10 Rules, Laws, and Theorems You Should Know

Bobamnertiopsis via Wikimedia Commons // Public Domain 
Bobamnertiopsis via Wikimedia Commons // Public Domain  / Bobamnertiopsis via Wikimedia Commons // Public Domain 

You may be familiar with Murphy’s Law and the Peter Principle, but the world is full of wisdom distilled into simple rules for understanding life, human nature, and the world around us.


The Pizza Theorem [PDF] states that you can pick an arbitrary point on a pizza, arrange an even number of slices to meet at that point, and you’ll find that the sum of the areas of alternate slices are equal. This is fine if you're sharing a pizza with only one other person. But the easier Pizza Theorem by Eric W. Weisstein is for calculating the volume of a pizza using the thickness (a) and radius (z). The formula is: pi z z a.


Occam's Razor proposes that when more than one explanation is available to solve a problem and/or predict outcomes, the simplest one is probably your best bet. The opposite rule is Arkham's Razor, which holds true in fiction, particularly comedy: “When given multiple explanations for an event, the oddest one is most likely to be true.” After all, the essence of comedy is the unexpected.


Getty Images

Trying to suppress something, only to have it blow up in the news as a result, is known as the Streisand Effect. It takes its name from singer Barbra Streisand, who, in 2003, sued the California Coastal Records Project over pictures an aerial photographer took of her house, claiming the photos violated her privacy. Few knew about the images before the lawsuit (in fact, they'd only been viewed six times—and two of those were her lawyers); now everyone does. She lost the lawsuit.


Betteridge's Law of Headlines states that "Any headline which ends in a question mark can be answered by the word no." If the answer is yes, then the headline would simply make that declaration. A question in a headline implies that either 1.) The writer doesn't have enough facts to be sure of the answer, 2.) The question makes the available information more sensational, or 3.) The writer is honestly just asking for the reader’s input.

Ian Betteridge responded to such a headline in 2009, leading to the law in his name. In academia, the same principle is enshrined in Hinchcliffe’s Rule.


When two laws contradict each other, we have a paradox. The Buttered Cat Paradox states that since a slice of buttered toast, when dropped, always lands butter side down, and cats always land on their feet, then if you attach buttered toast to the back of a cat and drop it, neither the cat nor the toast will land on the ground. The working theory is that this phenomenon can be harnessed for its potential energy, but no one has yet demonstrated this.


Geoff Cohen observed that “The likelihood that any unmoderated group will eventually get into a flame-war about whether or not to have a moderator approaches one as time increases.” This became known as Cohen’s Law. Shirky expounds on the internet group dynamics at work here.


If you're tempted to leave a comment to correct someone’s grammar or spelling, beware of Skitt’s Law, which states, “Any post correcting an error in another post will contain at least one error itself.” While such an occurrence appears to be karma, a different wording shows a more generous view of the poster’s intentions: “The likelihood of an error in a post is directly proportional to the embarrassment it will cause the poster.” Skitt wasn't the first to propose this law. It appears under other names as far back as 1990, when Bell’s First Law of Usenet was proposed. The easiest-remembered name for this law is Muphry’s Law, which is a typo of Murphy’s Law, first proposed in 1992.


Cunningham's Law is related to Skitt’s law in that it is born from the urge to correct others’ mistakes. According to the law, “The best way to get the right answer on the Internet is not to ask a question, but rather to post the wrong answer." Internet users can easily ignore a request for help, but have a hard time resisting the urge to appear smarter than the original poster.


Randall Munroe at xkcd // CC BY-NC 2.5

The worst thing you can say about someone is that they remind you of Adolf Hitler, right? It's an easy insult to hurl, so it shouldn't come as a surprise that the comparison is used even when it isn't called for. Mike Godwin noticed this trend on the internet and coined Godwin’s Law in 1990. The law states, “As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1." The takeaway is that the person who mentions Hitler has no further information to add at that point, but wishes to emphasize his hatred for the subject of the discussion.


Although most of Clay Shirky’s writing revolves around the internet and new media, the Shirky Principle covers the world at large as well. It reads, “Institutions will try to preserve the problem to which they are the solution.” For example, an organization may want to make their procedures simpler, so they form a committee, or even a new management level, to simplify things. However, adding an extra layer of bureaucracy only makes what you’re doing more complicated.