Difference between revisions of "Scientific method"

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[[Image:Aristotle Altemps Inv8575.jpg|thumb|150px|Aristotle, 384 BC–322 BC. "As regards his method, Aristotle is recognized as the inventor of scientific method because of his refined analysis of logical implications contained in demonstrative discourse, which goes well beyond natural logic and does not owe anything to the ones who philosophized before him."—Riccardo Pozzo<ref name="PozzoArist">{{cite book |url=http://books.google.com/books?id=vayp8jxcPr0C&lpg=PP1&pg=PA41 |title=The Impact of Aristotelianism on Modern Philosophy |author=Pozzo, Riccardo |publisher=CUA Press |year=2004 |page=41 |isbn=0813213479}}</ref>]] The '''scientific method''' is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.<ref name="Goldhaber940">{{cite journal |url=http://rmp.aps.org/abstract/RMP/v82/i1/p939_1 |first1=Alfred Scharff |last1=Goldhaber |first2=Michael Martin |last2=Nieto |year=2010 |date=January–March 2010 |title=Photon and graviton mass limits |journal=Reviews of Modern Physics |volume=82 |page=939–979 |publisher=American Physical Society |doi=10.1103/RevModPhys.82.939}}</ref> To be termed scientific, a method of inquiry must be based on empirical and measurable evidence subject to specific principles of reasoning.<ref name="Newton">{{cite book |last=Newton |first=Isaac |year=1999 |date=1687, 1713, 1726 |title=Philosophiae Naturalis Principia Mathematica |publisher=University of California Press |edition=Third |pages=794–6 |isbn=0-520-08817-4}}</ref> The ''Oxford English Dictionary'' defines the scientific method as "a method or procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses."<ref name="OED_SciMeth">{{cite web |url=http://oxforddictionaries.com/us/definition/american_english/scientific-method?q=scientific+method |work=Oxford Dictionaries (US English) |title=scientific method |publisher=Oxford University Press |accessdate=01 June 2013}}</ref>
{{Science}}
<!--Please see talk page for discussion on why the word "the" is not used here-->'''Scientific method''' refers to a body of [[Scientific technique|technique]]s for investigating [[phenomenon|phenomena]], acquiring new [[knowledge]], or correcting and integrating previous knowledge.<ref>{{harvnb|Goldhaber|Nieto|2010|page=940}}</ref> To be termed scientific, a method of inquiry must be based on gathering observable, [[empirical]] and [[Measurement|measurable]] evidence subject to specific principles of reasoning.<ref>
"[4] Rules for the study of [[natural philosophy]]", {{harvnb|Newton|1999|pp=794–6}}, from Book '''3''', ''The System of the World''.
</ref> The [[Oxford English Dictionary]] says that scientific method is: "a method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses."<ref>Oxford English Dictionary - entry for ''scientific''.</ref>


Although procedures vary from one [[fields of science|field of inquiry]] to another, identifiable features distinguish scientific inquiry from other methods of obtaining knowledge. Scientific researchers propose hypotheses as explanations of phenomena, and design [[experiment]]al studies to test these hypotheses. These steps must be repeatable, to predict future results. [[Scientific theory|Theories]] that encompass wider domains of inquiry may bind many independently derived hypotheses together in a coherent, supportive structure. Theories, in turn, may help form new hypotheses or place groups of hypotheses into context.
The chief characteristic which arguably distinguishes the scientific method from other methods of acquiring knowledge is that scientists attempt to let the scientific method deliver truths about reality, supporting a theory when a theory's predictions are confirmed and challenging a theory when its predictions prove false.<ref name="SciMethHistPhilo">{{cite book |url=http://books.google.com/books?id=D3rV2t2XkWYC&pg=PA126 |title=Scientific Method: An Historical and Philosophical Introduction |author=Gower, Barry |year=1997 |page=126 |publisher=Psychology Press |isbn=0415122821}}</ref> Although procedures vary from one field of inquiry to another, identifiable features distinguish scientific inquiry from other methods of obtaining knowledge. Scientific researchers propose hypotheses as explanations of phenomena, and design experimental studies to test these hypotheses via predictions which can be derived from them. These steps must be repeatable, to guard against mistake or confusion in any particular experimenter. Theories that encompass wider domains of inquiry may bind many independently derived hypotheses together in a coherent, supportive structure. Theories, in turn, may help form new hypotheses or place groups of hypotheses into context.


Scientific inquiry is generally intended to be as [[objectivity (science)|objective]] as possible, to reduce biased interpretations of results. Another basic expectation is to document, [[Scientific data archiving|archive]] and [[Data sharing (Science)|share]] all data and [[methodology]] so they are available for careful scrutiny by other scientists, giving them the opportunity to verify results by attempting to [[Reproducibility|reproduce]] them. This practice, called ''full disclosure'', also allows statistical measures of the [[reliability (statistics)|reliability]] of these data to be established.
Scientific inquiry is generally intended to be as objective as possible in order to reduce biased interpretations of results. Another basic expectation is to document, archive, and share all data and methodology so they are available for careful scrutiny by other scientists, giving them the opportunity to verify results by attempting to reproduce them. This practice is sometimes referred to as ''replicability'' or ''full disclosure'', and it allows statistical measures of the reliability of these data to be established, especially when data is sampled or compared to chance.<ref name="CorpusReplic">{{cite book |url=http://books.google.com/books?id=3j3Wn_ZT1qwC&pg=PA16 |title=Corpus Linguistics: Method, Theory and Practice |author=McEnery, Tony; Hardie, Andrew |publisher=Cambridge University Press |year=2011 |page=14–16 |isbn=1139502441}}</ref>
{{TOC limit|limit=3}}
 
==Introduction to scientific method==
{{See also|History of scientific method|Timeline of the history of scientific method}}
{| align=right cellspacing=0
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|[[Image:Ibn al-Haytham.png|thumb|150px|[[Ibn al-Haytham]] (Alhazen), 965–1039, [[Basra]].]]
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|[[Image:Galileo.arp.300pix.jpg|thumb|150px|"Modern science owes its origins and present flourishing state to a new scientific method which was fashioned almost entirely by [[Galileo Galilei]] (1564-1642)" —Morris Kline<ref>[[Morris Kline]] (1985) [http://books.google.com/books?id=f-e0bro-0FUC&pg=PA284&dq&hl=en#v=onepage&q=&f=false ''Mathematics for the nonmathematician'']. [[Courier Dover Publications]]. p. 284. ISBN 0-486-24823-2</ref>]]
|-
|[[File:Johannes Kepler 1610.jpg|thumb|150px| [[Johannes Kepler]] (1571–1630). "Kepler shows his keen logical sense in detailing the whole process by which he finally arrived at the true orbit. This is the greatest piece of Retroductive reasoning ever performed." —[[Charles Sanders Peirce|C.&nbsp;S. Peirce]], circa 1896, on Kepler's reasoning through explanatory hypotheses<ref>Peirce, C. S., ''Collected Papers'' v. 1, paragraph 74.</ref>]]
|}
Since [[Ibn al-Haytham ]] (Alhazen, 965–1039), one of the key figures in the [[history of scientific method|development of scientific method]], the emphasis has been on seeking [[#Truth and belief|truth]]:
 
{{quote|Truth is sought for its own sake. And those who are engaged upon the quest for anything for its own sake are not interested in other things. Finding the truth is difficult, and the road to it is rough.<ref>[[Alhazen]] ([[Ibn Al-Haytham]]) ''[[Critique of Ptolemy]]'', translated by S. Pines, ''Actes X Congrès internationale d'histoire des sciences'', Vol '''I''' Ithaca 1962, as quoted in {{harvnb|Sambursky|1974|p=139}}
</ref>}}
[[Image:Thesaurus_opticus_Titelblatt.jpg|thumb|left|"Light travels through transparent bodies in straight lines only" — Alhazen in ''[[Book of Optics]]'' (1021 {{lang-ar|'''''Kitāb al-Manāẓir'''''}}) as shown in a [[Basle]] 1572 Latin translation, [[Friedrich Risner]], ed., ''Opticae Thesaurus Alhazeni Arabis'',<ref>Edward Grant (1974), ''A source book in medieval science'' '''Volume one''' Cambridge MA: Harvard University Press [http://books.google.com/books?id=fAPN_3w4hAUC&pg=PA392&lpg=PA392&dq=opticae+thesaurus+alhazen&source=bl&ots=2rgm-0Pxh4&sig=5Oace7_5H508yE6rkKLd7NMVTxU&hl=en&ei=aXmHTbbcFI72tgPgy8HlAQ&sa=X&oi=book_result&ct=result&resnum=3&ved=0CCQQ6AEwAg#v=onepage&q=opticae%20thesaurus%20alhazen&f=false p.392]</ref> frontispiece showing optical phenomena: transmission of light through the atmosphere, reflection of light rays from parabolic mirrors during the defense of [[Syracuse]] by [[Archimedes]] against ships of the [[Roman Republic]], refraction of light rays by water, and the production of colors in a [[rainbow]]. ]]
{{quote|How does light travel through transparent bodies? Light travels through transparent bodies in straight lines only.... We have explained this exhaustively in our ''[[Book of Optics]]''. But let us now mention something to prove this convincingly: the fact that light travels in straight lines is clearly observed in the lights which enter into dark rooms through holes.... [T]he entering light will be clearly observable in the dust which fills the air.<ref>Alhazen, translated into English from German by M. Schwarz, from "Abhandlung über das Licht", J. Baarmann (ed. 1882) ''[[Zeitschrift der Deutschen Morgenländischen Gesellschaft]]'' Vol '''36''' as quoted in {{harvnb|Sambursky|1974|p=136}}</ref>}}
 
The conjecture that "light travels through transparent bodies in straight lines only" was corroborated by Alhazen only after years of effort. His demonstration of the conjecture was to place a straight stick or a taut thread next to the light beam,<ref>
as quoted in {{harvnb|Sambursky|1974|p=136}}</ref> to prove that light travels in a straight line.
 
Scientific methodology has been practiced in some form for at least one thousand years.<ref>"Truth is sought for its own sake. And those who are engaged upon the quest for anything for its own sake are not interested in other things. Finding the truth is difficult, and the road to it is rough."—[[Alhazen]] ([[Ibn Al-Haytham]] 965-c.1040) ''[[Critique of Ptolemy]]'', translated by S. Pines, ''Actes X Congrès internationale d'histoire des sciences'', Vol '''I''' Ithaca 1962, as quoted in {{harvnb|Sambursky|1974|p=139}}. (This quotation is from Alhazen's critique of  Ptolemy's books ''[[Almagest]]'', ''Planetary Hypotheses'', and  [http://books.google.com/books?id=mhLVHR5QAQkC&pg=PA59&lpg=PA59&dq=Opticae+thesaurus+alhazen&source=bl&ots=noo2fzmnU-&sig=fHI2OZUVkiKuxyOGw-nt08p9lSM&hl=en&ei=QHU1TZnCJsT68AbywuTyCA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBIQ6AEwADgK#v=onepage&q=Opticae%20thesaurus%20alhazen&f=false  ''Optics'' as translated into English by  A. Mark Smith].)
</ref> There are difficulties in a formulaic statement of method, however. As [[William Whewell]] (1794–1866) noted in his ''History of Inductive Science'' (1837) and in ''Philosophy of Inductive Science'' (1840), "invention, sagacity, genius" are required at [[William Whewell#Whewell's three steps of induction|every step in scientific method]]. It is not enough to base scientific method on [[empiricism|experience]] alone;<ref>
 
"...the statement of a law—A depends on B—always transcends experience." —{{harvnb|Born|1949|p=6}}</ref> multiple steps are needed in scientific method, ranging from our experience to our imagination, back and forth.
 
