Editing Reality (section)

== Physical sciences ==

=== Scientific realism ===
[[Scientific realism]] is, at the most general level, the view that the world (the universe) described by science (perhaps ideal science) is the real world, as it is, independent of what we might take it to be. Within [[philosophy of science]], it is often framed as an answer to the question "how is the success of science to be explained?" The debate over what the success of science involves centers primarily on the status of entities that are [[unobservable|not directly observable]] discussed by [[scientific theory|scientific theories]]. Generally, those who are scientific realists state that one can make reliable claims about these entities (viz., that they have the same [[Ontology|ontological]] status) as directly observable entities, as opposed to [[instrumentalism]]. The most used and studied scientific theories today state more or less the truth.

=== Realism and locality in physics ===
{{main | Principle of locality}}
''Realism'' in the sense used by physicists does not equate to [[Philosophical realism|realism]] in metaphysics.<ref>{{cite journal|title=Against 'Realism'|first=Travis|last=Norsen|date=26 February 2007|journal=Foundations of Physics|volume=37|issue=3|pages=311–340|doi=10.1007/s10701-007-9104-1|arxiv=quant-ph/0607057|bibcode=2007FoPh...37..311N|s2cid=15072850}}</ref> The latter is the claim that the world is mind-independent: that even if the results of a measurement do not pre-exist the act of measurement, that does not require that they are the creation of the observer. Furthermore, a mind-independent property does not have to be the value of some physical variable such as position or [[momentum]]. A property can be ''[[disposition]]al'' (or potential), i.e. it can be a tendency: in the way that glass objects tend to break, or are disposed to break, even if they do not ''actually'' break. Likewise, the mind-independent properties of quantum systems could consist of a tendency to respond to particular measurements with particular values with ascertainable probability. Such an ontology would be metaphysically realistic, without being realistic in the physicist's sense of "local realism" (which would require that a single value be produced with certainty).

A closely related term is [[counterfactual definiteness]] (CFD), used to refer to the claim that one can meaningfully speak of the definiteness of results of measurements that have not been performed (i.e. the ability to assume the existence of objects, and properties of objects, even when they have not been measured).

[[Local realism]] is a significant feature of classical mechanics, of [[general relativity]], and of classical [[electrodynamics]]; but not [[quantum mechanics]]. In a work now called the [[EPR paradox]], Einstein relied on local realism to suggest that [[hidden variable theory| hidden variables]] were missing in quantum mechanics. However, [[John S. Bell]] subsequently showed that the predictions of quantum mechanics are inconsistent with hidden variables, a result known as [[Bell's theorem]]. The predictions of quantum mechanics have been verified: Bell's inequalities are violated. This means either particles have no definite positions independent of observation (no realism) ''or'' distant measurements can affect each other (no locality) or both. Different [[interpretation of quantum mechanics|interpretations of quantum mechanics]] violate different parts of local realism.<ref>{{cite book| last1=Nielsen |first1=Michael A. |last2=Chuang |first2=Isaac L. |year=2000 |title=Quantum Computation and Quantum Information |publisher=[[Cambridge University Press]] |pages=112–113| isbn=978-0-521-63503-5}}</ref>{{rp|117}}

The transition from "possible" to "actual" is a major topic of [[quantum physics]], with related theories including [[quantum darwinism]].

==== Role of "observation" in quantum mechanics ====
{{See also|Quantum decoherence}}
The [[quantum mind]]–body problem refers to the philosophical discussions of the [[mind–body problem]] in the context of quantum mechanics. Since quantum mechanics involves [[quantum superposition]]s, which [[Measurement in quantum mechanics|are not perceived by observers]], some [[interpretations of quantum mechanics]] place conscious observers in a special position.

The founders of quantum mechanics debated the role of the observer, and of them, [[Wolfgang Pauli]] and [[Werner Heisenberg]] believed that quantum mechanics expressed the observers knowledge and when an experiment was completed the additional knowledge should be incorporated in the wave function, an effect that came to be called state reduction or [[wave function collapse|collapse]]. This point of view, which was never fully endorsed by [[Niels Bohr]], was denounced as mystical and anti-scientific by [[Albert Einstein]]. Pauli accepted the term, and described quantum mechanics as ''lucid mysticism''.<ref>{{cite journal |author=Marin |first=Juan Miguel |year=2009 |title='Mysticism' in quantum mechanics: the forgotten controversy |journal=European Journal of Physics |volume=30 |issue=4 |pages=807–822 |bibcode=2009EJPh...30..807M |doi=10.1088/0143-0807/30/4/014 |s2cid=122757714}} [http://www.iop.org/EJ/article/0143-0807/30/4/014/ejp9_4_014.pdf?request-id=9350419a-e5ea-42e2-b5f3-7878a09dfe42 link], summarized here [http://www.physorg.com/news163670588.html%7care/]. {{webarchive|url=https://web.archive.org/web/20110606092933/http://www.physorg.com/news163670588.html%7Care/|date=2011-06-06}}.</ref>

