Editing Entasis (section)

==Origin in Greek columns==
[[Image:PaestumBasilika.jpg|thumb| Entasis in columns at the [[Paestum#Historic buildings|first Hera temple at Paestum]], erroneously called a 'basilica' by eighteenth century authors]]

No record of the rationale for using entasis in columns by Classical builders has yet been discovered.{{cn|date=August 2023}}. As a result, there has been extensive conjecture over its purpose.

An early view, often articulated and still widespread, espoused by [[Hero of Alexandria]], is that entasis corrects the [[optical illusion]] of concavity in the columns that the fallible [[human eye]] would create if the correction were not made.<ref>[[Hero of Alexandria]], ''Horoi ton geometrias onomaton'', 135, 14: "Thus, since a cylindrical column would, when looked at, seem irregularly narrower in the middle, he makes this part of it wider" (translation given by Ralph Hancock, The Department of Greek and Latin at The Ohio State University) [http://omega.cohums.ohio-state.edu/mailing_lists/CLA-L/2000/11/0299.php] {{Webarchive|url=https://web.archive.org/web/20071107104242/http://omega.cohums.ohio-state.edu/mailing_lists/CLA-L/2000/11/0299.php|date=2007-11-07}}</ref> However, modern psychological research suggests that people do not actually experience any illusion that could be compensated by this design.<ref>{{Cite journal |last=Thompson |first=Peter |last2=Papadopoulou |first2=Georgia |last3=Vassiliou |first3=Eleni |date=2007 |title=The origins of entasis: illusion, aesthetics or engineering? |url=https://pubmed.ncbi.nlm.nih.gov/18073045/ |journal=Spatial Vision |volume=20 |issue=6 |pages=531–543 |doi=10.1163/156856807782758359 |issn=0169-1015 |pmid=18073045}}</ref> {{external media | width = 210px | float = right | video1 =[http://smarthistory.khanacademy.org/ancient-greek-temples-at-paestum-italy.html smARThistory – Ancient Greek Temples at Paestum, Italy]<ref name="smarth">{{cite web | title =Ancient Greek Temples at Paestum, Italy | publisher =smARThistory at Khan Academy | url =http://smarthistory.khanacademy.org/ancient-greek-temples-at-paestum-italy.html | access-date =December 18, 2012 | archive-date =October 6, 2014 | archive-url =https://web.archive.org/web/20141006214650/http://smarthistory.khanacademy.org/ancient-greek-temples-at-paestum-italy.html | url-status =dead }}</ref> }}

Some descriptions of entasis<ref>''entasis'', article by Anthony Rich, Jun. B.A. of Caius College, Cambridge, on p. 461 of William Smith, D.C.L., LL.D.: ''A Dictionary of Greek and Roman Antiquities'', John Murray, London, 1875. [https://penelope.uchicago.edu/Thayer/E/Roman/Texts/secondary/SMIGRA*/Entasis.html]</ref> state simply that the technique was an enhancement applied to the more primitive conical columns to make them appear more substantial. Other descriptions argue that the technique emphasizes the substantiality of, not the columns, but rather, of some other part or of the building while being viewed as a whole. [[Yale University|Yale]] architectural historian [[Vincent Scully]] argues that entasis emphasizes the weight of the roof of a building by making the building columns appear to bulge under the pressure distributed among them. Danish architect Steen Eiler Rasmussen believed that the effect represented strength by imitating the swelling of a strained muscle,<ref>Steen Eiler Rasmussen, ''Experiencing Architecture'', The [[MIT Press]], 1959, p. 37.</ref> a theory that accords well with the etymology of the word, from the Greek meaning "to strain".<ref>"entasis", [[Oxford English Dictionary]], Second Edition, 1989</ref>

It also has been argued that a "stunted cycloid" column that bulges in the middle is stronger structurally than is a column whose diameter changes according to a linear progression, therefore, having a sound engineering purpose. Because their discussion of the application of the principle has never been discovered, it is unknown, however, whether the early Greeks knew this.<ref>Peter Thompson et al., "Entasis: architectural illusion compensation, aesthetic preference or engineering necessity?", Journal of Vision, Volume 7, Number 9, ISSN 1534-7362 [http://www.journalofvision.org/7/9/355/] – abstract argues against traditional explanations for entasis and mentions possible engineering reasons</ref>