Editing No such thing as a free lunch (section)

===Meanings===
;Science
In the sciences, no free lunch means that the universe as a whole is ultimately a [[closed system]]. There is no source of matter, energy, or light that draws resources from something else which will not eventually be exhausted. Therefore, the no free lunch argument may also be applied to natural physical processes in a closed system (either the universe as a whole, or any system that does not receive energy or matter from outside). (See [[Second law of thermodynamics]].) The bio-ecologist [[Barry Commoner]] used this concept as the last of his famous "[[Barry Commoner#Environmental books|Four Laws of Ecology]]".

According to American theoretical physicist and cosmologist [[Alan Guth]] "the universe is the ultimate free lunch", given that in the early stage of its expansion the total amount of energy available to make particles was very large.<ref>{{cite book | last = Hawking| first = Stephen| title = A brief history of time| url = https://archive.org/details/briefhistoryofti00step_1| url-access = registration| publisher = Bantam books| year = 1988| page = [https://archive.org/details/briefhistoryofti00step_1/page/144 144]| isbn = 0553175211}}</ref>

==== Economics ====
In economics, no free lunch demonstrates [[opportunity cost]]. [[N. Gregory Mankiw|Greg Mankiw]] described the concept as follows: "To get one thing that we like, we usually have to give up another thing that we like. Making decisions requires trading off one goal against another."<ref>''Principles of Economics'' (4th edition), p. 4.</ref> The idea that there is no free lunch at the societal level applies only when all resources are being used completely and appropriately – i.e., when [[economic efficiency]] prevails. If not, a 'free lunch' can be had through a more efficient utilization of resources. Or, as [[Fred Brooks]] put it, "You can only get something for nothing if you have previously gotten nothing for something."  If one individual or group gets something at no cost, somebody else ends up paying for it. If there appears to be no direct cost to any single individual, there is a [[social cost]].  Similarly, someone can benefit for "free" from an [[externality]] or from a [[Public good (economics)|public good]], but someone has to pay the cost of producing these benefits. (See [[Free rider problem]] and [[Tragedy of the commons]].)

==== Finance ====
In [[mathematical finance]], the term is also used as an informal synonym for the principle of no-[[arbitrage]]. This principle states that a combination of securities that has the same cash-flows as another security must have the same net price in equilibrium.

==== Statistics ====
In [[statistics]], the term has been used to describe the tradeoffs of statistical learners (e.g., in [[machine learning]]) which are unavoidable according to the [[No free lunch theorem|"No free lunch" theorem]]. That is, any model that claims to offer superior flexibility in analyzing data patterns usually does so at the cost of introducing extra assumptions, or by sacrificing generalizability in important situations.<ref>{{cite arXiv | last1 = Simon | first1 = N. | last2 = Tibshirani | first2 = R. |eprint=1401.7645 |title=Comment on "Detecting Novel Associations In Large Data Sets" by Reshef Et Al, Science Dec 16, 2011 |date=2014 | class = stat.ME }}</ref>

==== Technology ====
No free lunch is sometimes used as a response to claims of the virtues of [[free software]]. Supporters of free software often counter that the use of the term "free" in this context is primarily a reference to a lack of constraint ("libre") rather than a lack of cost ("[[Gratis versus libre|gratis]]"). [[Richard Stallman]] has described it as {{Double+space}}[[Gratis versus libre|'free' as in 'free speech', not as in 'free beer']]{{Space+double}}.

The prefix "TANSTAA-" (or "TINSTAA-") is used in numerous other contexts as well to denote some immutable property of the system being discussed. For example, "TANSTAANFS" is used by [[electrical engineering]] professors to stand for "There Ain't No Such Thing As A Noise-Free System".{{Citation needed|date=June 2016}}

==== Sports ====
[[Baseball Prospectus]] coined the abbreviation "TINSTAAPP", for "There Is No Such Thing As A Pitching Prospect",<ref>{{cite news | url=http://mlb.mlb.com/news/article.jsp?ymd=20130411&content_id=44526640&vkey=news_mlb&c_id=mlb | title=Even top pitching prospects are no sure thing | work=MLB.com | date=12 April 2013 | access-date=6 May 2013 | author=Leach, Matthew}}</ref> as many young pitchers hurt their arms before they can be effective at a [[Major League Baseball|major league]] level.

==== Social policy ====
Hungarian prime minister [[Ferenc Gyurcsány]] used this adage to justify his social reforms in the mid-2000s. As a post-socialist country, Hungary struggled with the illusion of the state as a caring and giving, independent entity, rather than being the embodiment of the community. The saying "there is no free lunch" represented that even if the state provides welfare or something else for the people in need, it is in fact bought or provided by other people of the same community through taxes. Therefore, the state cannot provide everything for everyone, and increased provisions given by the state can only be financed by economic growth, increased taxes or public debt.

==== Exceptions ====
Some exceptions from the "no free lunch" tenet have been put forward, such as the [[Sun]] and [[carbon dioxide]].<ref name="Friend">{{cite book| last = Friend| first = Tim| title = The Third Domain: The Untold Story of Archaea and the Future of Biotechnology| publisher = National Academies Press| year = 2007| page = [https://archive.org/details/thirddomainun00frie/page/21 21]| isbn = 978-0309102377| url = https://archive.org/details/thirddomainun00frie/page/21}}</ref> It was argued in particular that [[metabolism]] evolved to take advantage of the free lunch provided by the Sun, which also triggers production of vital oxygen in plants.<ref name="Friend"/>  However, these too fall short in that the viewpoint is an [[open system (systems theory)|open system]], Earth, with "free" inputs from the Sun.  When viewed from the larger system context, the Sun/Earth or Solar System, there is no net energy exchange, and still "no free lunch".<ref>{{cite news | title = Is the earth a 'closed system' with the Sun providing the sole input?| url=https://www.quora.com/Is-the-earth-a-closed-system-with-the-Sun-providing-the-sole-input| date=11 December 2013 | access-date=26 November 2016| author = Wilson, Richard}}</ref>