->''"Marty, we already agreed that having information about the future can be extremely dangerous! Even if your intentions are good, it can backfire drastically!"''
-->-- '''Dr. Emmett Brown''', ''Film/BackToTheFuture''

This is Finagle's Law:

''The perversity of the universe always tends toward a maximum.''

Sometimes called "Finagle's Law of Dynamic Negatives." [[LaymansTerms A simplified version]], often called Murphy's law, is this:

''Anything that can go wrong, '''will''' go wrong.''[[note]]And in the most inconvenient way possible.[[/note]]

There is another related Murphy's Law -- "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." In layman's terms, that means that if someone plugs in a toaster [[ReversePolarity backwards]] and it fries itself, the problem isn't just that some idiot plugged it in backward, but that it was able to be plugged in backwards in the first place. ''Someone's'' going to try and mess it up [[HanlonsRazor (or mess it up without trying)]].

The name "Finagle's Law" was coined in order to distinguish it from Murphy's. The term was popularized by SF writer Creator/LarryNiven. More on Finagle's Law can be found in the [[http://catb.org/~esr/jargon/html/F/Finagles-Law.html Hacker's Jargon File]]. (The concept can sometimes also be used seriously in certain real-life situations. For example in computer programming this is the driving principle behind so-called [[http://en.wikipedia.org/wiki/Defensive_programming defensive programming]].)

The true Finagle's Law is stronger than "anything that can go wrong ''will'' go wrong". It allows for things going well, as the universe is merely lulling you into a false sense of security before proceeding to screw things up for you. It also allows for things that can't go wrong going wrong; some cases of this count as GoneHorriblyRight.

Finagle's Law in storyland owes its existence more or less entirely to the RuleOfDrama, and is especially common in {{Crapsack World}}s where things that do go wrong tend to go wrong in the worst possible way. Can also happen to Real Life in a limited pace, as entropy indicates. One is generally left with the impression that the universe is controlled by [[GodIsEvil a malevolent (or at least mischievous) deity]] -- some might say author -- who is obsessed with making your life as difficult and humiliating as possible.

At some level, this underwrites a huge percentage of TV plots, especially in comedy. The odds of something happening as the plot unfolds depends not on its actual likelihood, but on its potential for disaster.

The term was also played to both seriousness and hilarity in Christopher Stasheff's "The Warlock Unlocked" and "St. Vidicon to the Rescue" which essentially spotlight an ''entire order'' of Catholic monk-engineers dedicated to the philosophy of Murphy's and Finagle's Laws, with the Imp of the Perverse thrown in for good measure.

Compare with [[RuleOfCool the Rule of Cool]] in terms of how events may ignore the laws of physics, biology, good manners and others to a proportionate degree that the events in question serve the plot or otherwise catch the attention of the reader/viewer.

See also HanlonsRazor. No relation to [[Film/TheHorrorOfPartyBeach Fingal's Quarry]]; nor to Webcomic/MurphysLaw, a webcomic. For other uses of Murphy's Law, see [[MurphysLaw the disambiguation page]].

Expressions of Finagle's Law include:

* ASimplePlan
* ButterflyOfDoom
* CapsLockNumLockMissilesLock
* ConsolationBackfire
* CosmicPlaything
* DisasterDominoes
* DestructiveSaviour
* DeusAngstMachina when taken UpToEleven
* EmptyQuiver
* EverythingTryingToKillYou in videogames
* FailsafeFailure
* FailureIsTheOnlyOption
* FirstDayFromHell
* FromBadToWorse
* TheFunInFuneral
* GaveUpTooSoon
* HardToLightFire
* InstantlyProvenWrong
* InverseLawOfUtilityAndLethality
* LawOfDisproportionateResponse
* MagnumOpusDissonance
* MaternityCrisis
* MisaimedFandom
* MistakenForIndex
* MistimedRevival
* MurphysBed
* MurphysBullet
* MyCarHatesMe
* NotInFrontOfTheParrot
* NotMyDriver
* NotQuiteTheRightThing
* NothingCanStopUsNow
* OutOfTheFryingPan
* OutWithABang
* PhlebotinumBreakdown
* PointyHairedBoss
* PricelessMingVase
** AshesToCrashes
** DoomedNewClothes
** WatchThePaintJob
*** ThePreciousPreciousCar
* RandomNumberGod
* {{Retirony}}
* SpringtimeForHitler
* StatusQuoGameShow
* TaxmanTakesTheWinnings
* TemptingFate
* UnfoldingPlanMontage
* UnspokenPlanGuarantee
* UselessSuperpowers
* VengefulVendingMachine
* WhatCouldPossiblyGoWrong
* WheresTheKaboom
* YankTheDogsChain
* YouCantThwartStageOne
* YourPrincessIsInAnotherCastle