In the 20th century, a [[hypothetico-deductive model]]<ref>{{harvnb|Godfrey-Smith|2003}} p. 236.</ref> for scientific method was formulated (for a more formal discussion, see [[Scientific method#Elements of scientific method|below]]):
 
<div style="padding-left:1.25em;text-indent:-1.25em">
:'''''1'''''. [[#Characterizations|Use your experience]]: Consider the problem and try to make sense of it. Look for previous explanations. If this is a new problem to you, then move to step&nbsp;'''''2'''''.
:'''''2'''''. [[#Hypothesis development|Form a conjecture]]: When nothing else is yet known, try to state an explanation, to someone else, or to your notebook.
:'''''3'''''. [[#Predictions from the hypothesis|Deduce a prediction from that explanation]]: If you assume&nbsp;'''''2''''' is true, what consequences follow?
:'''''4'''''. [[#Experiments|Test]]: Look for the opposite of each consequence in order to disprove&nbsp;'''''2'''''. It is a logical error to seek&nbsp;'''''3''''' directly as proof of&nbsp;'''''2'''''. This error is called ''[[affirming the consequent]]''.<ref>{{harvnb|Taleb|2007}} e.g., p. 58, devotes his chapter 5 to ''the error of confirmation''.</ref>
</div>
 
This model underlies the [[scientific revolution]]. One thousand years ago, [[Alhazen]] demonstrated the importance of steps '''''1''''' and '''''4'''''.<ref>"How does light travel through transparent bodies? Light travels through transparent bodies in straight lines only.... We have explained this exhaustively in our ''[[Book of Optics]]''. But let us now mention something to prove this convincingly: the fact that light travels in straight lines is clearly observed in the lights which enter into dark rooms through holes.... [T]he entering light will be clearly observable in the dust which fills the air. —Alhazen, translated into English from German by M. Schwarz, from "Abhandlung über das Licht", J. Baarmann (ed. 1882) ''[[Zeitschrift der Deutschen Morgenländischen Gesellschaft]]'' Vol '''36''' as quoted in {{harvnb|Sambursky|1974|p=136}}.
 
*The conjecture that "light travels through transparent bodies in straight lines only" was corroborated by Alhazen only after years of effort. His demonstration of the conjecture was to place a straight stick or a taut thread next to the light beam, as quoted in {{harvnb|Sambursky|1974|p=136}} to prove that light travels in a straight line.
*[[David Hockney]], (2001, 2006) in ''Secret Knowledge: rediscovering the lost techniques of the old masters'' ISBN 0-14-200512-6 (expanded edition) cites Alhazen several times as the likely source for the portraiture technique using the [[camera obscura]], which Hockney rediscovered with the aid of an optical suggestion from [[Charles M. Falco]]. ''Kitab al-Manazir'', which is Alhazen's ''[[Book of Optics]]'', at that time denoted ''Opticae Thesaurus, Alhazen Arabis'', was translated from Arabic into Latin for European use as early as 1270. Hockney cites Friedrich Risner's 1572 Basle edition of ''Opticae Thesaurus''. Hockney quotes Alhazen as the first clear description of the camera obscura in Hockney, p. 240.
</ref> {{harvnb|Galileo|1638}} also showed the importance of step '''''4''''' (also called [[Experiment]]) in ''[[Two New Sciences]]''.<ref>{{Citation|last=Galilei|first=Galileo|author-link=Galileo|title=[[Two New Sciences|Discorsi e Dimonstrazioni Matematiche, intorno a due nuoue scienze]]|location=[[Leiden|Leida]]|publisher=Apresso gli [[House of Elzevir|Elsevirri]]|date=[[1638|M.D.C.XXXVIII]]|isbn=0-486-60099-8}}, Dover reprint of the 1914 Macmillan translation by Henry Crew and Alfonso de Salvio of ''Two New Sciences'', [[Galileo Galilei]] [[Accademia dei Lincei|Linceo]] (1638). Additional publication information is from the collection of first editions of the Library of Congress surveyed by {{harvnb|Bruno|1989|pp=261–264}}.
</ref> One possible sequence in this model would be '''''1''''', '''''2''''', '''''3''''', '''''4'''''. If the outcome of '''''4''''' holds, and '''''3''''' is not yet disproven, you may continue with '''''3''''', '''''4''''', '''''1''''', and so forth; but if the outcome of '''''4''''' shows '''''3''''' to be false, you will have to go back to '''''2''''' and try to invent a '''''new 2''''', deduce a '''''new 3''''', look for '''''4''''', and so forth.
 
Note that this method can never absolutely '''verify''' (prove the truth of) '''''2'''''. It can only '''[[Falsifiability|falsify]]''' '''''2'''''.<ref>
"I believe that we do not know anything for certain, but everything probably." —[[Christiaan Huygens]], Letter to Pierre Perrault, 'Sur la préface de M. Perrault de son traité del'Origine des fontaines' [1763], ''Oeuvres Complétes de Christiaan Huygens'' (1897), Vol. '''7''', 298. Quoted in Jacques Roger, ''The Life Sciences in Eighteenth-Century French Thought'', ed. Keith R. Benson and trans. Robert Ellrich (1997), 163. Quotation selected by {{harvnb|Bynum|Porter|2005|p=317}} Huygens 317#4.</ref> (This is what Einstein meant when he said, "No amount of experimentation can ever prove me right; a single experiment can prove me wrong."<ref>
As noted by Alice Calaprice (ed. 2005) ''The New Quotable Einstein'' Princeton University Press and Hebrew University of Jerusalem, ISBN 0-691-12074-9 p. 291. Calaprice denotes this not as an exact quotation, but as a paraphrase of a translation of A. Einstein's "Induction and Deduction". ''Collected Papers of Albert Einstein'' '''7''' Document 28. Volume 7 is ''The Berlin Years: Writings, 1918-1921''. A. Einstein; M. Janssen, R. Schulmann, et al., eds.
</ref>)
However, as pointed out by [[Carl Hempel]] (1905–1997) this simple view of scientific method is incomplete; the formulation of the conjecture might itself be the result of [[inductive reasoning]]. Thus the likelihood of the prior observation being true is statistical in nature<ref>Murzi, Mauro (2001, 2008), "[http://www.iep.utm.edu/h/hempel.htm Carl Gustav Hempel (1905—1997)]", ''Internet Encyclopedia of Philosophy''.</ref> and would strictly require a [[Bayes theorem|Bayesian]] analysis. To overcome this uncertainty, experimental scientists must formulate a ''[[crucial experiment]]'',<ref>{{harvnb|Poincaré|1905}} p.142 notes that [[Francis Bacon]] introduced the term; on a related note, [[Ørsted]] introduced the term '[[thought experiment]]'; of course, [[Galileo]], a contemporary of Bacon, had previously made liberal use of these concepts in his writings centuries earlier than Poincaré or Ørsted.</ref> in order for it to corroborate a more likely hypothesis.
 
In the 20th century, [[Ludwik Fleck]] (1896–1961) and others argued that scientists need to consider their experiences more carefully, because their experience may be biased, and that they need to be more exact when describing their experiences.<ref>{{harvnb|Fleck|1979|pp=xxvii-xxviii}}</ref>
 
===DNA example===
{| cellspacing=0
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| style="vertical-align:top; padding:0.45em 0.4em 0 0;" rowspan="2"|[[Image:DNA icon (25x25).png]]
| vAlign=top |Four basic [[#Elements of scientific method|elements of scientific method]] are illustrated below, by example from the discovery of the structure of [[DNA]]:
*''[[#DNA-characterizations|DNA-characterizations]]'': in this case, although the significance of the gene had been established, the mechanism was unclear to anyone, as of 1950.
*''[[#DNA-hypotheses|DNA-hypotheses]]'': [[Francis Crick|Crick]] and [[James D. Watson|Watson]] hypothesized that the gene had a physical basis&ndash;it was helical.<ref>October, 1951. as noted in {{harvnb|McElheny|2004|p=40}}:"That's what a helix should look like!" Crick exclaimed in delight (This is the Cochran-Crick-Vand&Stokes theory of the transform of a helix).
</ref>
*''[[#DNA-predictions|DNA-predictions]]'': from earlier work on [[tobacco mosaic virus]],<ref>
June, 1952. as noted in {{harvnb|McElheny|2004|p=43}}: Watson had succeeded in getting X-ray pictures of TMV showing a helical pattern.
</ref> Watson was aware of the significance of Crick's formulation of the transform of a helix.<ref name="HelixTransform">
Cochran W, Crick FHC and Vand V. (1952) "The Structure of Synthetic Polypeptides. I. The Transform of Atoms on a Helix", ''[[Acta Crystallographica|Acta Cryst.]]'', '''5''', 581-586.</ref> Thus he was primed for the significance of the X-shape in photo 51.
*''[[#DNA-experiments|DNA-experiments]]'': Watson sees [[photo 51]].<ref name="TeaTime">Friday, January 30, 1953. Tea time. as noted in {{harvnb|McElheny|2004|p=52}}: Franklin confronts Watson and his paper - "Of course it [Pauling's pre-print] is wrong. DNA is not a helix." Watson runs away from Franklin and runs into Wilkins; they retreat to Wilkins' office, where Wilkins shows Watson [[photo 51]]. Watson immediately recognizes the diffraction pattern of a helix.
</ref>
 
The examples are continued in [[#Evaluation and improvement|"Evaluations and iterations"]] with ''[[#DNA-iterations|DNA-iterations]]''.<ref name="SameShape">
Saturday, February 28, 1953, as noted in {{harvnb|McElheny|2004|pp=57–59}}: Watson finds the base pairing which explains [[Chargaff's rules]] using his cardboard models.
</ref>
|}
 
==Truth and belief==
{{Main|Truth}}
In the same way that the Muslim scholar [[Alhazen]] sought truth during his pioneering studies in optics 1000 years ago, arriving at the truth is the goal of a scientific inquiry.<ref>"People start off with a belief and a prejudice—we all do. And the job of science is to set that aside to get to the truth." —[[Simon Singh]], as quoted in ''Wired'' [http://www.wired.com/magazine/2010/08/mf_qa_singh/ (August 30, 2010) interview by Robert Capps]</ref>
 
===Beliefs and biases===
[[Image:Jean Louis Théodore Géricault 001.jpg|thumb|Flying gallop [[Falsifiability|falsified]]; see image below.]]
 