Heisenberg and Bohr always described quantum mechanics in [[logical positivism|logical positivist]] terms. Bohr also took an active interest in the philosophical implications of quantum theories such as his [[Complementarity (physics)|complementarity]], for example.<ref>{{cite journal |author=Honner |first=John |year=2005 |title=Niels Bohr and the Mysticism of Nature |journal=Zygon: Journal of Religion & Science |volume=17-3 |pages=243–253}}</ref> He believed quantum theory offers a complete description of nature, albeit one that is simply ill-suited for everyday experiences&nbsp;– which are better described by classical mechanics and probability. Bohr famously avoided any characterization of "reality".<ref>Symposium On The Foundations Of Modern Physics 1987 - The Copenhagen Interpretation 60 Years After The Como Lecture. (1988). Singapore: World Scientific Publishing Company.</ref>{{rp|163}}

[[Eugene Wigner]] reformulated the "[[Schrödinger's cat]]" [[thought experiment]] as "[[Wigner's friend]]" and proposed that the consciousness of an observer is the demarcation line which precipitates collapse of the wave function, independent of any realist interpretation. Commonly known as "[[consciousness causes collapse]]", this controversial [[interpretation of quantum mechanics]] states that [[observation]] by a [[conscious]] observer is what makes the wave function collapse. However, this is a minority view among quantum philosophers, considering it a misunderstanding.<ref>{{cite journal |last1=Schlosshauer |first1=M. |last2=Koer |first2=J. |last3=Zeilinger |first3=A. |year=2013 |title=A Snapshot of Foundational Attitudes Toward Quantum Mechanics |journal=Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics |volume=44 |issue=3 |pages=222–230 |arxiv=1301.1069 |bibcode=2013SHPMP..44..222S |doi=10.1016/j.shpsb.2013.04.004 |s2cid=55537196}}</ref> There are other possible solutions to the "[[Wigner's friend]]" thought experiment, which do not require consciousness to be different from other physical processes. Moreover, Wigner shifted to those interpretations in his later years.<ref name="Esfeld">Michael Esfeld, (1999), [http://www.unil.ch/webdav/site/philo/shared/DocsPerso/EsfeldMichael/1999/SHPMP99.pdf Essay Review: Wigner's View of Physical Reality] {{Webarchive|url=https://web.archive.org/web/20140201151438/http://www.unil.ch/webdav/site/philo/shared/DocsPerso/EsfeldMichael/1999/SHPMP99.pdf |date=2014-02-01 }}, published in Studies in History and Philosophy of Modern Physics, 30B, pp. 145–154, Elsevier Science Limited.</ref>

=== Multiverse ===
The [[multiverse]] is the [[hypothetical]] set of multiple possible [[universe]]s (including the historical universe we consistently experience) that together comprise everything that exists: the entirety of [[space]], time, [[matter]], and energy as well as the [[physical law]]s and [[physical constant|constants]] that describe them. The term was coined in 1895 by the American philosopher and psychologist [[William James]].<ref>James, William, ''The Will to Believe'', 1895; and earlier in 1895, as cited in [[OED]]'s new 2003 entry for "multiverse": "1895 W. JAMES in Internat. Jrnl. Ethics 6 10 Visible nature is all plasticity and indifference, a multiverse, as one might call it, and not a universe."</ref> In the [[many-worlds interpretation]] (MWI), one of the mainstream [[interpretations of quantum mechanics]], there are an infinite number of universes and every possible quantum outcome occurs in at least one universe, albeit there is [[Many-worlds interpretation#Debate whether the other worlds are real|a debate as to how real the (other) worlds are]].

The structure of the multiverse, the nature of each universe within it and the relationship between the various constituent universes, depend on the specific multiverse hypothesis considered. Multiverses have been hypothesized in [[cosmology]], physics, [[astronomy]], religion, philosophy, [[transpersonal psychology]] and fiction, particularly in science fiction and fantasy. In these contexts, parallel universes are also called "alternative universes", "quantum universes", "interpenetrating dimensions", "parallel dimensions", "parallel worlds", "alternative realities", "alternative timelines", and "dimensional planes", among others.

