What Is… A Philosophical Razor

Philosophical razors: Occam's razor and Hanlon's razor

In this series, I dig a little deeper into the meaning of psychology-related terms. This week, we take a bit of a detour to look at philosophical razors.

I first heard of philosophical razors quite recently, in a poem by Suzette Benjamin that mentioned Occam’s razor. So, what is it and why is philosophy doing some shaving?

Well, a philosophical razor is a type of heuristic, or rule of thumb. It lets you shave away extraneous noise by eliminating unlikely solutions to logical problems. Occam’s razor is the classic example, but there are some more modern ones that have also been described.

Occam’s razor

The original razor, Occam’s razor, is also known as the law of economy or law of parsimony. The principle states that things should not be multiplied unnecessarily. Essentially, this means that, when faced with two competing explanations, the simpler is more likely to be correct. This concept was described by scholars going as far back as Aristotle in Ancient Greece, but in the early 1300s, William of Ockham used it so frequently and sharply that it later became known as Occam’s razor. Ockham himself never actually called it Occam’s razor, and I’m not sure why the Ockham/Occam spelling difference.

Ockham was a strong believer in minimizing assumptions, since each time you assume, besides making an ass out of u and me, you introduce the potential for error into the mix. His razoring focused heavily on reducing error.

This doesn’t always lead to the “correct” explanation, but it gives you a good place to start. For example, if your car abruptly dies and the fuel gauge is on empty, the most likely explanation is that your car ran out of guess. It could be something else, but you’ll want to at least start with the fuel issue rather than faffing about unnecessarily.

While I hadn’t heard of Occam’s razor until recently, it is out there in the popular realm. It was mentioned in The X-Files, House, and the 1997 movie Contact, which I remember seeing and being fascinated by back in the day (although not fascinated enough to remember the razor).

Other philosophical razors

Some more modern, less established, razors include:

  • Hanlon’s razor: “Never attribute to malice that which is adequately explained by stupidity” (and there’s certainly enough of that to go around)
  • Hitchens’ razor: The burden of proof for a claim lies on whoever makes it, and if that burden is not met, no further argument against it is needed
  • Hume’s guillotine: This was described by philosopher David Hume in the 1700s, and says that statements of fact (i.e. what is) and moral statements (i.e. what ought to be) can’t be used interchangeably, and one can’t infer moral conclusions from facts alone.
  • Alder’s razor, aka Newton’s flaming laser sword: This comes from mathematician Michael Alder, who argues that there’s no point debating a scenario involving two impossibilities. His response to the irresistible force paradox (“What happens when an irresistible force is exerted on an immovable object?”) was that the paradox itself is flawed, because “Either the object would move or it wouldn’t, which would tell us only that either the hitherto immovable object was not in fact immovable, or that the hitherto irresistible force was in fact resistible.” May the force resist you… or something like that.

Razoring (and lack thereof)

Conspiracy theorizing seems like a good example of a lack of Occam’s razoring. It actively rejects the simplest explanation and looks for the most complicated.

Now let’s have some fun and look at the recent US presidential election. The simple explanation? Joe Biden won. The anti-Occam’s razor answer? Please refer to Trump’s Twitter feed. Hanlon’s razor and adequately explained by stupidity? Rudy Giuliani’s appearance in Borat, perhaps? Hitchen’s razor and burden of proof? Giuliani and friends can dig their own hole without any assistance (okay, maybe Four Seasons Total Landscaping will help out). Hume’s guillotine separates what is (Biden won) and what ought to be (Trump’s pretend win). Flaming laser sword? Would the moon fall out of the sky if Trump won and his orange face was natural?

Fun times. Had you ever heard of Occam’s razor or philosophical razors in general?


The Psychology Corner: Insights into psychology and psychological tests

The Psychology Corner has an overview of terms covered in the What Is… series, along with a collection of scientifically validated psychological tests.

Ashley L. Peterson headshot

Ashley L. Peterson


Ashley is a former mental health nurse and pharmacist and the author of four books.

27 thoughts on “What Is… A Philosophical Razor”

  1. Had you heard of Occam’s razor before, or philosophical razors in general?

    I had heard of Occam’s Razor, but not the others you shared. Interesting. Thanks!

  2. I appreciate use of it related to our politics, sadly fitting. And, your description gave me a good and needed laugh. I always appreciate that. I also like learning this term, in particular as it relates to assumptions. A hard , but necessary, thing to avoid.

  3. Hi Ashley, thanks for the links. This was another great read, and in particular I find it fascinating how all of the razors selected might apply to the incredulity over current election results in the U.S.A. We really do need to emphasize critical thinking a little more strongly in our educational system. Rather than think for themselves logically, people seem more prone to believe whatever it is that the crowd is believing — especially when it’s convenient.

  4. Not sure what it’s like in Canada, but here in the U.S. I find they’re definitely not delivering. Combine that with that the bulk of young people’s “education” (pre-college level) is probably coming from Twitter and Facebook feeds, and we have a pretty sorry situation.

  5. I had heard of most of these, although I think Occam’s is the only one I had seen referred to as a razor. Occam vs. Ockham I would guess is because there was no standardised spelling in the fourteenth century.

    Alder’s razor, aka Newton’s flaming laser sword would throw out questions of the “Who would win in a fight between Superman and Batman?” kind, so would be a bad thing for the internet.

  6. Loved this article. Found it to be really educational, well written and concise. I’ve never heard of Occam’s razor prior to this, it’s apt link to today’s politics was also great.

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