Editing Inertia (section)

=== Early understanding of inertial motion ===
<!-->[[Joseph Needham]]<-->Professor [[John H. Lienhard]] points out the [[Mozi (book)|Mozi]] – based on a Chinese text from the [[Warring States period]] (475–221 BCE) – as having given the first description of inertia.<ref>{{cite web|url=http://www.uh.edu/engines/epi2080.htm|title=No. 2080 The Survival of Invention|website=www.uh.edu}}</ref> Before the European [[Renaissance]], the prevailing theory of motion in [[western philosophy]] was that of [[Aristotle]] (384–322 BCE). On the surface of the Earth, the inertia property of physical objects is often masked by [[gravity]] and the effects of [[friction]] and [[Drag (physics)|air resistance]], both of which tend to decrease the speed of moving objects (commonly to the point of rest). This misled the philosopher [[Aristotle]] to believe that objects would move only as long as force was applied to them.<ref>{{Citation| last =  Aristotle: Minor works| title = ''Mechanical Problems'' (''Mechanica'')| publisher =  Loeb Classical Library Cambridge (Mass.) and London| year = 1936| location = [[University of Chicago Library]]| url = https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Aristotle/Mechanica*.html<!-->#:~:text=stops%20when%20the%20force<--> | page= 407|quote=...it [a body] stops when the force which is pushing the travelling object has no longer power to push it along...}}</ref><ref>Pages 2 to 4, Section 1.1, [https://books.google.com/books?id=_ZNxDwAAQBAJ&q=skating "Skating"], Chapter 1, "Things that Move", Louis Bloomfield, Professor of Physics at the [[University of Virginia]], ''How Everything Works: Making Physics Out of the Ordinary'', John Wiley & Sons (2007), hardcover, {{ISBN|978-0-471-74817-5}}</ref> Aristotle said that all moving objects (on Earth) eventually come to rest unless an external power (force) continued to move them.<ref>{{cite book |title=Aristotle's Science of Matter and Motion |first1=Christopher |last1=Byrne |publisher=University of Toronto Press |year=2018 |isbn=978-1-4875-0396-3 |page=21 |url=https://books.google.com/books?id=kYllDwAAQBAJ}} [https://books.google.com/books?id=kYllDwAAQBAJ&pg=PA21 Extract of page 21]</ref> Aristotle explained the continued motion of projectiles, after being separated from their projector, as an (itself unexplained) action of the surrounding medium continuing to move the projectile.<ref>Aristotle, ''Physics'', 8.10, 267a1–21; <!-->[http://etext.library.adelaide.edu.au/a/aristotle/a8ph/]<--> [http://www.documentacatholicaomnia.eu/03d/-384_-322,_Aristoteles,_02_Physics,_EN.pdf Aristotle, ''Physics'', trans. by R. P. Hardie and R. K. Gaye, <small>'projectile'</small>] {{webarchive|url=https://web.archive.org/web/20070129111002/http://etext.library.adelaide.edu.au/a/aristotle/a8ph/ |date=2007-01-29 }}.</ref>

Despite its general acceptance, Aristotle's concept of motion<ref name=Darling_2006>{{Cite book | last = Darling  | first = David  | title = Gravity's arc: the story of gravity, from Aristotle to Einstein and beyond  | publisher = John Wiley and Sons  | date = 2006  | pages =  [https://archive.org/details/gravitysarcstory00darl/page/17 17], 50 | url = https://archive.org/details/gravitysarcstory00darl | url-access = registration  | isbn = 978-0-471-71989-2}}</ref> was disputed on several occasions by notable philosophers over nearly two [[millennia]]. For example, [[Lucretius]] (following, presumably, [[Epicurus]]) stated that the "default state" of the matter was motion, not stasis (stagnation).<ref>Lucretius, ''On the Nature of Things'' (London: Penguin, 1988), [https://upload.wikimedia.org/wikipedia/commons/2/27/Lucretius_On_the_nature_of_things_%28IA_lucretiusonnatu00lucr%29.pdf pp. 80–85, <small>'all must move'</small>]</ref> In the 6th century, [[John Philoponus]] criticized the inconsistency between Aristotle's discussion of projectiles, where the medium keeps projectiles going, and his discussion of the void, where the medium would hinder a body's motion. Philoponus proposed that motion was not maintained by the action of a surrounding medium, but by some property imparted to the object when it was set in motion. Although this was not the modern concept of inertia, for there was still the need for a power to keep a body in motion, it proved a fundamental step in that direction.<ref>{{cite book|last=Sorabji|first=Richard|title=Matter, space and motion : theories in antiquity and their sequel|url=https://books.google.com/books?id=TN_aAAAAMAAJ&q=inertia|date=1988|publisher=Cornell University Press|location=Ithaca, N.Y.|isbn=978-0801421945|edition=1st |pages=227–228}}</ref><ref>{{cite encyclopedia |url=http://plato.stanford.edu/entries/philoponus/#2.1 |encyclopedia=Stanford Encyclopedia of Philosophy |title=John Philoponus |date=8 June 2007 |access-date=26 July 2012}}</ref> This view was strongly opposed by [[Averroes]] and by many [[Scholasticism|scholastic]] philosophers who supported Aristotle. However, this view did not go unchallenged in the [[Islamic Golden Age|Islamic world]], where Philoponus had several supporters who further developed his ideas.

In the 11th century, Persian [[polymath]] [[Ibn Sina]] (Avicenna) claimed that a projectile in a vacuum would not stop unless acted upon.<ref>Espinoza, Fernando. "An Analysis of the Historical Development of Ideas About Motion and its Implications for Teaching". Physics Education. Vol. 40(2). [https://profilpelajar.com/article/History_of_classical_mechanics#:~:text=ibn Medieval thought.]</ref>