Belief can alter observations; the human [[confirmation bias]] is a [[heuristic]] that leads a person with a particular belief to see things as reinforcing their belief, even if another observer would disagree. Researchers have often admitted that the first observations were a little imprecise, whereas the second and third were "adjusted to the facts". Eventually, factors such as [[openness to experience]], [[self-esteem]], time, and comfort can produce a readiness for new perception.<ref>"Observation and experiment are subject to a very popular myth. ... The knower is seen as a ... Julius Caesar winning his battles according to ... formula. Even research workers will admit that the first observation may have been a little imprecise, whereas the second and third were 'adjusted to the facts' ... until tradition, education, and familiarity have produced ''a readiness for stylized (that is directed and restricted) perception and action;'' until an answer becomes largely pre-formed in the question, and a decision confined merely to 'yes' or 'no' or perhaps to a numerical determination; until methods and apparatus automatically carry out the greatest part of the mental work for us." [[Ludwik Fleck]] labels this ''thought style''(''Denkstil''). {{harvnb|Fleck|1979| p=84}}.</ref>
 
[[Image:Muybridge race horse animated.gif|thumb|left|[[Eadweard Muybridge]]'s studies of a [[horse]] [[Horse gait#Gallop|galloping]]]]
[[Joseph Needham|Needham's]] ''Science and Civilization in China'' uses the 'flying gallop' image as an example of observation bias:<ref>{{harvnb|Needham|Wang|1954}} p.166 shows how the 'flying gallop' image propagated from China to the West.</ref> In these types of images, the legs of a [[Horse gait#Gallop|gallop]]ing horse are depicted as splayed, while the stop-action pictures of a horse's gallop by [[Eadweard Muybridge]] show otherwise. In a gallop, at the moment that no hoof is touching the ground, a horse's legs are gathered together and are not splayed. Earlier paintings depict the incorrect flying gallop observation.<!--But _why_ would observers be biased in favour of recalling splayed legs on a galloping horse?-->
 
This image demonstrates [[Ludwik Fleck|Ludwik Fleck's]] caution that people observe what they expect to observe, until shown otherwise; their beliefs will affect their observations (and, therefore, their subsequent actions, in a [[self-fulfilling prophecy]]). It is for this reason that scientific methodology prefers that [[Hypothesis|hypotheses]] be tested in [[Scientific control|controlled]] conditions which can be [[Reproducibility|reproduced]] by multiple researchers. With the [[scientific community|scientific community's]] pursuit of experimental control and reproducibility, cognitive biases are diminished.
 
===Certainty and myth===
A scientific theory hinges on [[empirical]] findings, and remains subject to [[falsifiability|falsification]] if new evidence is presented. That is, no theory is ever considered [[Certainty|certain]]. Theories very rarely result in vast changes in human understanding. Knowledge in science is gained by a gradual synthesis of information from different experiments, by various researchers, across different domains of science.<ref>Stanovich, Keith E. (2007). ''How to Think Straight About Psychology''. Boston: Pearson Education. pg 123</ref> Theories vary in the extent to which they have been tested and retained, as well as their acceptance in the scientific community.
 
In contrast to the always-provisional status of scientific theory, a [[myth]] can be enjoyed irrespective of its truth.<ref>"A myth is a belief given uncritical acceptance by members of a group ..." —Weiss, ''Business Ethics'' p. 15, as cited by Ronald R. Sims (2003) ''Ethics and corporate social responsibility: why giants fall'' p.21</ref> [[Imre Lakatos]] has noted that once a narrative is constructed its elements become easier to believe (this is called the [[narrative fallacy]]).<ref>[[Imre Lakatos]] (1976), ''[[Proofs and Refutations]]''</ref><ref>For more on the narrative fallacy, see also {{harvnb|Fleck|1979|p=27}}: "Words and ideas are originally phonetic and mental equivalences of the experiences coinciding with them. ... Such proto-ideas are at first always too broad and insufficiently specialized. ... Once a structurally complete and closed system of opinions consisting of many details and relations has been formed, it offers enduring resistance to anything that contradicts it."</ref>  That is, theories become accepted by a scientific community as evidence for the theory is presented, and as presumptions that are inconsistent with the evidence are falsified. -- The difference between a theory and a myth reflects a preference for [[A priori and a posteriori|''a posteriori'' versus ''a priori'']] knowledge. --{{Citation needed|date=April 2011}}
 
Thomas Brody notes that confirmed theories are subject to subsumption by other theories, as special cases of a more general theory. For example, thousands of years of scientific observations of the planets were explained by Newton's laws.  Thus the body of independent scientific statements can diminish.<ref>Thomas Brody (1993), ''The Philosophy Behind Physics'' pp.44-45</ref> Yet there is a preference in the scientific community for new, surprising statements, and the search for evidence that the new is true.<ref>{{harvnb|Goldhaber|Nieto|2010|page=940}}</ref> {{harvnb|Goldhaber|Nieto|2010|page=941}} additionally state that "If many closely neighboring subjects are described by connecting theoretical concepts, then a theoretical structure acquires a robustness which makes it increasingly hard —though certainly never impossible— to overturn."
 
==Elements of scientific method==
There are different ways of outlining the basic method used for scientific inquiry. The [[scientific community]] and [[philosophers of science]] generally agree on the following classification of method components. These methodological elements and organization of procedures tend to be more characteristic of [[natural science]]s than [[social science]]s. Nonetheless, the cycle of formulating hypotheses, testing and analyzing the results, and formulating new hypotheses, will resemble the cycle described below.
 
:Four essential elements<ref>See [[Hypothetico-deductive model|the hypothethico-deductive method]], for example, {{harvnb|Godfrey-Smith|2003|p=236}}.</ref><ref>{{harvnb|Jevons|1874|pp=265–6}}.</ref><ref>pp.65,73,92,398 —Andrew J. Galambos, ''Sic Itur ad Astra'' ISBN 0-88078-004-5(AJG learned scientific method from Felix Ehrenhaft</ref> of a scientific method<ref>{{harvnb|Galileo|1638|pp=v-xii,1–300}}</ref> are [[iteration]]s,<ref>{{harvnb|Brody|1993|pp=10–24}} calls this the "epistemic cycle": "The epistemic cycle starts from an initial model; iterations of the cycle then improve the model until an adequate fit is achieved."</ref><ref>Iteration example: Chaldean astronomers such as [[Kidinnu]] compiled astronomical data. [[Hipparchus]] was to use this data to calculate the [[precession]] of the [[Earth]]'s axis. Fifteen hundred years after Kidinnu, [[Al-Batani]], born in what is now Turkey, would use the collected data and improve Hipparchus' value for the precession of the Earth's axis. Al-Batani's value, 54.5 arc-seconds per year, compares well to the current value of 49.8 arc-seconds per year (26,000 years for Earth's axis to round the circle of [[nutation]]).</ref> [[recursion]]s,<ref>Recursion example: the Earth is itself a magnet, with its own North and South Poles [[William Gilbert (astronomer)|William Gilbert]] (in Latin 1600) ''De Magnete'', or ''On Magnetism and Magnetic Bodies''. Translated from Latin to English, selection by {{harvnb|Moulton|Schifferes|1960|pp=113–117}}. Gilbert created a ''terrella'', a lodestone ground into a spherical shape, which served as Gilbert's model for the Earth itself, as noted in {{harvnb|Bruno|1989|p=277}}.</ref> [[interleaving]]s, or [[Partially ordered set|orderings]] of the following:
:* [[#Characterizations|Characterizations]] (observations,<ref>"The foundation of general physics ... is experience. These ... everyday experiences we do not discover without deliberately directing our attention to them. Collecting information about these is ''observation''." —[[Hans Christian Ørsted]]("First Introduction to General Physics" ¶13, part of a series of public lectures at the University of Copenhagen. Copenhagen 1811, in Danish, printed by Johan Frederik Schulz. In Kirstine Meyer's 1920 edition of Ørsted's works, vol.'''III''' pp. 151-190. ) "First Introduction to Physics: the Spirit, Meaning, and Goal of Natural Science". Reprinted in German in 1822, Schweigger's ''Journal für Chemie und Physik'' '''36''', pp.458-488, as translated in {{harvnb|Ørsted|1997|p=292}}</ref> definitions, and measurements of the subject of inquiry)
:* [[#Hypothesis development|Hypotheses]]<ref>"When it is not clear under which law of nature an effect or class of effect belongs, we try to fill this gap by means of a guess. Such guesses have been given the name ''conjectures'' or ''[[hypotheses]]''." —[[Hans Christian Ørsted]](1811) "First Introduction to General Physics" as translated in {{harvnb|Ørsted|1997|p=297}}.</ref><ref>"In general we look for a new law by the following process. First we guess it. ...", —{{harvnb|Feynman|1965|p=156}}</ref> (theoretical, hypothetical [[explanation]]s of observations and measurements of the subject)<ref>"... the statement of a law - A depends on B - always transcends experience."—{{harvnb|Born|1949|p=6}}</ref>
:* [[#Predictions from the hypothesis|Predictions]] ([[reasoning]] including [[logic]]al [[Deductive reasoning|deduction]]<ref>"The student of nature ... regards as his property the experiences which the mathematician can only borrow. This is why he deduces theorems directly from the nature of an effect while the mathematician only arrives at them circuitously." —[[Hans Christian Ørsted]](1811) "First Introduction to General Physics" ¶17. as translated in {{harvnb|Ørsted|1997|p=297}}.</ref> from the [[hypothesis]] or [[theory]])
:* [[#Experiments|Experiments]]<ref>Salviati speaks: "I greatly doubt that Aristotle ever tested by experiment whether it be true that two stones, one weighing ten times as much as the other, if allowed to fall, at the same instant, from a height of, say, 100 cubits, would so differ in speed that when the heavier had reached the ground, the other would not have fallen more than 10 cubits." [http://galileo.phys.virginia.edu/classes/109N/tns61.htm Two New Sciences (1638)] —{{harvnb|Galileo|1638|pp=61–62}}. A more extended quotation is referenced by {{harvnb|Moulton|Schifferes|1960|pp=80–81}}.</ref> ([[Experiment|tests]] of all of the above)
 
Each element of a scientific method is subject to [[peer review]] for possible mistakes. These activities do not describe all that scientists do ([[#Dimensions of practice|see below]]) but apply mostly to experimental sciences (e.g., physics, chemistry, and  biology). The elements above are often taught in [[education|the educational system]].<ref>In the [[Inquiry-based learning|inquiry-based education]] paradigm, the stage of "characterization, observation, definition, …" is more briefly summed up under the rubric of a Question</ref>
 
Scientific method is not a recipe: it requires intelligence, imagination, and creativity.<ref>"To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science." —{{harvnb|Einstein|Infeld|1938|p=92}}.</ref> In this sense, it is not a mindless set of standards and procedures to follow,
but is rather an [[#Evaluation and improvement|ongoing cycle]], constantly developing more useful, accurate and comprehensive models and methods. For example, when Einstein developed the Special and General Theories of Relativity, he did not in any way refute or discount Newton's ''Principia''. On the contrary, if the astronomically large, the vanishingly small, and the extremely fast are reduced out from Einstein's theories — all phenomena that Newton could not have observed — Newton's equations remain. Einstein's theories are expansions and refinements of Newton's theories and, thus, increase our confidence in Newton's work.
 
