What is Occam’s Razor?

If you’ve seen the movie “Contact” with Jodie Foster, you might be familiar with the concept of Occam’s Razor, which states the principle that, all things being equal, the simplest answer is usually the right one.

William of Occam was a 14th-century English logician and Catholic friar upon whose writings the phrase “entities should not be multiplied beyond necessity” is attributed.

What Occam was saying, was that when trying to explain or prove something, we should refrain from making more assumptions than are necessary.

One should not increase, beyond what is necessary, the number of entities required to explain anything.  In other words, don’t make more assumptions than the minimum needed.  If we can manage to literally ‘shave off’ , with Occam’s Razor, anything that is really not required to explain something, there’s less chance of encountering and introducing inconsistencies, redundancies, and ambiguities.

This principle, which finds it’s kissing cousins in the Law of Parsimony/Law of Least Effort and the Rule of Simplicity goes back at least as far as Aristotle, who wrote “Nature operates in the shortest way possible.”  Aristotle, though, went too far in believing that experiment and observation were unnecessary, however.  The principle of simplicity works as a heuristic, or rule of thumb, in many applications, but some mistakenly commute it to the world of physics, not to mention REAL LIFE, where things more than not turn out to be a helluva lot more complicated than we could have ever expected.  The principle has also been used to justify uncertainty in quantum mechanics. Shakespeare certainly had it right when he wrote “There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.”.

Occam’s Razor is a process used to decide which interpretation is the most logical by taking the one that uses the least number of assumptions. In science, Occam’s razor is used as a heuristic (rule of thumb)in many scientific as well as non-scientific theory-making.   It’s very closely related to the principle of least action by Pierre Louis Maupertuis and Leonhard Euler, which I’ll discuss in a future post.

One argument against Occam’s Razor is that science simply does not progress through logic, it progresses through demonstration and experimentation, trial and error, to better construct theories that fit the data gathered.   Many in the scientific , as well as the non-scientific community, feel that this is a much better guide to theory choice than Occam’s Razor.  In terms of constructing viable and effective positive action action strategies, as we do in M.O.S.T  trainings, we, in the parlance of the old-time barber, ‘take a little off the top’.  we don’t shave the whole thing off…we leave a little Don Johnson-esque shadow, to remind us that the best outcomes come from a policy of non-strict adherence to any methodology, except one that increases the odds for success!

The most useful statement of the principle for scientists is “when you have two competing theories that make exactly the same predictions, the simpler one is the better.”

or

“If you have two theories that both explain the observed facts, then you should use the simplest until more evidence comes along”

or

“The simplest explanation for some phenomenon is more likely to be accurate than more complicated explanations.”

or

“If you have two equally likely solutions to a problem, choose the simplest.”

or

“The explanation requiring the fewest assumptions is most likely to be correct.”

But is it true……..

Ernst Mach advocated a version of Occam’s razor which he called the Principle of Economy, stating that “Scientists must use the simplest means of arriving at their results and exclude everything not perceived by the senses.”  Exclude everything not perceived by the senses?  Hmmmmmmmm.  This is the guy who came up with the Mach Number, by the way!

Stephen Hawking writes in A Brief History of Time, “We could still imagine that there is a set of laws that determines events completely for some supernatural being, who could observe the present state of the universe without disturbing it.  However, such models of the universe are not of much interest to us mortals.  It seems better to employ the principle known as Occam’s razor and cut out all the features of the theory that cannot be observed.”

“Everything should be made as simple as possible, but not simpler”…..Albert Einstein

He very well could have coined the injunction now known as K.I.S.S. aka “Keep it simple, stupid!”

Last words:  In the real world, Occam’s Razor rarely, if ever, works, and never, ever call someone stupid.

References:

Stephen Hawking, A Brief History of Time.

Albert Einstein, Autobiographical notes

Please go to this page to see the Program Outline for the M.O.S.T. Seminar.