Editing Systems thinking (section)

==History==
{{Main|Systems theory#History}}

===Ptolemaic system versus the Copernican system===
The term ''[[#System|system]]'' is [[polysemy|polysemic]]: [[Robert Hooke]] (1674) used it in multiple senses, in his System of the World,<ref name="hooke1674" />{{rp|p.24}} but also in the sense of the [[Ptolemaic system]] versus the [[Copernican heliocentrism|Copernican system]]<ref name="marchal" />{{rp|450}} of the relation of the planets to the fixed stars<ref name="voisey">Jon Voisey ''Universe Today''  [https://www.universetoday.com/159885/the-historic-discussion-of-ptolemys-star-catalog/ (14 Oct 2022) Scholarly History of Ptolemy’s Star Catalog Index]</ref> which are cataloged in [[Hipparchus star catalog|Hipparchus]]' and [[Almagest|Ptolemy's Star catalog]].<ref>Jessica Lightfoot ''Greek, Roman, and Byzantine Studies'' '''57''' (2017) 935–9672017  [https://www.scribd.com/document/397984078/Hipparchus-Commentary-on-Aratus-and-Eudoxus-Introduction-pdf Hipparchus Commentary On Aratus and Eudoxus ]</ref> Hooke's claim was answered in magisterial detail by Newton's (1687) ''[[Philosophiæ Naturalis Principia Mathematica]]'', Book three, ''The System of the World''<ref name="systemateMundi">Newton, Isaac (1687) ''[[Philosophiæ Naturalis Principia Mathematica]]''</ref>{{rp|Book three}} (that is, ''the system of the world'' is a [[physical system]]).<ref name="hooke1674">Hooke, Robert [https://echo.mpiwg-berlin.mpg.de/ECHOdocuView?url=/mpiwg/online/permanent/library/XXTBUC3U/pageimg&pn=25&mode=imagepath (1674)  An attempt to prove the motion of the earth from observations ]</ref>

Newton's approach, using [[dynamical system]]s continues to this day.<ref name="marchal">{{cite journal | last=Marchal | first=J. H. | title=On the Concept of a System | journal=Philosophy of Science | publisher=[Cambridge University Press, The University of Chicago Press, Philosophy of Science Association] | volume=42 | issue=4 | year=1975 | issn=0031-8248 | jstor=187223 | pages=448–468 | doi=10.1086/288663 | url=http://www.jstor.org/stable/187223 | access-date=2024-05-31| url-access=subscription }} as reprinted in Gerald Midgely (ed.) (2002) ''Systems thinking'' vol '''One'''</ref> In brief, Newton's equations (a [[system of equations]]) have methods for [[equation solving|their solution]].

===Feedback control systems===
[[File:Ideal feedback model.svg|thumb|left|upright=1.5|System output can be controlled with [[feedback]].]]
By 1824, the [[Carnot cycle]] presented an engineering challenge, which was how to maintain the operating temperatures of the hot and cold working fluids of the [[physical plant]].<ref name="carnot1824">Sadi Carnot (1824) [[Reflections on the Motive Power of Fire]]</ref> In 1868, [[James Clerk Maxwell]] presented a framework for, and a limited solution to, the problem of controlling the rotational speed of a physical plant.<ref name="jcmaxwell1868">James Clerk Maxwell [[:File:On Governors.pdf| (1868) On Governors]] 12 pages</ref> Maxwell's solution echoed [[James Watt|James Watt's]] [[:File:SteamEngine_Boulton&Watt_1784.png| (1784) centrifugal moderator (denoted as element '''Q''')]] for maintaining (but not enforcing) the constant speed of a physical plant (that is, ''Q'' represents a moderator, but not a governor, by Maxwell's definition).<ref name="mayr1971">Otto Mayr
 [https://www.jstor.org/stable/229816 (1971) Maxwell and the Origins of Cybernetics] ''Isis'', Vol. '''62''', No. 4 (Winter, 1971), pp. 424-444 (21 pages)</ref>{{efn|name=stabilityOfSolution|1=A solution to the equations for a dynamical system can be afflicted by instability or oscillation.<ref name="sepulchre">The Royal Society of Edinburgh [https://www.youtube.com/watch?v=U8MFOoa61k4&t=150s (2016) Celebrating Maxwell's Genius and Legacy: Prof Rodolphe Sepulchre]</ref>{{rp|7:33}} The Governor: A corrective action against error can solve the dynamical equation by integrating the error.<ref name="sepulchre" />{{rp|29:44}}<ref name="ÅströmMurray">Karl Johan Åström and Richard M. Murray (2021) [https://press.princeton.edu/books/hardcover/9780691193984/feedback-systems Feedback Systems: An Introduction for Scientists and Engineers, Second Edition]</ref> }}

