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.
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 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!
Finagle's Law n. The generalized or `folk' version of Murphy's Law, fully named "Finagle's Law of Dynamic Negatives" and usually rendered "Anything that can go wrong, will". One variant favored among hackers is "The perversity of the Universe tends towards a maximum" (but see also Hanlon's Razor). The label `Finagle's Law' was popularized by SF author Larry Niven in several stories depicting a frontier culture of asteroid miners; this `Belter' culture professed a religion and/or running joke involving the worship of the dread god Finagle and his mad prophet Murphy.
Hanlon's Razor prov. A corollary of Finagle's Law, similar to Occam's Razor, that reads "Never attribute to malice that which can be adequately explained by stupidity." The derivation of the common title Hanlon's Razor is unknown; a similar epigram has been attributed to William James. Quoted here because it seems to be a particular favorite of hackers, often showing up in sig blocks, fortune cookie files and the login banners of BBS systems and commercial networks. This probably reflects the hacker's daily experience of environments created by well-intentioned but short-sighted people. Compare Sturgeon's Law.
Sturgeon's Law prov. "Ninety percent of everything is crap". Derived from a quote by science fiction author Theodore Sturgeon, who once said, "Sure, 90% of science fiction is crud. That's because 90% of everything is crud." Oddly, when Sturgeon's Law is cited, the final word is almost invariably changed to `crap'. Compare Hanlon's Razor, Ninety-Ninety Rule. Though this maxim originated in SF fandom, most hackers recognize it and are all too aware of its truth.
The Way It Goes Sometimes... Murphy's Laws