How Murphy's Law Works

Etorre’s Observation of Murphy’s Law dictates that the other line will always move faster.
Photo Liu Jin/AFP/Getty Images

You're sitting in eight lanes of bumper-to-bumper traffic. You're more than ready to get home, but you notice, to your great dismay, that all of the other lanes seem to be moving. You change lanes. But once you do, the cars in your new lane come to a dead halt. At a standstill, you notice every lane on the highway (including the one you just left) is moving -- except yours.

Welcome to the aggravating world of Murphy's Law. This idiom says that whatever can go wrong will go wrong. And it may just be right. This isn't because of some mysterious power the law possesses. In reality, it's us who give Murphy's Law relevance. When life goes well, little is made of it. After all, we expect that things should work out in our favor. But when things go badly, we look for reasons.


Think about walking. How many times have you reached a destination and thought, "Wow, I walk really well"? But when you trip over a curb and skin your knee, it's a pretty good bet you'll wonder why this had to happen to you.

Murphy's Law taps into our tendency to dwell on the negative and overlook the positive. It seems to poke fun at us for being such hotheads, and it uses the rules of probability -- the mathematical likeliness that something will occur -- to support itself.

The law captures our imagination. Murphy's Law and its offshoots have been collected in books and Web sites. Several bands are named after Murphy's Law, and it's also a popular name for Irish pubs and taverns around the world. It was also used as the title of an action movie.

But Murphy's Law is a relatively new concept, dating back to the middle of the last century. Magician Adam Hull Shirk wrote in the 1928 essay, "On Getting Out of Things," that in a magic act, nine out of 10 things that can go wrong usually will [source: American Dialect Society]. Even before this, it was called Sod's Law, which states that any bad thing that can happen to some poor sod will. In fact, Murphy's Law is still referred to as Sod's Law in England [source: Murphy's Laws].

In this article, we'll explore Murphy's Law, its consequences and the impact it's had on our world. In the next section, we'll look at the story behind Murphy's Law.


Who was Captain Edward A. Murphy Jr.?

Col. John Paul Stapp aboard the “Gee Whiz” rocket sled at Edwards Air Force Base.
Photo courtesy Edwards Air Force Base

Believe it or not, there really was a Murphy, and he lived in the United States until his death in 1990. Captain Edward A. Murphy Jr. was an engineer in the Air Force. Although he took part in other engineering design tests throughout both his military and civilian careers, it was one test that he attended -- almost as a fluke -- that gave rise to Murphy's Law.

In 1949, at Edwards Air Force Base in California, officers were conducting project MX981 tests to determine once and for all how many Gs -- the force of gravity -- a human being could withstand. They hoped that their findings could be applied to future airplane designs.


The project team used a rocket sled dubbed the "Gee Whiz" to simulate the force of an airplane crash. The sled traveled more than 200 miles per hour down a half-mile track, coming to an abrupt stop in less than a second. The problem was that, in order to find out just how much force a person could take, the team needed an actual person to experience it. Enter Colonel John Paul Stapp. Stapp was a career physician for the Air Force, and he volunteered to ride the rocket sled. Over the course of several months, Stapp took ride after physically grueling ride. He was subjected to broken bones, concussions and broken blood vessels in his eyes, all in the name of science [source: Spark].

Murphy attended one of the tests, bearing a gift: a set of sensors that could be applied to the harness that held Dr. Stapp to the rocket sled. These sensors were capable of measuring the exact amount of G-force applied when the rocket sled came to a sudden stop, making the data more reliable.

There are several stories about what happened that day, and about who exactly contributed what to the creation of Murphy's Law, but what follows is a good approximation of what happened.

The first test after Murphy hooked up his sensors to the harness produced a reading of zero -- all of the sensors had been connected incorrectly. For each sensor, there were two ways of connecting them, and each one was installed the wrong way.

When Murphy discovered the mistake, he grumbled something about the technician, who was allegedly blamed for the foul-up. Murphy said something along the lines of, "If there are two ways to do something, and one of those ways will result in disaster, he'll do it that way" [source: Improbable Research].