A linearized, pragmatic scheme of the four points above is sometimes offered as a guideline for proceeding:<ref>Crawford S, Stucki L (1990), "Peer review and the changing research record", "J Am Soc Info Science", vol. 41, pp 223-228</ref>
 
# Define the question
# Gather information and resources (observe)
# Form hypothesis
# Perform experiment and collect data
# Analyze data
# Interpret data and draw conclusions that serve as a starting point for new hypothesis
# Publish results
# Retest (frequently done by other scientists)
 
The iterative cycle inherent in this step-by-step methodology goes from point 3 to 6 back to 3 again.
 
While this schema outlines a typical hypothesis/testing method,<ref>''See, e.g.'', {{harvnb|Gauch|2003}}, esp. chapters 5-8</ref> it should also be noted that a number of philosophers, historians and sociologists of science (perhaps most notably [[Paul Feyerabend]]) claim that such descriptions of scientific method have little relation to the ways science is actually practiced.
 
The "operational" paradigm combines the concepts of [[operational definition]], [[instrumentalism]], and [[utility]]:
 
The essential elements of a scientific method are [[operation (mathematics)|operations]], [[observation]]s, [[scientific modeling|models]], and a [[utility function]] for evaluating models.<ref>Cartwright, Nancy (1983), ''How the Laws of Physics Lie''. Oxford: Oxford University Press. ISBN 0-19-824704-4</ref>{{Failed verification|date=July 2009}}
* [[Operation (mathematics)|Operation]] - Some action done to the system being investigated
* [[Observation]] - What happens when the operation is done to the system
* [[Scientific modeling|Model]] - A [[fact]], [[hypothesis]], [[theory]], or the phenomenon itself at a certain moment
* [[Utility function|Utility Function]] - A measure of the usefulness of the model to explain, predict, and control, and of the cost of use of it. One of the elements of any scientific utility function is the [[Scientific modeling|refutability]] of the model. Another is its [[simplicity]], on the [[Principle of Parsimony]] also known as [[Occam's Razor]].
 
===Characterizations===
Scientific method depends upon increasingly sophisticated characterizations of the subjects of investigation. (The ''subjects'' can also be called [[:Category:Lists of unsolved problems|''unsolved problems'']] or the ''unknowns''.) For example, [[Benjamin Franklin]] correctly characterized [[St. Elmo's fire]] as [[electrical]] in [[nature]], but it has taken a long series of experiments and theory to establish this. While seeking the pertinent properties of the subjects, this careful thought may also entail some definitions and observations; the [[observations]] often demand careful [[measurements]] and/or counting.
 
The systematic, careful collection of measurements or counts of relevant quantities is often the critical difference between [[Pseudoscience|pseudo-sciences]], such as alchemy, and a science, such as chemistry or biology. Scientific measurements taken are usually tabulated, graphed, or mapped, and statistical manipulations, such as [[correlation]] and [[regression analysis|regression]], performed on them. The measurements might be made in a controlled setting, such as a laboratory, or made on more or less inaccessible or unmanipulatable objects such as stars or human populations. The measurements often require specialized [[scientific instrument]]s such as thermometers, spectroscopes, or voltmeters, and the progress of a scientific field is usually intimately tied to their invention and development.
 
{{Quotation2|"I am not accustomed to saying anything with certainty after only one or two observations."—[[Andreas Vesalius]] (1546) <ref>
Andreas Vesalius, ''Epistola, Rationem, Modumque Propinandi Radicis Chynae Decocti'' (1546), 141. Quoted and translated in C.D. O'Malley, ''Andreas Vesalius of Brussels'', (1964), 116. As quoted by {{harvnb|Bynum|Porter|2005|p=597}}: Andreas Vesalius,597#1.
</ref> }}
 
====Uncertainty====
Measurements in scientific work are also usually accompanied by estimates of their [[uncertainty]]. The uncertainty is often estimated by making repeated measurements of the desired quantity. Uncertainties may also be calculated by consideration of the uncertainties of the individual underlying quantities that are used. Counts of things, such as the number of people in a nation at a particular time, may also have an uncertainty due to limitations of the method used. Counts may only represent a sample of desired quantities, with an uncertainty that depends upon the sampling method used and the number of samples taken.
 
====Definition====
Measurements demand the use of ''[[operational definition]]s'' of relevant quantities. That is, a scientific quantity is described or defined by how it is measured, as opposed to some more vague, inexact or "idealized" definition. For example, [[electrical current]], measured in amperes, may be operationally defined in terms of the mass of silver deposited in a certain time on an electrode in an electrochemical device that is described in some detail. The operational definition of a thing often relies on comparisons with standards: the operational definition of "mass" ultimately relies on the use of an artifact, such as a certain kilogram of platinum-iridium kept in a laboratory in France.
 
The scientific definition of a term sometimes differs substantially from its [[natural language]] usage. For example, [[mass]] and [[weight]] overlap in meaning in common discourse, but have distinct meanings in [[mechanics]]. Scientific quantities are often characterized by their [[units of measurement|units of measure]] which can later be described in terms of conventional physical units when communicating the work.
 
New theories sometimes arise upon realizing that certain terms had not previously been sufficiently clearly defined. For example, [[Albert Einstein|Albert Einstein's]] first paper on [[Special relativity|relativity]] begins by defining [[Relativity of simultaneity|simultaneity]] and the means for determining [[length]]. These ideas were skipped over by [[Isaac Newton]] with, "''I do not define [[time in physics#Galileo: the flow of time|time]], space, place and [[motion (physics)|motion]], as being well known to all.''" Einstein's paper then demonstrates that they (viz., absolute time and length independent of motion) were approximations. [[Francis Crick]] cautions us that when characterizing a subject, however, it can be premature to define something when it remains ill-understood.<ref>
Crick, Francis (1994), ''The Astonishing Hypothesis'' ISBN 0-684-19431-7 p.20
</ref> In Crick's study of [[consciousness]], he actually found it easier to study [[awareness]] in the [[visual system]], rather than to study [[free will]], for example. His cautionary example was the gene; the gene was much more poorly understood before Watson and Crick's pioneering discovery of the structure of DNA; it would have been counterproductive to spend much time on the definition of the gene, before them.
 
====DNA-characterizations====
 
<span style="vertical-align:-120%">[[Image:DNA icon (25x25).png|left]]</span> The [[DNA#History_of_DNA_research|history]] of the discovery of the structure of DNA is a classic example of [[#Elements of scientific method|the elements of scientific method]]: in 1950 it was known that [[genetic inheritance]] had a mathematical description, starting with the studies of [[Gregor Mendel]]. But the mechanism of the gene was unclear. Researchers in [[William Lawrence Bragg|Bragg's]] laboratory at [[University of Cambridge|Cambridge University]] made [[X-ray]] [[diffraction]] pictures of various [[molecule]]s, starting with [[crystal]]s of [[salt]], and proceeding to more complicated substances. Using clues which were painstakingly assembled over the course of decades, beginning with its chemical composition, it was determined that it should be possible to characterize the physical structure of DNA, and the X-ray images would be the vehicle.<ref>{{harvnb|McElheny|2004}} p.34</ref> [[Scientific method#DNA-hypotheses|..''2. DNA-hypotheses'']]
 
====Another example: precession of Mercury====
[[Image:Perihelion precession.jpg|thumb|right|[[Apsidal precession|Precession]] of the [[perihelion]] (exaggerated)]]
 
The characterization element can require extended and extensive study, even centuries. It took thousands of years of measurements, from the [[Chaldea]]n, [[India]]n, [[Persian Empire|Persian]], [[Greece|Greek]], [[Arab]]ic and [[European ethnic groups|European]] astronomers, to record the motion of planet [[Earth]]. Newton was able to condense these measurements into consequences of his [[Newton's laws of motion|laws of motion]]. But the [[perihelion]] of the planet [[Mercury (planet)|Mercury]]'s [[orbit]] exhibits a precession that is not fully explained by Newton's laws of motion (see diagram to the right). The observed difference for Mercury's [[Apsidal precession|precession]] between Newtonian theory and relativistic theory (approximately 43 arc-seconds per century), was one of the things that occurred to Einstein as a possible early test of his theory of [[General Relativity]].
 
===Hypothesis development===
{{Main|Hypothesis formation}}
 
A [[hypothesis]] is a suggested explanation of a phenomenon, or alternately a reasoned proposal suggesting a possible correlation between or among a set of phenomena.
 
Normally hypotheses have the form of a [[mathematical model]]. Sometimes, but not always, they can also be formulated as [[existential quantification|existential statements]], stating that some particular instance of the phenomenon being studied has some characteristic and causal explanations, which have the general form of [[universal quantification|universal statements]], stating that every instance of the phenomenon has a particular characteristic.
 
Scientists are free to use whatever resources they have — their own creativity, ideas from other fields, [[inductive reasoning|induction]], [[Bayesian inference]], and so on — to imagine possible explanations for a phenomenon under study. [[Charles Sanders Peirce]], borrowing a page from [[Aristotle]] (''[[Prior Analytics]]'', [[Inquiry#Abduction|2.25]]) described the incipient stages of [[inquiry]], instigated by the "irritation of doubt" to venture a plausible guess, as [[Inquiry#Abduction|''abductive reasoning'']]. The history of science is filled with stories of scientists claiming a "flash of inspiration", or a hunch, which then motivated them to look for evidence to support or refute their idea. [[Michael Polanyi]] made such creativity the centerpiece of his discussion of methodology.
 
[[William Glen (geologist and historian)|William Glen]] observes that
 
: the success of a hypothesis, or its service to science, lies not simply in its perceived "truth", or power to displace, subsume or reduce a predecessor idea, but perhaps more in its ability to stimulate the research that will illuminate … bald suppositions and areas of vagueness.<ref>{{harvnb|Glen|1994|pp=37–38}}.</ref>
 
In general scientists tend to look for theories that are "[[Elegance|elegant]]" or "[[beauty|beautiful]]". In contrast to the usual English use of these terms, they here refer to a theory in accordance with the known facts, which is nevertheless relatively simple and easy to handle. [[Occam's Razor]] serves as a rule of thumb for making these determinations.
 
