Etiology 10055 225296440 2008-07-12T23:12:21Z SmackBot 433328 Date the maintenance tags or general fixes {{otheruses4|the medical term|the pro-science blog| Aetiology (blog)}} '''Etiology''' (alternately '''aetiology''', '''aitiology''') is the study of [[Causality|causation]]. Derived from the [[Ancient Greek|Greek]] {{lang|grc|αιτιολογία}}, "giving a reason for" ({{lang|grc|αἰτία}} "cause" + {{lang|grc|[[-logy|-λογία]]}}).<ref>{{cite book | title = Aetiology | work = Oxford English Dictionary | edition = 2nd ed. | year = 2002 | publisher = Oxford University Press | isbn = 0195219422}}</ref> The word is most commonly used in medical and philosophical theories, where it is used to refer to the study of why things occur, or even the reasons behind the way that things act, and is used in [[philosophy]], [[physics]], [[psychology]], [[government]], [[medicine]], and [[biology]] in reference to the causes of various phenomena. An '''etiological myth''' is a [[mythology|myth]] intended to explain a name or create a mythic history for a place or family. == Medicine == In medicine in particular, the term refers to the causes of [[disease]]s or [[pathology|pathologies]].<ref>{{cite web | author = Greene J | url = http://www.widesmiles.org/cleftlinks/WS-364.html | title = The three C's of aetiology | work = Wide Smiles | year = 1996 | accessdate = 2007-08-20}} Discusses several examples of the medical usage of the term ''aetiology'' in the context of [[cleft lip]]s and explains methods used to study causation.</ref> The study of etiology in medicine dates back to [[Islamic medicine|Muslim physicians]] in the [[Islamic Golden Age|medieval Islamic world]], who discovered the contagious nature of [[infectious disease]]s such as [[scabies]], [[tuberculosis]] and [[sexually transmitted disease]]. In ''[[The Canon of Medicine]]'', [[Avicenna]] discovered that they are caused by contagion that can spread through bodily contact or through [[water]] and [[soil]].<ref name=Sarton>[[George Sarton]], ''Introduction to the History of Science''.<br>([[cf.]] Dr. A. Zahoor and Dr. Z. Haq (1997), [http://www.cyberistan.org/islamic/Introl1.html Quotations From Famous Historians of Science], Cyberistan.</ref> He also stated that bodily [[secretion]] is contaminated by foul foreign earthly bodies before being infected.<ref name=Syed>Ibrahim B. Syed, Ph.D. (2002). "[http://www.irfi.org/articles/articles_1_50/islamic_medicine.htm Islamic Medicine: 1000 years ahead of its times]", ''[[The Islamic Medical Association of North America|Journal of the Islamic Medical Association]]'' '''2''', p. 2-9.</ref> [[Ibn Zuhr]] (Avenzoar) was the first physician to provide a scientific etiology for the [[Inflammation| inflammatory diseases]] of the [[ear]], and the first to clearly discuss the causes of [[stridor]].<ref>Prof. Dr. Mostafa Shehata, "The Ear, Nose and Throat in Islamic Medicine", ''Journal of the International Society for the History of Islamic Medicine'', 2003 (1): 2-5 [4].</ref> Through his [[dissection]]s, he proved that the [[List of skin diseases|skin disease]] [[scabies]] was caused by a [[parasite]], a discovery which upset the [[Galen]]ic theory of [[humorism]], and he was able to successfully remove the parasite from a patient's body without any [[purging]] or [[bleeding]].<ref name=Hutchinson>[http://encyclopedia.farlex.com/Islamic+medicine Islamic medicine], ''[[Hutchinson Encyclopedia]]''.</ref> {{Citations missing|date=July 2008}} When the [[Black Death]] [[bubonic plague]] reached [[al-Andalus]] in the 14th century, [[Ibn Khatima]] posited that [[infectious disease]]s are caused by [[microorganism]]s which enter the human body. Another Andalusian physician, [[Ibn al-Khatib]] (1313-1374), wrote a treatise called ''On the Plague'', stating that [[contagion]] can spread through [[garment]]s, [[vessel]]s and [[earring]]s.