Date: Mon, 13 Jan 1997 00:08:07 -0600

From: Dan Goodman dsgood[AT SYMBOL GOES HERE]VISI.COM

Subject: Murphy's Law -- 1949

Murphy's Law

prov. The correct, *original* Murphy's Law reads: "If there are two or

more ways to do something, and one of those ways can result in a

catastrophe, then someone will do it." This is a principle of

defensive design, cited here because it is usually given in mutant

forms less descriptive of the challenges of design for lusers. For

example, you don't make a two-pin plug symmetrical and then label it

`THIS WAY UP'; if it matters which way it is plugged in, then you make

the design asymmetrical (see also the anecdote under [1]magic smoke).

Edward A. Murphy, Jr. was one of the engineers on the rocket-sled

experiments that were done by the U.S. Air Force in 1949 to test human

acceleration tolerances (USAF project MX981). One experiment involved

a set of 16 accelerometers mounted to different parts of the subject's

body. There were two ways each sensor could be glued to its mount, and

somebody methodically installed all 16 the wrong way around. Murphy

then made the original form of his pronouncement, which the test

subject (Major John Paul Stapp) quoted at a news conference a few days


Within months `Murphy's Law' had spread to various technical cultures

connected to aerospace engineering. Before too many years had gone by

variants had passed into the popular imagination, changing as they

went. Most of these are variants on "Anything that can go wrong,

will"; this is sometimes referred to as [2]Finagle's Law. The memetic

drift apparent in these mutants clearly demonstrates Murphy's Law's_Law.html