Murphy's Law
    n 1: humorous axiom stating that anything that can go wrong will
         go wrong [syn: Murphy's Law, Sod's Law]

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 magic smoke).

    Edward A. Murphy, Jr. was one of McDonnell-Douglas's test 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 in a replacement set the
    wrong way around. Murphy then made the original form of his pronouncement,
    which the test subject (Major John Paul Stapp) mis-quoted (apparently in
    the more general form ?Whatever can go wrong, will go wrong)? at a news
    conference a few days later.

    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
    more correctly referred to as Finagle's Law. The memetic drift apparent
    in these mutants clearly demonstrates Murphy's Law acting on itself!

Murphy's Law

    (Or "Sod's Law") 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
   magic smoke).

   Edward A. Murphy, Jr. was one of the engineers on the
   rocket-sled experiments that were done by the US 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 later.

   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 Finagle's Law.  The memetic drift
   apparent in these mutants clearly demonstrates Murphy's Law
   acting on itself!

   [Jargon File]

   (1998-02-14)