Murphy's Law

At Edwards Air Force Base in California, a team led by Dr. John Stapp was testing the limits of human tolerance for rapid deceleration. They strapped volunteers—often Stapp himself—into a rocket sled and fired them down a track at extreme speeds before slamming on hydraulic brakes. The purpose was to understand what pilots might survive in crashes and ejections. Stapp personally endured forces that would kill most people, suffering cracked ribs, broken wrists, and temporarily blinding himself by bursting blood vessels in his eyes.

Murphy, an engineer from Wright Air Development Center, was brought in to improve the accuracy of the measurements. He designed a harness with sixteen electronic strain gauges that would record the g-forces acting on different parts of the subject's body. Each gauge could be installed in one of two orientations, one correct and one backwards.

When the experiment ran, every single sensor returned a reading of zero. Somebody had installed all sixteen gauges the wrong way around.

Murphy was not pleased. According to accounts from those present, he blamed the technician who had wired the sensors, saying something to the effect of: "If there's more than one way to do a job, and one of those ways will result in disaster, then somebody will do it that way." The exact phrasing varies by source, but the sentiment was clear.

What happened next gave Murphy immortality. A few weeks later, Stapp was interviewed by reporters asking how his team had avoided serious injuries during such dangerous experiments. Stapp explained that they operated under Murphy's Law: if anything can go wrong, it will. The idea was that anticipating failure helped them prevent it.

The phrase spread through aerospace engineering and then into the wider world. Murphy spent the rest of his life getting credit for a principle that humans have understood, in one form or another, for centuries.