Murphy’s Law, Occam’s Razor

Ed, an aerospace engineer, and Bill, a 14th-century philosopher, walk into your workshop. If you’re smart, you’ll let them stay and hear them out. They’ll support you through your entire project, offering valuable advice while you fly and maintain the aircraft. And they won’t drink your beer. (Well, Bill might.) All you have to do to benefit from their presence is heed their repetitious words of wisdom.

Edward Murphy

Edward Murphy was an aerospace engineer on the MX-981 deceleration tests at Muroc Army Air Field (now Edwards Air Force Base). Those tests used rocket-powered sleds and water brakes to measure the effects of rapid deceleration on humans. The first tests used dummies. Then John Paul Stapp volunteered to be a dummy. I’m stating facts, not passing judgment.

Murphy had the idea to attach strain gauges to record the forces Stapp experienced during deceleration. The first test failed to deliver data because Murphy’s assistant incorrectly attached the sensor wires. Murphy fumed, “If there’s more than one way to do a job, and one of those ways will result in disaster, then he will do it that way.” His words were distilled to, “If something can go wrong, it will.” Murphy’s Law was born.

Murphy is, in my opinion, misunderstood. His words should not be considered a pessimistic statement of inevitability, to be uttered after a failure. They should be a rallying cry that encourages closer attention to detail. We invoke Murphy’s words after a failure when we should embrace them as a precaution. For instance, before drilling holes for fasteners, make sure you have the correct drill bit. Discovering you used a #21 bit instead of a #30 bit after drilling two hundred rivet holes is your failure to confirm—not Murphy stepping in to muck things up. Murphy warned it could happen. You didn’t listen.

William of Ockham

William of Ockham was a medieval philosopher who couldn’t imagine airplanes being built in garages. For that matter, he couldn’t imagine airplanes. But he knew a thing or two about problem-solving.

Ockham didn’t invent the idea of seeking the most logical answer to a problem, but he was an ardent practitioner of it. He applied it to his practice, which was nothing less than explaining miracles. (And you thought fitting a canopy was difficult?) He is credited with saying, “Entities should not be multiplied needlessly.” That was William’s Old World way of saying, “The simplest answer is most often correct.” It’s known as Occam’s Razor. Thankfully, like the less-than-elegant outburst that gave birth to Murphy’s Law, Occam’s Razor is distilled from what Ockham most likely said: Entia non sunt multiplicanda praeter necessitatem. He may have been drinking.

The term “razor” means exactly what you think it does—to shave away. Focus on the most likely causes of a problem by shaving away, or eliminating, the unlikely scenarios. For instance, if an engine stumbles to a stop, it is far more likely to have run out of gas than to have had two independent ignition systems fail within moments of each other.

Team Players

Murphy and Ockham are valuable team members whether you are building, flying, or maintaining an aircraft (or a British sports car). Murphy, whose law is loosely rooted in aviation, reminds us everything must be assured, even the most mundane details. While Murphy encourages us to check everything, Ockham reminds us that if something does go wrong, it is usually one thing that failed—and usually the most likely thing.

If an engine doesn’t start after a fuel stop, it is more likely you (or, ahem, me in this particular example) failed to turn the fuel valve on than that the engine broke. Murphy anticipated this could happen when I didn’t use my checklist. Ockham, lurking in the shadows, knew I had failed to turn on either the fuel valve or the ignition switch. When we ignore Murphy, our first line of defense against a problem, we should lean on Ockham’s guidance. Ignore Ockham, and frustrations rise.

Let’s consider the condition inspection. Unlike repair work, which targets a known defect, condition inspections are meant to find and prevent problems that may be developing. Ironically, they also introduce a heightened possibility of disabling an aircraft. They can disturb the happy existence of functioning parts and sound connections.

Example: You replace the functioning but aging distributor caps on a Jabiru engine. Your proactive approach is applauded. Murphy, however, rightfully reminds you there may be pitfalls. You may damage or disturb the rotor, loosen or incorrectly replace the spark plug wires, or install a new-but-defective distributor cap. If the freshly tuned engine stumbles on start-up, Murphy gets blamed with the exclamation, “Now what?! I swear, if it can go wrong, it does!”

Your thoughts may go to stuck valves, incorrect timing, or blindly making carburetor adjustments. Because humans are good at worrying, your thoughts may stray as far as a broken crank and an expensive engine rebuild. Having ignored Murphy, who tried to warn you to make sure the spark plug wires were reinstalled correctly, you should embrace Ockham. He knows nothing about airplanes but plenty about problem-solving. He’ll tell you it is something you touched, not something you didn’t. He’ll assure you nothing broke of its own free will while you were trying to make things better.

Embrace Bill and Ed as partners in your aviation adventure (and all other parts of your life). Their wise words can serve us well—though I don’t recommend the Latin version of Occam’s Razor as a motivational poster for your workshop.