value is plain to see for me.

EDITED for clarity


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