====DNA-hypotheses====
 
<span style="vertical-align:-120%">[[Image:DNA icon (25x25).png|left]]</span> [[Linus Pauling]] proposed that DNA might be a triple helix.<ref>
"The structure that we propose is a three-chain structure, each chain being a helix" — Linus Pauling, as quoted on p. 157 by Horace Freeland Judson (1979), ''The Eighth Day of Creation'' ISBN 0-671-22540-5</ref> This hypothesis was also considered by [[Francis Crick]] and [[James D. Watson]] but discarded. When Watson and Crick learned of Pauling's hypothesis, they understood from existing data that Pauling was wrong<ref>
{{harvnb|McElheny|2004|pp=49–50}}: January 28, 1953 - Watson read Pauling's pre-print, and realized that in Pauling's model, DNA's phosphate groups had to be un-ionized. But DNA is an acid, which contradicts Pauling's model.
</ref> and that Pauling would soon admit his difficulties with that structure. So, the race was on to figure out the correct structure (except that Pauling did not realize at the time that he was in a race&mdash;[[#DNA-predictions|see section on "DNA-predictions" below)]]
 
===Predictions from the hypothesis===
{{Main|Prediction in science}}
 
Any useful hypothesis will enable [[prediction]]s, by [[reasoning]] including [[deductive reasoning]]. It might predict the outcome of an experiment in a laboratory setting or the observation of a phenomenon in nature. The prediction can also be statistical and only talk about probabilities.
 
It is essential that the outcome be currently unknown. Only in this case does the eventuation increase the probability that the hypothesis be true. If the outcome is already known, it's called a consequence and should have already been considered while [[Scientific method#Hypothesis development|formulating the hypothesis]].
 
If the predictions are not accessible by observation or experience, the hypothesis is not yet useful for the method, and must wait for others who might come afterward, and perhaps rekindle its line of reasoning. For example, a new technology or theory might make the necessary experiments feasible.
 
====DNA-predictions====
 
<span style="vertical-align:-120%">[[Image:DNA icon (25x25).png|left]]</span> [[James D. Watson]], [[Francis Crick]], and others hypothesized that DNA had a helical structure. This implied that DNA's X-ray diffraction pattern would be 'x shaped'.<ref>
June, 1952. as noted in {{harvnb|McElheny|2004|p=43}}: Watson had succeeded in getting X-ray pictures of TMV showing a diffraction pattern consistent with the transform of a helix.
</ref><ref>
Watson did enough work on [[Tobacco mosaic virus]] to produce the diffraction pattern for a helix, per Crick's work on the transform of a helix. pp. 137-138, Horace Freeland Judson (1979) ''The Eighth Day of Creation'' ISBN 0-671-22540-5
</ref>  This prediction followed from the work of Cochran, Crick and Vand<ref name="HelixTransform"/> (and independently by Stokes). The Cochran-Crick-Vand-Stokes theorem provided a mathematical explanation for the empirical observation that diffraction from helical structures produces x shaped patterns.
 
Also in their first paper, Watson and Crick predicted that the [[double helix]] structure provided a simple mechanism for [[DNA replication]], writing "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material".<ref>{{harvnb|McElheny|2004}} p.68: ''Nature'' April 25, 1953.</ref> [[Scientific method#DNA-experiments|'' ..4. DNA-experiments'']]
 
====Another example: general relativity====
 
[[Image:Gravitational lens-full.jpg|right|thumb|200px|[[gravitational lensing|Einstein's prediction (1907): Light bends in a gravitational field]]]]
 
Einstein's theory of [[General Relativity]] makes several specific predictions about the observable structure of [[space-time]], such as a prediction that [[light]] bends in a [[gravitational field]] and that the amount of bending depends in a precise way on the strength of that gravitational field. [[Arthur Eddington]]'s observations made during a 1919 [[solar eclipse]] supported General Relativity rather than Newtonian [[gravitation]].<ref>In March 1917, the [[Royal Astronomical Society]] announced that on May 29, 1919, the occasion of a [[total eclipse]] of the sun would afford favorable conditions for testing Einstein's [[General theory of relativity]]. One expedition, to [[Sobral, Ceará]], [[Brazil]], and Eddington's expedition to the island of [[Principe]] yielded a set of photographs, which, when compared to photographs taken at [[Sobral, Ceará|Sobral]] and at [[Greenwich Observatory]] showed that the deviation of light was measured to be 1.69 [[arc-second]]s, as compared to Einstein's desk prediction of 1.75 [[arc-second]]s. — Antonina Vallentin (1954), ''Einstein'', as quoted by Samuel Rapport and Helen Wright (1965), ''Physics'', New York: Washington Square Press, pp 294-295.</ref>
 
===Experiments===
{{Main|Experiment}}
{{merge|Scientific control|discuss=Talk:Scientific method#Merger proposal|date=March 2011}}
 
Once predictions are made, they can be tested by experiments. If test results contradict predictions, then the hypotheses are called into question and explanations may be sought. Sometimes experiments are conducted incorrectly and are at fault. If the results confirm the predictions, then the hypotheses are considered likely to be correct but might still be wrong and are subject to [[#Evaluation and improvement|further testing.]] The [[experimental control]] is a technique for dealing with observational error. This technique uses the contrast between multiple samples (or observations) under differing conditions, to see what varies or what remains the same. We vary the conditions for each measurement, to help isolate what has changed. [[Mill's canons]] can then help us figure out what the important factor is.<ref>[[John Stuart Mill|Mill, John Stuart]], "A System of Logic", University Press of the Pacific, Honolulu, 2002, ISBN 1-4102-0252-6.</ref> [[Factor analysis]] is one technique for discovering the important factor in an effect.
 
Depending on the predictions, the experiments can have different shapes. It could be a classical experiment in a laboratory setting, a [[double-blind]] study or an archaeological [[excavation (archaeology)|excavation]]. Even taking a plane from [[New York]] to [[Paris]] is an experiment which tests the [[aerodynamics|aerodynamical]] hypotheses used for constructing the plane.
 
Scientists assume an attitude of openness and accountability on the part of those conducting an experiment. Detailed record keeping is essential, to aid in recording and reporting on the experimental results, and providing evidence of the effectiveness and integrity of the procedure. They will also assist in reproducing the experimental results. Traces of this tradition can be seen in the work of [[Hipparchus]] (190-120 BCE), when determining a value for the precession of the Earth, while [[Scientific control|controlled experiments]] can be seen in the works of [[Islamic science|Muslim scientists]] such as [[Jābir ibn Hayyān]] (721-815 CE), [[Muhammad ibn Jābir al-Harrānī al-Battānī|al-Battani]] (853–929) and [[Ibn al-Haytham|Alhacen]] (965-1039).
 
====DNA-experiments====
 
<span style="vertical-align:-120%">[[Image:DNA icon (25x25).png|left]]</span> Watson and Crick showed an initial (and incorrect) proposal for the structure of DNA to a team from Kings College - [[Rosalind Franklin]], [[Maurice Wilkins]], and [[Raymond Gosling]]. Franklin immediately spotted the flaws which concerned the water content. Later Watson saw Franklin's detailed [[Photo 51|X-ray diffraction images]] which showed an [http://www.pbs.org/wgbh/nova/photo51/ X-shape] and confirmed that the structure was helical.<ref name="TeaTime"/><ref>
"The instant I saw the picture my mouth fell open and my pulse began to race." —{{harvnb|Watson|1968|p=167}} Page 168 shows the X-shaped pattern of the B-form of [[DNA]], clearly indicating crucial details of its helical structure to Watson and Crick.
*{{harvnb|McElheny|2004}} p.52 dates the Franklin-Watson confrontation as Friday, January 30, 1953. Later that evening, Watson urges Wilkins to begin model-building immediately. But Wilkins agrees to do so only after Franklin's departure.
</ref> This rekindled Watson and Crick's model building and led to the correct structure. [[Scientific method#DNA-characterizations|''..1. DNA-characterizations'']]
 
===Evaluation and improvement===
The scientific process is iterative. At any stage it is possible to refine its [[accuracy and precision]], so that some consideration will lead the scientist to repeat an earlier part of the process. Failure to develop an interesting hypothesis may lead a scientist to re-define the subject they are considering. Failure of a hypothesis to produce interesting and testable predictions may lead to reconsideration of the hypothesis or of the definition of the subject. Failure of the experiment to produce interesting results may lead the scientist to reconsidering the experimental method, the hypothesis or the definition of the subject.
 
Other scientists may start their own research and enter the process at any stage. They might adopt the characterization and formulate their own hypothesis, or they might adopt the hypothesis and deduce their own predictions. Often the experiment is not done by the person who made the prediction and the characterization is based on experiments done by someone else. Published results of experiments can also serve as a hypothesis predicting their own reproducibility.
 
====DNA-iterations====
 
<span style="vertical-align:-120%">[[Image:DNA icon (25x25).png|left]]</span> After considerable fruitless experimentation, being discouraged by their superior from continuing, and numerous false starts,<ref>{{harvnb|McElheny|2004}} p.53: The weekend (January 31-February 1) after seeing photo 51, Watson informs Bragg of the X-ray diffraction image of DNA in B form. Bragg gives them permission to restart their research on DNA (that is, model building).</ref><ref>{{harvnb|McElheny|2004}} p.54:  On Sunday February 8, 1953, Maurice Wilkes gives Watson and Crick permission to work on models, as Wilkes is not yet going to build models until Franklin has left DNA research.</ref><ref>{{harvnb|McElheny|2004}} p.56: [[Jerry Donohue]], on sabbatical from Pauling's lab and visiting Cambridge, advises Watson that textbook form of the base pairs was incorrect for DNA base pairs; rather, the keto form of the base pairs should be used instead. This form allowed the bases' hydrogen bonds to pair 'unlike' with 'unlike', rather than to pair 'like' with 'like', as Watson was inclined to model, on the basis of the textbook statements. On February 27, 1953, Watson was convinced enough to cut out cardboard models of the nucleotides in the keto form.</ref> Watson and Crick were able to infer the essential structure of [[DNA]] by concrete [[model (abstract)|modeling]] [[DNA#History_of_DNA_research|of the physical shapes]] of the [[nucleotide]]s which comprise it.<ref name="SameShape" /><ref>
"Suddenly I became aware that an [[adenine]]-[[thymine]] pair held together by two [[hydrogen bond]]s was identical in shape to a [[guanine]]-[[cytosine]] pair held together by at least two hydrogen bonds. ..." —{{harvnb|Watson|1968|pp=194–197}}.
*{{harvnb|McElheny|2004}} p.57 Saturday, February 28, 1953, Watson tries 'like with like' and admits these base pairs don't have hydrogen bonds that line up. But after trying 'unlike with unlike', and getting [[Jerry Donohue]]'s approval, the base pairs are identical in shape (as Watson has stated above in his 1968 ''Double Helix'' memoir quoted above). Watson now feels confident enough to inform Crick. (Of course, 'unlike with unlike' increases the number of possible [[codon]]s, if this scheme were a [[genetic code]].)
</ref> They were guided by the bond lengths which had been deduced by [[Linus Pauling]] and by [[Rosalind Franklin]]'s X-ray diffraction images. [[Scientific method#DNA example|..''DNA Example'']]
 
===Confirmation===
Science is a social enterprise, and scientific work tends to be accepted by the community when it has been confirmed. Crucially, experimental and theoretical results must be reproduced by others within the scientific community. Researchers have given their lives for this vision; [[Georg Wilhelm Richmann]] was killed by [[ball lightning]] (1753) when attempting to replicate the 1752 kite-flying experiment of [[Benjamin Franklin]].<ref>
See, e.g., ''Physics Today'', '''59'''(1), p42. [http://ptonline.aip.org/journals/doc/PHTOAD-ft/vol_59/iss_1/42_1.shtml?bypassSSO=1 Richmann electrocuted in St. Petersburg (1753)]
</ref>
 
To protect against bad science and fraudulent data, governmental research-granting agencies such as the [[National Science Foundation]], and science journals including ''Nature'' and ''Science'', have a policy that researchers must archive their data and methods so other researchers can access it, test the data and methods and build on the research that has gone before. [[Scientific data archiving]] can be done at a number of national archives in the U.S. or in the [[World Data Center]].
 