Shortly thereafter, Murphy headed back to Wright Airfield where he was stationed. But Stapp, a man who was known for his sense of humor and quick wit, recognized the universality of what Murphy had said, and in a press conference he mentioned that the rocket sled team's good safety record had been due to its awareness of Murphy's Law. He told the press that it meant "Whatever can go wrong, will go wrong" [source: The Jargon File].

That was all it took. Murphy's Law turned up in aerospace publications and shortly thereafter made its way into popular culture, including being made into a book in the 1970s.

Since then, the law has been added to and expanded upon. In the next section, we'll look at some of Murphy's Laws interpretations and consequences.


Other Universal Truths

Luis Enrique Ascui/Getty Images The science fiction author Arthur C. Clarke came up with his own “unnatural law," Clarke's Third Law.

Although Murphy's Law captures the jaded, pessimistic view of the world very well, it doesn't stand alone. Since its popularization following the rocket sled tests at Edwards Air Force Base, shrewd observers have come up with some of their own laws.

Some have become famous in their own right, like the Peter Principle, which states that all people will eventually be promoted to their level of incompetence, or O'Toole's Commentary on Murphy's Law, which argues that Murphy was an optimist. There are literally thousands of rules, laws, principles and observations that have been created since Murphy's Law. Some are funny, some are wise and some are just plain cool. Others are old, tried-and-true observations:


  • Etorre's Observation - The other line moves faster.
  • Barth's Distinction - There are two types of people in the world: those who divide people into types and those who don't.
  • Acton's Law - Power corrupts, absolute power corrupts absolutely
  • Boob's Law - You always find something in the last place you look.
  • Clarke's Third Law - Any sufficiently advanced society is indistinguishable from magic.
  • Franklin's Rule - Blessed is he who expects nothing, for he will not be disappointed.
  • Issawi's Law of the Path of Progress - A shortcut is the longest distance between two points.
  • Mencken's Law - Those who can, do. Those who cannot, teach.
  • Patton's Law - A good plan today is better than a perfect plan tomorrow.

Each of these sayings explains some aspect of the universe and puts it into an easily understood (and often funny) form. Even so, Murphy's Law remains the granddaddy of all maxims. What is it about this law that we find so perfectly captures life? In the next section, we'll look at why Murphy's Law is such a universal concept.


Fatalism and the Appeal of Murphy's Law

Fatalism? An untouched swimming pool is all that remains after a house was destroyed by a tornado in Laguna Beach, Ca.
Vince Bucci/AFP/Getty Images

So why is Murphy's Law such a sound universal concept? After all, when approaching an electrical socket with a two-pronged plug engineered to only fit one way, we have a 50-percent chance of getting it right. Then again, we have a 50-percent chance of getting it wrong, too. Perhaps the best explanation for our attraction to Murphy's Law is an underlying sense of fatalism.

Fatalism is the idea that we're all powerless to the whims of fate. This notion says that the things that happen to us are unavoidable, for example, that skinned knee. It's the idea that there's some kind of universal law at work that takes a certain glee at toying with us.


Fatalism contradicts another concept -- free will. This is the idea that humans possess free will and that all of our choices, along with the consequences that come with those choices, are our own.

Perhaps our connection to Murphy's Law is the result of the collision between free will and fatalism. On the one hand, Murphy's Law reveals to us our own undeniable stupidity. If given a chance to do something wrong, we'll do so around half of the time. But that comes from our own choices. On the other hand, Murphy's Law also reveals to us our lack of control, as in the case of always seeming to be stuck in the slowest lane of traffic.

Murphy's Law doesn't prove anything. It doesn't even explain anything. It simply states a maxim: that things will go wrong. But we forget that there are other forces at work when we consider Murphy's Law. Allegedly, It was the author Rudyard Kipling who said that no matter how many times you drop a slice of bread, it always seems to land on the floor butter-side down. Kipling, the author of "The Jungle Book," among others, was making an observation that most of us can relate to: Life is hard, almost to a laughable degree.

But with a buttered slice of bread, you must take into account the fact that one side is heavier than another. This means that on the way to the ground, the heavy side will flip toward the ground thanks to gravity, but it will not flip all the way around back to the top for the same reason. It is, after all, heavier than the side without the butter. So Kipling was right -- a piece of buttered bread will always land butter-side down.