<ref name=Syed/> Etiological discovery in medicine has a history in [[Robert Koch]]'s demonstration that the tubercle bacillus (''[[Mycobacterium tuberculosis]]'' complex) causes the disease [[tuberculosis]], ''[[Bacillus anthracis]]'' causes [[anthrax]], and ''[[Vibrio cholerae]]'' causes [[cholera]]. This line of thinking and evidence is summarized in [[Koch's postulates]]. But proof of causation in infectious diseases is limited to individual cases that provide experimental evidence of etiology. In epidemiology, several lines of evidence together are required to infer causation. [[Sir Austin Bradford-Hill]] demonstrated a causal relationship between smoking and lung cancer, and summarized the line of reasoning in the [[epidemiological criteria for causation]]. Dr. [[Al Evans]], a US epidemiologist, synthesized his predecessors' ideas in proposing the [[Unified Concept of Causation]]. Further thinking in [[epidemiology]] was required to distinguish [[correlation is not causation|causation from association or statistical correlation]]. Events may occur together simply due to [[chance]], [[bias]] or [[confounding]], instead of one event being caused by the other. It is also important to know which event is the cause. Careful sampling and measurement are more important than sophisticated statistical analysis to determine causation. Experimental evidence, involving interventions (providing or removing the supposed cause), gives the most compelling evidence of etiology. Etiology is sometimes a part of a chain of causation. An etiological agent of disease may require an independent co-factor, and be subject to a promoter (increases expression) to cause disease. An example of all the above, which was recognized late, is that [[peptic ulcer disease]] may be induced by stress, requires the presence of acid secretion in the stomach, and has primary etiology in ''[[Helicobacter pylori]]'' infection. Many chronic diseases of unknown cause may be studied in this framework to explain multiple epidemiological associations or risk factors which may or may not be causally related, and to seek the actual etiology. Some diseases, such as [[diabetes]] or [[hepatitis]], are syndromically defined, by their signs and [[symptom]]s, but include different conditions with different etiologies. Conversely, one etiology, such as [[Epstein-Barr virus]], may in different circumstances produce different diseases, such as [[mononucleosis]], or [[nasopharyngeal carcinoma]], or [[Burkitt's lymphoma]]. == Mythology == An '''etiological myth''' is a [[mythology|myth]] intended to explain the origins of cult practices, natural phenomena, proper names and the like. For example, the name [[Delphi]] and its associated deity, ''[[Apollo|Apollon Delphinios]]'', are explained in the [[Homeric Hymn]] which tells of how Apollo carried [[Crete|Cretans]] over the sea in the shape of a [[dolphin]] (''delphus'') to make them his priests. While Delphi is actually related to the word ''delphus'' ("womb"), many etiological myths are similarly based on [[folk etymology]] (the term "[[Amazons|Amazon]]", for example). In the ''[[Aeneid]]'' (published circa 17 BC), [[Vergil]] claims the descent of [[Augustus Caesar]]'s Julian clan from the hero [[Aeneas]] through his son Ascanius, also called Julus. Other examples of etiological myth come from the Bible, such as the setting of the rainbow in the heavens as a sign of God's [[covenant]] with [[Noah]] (Genesis 9); or the story of [[Lot (Bible)#Lot's wife and the pillar of salt|Lot's wife]] in Genesis 19 (specifically 26), which explains why there are pillars of salt in the area of the [[Dead Sea]].<ref>{{cite book | title = Oxford Annotated Edition, Revised Standard Version of the Bible | year = 1973}}</ref> The story of [[Prometheus]]' sacrifice-trick in [[Hesiod]]'s ''[[Theogony]]'' relates how Prometheus tricked [[Zeus]] into choosing the bones and fat of the first sacrificial animal rather than the meat to justify why, after a sacrifice, the Greeks offered the bones wrapped in fat to the gods while keeping the meat for themselves. ==See also== * [[Eschatology]] * [[Geomythology]] * [[Just-so story]] (comparable to etiological myth) == References == {{reflist}} == External links == {{Wiktionarypar|etiology}} {{Time in philosophy}} [[Category:Causality]] [[Category:Philosophy of science]] [[Category:Pathology]] [[Category:Mythology]] [[Category:Greek loanwords]] [[bg:Етиология]] [[ca:Etiologia]] [[de:Ätiologie]] [[et:Etioloogia]] [[es:Etiología]] [[fr:Étiologie]] [[gl:Etioloxía]] [[it:Eziologia]] [[he:אטיולוגיה]] [[lt:Etiologija]] [[hu:Etiológia]] [[nl:Etiologie]] [[no:Etiologi]] [[nn:Etiologi]] [[pl:Etiologia]] [[pt:Etiologia]] [[ro:Etiologie]] [[ru:Этиология]] [[sk:Etiológia]] [[sr:Етиологија]] [[sh:Etiologija]] [[sv:Etiologi]] [[tr:Etiyoloji]] [[uk:Етіологія]] [[ur:سببیات]] [[zh:原因論]]