Rule of thumb
A rule of thumb is a principle with broad application that is not intended to be strictly accurate or reliable for every situation. It is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination. It is based not on theory but on practical experience. Compare this to heuristic, a similar concept used in mathematical discourse, psychology, and computer science, particularly in algorithm design.
Origin of the phrase
The exact origin of the phrase is uncertain. The earliest known citation comes from J. Durham’s Heaven upon Earth, 1685, ii. 217: "Many profest Christians are like to foolish builders, who build by guess, and by rule of thumb."[a]
Sir William Hope wrote in his The Compleat Fencing Master, 1692: "What he doth, he doth by rule of Thumb, and not by Art." James Kelly's The Complete Collection of Scottish Proverbs, 1721, pg 257, includes: "No Rule so good as Rule of Thumb, if it hit."
Thumb as measurement device
The term is thought to originate with carpenters who used the length of the tip of their thumbs (i.e., inches) rather than rulers for measuring things, cementing its modern use as an imprecise yet reliable and convenient standard.[b][c]
Reference to spousal abuse
It is often claimed that the term rule of thumb is derived from a law that limited the maximum thickness of a stick with which it was permissible for a man to beat his wife. English common law before the reign of Charles II permitted a man to give his wife "moderate correction", but no "rule of thumb" (whether called by this name or not) has ever been the law in England.[d]
Belief in the existence of a "rule of thumb" to excuse spousal abuse can be traced as far back as 1782, the year that James Gillray published his satirical cartoon Judge Thumb. The cartoon lambastes English judge Sir Francis Buller for allegedly ruling that a man may legally beat his wife provided that he used a stick no thicker than his thumb, although there is no other written record of Buller making such a pronouncement.
In the United States, where the "rule of thumb" was mentioned in case law, it was usually to reject it as a legal standard. Legal decisions in Mississippi (1824) and North Carolina (1868 and 1874) make reference to—and reject—an unnamed "old doctrine" or "ancient law" by which a man was allowed to beat his wife with a stick no wider than his thumb.[e][f] In 1976, women's rights activist Del Martin used the phrase "rule of thumb" as a metaphorical reference to describe such a doctrine. She was interpreted by many as claiming the doctrine as a direct origin of the phrase, and the connection gained currency in 1982, when the U.S. Commission on Civil Rights issued a report on wife abuse titled "Under the Rule of Thumb".
- Right-hand rule
- Oersted's law
- Rule of 72
- Pattern language
- Heuristic argument
- Common sense
- Back-of-the-envelope calculation
- The phrase also exists in other languages, for example Italian Regola del pollice, Swedish tumregel, Norwegian and Danish tommelfingerregel, sometimes in the variant "rule of fist", for example Finnish nyrkkisääntö, Estonian rusikareegel, German Faustregel and Pi mal Daumen, Hungarian ökölszabály or Dutch vuistregel, as well as in Turkish parmak hesabı, and in Hebrew כלל אצבע (rule of finger) and in Persian قاعده سرانگشتی, which is translated as "finger tip's rule".
- This sense of thumb as a unit of measure also appears in Dutch, in which the word for thumb, duim, also means inch.[non-primary source needed]
- The use of a single word or cognate for "inch" and "thumb" is common in many Indo-European languages, for example, French: pouce inch/thumb; Italian: pollice inch/thumb; Spanish: pulgada inch, pulgar thumb; Portuguese: polegada inch, polegar thumb; Swedish: tum inch, tumme thumb; Sanskrit: angulam inch, anguli finger; Slovak: palec, Slovene: palec inch/thumb, Czech: palec inch/thumb. Also in some other languages such as Thai: nîw inch/finger, Hungarian: hüvelyk inch/thumb.[original research?]
- According to Jonathan Fast, "no British law, Common or Parliamentary, ever permitted wife beating under any circumstances".
- In State v. Oliver (North Carolina, 1874), the judge's ruling stated: "We assume that the old doctrine that a husband had the right to whip his wife, provided that he used a switch no larger than his thumb, is not the law in North Carolina."
- The Massachusetts Body of Liberties adopted in 1641 by the Massachusetts Bay colonists states, “Every married woman shall be free from bodily correction or stripes by her husband, unless it be in his own defense from her assault.”
- "rule of thumb, n. and adj.". OED Online. September 2016. Oxford University Press. Retrieved 25 October 2016
- Martin, Gary. "'Rule of thumb' - the meaning and origin of this phrase". Phrasefinder.
- Kelly, James (1721). The Complete Collection of Scottish Proverbs, p. 257.
- Sommers, Christina Hoff (1995). Who stole feminism? : how women have betrayed women (1st Touchstone ed.). New York: Touchstone/Simon & Schuster. ISBN 978-0684801568.[page needed]
- Kramers, Jacob (1974) Kramers Woordenboek Nederlands. Van Goor, the Hauge.
- Freyd, Jennifer; Johnson, JQ (1998). "Commentary: Domestic Violence, Folk Etymologies, & 'Rule of Thumb'". dynamic.uoregon.edu.
- Does "rule of thumb" refer to an old law permitting wife beating?, The Straight Dope, May 12, 2000
- Fast, Jonathan. Beyond Bullying: Breaking the Cycle of Shame, Bullying, and Violence. Oxford University Press. p. 105. ISBN 9780199383665.
- Foyster, Elizabeth (2005). Marital violence : an English family history, 1660-1857 (1st ed.). New York: Cambridge University Press. p. 12. ISBN 0521834511.
There is absolutely no proof that Buller, who became known as 'Judge Thumb', ever made this statement in any formal capacity, and it did not become a legal precedent.
- Calvert, Robert (1974). "Criminal and Civil Liability in Husband-Wife Assaults". In Steinmetz, S.K.; Straus, M.A. Violence in the Family. New York: Harper and Row.
- "The Massachusetts Body of Liberties (1641)". history.hanover.edu. Hanover, Indiana: Hanover College, Department of History.
- Kelly, Henry Ansgar (September 1994). "Rule of Thumb and the Folklaw of the Husband's Stick" (PDF). Journal of Legal Education. 44 (3): 341–365. JSTOR 42893341.
|Look up rule of thumb in Wiktionary, the free dictionary.|
- Rules of Thumb.org: Collection of reader-submitted rules of thumb, compiled by Tom Parker
- North Carolina – Violence women, European Men Profeminist Network: Discussion of spurious legal "rule of thumb"
- Babelite: Multilingual Idioms Dictionary.