==Models of scientific inquiry==
{{Main|Models of scientific inquiry}}
 
===Classical model===
The classical model of scientific inquiry derives from Aristotle,<ref>
[[Aristotle]], "[[Prior Analytics]]", [[Hugh Tredennick]] (trans.), pp. 181-531 in ''Aristotle, Volume&nbsp;1'', [[Loeb Classical Library]], William Heinemann, London, UK, 1938.
</ref> who distinguished the forms of approximate and exact reasoning, set out the threefold scheme of [[abductive reasoning|abductive]], [[deductive reasoning|deductive]], and [[inductive reasoning|inductive]] inference, and also treated the compound forms such as reasoning by [[analogy]].
 
===Pragmatic model===
{{See also|Pragmatic theory of truth}}
In 1877,<ref name=Fixation>Peirce (1877), "The Fixation of Belief", ''Popular Science Monthly'', v. 12, pp. 1–15. Reprinted often, including (''Collected Papers of Charles Sanders Peirce'' v. 5, paragraphs 358–87), (''The Essential Peirce'', v. 1, pp. 109–23). ''Peirce.org'' [http://www.peirce.org/writings/p107.html Eprint]. ''Wikisource'' [[s:The Fixation of Belief|Eprint]].</ref> [[Charles Sanders Peirce]] ({{IPAc-en|icon|ˈ|p|ɜr|s}} like "purse"; 1839–1914) characterized inquiry in general not as the pursuit of truth ''per se'' but as the struggle to move from irritating, inhibitory doubts born of surprises, disagreements, and the like, and to reach a secure belief, belief being that on which one is prepared to act. He framed scientific inquiry as part of a broader spectrum and as spurred, like inquiry generally, by actual doubt, not mere verbal or [[hyperbolic doubt]], which he held to be fruitless.<ref>"What one does not in the least doubt one should not pretend to doubt; but a man should train himself to doubt," said Peirce in a brief intellectual autobiography; see Ketner, Kenneth Laine (2009) "Charles Sanders Peirce: Interdisciplinary Scientist" in ''The Logic of Interdisciplinarity''). Peirce held that actual, genuine doubt originates externally, usually in surprise, but also that it is to be sought and cultivated, "provided only that it be the weighty and noble metal itself, and no counterfeit nor paper substitute"; in "Issues of Pragmaticism", ''The Monist'', v. XV, n. 4, pp. 481-99, see [http://www.archive.org/stream/monistquart15hegeuoft#page/484/mode/1up p. 484], and [http://www.archive.org/stream/monistquart15hegeuoft#page/491/mode/1up p. 491]. (Reprinted in ''Collected Papers'' v. 5, paragraphs 438-63, see 443 and 451).</ref> He outlined four methods of settling opinion, ordered from least to most successful:
# The method of tenacity (policy of sticking to initial belief) — which brings comforts and decisiveness but leads to trying to ignore contrary information and others' views as if truth were intrinsically private, not public. It goes against the social impulse and easily falters since one may well notice when another's opinion is as good as one's own initial opinion. Its successes can shine but tend to be transitory.
# The method of authority — which overcomes disagreements but sometimes brutally. Its successes can be majestic and long-lived, but it cannot operate thoroughly enough to suppress doubts indefinitely, especially when people learn of other societies present and past.
# The method of congruity or the ''a priori'' or the dilettante or "what is agreeable to reason" — which promotes conformity less brutally but depends on taste and fashion in [[paradigm]]s and can go in circles over time, along with barren disputation. It is more intellectual and respectable but, like the first two methods, sustains capricious and accidental beliefs, destining some minds to doubts.
# The scientific method — the method wherein inquiry regards itself as [[Fallibilism|fallible]] and purposely tests itself and criticizes, corrects, and improves itself.
 
Peirce held that slow, stumbling [[wikt:ratiocination|ratiocination]] can be dangerously inferior to instinct and traditional sentiment in practical matters, and that the scientific method is best suited to theoretical research,<ref>Peirce (1898), "Philosophy and the Conduct of Life", Lecture 1 of the Cambridge (MA) Conferences Lectures, published in ''Collected Papers'' v. 1, paragraphs 616-48 in part and in ''Reasoning and the Logic of Things'', Ketner (ed., intro.) and Putnam (intro., comm.), pp. 105-22, reprinted in ''Essential Peirce'' v. 2, pp. 27-41.</ref> which in turn should not be trammeled by the other methods and practical ends; reason's "first rule" is that, in order to learn, one must desire to learn and, as a corollary, must not block the way of inquiry.<ref>Peirce (1899), "F.R.L." [First Rule of Logic], ''Collected Papers'' v. 1, paragraphs 135-40, [http://www.princeton.edu/~batke/peirce/frl_99.htm Eprint]</ref> The scientific method excels the others by being deliberately designed to arrive — eventually — at the most secure beliefs, upon which the most successful practices can be based. Starting from the idea that people seek not truth ''per se'' but instead to subdue irritating, inhibitory doubt, Peirce showed how, through the struggle, some can come to submit to truth for the sake of belief's integrity, seek as truth the guidance of potential practice correctly to its given goal, and wed themselves to the scientific method.<ref name=Fixation/><ref>''Collected Papers'' v. 5, in paragraph 582, from 1898:
{{quote|... [rational] inquiry of every type, fully carried out, has the vital power of self-correction and of growth. This is a property so deeply saturating its inmost nature that it may truly be said that there is but one thing needful for learning the truth, and that is a hearty and active desire to learn what is true.}}</ref>
 
For Peirce, rational inquiry implies presuppositions about truth and the real; to reason is to presuppose (and at least to hope), as a principle of the reasoner's self-regulation, that the real is discoverable and independent of our vagaries of opinion. In that vein he defined truth as the correspondence of a sign (in particular, a proposition) to its object and, pragmatically, not as actual consensus of some definite, finite community (such that to inquire would be to poll the experts), but instead as that final opinion which all investigators ''would'' reach sooner or later but still inevitably, if they were to push investigation far enough, even when they start from different points.<ref name=How>Peirce (1877), "How to Make Our Ideas Clear", ''Popular Science Monthly'', v. 12, pp. 286–302. Reprinted often, including ''Collected Papers'' v. 5, paragraphs 388–410, ''Essential Peirce'' v. 1, pp. 124–41. ''Arisbe''[http://www.cspeirce.com/menu/library/bycsp/ideas/id-frame.htm Eprint]. ''Wikisource'' [[s:How to Make Our Ideas Clear|Eprint]].</ref> In tandem he defined the real as a true sign's object (be that object a possibility or quality, or an actuality or brute fact, or a necessity or norm or law), which is what it is independently of any finite community's opinion and, pragmatically, depends only on the final opinion destined in a sufficient investigation. That is a destination as far, or near, as the truth itself to you or me or the given finite community. Thus his theory of inquiry boils down to "Do the science." Those conceptions of truth and the real involve the idea of a community both without definite limits (and thus potentially self-correcting as far as needed) and capable of definite increase of knowledge.<ref>Peirce (1868), "Some Consequences of Four Incapacities", ''Journal of Speculative Philosophy'' v. 2, n. 3, pp. 140–57. Reprinted ''Collected Papers'' v. 5, paragraphs 264–317, ''The Essential Peirce'' v. 1, pp. 28–55, and elsewhere. [http://www.cspeirce.com/menu/library/bycsp/conseq/cn-frame.htm ''Arisbe'' Eprint]</ref> As inference, "logic is rooted in the social principle" since it depends on a standpoint that is, in a sense, unlimited.<ref>Peirce (1878), "The Doctrine of Chances", ''Popular Science Monthly'' v. 12, pp. 604-15, see pp. [http://www.archive.org/stream/popscimonthly12yoummiss#page/618/mode/1up 610]-11 via ''Internet Archive''. Reprinted ''Collected Papers'' v. 2, paragraphs 645-68, ''Essential Peirce'' v. 1, pp. 142-54. "...death makes the number of our risks, the number of our inferences, finite, and so makes their mean result uncertain. The very idea of probability and of reasoning rests on the assumption that this number is indefinitely great. .... ...logicality inexorably requires that our interests shall not be limited. .... Logic is rooted in the social principle."</ref>
 
Paying special attention to the generation of explanations, Peirce outlined scientific method as a coordination of three kinds of inference in a purposeful cycle aimed at settling doubts, as follows (in §III–IV in "A Neglected Argument"<ref name=NA>Peirce (1908), "A Neglected Argument for the Reality of God", ''Hibbert Journal'' v. 7, pp. 90-112. [[Wikisource:A Neglected Argument for the Reality of God]] with added notes. Reprinted with previously unpublished part, ''Collected Papers'' v. 6, paragraphs 452-85, ''The Essential Peirce'' v. 2, pp. 434-50, and elsewhere.</ref> except as otherwise noted):
 
