Shaving with Occam’s Razor

I was on Twitter on Christmas Eve, wasting time that should have been spent working out what my very first blog post should be, when I saw the following tweet:

sorry to bother you @BrianDunning -& plz forgive me if it’s been covered- but people butchering occam’s razor needs to be addressed i think

Well, there was my inspiration. Sure, Brian Dunning responded to the tweet by pointing out that it will be addressed in Principles of Curiosity (go fund it on GoFundMe), but it got me curious. And indulging my own curiosity is why I write.  So, let’s start with the obvious question:

What is Occam’s Razor?

Not so much this, really. Via Wikimedia.

Occam’s razor is bandied about quite a bit on the internet, particularly among skeptical circles. Most of my life, I’d assumed that it was identical to the famous Sherlock Holmes axiom from The Sign of the Four (1890): “How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?” And it turns out that, for most of my life, I’ve been wrong. This quote, although it works along similar lines, is not Occam’s razor.

A depiction of William of Ockham, for whom the adage is named. Via Wikimedia.

Occam’s razor is actually based on two “laws,” the lex parsimoniae (or law of parsimony) and the lex pluralitatem (or law of plurality, and I’m trusting Google Translate for the Latin on that one). Both must be applied to fully make use of the razor. Even then, as we’ll soon see, it must also be remembered that the razor does not guarantee accuracy. It is merely a tool that gives you a starting point for reasoning about a problem.

The lex parsimoniae can be stated “frustra fit per plura, quod potest fieri per pauciora,” and usually translated into English as “it is pointless to do with more what can be done with fewer.” The lex pluralitatem on the other hand, can be stated “numquam ponenda est pluralitas sine necessitate,” “plurality is never to be posited without necessity.” Combining the two laws, Occam’s razor is, simply put: “Keep it simple. Because, all else being equal, the simplest answer is most likely to be the correct one.”

Is Occam’s Razor an Actual Law, Then?

Well that depends on what you mean by “law,” really. It’s not considered one of the axiomatic laws of thought, though, so it’s not considered to be a foundational principle of philosophy. Really, it’s a maxim. A guideline. A tool to help you cut through the Gordian knot of options and alternatives that come up when you research anything, allowing you to pick a place to investigate. It’s not foolproof, though, because the real world is messy and determining what is the “simplest” explanation with the “fewest” moving parts can be extremely difficult.

Occam’s razor is a tool, just like any other tool. Use it correctly, and it will work well. Use it incorrectly, and you risk injuring yourself or damaging its usefulness. If you don’t believe me, try using a coping saw to hammer a nail into a two by four. (Note: Do not actually try this. It will end in tears and blood.)

Butchering Occam’s Razor

It bears repeating: Occam’s razor is a tool, not a rock-solid unbeatable guide to The Truth™. The utility of the razor is that it allows you to make a choice between two or more possible solutions, but those possible solutions need to be equally likely before application of the razor points with any accuracy towards any sort of accurate result. Allow me to illustrate, absurdly, using gravity as an example.

One explanation for gravity is that it is caused by an object’s mass warping space-time. Other objects moving through space-time have their trajectories altered by the warp, deflecting them into a new trajectory. If the mass is sufficiently large, space-time is warped so much that the moving object is deflected towards the warping mass, creating what is perceived as “gravitational attraction.” A second explanation is that the Flying Spaghetti Monster, in His noodly wisdom, holds us to the Earth in his loving pasta embrace. An ill-advised application of Occam’s razor would hold that the FSM explanation is most likely the correct one, because it only postulates one entity (the FSM) and is also the simplest (He holds us to the Earth with his noodly love). The warped space-time explanation requires such entities as “mass” and “space-time” and “trajectories” and is, quite simply, difficult to wrap your head around. The only catch about the FSM solution is that it isn’t true.

Occam’s razor does not, and can not, dispose of facts. Occam’s razor only disposes of messy and complicated explanations for existing facts, and even then it only disposes of them until such time as more facts arise. Then, if those new facts reveal that the disposed-of messy and complicated explanation is actually more correct, then Occam’s razor needs to be reapplied in light of the new information. Because, at the end of the day, the best explanation for reality is what is really there. All of our tools and principles and laws are just there to help us work that out.

About Richard Gant

Richard Gant is a husband, a father, and a huge nerd with a deep love of science, science fiction, and fantasy. He works for a brokerage firm he won't name here in order to keep his Compliance department happy, and frequently talks to inanimate objects as if they can understand him. He also has a difficult time writing seriously about himself in the third person.
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8 Responses to Shaving with Occam’s Razor

  1. Fred Bunting says:

    Great blog … but I balked at your FSM example. The problem with the FSM solution is not that it “isn’t true” (as we have no empirical way of proving that it isn’t true). The problem with the FSM solution is it isn’t actually an *explanation*. It is a statement so vague that it can be extended to explain ANYTHING, and thus explains NOTHING. Gravity, electromagnetism, the stock market, airplane turbulence, slot-machine payouts … all equally explainable as the whim of the FSM and his noodly love.

    Or another way to put it, which backs your point about it being a bogus application of Occam’s Razor … it is NOT true that that the directed actions of an (apparently) all-powerful FSM posits a ‘single’ entity with a ‘simple’ explanation. To the contrary, it is so vague that it is maybe this entity may be *infinitely* more complex … it is an ‘explanation’ that raises FAR more questions than it answers.

    • Graham Zaretsky says:

      I had the same exact thought, but you beat me to it. Once you posit some entity as the cause for anything, you then have to explain that entity, is there one FSM? Many? Where did it come from? How did it come into being? How does it work? What does it look like? And, for every question, that is answered, there are even more questions, such as, How do you know this to be true? No, the FSM is only simple on its, albeit Noodly, surface.

      • Richard1941 says:

        Applying your own criticism to space-time, is there only one? Where did it come from? Did it come into being, and if so, how? What does it look like? How do you know any of this?

        To me, it is clear that a FSM must have done it.

        • Anselm says:

          FSM aside, I’m not overly well-endowed in the imagination department, so I’m struggling to think of any real-life examples of where a messy explanation is indubitably the correct one, while its more simple – and plausible – cousin manifestly isn’t. (Might a hypothetical example be if the Holy Grail of physics, the Grand Unified Theory, can be shown not to exist, and that the universe really is a mess of distinct forces?)

  2. Patricia says:

    Reminds me of the time a male friend asked me “Well, where do YOU think electricity comes from.”
    “From underneath Niagara Falls,” sez me. “I thought everyone knew that.”

    He used up an entire paper tablecloth and multiple napkins explaining to me something about electricity–more than I could possibly understand.

    Great Blog! LOVE IT. I’ll be back. Thanks for a fun read.

  3. Walter Clark says:

    The best example of Occam’s Razor, gone wrong is government solutions to problems. The defense of Free Trade, no minimum wage, no barriers to immigration, dropping capital gains tax… are extremely difficult to explain in spite of almost universal agreement among economists. Any explanation whatsoever falls prey to Occam’s Razor of a theory that is not only simpler but argues for just what every politician wants. That simpler theory: see a problem, pass a law.

    • John Mayer says:

      Your example of Occam’s Razor going off the rails is a good example not of how economists—who don’t “universally” on much of anything (as is well known, if you put all the economists in the world end to end they couldn’t reach a conclusion)—over-simplify things, but how certain voters, usually conservatives, perceive complex issues in simple terms. These conservatives dismiss messy “entities” out of hand till they arrive at a principle that will fit on a baseball cap.

  4. Ron A. Zajac says:

    Always like this statement, attributed to Einstein:

    “Things should be as simple as possible, but no simpler.”

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