{{Excerpt|Multiverse#Cyclic theories|hat=no}}

===Anthropic principle===
{{Excerpt|Anthropic principle|only=paragraph|files=0}}

===Personal and collective reality===
[[File:White Matter Connections Obtained with MRI Tractography.png|thumb|[[Nerve tract|White matter tracts]] within a human brain, as visualized by [[MRI]] [[tractography]]]]
Each individual has a different [[Point of view (philosophy)|view of reality]], with different memories and personal history, knowledge, personality traits and experience.<ref>{{cite journal |last1=Savin-Baden |first1=Maggi |last2=Burden |first2=David |title=Digital Immortality and Virtual Humans |journal=Postdigital Science and Education |date=1 April 2019 |volume=1 |issue=1 |pages=87–103 |doi=10.1007/s42438-018-0007-6 |s2cid=149797460 |language=en |issn=2524-4868|doi-access=free }}</ref> This system, mostly referring to the [[human brain]], affects [[cognition]] and behavior and into this complex new [[knowledge integration|knowledge]], memories,<ref>{{cite journal |last1=van Kesteren |first1=Marlieke T. R. |last2=Rignanese |first2=Paul |last3=Gianferrara |first3=Pierre G. |last4=Krabbendam |first4=Lydia |last5=Meeter |first5=Martijn |title=Congruency and reactivation aid memory integration through reinstatement of prior knowledge |journal=Scientific Reports |date=16 March 2020 |volume=10 |issue=1 |pages=4776 |doi=10.1038/s41598-020-61737-1 |pmid=32179822 |pmc=7075880 |bibcode=2020NatSR..10.4776V |language=en |issn=2045-2322}}</ref> information, [[thought]]s and experiences are continuously integrated.<ref>{{cite news |title=Understanding reality through algorithms |url=https://news.mit.edu/2022/understanding-reality-through-algorithms-fernanda-de-la-torre-0925 |access-date=6 November 2022 |work=MIT News {{!}} Massachusetts Institute of Technology |language=en |archive-date=6 November 2022 |archive-url=https://web.archive.org/web/20221106174033/https://news.mit.edu/2022/understanding-reality-through-algorithms-fernanda-de-la-torre-0925 |url-status=live }}</ref>{{additional citation needed|date=November 2022}} The [[connectome]] – [[Neuron#Connectivity|neural networks/wirings]] in brains – is thought to be a key factor in [[human variability]] in terms of cognition or the way we perceive the world (as a context) and related features or processes.<ref>{{cite web |last1=Popova |first1=Maria |title=The Connectome: A New Way To Think About What Makes You You |url=https://www.theatlantic.com/health/archive/2012/03/the-connectome-a-new-way-to-think-about-what-makes-you-you/255023/ |website=The Atlantic |access-date=6 November 2022 |date=28 March 2012 |archive-date=31 March 2012 |archive-url=https://web.archive.org/web/20120331173723/https://www.theatlantic.com/health/archive/2012/03/the-connectome-a-new-way-to-think-about-what-makes-you-you/255023/ |url-status=live }}</ref><ref>{{cite book |last1=Seung |first1=Sebastian |title=Connectome: How the Brain's Wiring Makes Us Who We Are |year=2012 |publisher=HMH |isbn=978-0547508177 |url=https://books.google.com/books?id=GXwEuoYl3wQC |language=en}}</ref><ref>{{cite news |title=Quest for the connectome: scientists investigate ways of mapping the brain |url=https://www.theguardian.com/science/2012/may/07/quest-connectome-mapping-brain |access-date=6 November 2022 |work=The Guardian |date=7 May 2012 |language=en |archive-date=6 November 2022 |archive-url=https://web.archive.org/web/20221106174032/https://www.theguardian.com/science/2012/may/07/quest-connectome-mapping-brain |url-status=live }}</ref> [[Sensemaking]] is the process by which people give [[Semantics|meaning]] to their experiences and make sense of the world they live in. [[Personal identity]] is relating to questions like how a unique individual is persisting through time.