1. '''[[Abductive reasoning|Abduction]]''' (or retroduction). Guessing, inference to explanatory hypotheses for selection of those best worth trying. From abduction, Peirce distinguishes induction as inferring, on the basis of tests, the proportion of truth in the hypothesis. Every inquiry, whether into ideas, brute facts, or norms and laws, arises from surprising observations in one or more of those realms (and for example at any stage of an inquiry already underway). All explanatory content of theories comes from abduction, which guesses a new or outside idea so as to account in a simple, economical way for a surprising or complicative phenomenon. Oftenest, even a well-prepared mind guesses wrong. But the modicum of success of our guesses far exceeds that of sheer luck and seems born of attunement to nature by instincts developed or inherent, especially insofar as best guesses are optimally plausible and simple in the sense, said Peirce, of the "facile and natural", as by [[Galileo]]'s natural light of reason and as distinct from "logical simplicity". Abduction is the most fertile but least secure mode of inference. Its general rationale is inductive: it succeeds often enough and, without it, there is no hope of sufficiently expediting inquiry (often multi-generational) toward new truths.<ref>Peirce (c. 1906), "PAP (Prolegomena for an Apology to Pragmatism)" (Manuscript 293, not the like-named article), ''The New Elements of Mathematics'' (NEM) 4:319-320, see first quote under "[http://www.helsinki.fi/science/commens/terms/abduction.html Abduction]" at ''Commens Dictionary of Peirce's Terms''.</ref> Coordinative method leads from abducing a plausible hypothesis to judging it for its testability<ref>Peirce, Carnegie application (L75, 1902), ''New Elements of Mathematics'' v. 4, pp. 37-38: {{quote|For it is not sufficient that a hypothesis should be a justifiable one. Any hypothesis which explains the facts is justified critically. But among justifiable hypotheses we have to select that one which is suitable for being tested by experiment.}}</ref> and for how its trial would economize inquiry itself.<ref name=econ>Peirce (1902), Carnegie application, see MS L75.329-330, from [http://www.cspeirce.com/menu/library/bycsp/l75/ver1/l75v1-08.htm#m27 Draft D] of Memoir 27:
{{quote|Consequently, to discover is simply to expedite an event that would occur sooner or later, if we had not troubled ourselves to make the discovery. Consequently, the art of discovery is purely a question of economics. The economics of research is, so far as logic is concerned, the leading doctrine with reference to the art of discovery. Consequently, the conduct of abduction, which is chiefly a question of heuretic and is the first question of heuretic, is to be governed by economical considerations.}}</ref> Peirce calls [[Pragmaticism|his pragmatism]] "the logic of abduction".<ref>Peirce (1903), "Pragmatism — The Logic of Abduction", ''Collected Papers'' v. 5, paragraphs 195-205, especially 196. [http://www.textlog.de/7663.html Eprint].</ref> His [[pragmatic maxim]] is: "Consider what effects that might conceivably have practical bearings you conceive the objects of your conception to have. Then, your conception of those effects is the whole of your conception of the object".<ref name=How /> His pragmatism is a method of reducing conceptual confusions fruitfully by equating the meaning of any conception with the conceivable practical implications of its object's conceived effects — a method of experimentational mental reflection hospitable to forming hypotheses and conducive to testing them. It favors efficiency. The hypothesis, being insecure, needs to have practical implications leading at least to mental tests and, in science, lending themselves to scientific tests. A simple but unlikely guess, if uncostly to test for falsity, may belong first in line for testing. A guess's objective probability recommends it as worth testing, while subjective likelihood can be misleading. Guesses can be chosen for trial strategically, for which Peirce gave as example the game of [[Twenty Questions]].<ref>Peirce, "On the Logic of Drawing Ancient History from Documents", ''Essential Peirce'' v. 2, see pp. 107-9. On Twenty Questions, p. 109: {{quote|Thus, twenty skillful hypotheses will ascertain what 200,000 stupid ones might fail to do.}}</ref> One can hope to discover only that which time would reveal through a learner's sufficient experience anyway, so the point is to expedite it; the economy of research is what demands the "leap" of abduction and governs its art.<ref name=econ />
 
2. '''[[Deductive reasoning|Deduction]]'''. Two stages:
:i. Explication. Unclearly premissed, but deductive, analysis of the hypothesis in order to render its parts as clear as possible.
:ii. Demonstration: Deductive Argumentation, [[Euclid]]ean in procedure. Explicit deduction of hypothesis's consequences as predictions, for induction to test, about evidence to be found. Corollarial or, if needed, Theorematic.
 
3. '''[[Inductive reasoning|Induction]]'''. The long-run validity of the rule of induction is deducible from the principle (presuppositional to reasoning in general<ref name=How />) that the real is only the object of the final opinion to which adequate investigation would lead;<ref>Peirce (1878), "The Probability of Induction", ''Popular Science Monthly'', v. 12, pp. 705-18, see [http://books.google.com/books?id=ZKMVAAAAYAAJ&pg=PA718 718] ''Google Books''; [http://www.archive.org/stream/popscimonthly12yoummiss#page/728/mode/1up 718] via ''Internet Archive''. Reprinted often, including (''Collected Papers'' v. 2, paragraphs 669-93), (''The Essential Peirce'' v. 1, pp. 155-69).</ref> anything to which no such process would ever lead would not be real. Induction involving ongoing tests or observations follows a method which, sufficiently persisted in, will diminish its error below any predesignate degree. Three stages:
:i. Classification. Unclearly premissed, but inductive, classing of objects of experience under general ideas.
:ii. Probation: direct (and explicit) Inductive Argumentation. Crude (the enumeration of instances) or Gradual (new estimate of proportion of truth in the hypothesis after each test). Gradual Induction is Qualitative or Quantitative; if Quantitative, then dependent on measurements, [[Charles Sanders Peirce#Probability and statistics|or on statistics]], or on countings.
:iii. Sentential Induction. "...which, by Inductive reasonings, appraises the different Probations singly, then their combinations, then makes self-appraisal of these very appraisals themselves, and passes final judgment on the whole result".
 
===Computational approaches===
Many subspecialties of [[applied logic]] and [[computer science]], such as [[artificial intelligence]], [[machine learning]], [[computational learning theory]], [[inferential statistics]], and [[knowledge representation]], are concerned with setting out computational, logical, and statistical frameworks for the various types of inference involved in scientific inquiry. In particular, they contribute [[abductive reasoning|hypothesis formation]], [[deductive reasoning|logical deduction]], and [[inductive reasoning|empirical testing]]. Some of these applications draw on [[measure (mathematics)|measures]] of [[complexity]] from [[algorithmic information theory]] to guide the making of predictions from prior [[probability distribution|distributions]] of experience, for example, see the complexity measure called the ''[[speed prior]]'' from which a computable strategy for optimal inductive reasoning can be derived.
 
==Communication and community==
Frequently a scientific method is employed not only by a single person, but also by several people cooperating directly or indirectly. Such cooperation can be regarded as one of the defining elements of a [[scientific community]]. Various techniques have been developed to ensure the integrity of that scientific method within such an environment.
 
===Peer review evaluation===
Scientific journals use a process of ''[[peer review]]'', in which scientists' manuscripts are submitted by editors of scientific journals to (usually one to three) fellow (usually anonymous) scientists familiar with the field for evaluation. The referees may or may not recommend publication, publication with suggested modifications, or, sometimes, publication in another journal. This serves to keep the scientific literature free of unscientific or [[Pseudoscience|pseudoscientific]] work, to help cut down on obvious errors, and generally otherwise to improve the quality of the material. The peer review process can have limitations when considering research outside the conventional scientific paradigm: problems of "[[groupthink]]" can interfere with open and fair deliberation of some new research.<ref>. Brown, C. (2005) Overcoming Barriers to Use of Promising Research Among Elite Middle East Policy Groups, Journal of Social Behaviour and Personality, Select Press.</ref>
 
===Documentation and replication===
{{Main|Reproducibility}}
Sometimes experimenters may make systematic errors during their experiments, unconsciously veer from a scientific method ([[Pathological science]]) for various reasons, or, in rare cases, deliberately report false results. Consequently, it is a common practice for other scientists to attempt to repeat the experiments in order to duplicate the results, thus further validating the hypothesis.
 
====Archiving====
As a result, researchers are expected to practice [[scientific data archiving]] in compliance with the policies of government funding agencies and scientific journals. Detailed records of their experimental procedures, raw data, statistical analyses and source code are preserved in order to provide evidence of the effectiveness and integrity of the procedure and assist in [[Reproducibility|reproduction]]. These procedural records may also assist in the conception of new experiments to test the hypothesis, and may prove useful to engineers who might examine the potential practical applications of a discovery.
 
====Data sharing====
When additional information is needed before a study can be reproduced, the author of the study is expected to provide it promptly. If the author refuses to [[data sharing|share data]], appeals can be made to the journal editors who published the study or to the institution which funded the research.
 
====Limitations====
Since it is impossible for a scientist to record ''everything'' that took place in an experiment, facts selected for their apparent relevance are reported. This may lead, unavoidably, to problems later if some supposedly irrelevant feature is questioned. For example, [[Heinrich Hertz]] did not report the size of the room used to test Maxwell's equations, which later turned out to account for a small deviation in the results. The problem is that parts of the theory itself need to be assumed in order to select and report the experimental conditions. The observations are hence sometimes described as being 'theory-laden'.
 
===Dimensions of practice===
{{See|Rhetoric of science}}
 
The primary constraints on contemporary western science are:
* Publication, i.e. [[Peer review]]
* Resources (mostly funding)
It has not always been like this: in the old days of the "[[gentleman scientist]]" funding (and to a lesser extent publication) were far weaker constraints.
 
Both of these constraints indirectly bring in a scientific method — work that too obviously violates the constraints will be difficult to publish and difficult to get funded. Journals do not require submitted papers to conform to anything more specific than "good scientific practice" and this is mostly enforced by peer review. Originality, importance and interest are more important - see for example the [http://www.nature.com/nature/submit/get_published/index.html author guidelines] for [[Nature (journal)|''Nature'']].
 
==Philosophy and sociology of science==
{{Main|Philosophy of science|Sociology of science}}
 
Philosophy of science looks at the underpinning logic of the scientific method, at what separates [[Demarcation problem|science from non-science]], and the [[Research ethics|ethic]] that is implicit in science. There are basic assumptions derived from philosophy that form the base of the scientific method - namely, that reality is objective and consistent, that humans have the capacity to perceive reality accurately, and that rational explanations exist for elements of the real world. These assumptions from [[naturalism (philosophy)|methodological naturalism]] form the basis on which science is grounded. [[Logical positivism|Logical Positivist]], [[empiricism|empiricist]], [[falsifiability|falsificationist]], and other theories have claimed to give a definitive account of the logic of science, but each has in turn been criticized.
 
[[Thomas Kuhn]] examined the history of science in his ''[[The Structure of Scientific Revolutions]]'', and found that the actual method used by scientists differed dramatically from the then-espoused method. His observations of science practice are essentially sociological and do not speak to how science is or can be practiced in other times and other cultures.
 