In the next section, we'll look at Murphy's Law in math and science, and how the law can make the things we create safer and more reliable. ­


Preventing Murphy's Law

While most of us appreciate Murphy's Law for its ability to explain our sense of helplessness during certain events, others see it as a tool. At least one person sees it as a mathematical equation that can predict the chances of processes going awry. Joel Pel, a biological engineer at the University of British Columbia created a formula that predicts the occurrence of Murphy's Law.

The formula uses a constant equal to one, a factor that is unconstant, and a few variables. In this formula, Pel uses the importance of the event (I), the complexity of the system involved (C), the urgency of the need for the system to work (U) and the frequency the­ system is used (F).


In an essay he wrote for Science Creative Quarterly, Pel uses the example of predicting the occurrence of Murphy's Law when a driver needs to drive his Toyota Tercel a distance of about 60 miles to his home in a rainstorm without the clutch going out. Using Murphy's Equation, Pel comes up with an answer of 1, meaning the clutch on the Tercel will definitely go out in a rainstorm. While anyone familiar with a Tercel might've seen that coming, it's somehow comforting to know that it can also be predicted mathematically [source: Science Creative Quarterly].

Murphy's Law reminds engineers, computer programmers and scientists of a simple truth: systems fail. In some cases, a system's failure means that the experiment must be repeated. In other cases, the results of a failure can be much more costly.

NASA has learned this over and over again. The space agency has had numerous failures, and although the number is proportionately small to its successes, the failures are often very costly. Ironically, in the case of one unmanned orbiting vessel, a set of sensors had two ways of being connected and -- just as with Murphy's original Gee Whiz test-- the sensors were all connected incorrectly. When the sensors failed to operate the way they were designed, the parachutes that were meant to slow the spacecraft down didn't open, and the orbiter crashed into the desert [source: MSNBC].

It's an instance like this, in conjunction with an awareness of Murphy's Law that has caused designers to install fail-safes. There are examples of fail-safes all around us. Some are systems that use limited choices to reduce errors, like the mismatched prong sizes on an electrical plug. Others are mechanisms that prevent matters from going from bad to worse, like lawnmowers that have levers that must be held down in order for the mower to operate. If the person operating the mower lets go of the lever, the lawnmower stops running.

Fail-safes are also referred to as "idiot-proof." But Murphy's Law still has a tendency to strike, even when care has been taken to ensure against failure or catastrophe. This leads us to the last law we'll relate to Murphy's: Grave's Law, which states, "If you make something idiot-proof, the world will create a better idiot."

For lots more information on Murphy's Law, including related articles and links, check out the next page.


Murphy’s Law FAQ

What is Murphy's Law?
Murphy’s Law is the belief that anything that can go wrong will go wrong. It is a simple statement that reflects life’s truth in the form of an epigram.
Is Murphy's Law true?
Murphy’s Law is neither proven nor disproven. It’s really just a satirical statement with only qualitative evidence in support of it.
What is the opposite of Murphy’s Law?
It wasn’t very difficult for Richard Zeckhauser to come up with the opposite of Murphy’s Law, known as Yhprum’s Law (Murphy spelled backwards). It says “everything that can work, will work”.
Does Murphy’s Law predict something bad will happen?
No, it only claims that whatever is destined to happen, be it good or bad, will eventually happen. It is not a prediction that something bad will happen or that a person can prevent something from happening.
Can you avoid Murphy’s Law?
Generally speaking, Murphy’s Law simply defines the natural fact that what is to occur, will occur. While it can’t be avoided, you can always prepare for the worst.

Lots More Information

Related HowStufWorks Articles

More Great Links

  • Hecht, Jeff. "Murphy's Law honoured - 50 years late." New Scientist. October 3, 2003.
  • Pel, Joel. "The Murphy's Law Equation." The Science Creative Quarterly. September 07-April 08.
  • Spark, Nick T. "Why Everything You Know About Murphy's Law Is Wrong." Improbable Research.
  • "Murphy's Law."
  • "Murphy's Law." Socyberty.
  • "Murphy's Law."
  • "Murphy's Laws and Corollaries."
  • "Murphy's Laws Origin."