Sensemaking and determination of reality also occurs collectively, which is investigated in [[social epistemology]] and related approaches. From the [[collective intelligence]] perspective, the intelligence of the individual human (and potentially AI entities) is substantially limited and advanced intelligence emerges when multiple entities collaborate over time.<ref>{{cite journal |last1=Peeters |first1=Marieke M. M. |last2=van Diggelen |first2=Jurriaan |last3=van den Bosch |first3=Karel |last4=Bronkhorst |first4=Adelbert |last5=Neerincx |first5=Mark A. |last6=Schraagen |first6=Jan Maarten |last7=Raaijmakers |first7=Stephan |title=Hybrid collective intelligence in a human–AI society |journal=AI & Society |date=1 March 2021 |volume=36 |issue=1 |pages=217–238 |doi=10.1007/s00146-020-01005-y |s2cid=220050285 |language=en |issn=1435-5655 |url=https://ris.utwente.nl/ws/files/205948801/Peeters_2020_Hybrid_collective_intelligence_in_a.pdf |archive-date=3 September 2023 |access-date=3 September 2023 |archive-url=https://web.archive.org/web/20230903132808/https://ris.utwente.nl/ws/files/205948801/Peeters_2020_Hybrid_collective_intelligence_in_a.pdf |url-status=dead }}</ref>{{additional citation needed|date=November 2022}} [[Collective memory]] is an important component of the social construction of reality<ref>{{cite journal |last1=Luckmann |first1=Thomas |title=On Social Interaction and the Communicative Construction of Personal Identity, Knowledge and Reality |journal=Organization Studies |date=February 2008 |volume=29 |issue=2 |pages=277–290 |doi=10.1177/0170840607087260 |s2cid=145106025 |language=en |issn=0170-8406}}</ref> and communication and communication-related systems, such as media systems, may also be major components {{see below|[[#Technology]]}}.

Philosophy of perception raises questions based on the evolutionary history of humans' perceptual apparatuses, particularly or especially individuals' [[human senses|physiological senses]], described as "[w]e don't see reality—we only see what was useful to see in the past", partly suggesting that "[o]ur species has been so successful not in spite of our inability to see reality but because of it".<ref>{{cite journal |last1=Draaisma |first1=Douwe |title=Perception: Our useful inability to see reality |journal=Nature |date=April 2017 |volume=544 |issue=7650 |pages=296 |language=en |doi=10.1038/544296a|bibcode=2017Natur.544..296D |s2cid=4400770 |doi-access=free }}</ref>

=== Scientific theories of everything ===
A [[theory of everything]] (TOE) is a putative [[theory]] of [[theoretical physics]] that fully explains and links together all known physical phenomena, and predicts the outcome of ''any'' experiment that could be carried out ''in principle''. The theory of everything is also called the '''final theory'''.<ref>Weinberg (1993)</ref> Many candidate theories of everything have been proposed by theoretical physicists during the twentieth century, but none have been confirmed experimentally. The primary problem in producing a TOE is that [[general relativity]] and quantum mechanics are hard to unify. This is one of the [[unsolved problems in physics]].

Initially, the term "theory of everything" was used with an ironic connotation to refer to various overgeneralized theories. For example, a great-grandfather of [[Ijon Tichy]], a character from a cycle of [[Stanisław Lem]]'s science fiction stories of the 1960s, was known to work on the "General Theory of Everything". Physicist [[John Ellis (physicist, born 1946)|John Ellis]]<ref>{{cite journal
 | first = John | last = Ellis
 | year = 2002
 | journal = [[Nature (journal)|Nature]]
 | title = Physics gets physical (correspondence)
 | volume = 415 | page =957
 | doi =10.1038/415957b
|bibcode = 2002Natur.415..957E
 | issue=6875
 | pmid=11875539| doi-access = free
 }}</ref> claims to have introduced the term into the technical literature in an article in ''[[Nature (magazine)|Nature]]'' in 1986.<ref>{{Cite journal
 | first = John | last = Ellis
 | year = 1986
 | journal = Nature
 | title = The Superstring: Theory of Everything, or of Nothing?
 | volume = 323 | pages = 595–598
 | doi = 10.1038/323595a0
|bibcode = 1986Natur.323..595E
 | issue=6089| s2cid = 4344940
 }}</ref> Over time, the term stuck in popularizations of [[quantum physics]] to describe a theory that would unify or explain through a single model the theories of all [[fundamental interaction]]s and of all particles of nature: general relativity for gravitation, and the [[Standard Model|standard model]] of elementary particle physics&nbsp;– which includes quantum mechanics&nbsp;– for electromagnetism, the two nuclear interactions, and the known elementary particles.

Current candidates for a theory of everything include [[string theory]], [[M theory]], and [[loop quantum gravity]].