Maxwell's approach, which linearized the equations of motion of the system, produced a tractable method of solution.<ref name="mayr1971" />{{rp|428–429}} [[Norbert Wiener]] identified this approach as an influence on his studies of [[cybernetics]]{{efn|name=seeSystemScience |1="cybernetics: ''see system science.''";<ref name="ieee1972" />{{rp|135}} "system science: —the systematized knowledge of [[#System|system]]s"<ref name="ieee1972" />{{rp|583}} }} during [[World War II]]<ref name="mayr1971" /> and Wiener even proposed treating some [[#subsystem|subsystem]]s under investigation as [[#black box|black box]]es.<ref name="ontologyOfTheEnemy">Peter Galison [https://www.jstor.org/stable/1343893 (1994) The Ontology of the Enemy: Norbert Wiener and the Cybernetic Vision] ''Critical Inquiry'', Vol. '''21''', No. 1 (Autumn, 1994), pp. 228–266 (39 pages) ''JSTOR''</ref>{{rp|242}} Methods for solutions of the systems of equations then become the subject of study, as in [[feedback control system]]s, in [[stability theory]], in [[constraint satisfaction problem]]s, the [[unification algorithm]], [[Hindley–Milner type system|type inference]], and so forth.

===Applications===
:"So, how do we change the [[system dynamics|structure of systems]] to produce more of what we want and less of that which is undesirable? ... MIT’s [[Jay Forrester]] likes to say that the average manager can ... guess with great accuracy where to look for leverage points—places in the system where a small change could lead to a large shift in behavior".<ref name="meadows2008">[[Donella Meadows]], (2008) ''[[Thinking In Systems: A Primer]]''</ref>{{rp|146}}— [[Donella Meadows]], (2008) ''[[Thinking In Systems: A Primer]]'' p.145 {{efn|name=overview|1= Donella Meadows, ''Thinking In Systems: A Primer''<ref name="meadows2008"/><ref name="meadows1977">Donella H. Meadows [https://www.youtube.com/watch?v=XL_lOoomRTA (1977) A Philosophical Look at System Dynamics] 53:18</ref> Overview, in video clips: Chapter 1<ref name="ah1">Ashley Hodgson [https://www.youtube.com/watch?v=XBFpasY2Gd8 Thinking in Systems, Key Ideas (Ch. 1)]</ref> Chapter 2, part 1<ref name="ah2a">Ashley Hodgson [https://www.youtube.com/watch?v=xJLm5uq_QV8&t=37s Thinking in Systems, Ch. 2: Types of System Dynamics 2a]</ref> Chapter 2, part 2<ref name="ah2b">Ashley Hodgson [https://www.youtube.com/watch?v=gwUC7LlqAjI Thinking in Systems, Ch. 2, Part 2: Limiting Factors in Systems 2b]</ref> Chapter 3<ref name="ah3">Ashley Hodgson [https://www.youtube.com/watch?v=2qOc_0DMqaA Thinking in Systems, Ch. 3: Resilience, Self-Organization and Hierarchy 3]</ref> Chapter 4<ref name="ah4">Ashley Hodgson [https://www.youtube.com/watch?v=oHvtERyYvJU Thinking in Systems, Ch. 4: Why Systems Surprise Us 4]</ref> Chapter 5<ref name="ah5">Ashley Hodgson [https://www.youtube.com/watch?v=BYSFvq8sr7A Thinking in Systems, Ch. 5: System Traps 5]</ref> Chapter 6<ref name="ah6">Ashley Hodgson [https://www.youtube.com/watch?v=9qL4KxqbrFM Thinking in Systems, Ch. 6: Leverage Points in Systems 6]</ref> Chapter 7<ref name="ah7">Ashley Hodgson [https://www.youtube.com/watch?v=q8QYU2JL8no Thinking in Systems, Ch. 7: Living with Systems 7]</ref> <!--ref name= > [ ]</ref-->}}