[[Norwood Russell Hanson]], [[Imre Lakatos]] and [[Thomas Kuhn]] have done extensive work on the "theory laden" character of observation. Hanson (1958) first coined the term for the idea that all observation is dependent on the conceptual framework of the observer, using the concept of [[gestalt]] to show how preconceptions can affect both observation and description<ref>{{cite book
|last=Hanson
|first=Norwood
|title=Patterns of Discovery
|year=1958
|publisher=Cambridge University Press
|isbn=0-521-05197-5
}}</ref>. He opens Chapter 1 with a discussion of the [[Golgi_apparatus|Golgi bodies]] and their initial rejection as an artefact of staining technique, and a discussion of [[Tycho Brahe|Brahe]] and [[Johannes Kepler|Kepler]] observing the dawn and seeing a "different" sun rise despite the same physiological phenomenon.  Kuhn <ref>{{harvnb|Kuhn|1962|p=113}}
ISBN 978-1443255448
</ref> and Feyerabend <ref>Feyerabend, Paul K (1960) "Patterns of Discovery" The Philosophical Review (1960) vol. 69 (2) pp. 247-252</ref> acknowledge the pioneering significance of his work.
 
Kuhn (1961) said the scientist generally has a theory in mind before designing and undertaking experiments so as to make empirical observations, and that the "route from theory to measurement can almost never be traveled backward". This implies that the way in which theory is tested is dictated by the nature of the theory itself, which led Kuhn (1961, p.&nbsp;166) to argue that "once it has been adopted by a profession ... no theory is recognized to be testable by any quantitative tests that it has not already passed".<ref>[[Thomas Kuhn|Kuhn, Thomas S.]], "The Function of Measurement in Modern Physical Science", ''ISIS'' 52(2), 161–193, 1961.</ref>
 
[[Paul Feyerabend]] similarly examined the history of science, and was led to deny that science is genuinely a methodological process. In his book ''[[Against Method]]'' he argues that scientific progress is ''not'' the result of applying any particular method. In essence, he says that for any specific method or norm of science, one can find a historic episode where violating it has contributed to the progress of science. Thus, if believers in a scientific method wish to express a single universally valid rule, Feyerabend jokingly suggests, it should be 'anything goes'.<ref>[[Paul Feyerabend|Feyerabend, Paul K.]], ''Against Method, Outline of an Anarchistic Theory of Knowledge'', 1st published, 1975. Reprinted, Verso, London, UK, 1978.
</ref> Criticisms such as his led to the [[strong programme]], a radical approach to the [[sociology of science]].
 
In his 1958 book, ''Personal Knowledge'', chemist and philosopher [[Michael Polanyi]] (1891–1976) criticized the common view that the scientific method is purely objective and generates objective knowledge. Polanyi cast this view as a misunderstanding of the scientific method and of the nature of scientific inquiry, generally. He argued that scientists do and must follow personal passions in appraising facts and in determining which scientific questions to investigate. He concluded that a structure of liberty is essential for the advancement of science - that the freedom to pursue science for its own sake is a prerequisite for the production of knowledge through peer review and the scientific method.
 
The [[postmodernism|postmodernist]] critiques of science have themselves been the subject of intense controversy. This ongoing debate, known as the [[science wars]], is the result of conflicting values and assumptions between the postmodernist and [[Scientific realism|realist]] camps. Whereas postmodernists assert that scientific knowledge is simply another discourse (note that this term has special meaning in this context) and not representative of any form of fundamental truth, [[Scientific realism|realists]] in the scientific community maintain that scientific knowledge does reveal real and fundamental truths about reality. Many books have been written by scientists which take on this problem and challenge the assertions of the postmodernists while defending science as a legitimate method of deriving truth.<ref>
* ''Higher Superstition: The Academic Left and Its Quarrels with Science'', The Johns Hopkins University Press, 1997
* ''Fashionable Nonsense: Postmodern Intellectuals' Abuse of Science'', Picador; 1st Picador USA Pbk. Ed edition, 1999
* ''The Sokal Hoax: The Sham That Shook the Academy'', University of Nebraska Press, 2000 ISBN 0-8032-7995-7
* ''A House Built on Sand: Exposing Postmodernist Myths About Science'', Oxford University Press, 2000
* ''Intellectual Impostures'', Economist Books, 2003</ref>
 
===Luck and science===
[[File:Estudiante INTEC.jpg|thumb|right|130px|Highly controlled experimentation allows researchers to catch their mistakes, but it also makes anomalies (which no one knew to look for) easier to see]]
Somewhere between 33% and 50% of all scientific discoveries are estimated to have been ''stumbled upon'', rather than sought out. This may explain why scientists so often express that they were lucky.<ref name=DunbarLuck>Dunbar, K., & Fugelsang, J. (2005). Causal thinking in science: How scientists and students interpret the unexpected. In M. E. Gorman, R. D. Tweney, D. Gooding & A. Kincannon (Eds.), Scientific and Technical Thinking (pp. 57-79). Mahwah, NJ: Lawrence Erlbaum Associates.</ref> [[Louis Pasteur]] is credited with the famous saying that "Luck favours the prepared mind", but some psychologists have begun to study what it means to be 'prepared for luck' in the scientific context. Research is showing that scientists are taught various heuristics that tend to harness chance and the unexpected.'''<ref name="DunbarLuck"/><ref name="Oliver, J.E. 1991">Oliver, J.E. (1991) Ch2. of The incomplete guide to the art of discovery. New York:NY, Columbia University Press.</ref>''' This is what professor of economics [[Nassim Nicholas Taleb]] calls "Anti-fragility"; while some systems of investigation are fragile in the face of human error, human bias, and randomness, the scientific method is more than resistant or tough - it actually benefits from such randomness in many ways (it is anti-fragile). Taleb believes that the more anti-fragile the system, the more it will flourish in the real world.<ref>Talib contributes a brief description of anti-fragility, http://www.edge.org/q2011/q11_3.html</ref>
 
Psychologist Kevin Dunbar says the process of discovery often starts with researchers finding bugs in their experiments. These unexpected results lead researchers to try and fix what they ''think'' is an error in their methodology. Eventually, the researcher decides the error is too persistent and systematic to be a coincidence. The highly controlled, cautious and curious aspects of the scientific method are thus what make it well suited for identifying such persistent systematic errors. At this point, the researcher will begin to think of theoretical explanations for the error, often seeking the help of colleagues across different domains of expertise.<ref name="DunbarLuck"/><ref name="Oliver, J.E. 1991"/>
 
==History==
{{Main|History of scientific method}}
{{See also|Timeline of the history of scientific method}}
 
[[Image:Aristotle Altemps Inv8575.jpg|thumb|150px|[[Aristotle]], 384 BC–322 BC. "As regards his method, Aristotle is recognized as the inventor of scientific method because of his refined analysis of logical implications contained in demonstrative discourse, which goes well beyond natural logic and does not owe anything to the ones who philosophized before him."—Riccardo Pozzo<ref>Riccardo Pozzo (2004) [http://books.google.com/books?id=vayp8jxcPr0C&pg=&dq&hl=en#v=onepage&q=&f=false ''The impact of Aristotelianism on modern philosophy'']. CUA Press. p.41. ISBN 0813213479</ref>]]
 
The development of the scientific method is inseparable from the [[history of science]] itself. [[Ancient Egypt]]ian documents describe empirical methods in [[History of astronomy|astronomy]],<ref>The [[ancient Egypt]]ians observed that  [[heliacal rising]] of a certain star, ''Sothis'' (Greek for ''Sopdet'' (Egyptian), known to the West as ''[[Sirius]]''), marked the annual flooding of the [[Nile river]]. See {{Citation | edition = 2 | publisher = [[Dover Publications]] | last = Neugebauer | first = Otto | author-link = Otto E. Neugebauer | title = The Exact Sciences in Antiquity | origyear = 1957 | year = 1969 | isbn = 978-048622332-2 | url = http://books.google.com/?id=JVhTtVA2zr8C}}, p.82, and also the 1911 ''Britannica'', "Egypt".</ref> [[History of mathematics|mathematics]],<ref>The [[Rhind papyrus]] lists practical examples in [[arithmetic]] and [[geometry]]  —1911 ''Britannica'', "Egypt".</ref> and [[History of medicine#Egypt|medicine]].<ref>The [[Ebers papyrus]] lists some of the 'mysteries of the physician', as cited in the 1911 ''Britannica'', "Egypt"</ref> The ancient Greek philosopher [[Thales]] in the 6th century BC refused to accept supernatural, religious or mythological explanations for natural phenomena, proclaiming that every event had a natural cause.  The development of [[deductive reasoning]] by [[Plato]] was an important step towards the scientific method.  [[Empiricism]] seems to have been formalized by [[Aristotle]], who believed that universal truths could be reached via [[inductive reasoning|induction]].
 
There are hints of experimental methods from the Classical world (e.g., those reported by Archimedes in a report recovered early in the 20th century CE from an [[Archimedes Palimpsest|overwritten manuscript]]), but the first clear instances of an [[experiment]]al scientific method seem to have been developed in the Arabic world, by [[Islamic science|Muslim scientists]] (See [[Alhazen]]),<ref>Alhazen, ''[[Critique of Ptolemy]]'' as referenced in {{harvnb|Sambursky|1974|p=139}}</ref> who introduced the use of [[experiment]]ation and [[quantification]] to distinguish between competing scientific theories set within a generally empirical orientation, perhaps by [[Ibn al-Haitham|Alhazen]] in his [[optics|optical]] experiments reported in his ''[[Book of Optics]]'' (1021).<ref>
Rosanna Gorini (2003), "Al-Haytham the Man of Experience, First Steps in the Science of Vision", ''[[International Society for the History of Islamic Medicine]]'', Institute of Neurosciences, Laboratory of Psychobiology and Psychopharmacology, Rome, Italy:
{{quote|"According to the majority of the historians al-Haytham was the pioneer of the modern scientific method. With his book he changed the meaning of the term optics and established experiments as the norm of proof in the field. His investigations are based not on abstract theories, but on experimental evidences and his experiments were systematic and repeatable."}}</ref>{{Verify credibility|date=September 2010}} The modern scientific method crystallized no later than in the 17th and 18th centuries. In his work ''[[Novum Organum]]'' (1620) — a reference to Aristotle's ''[[Organon]]'' — [[Francis Bacon]] outlined a new [[system of logic]] to improve upon the old [[philosophy|philosophical]] process of [[syllogism]].<ref>[[Francis Bacon (philosopher)|Bacon, Francis]] ''[[Novum Organum]] (The New Organon)'', 1620. Bacon's work described many of the accepted principles, underscoring the importance of [[theory]], empirical results, data gathering, experiment, and independent corroboration.
</ref> Then, in 1637, [[René Descartes]] established the framework for a scientific method's guiding principles in his treatise, ''[[Discourse on Method]]''. The writings of Alhazen, Bacon and Descartes are considered critical in the historical development of the modern scientific method, as are those of [[John Stuart Mill]].<ref name="mill">
{{Cite web
|url=http://plato.stanford.edu/entries/mill/#SciMet
|title=John Stuart Mill (Stanford Encyclopedia of Philosophy)
|publisher=plato.stanford.edu
|accessdate=2009-07-31
}}</ref>
 
In the late 19th century, [[Charles Sanders Peirce]] proposed a schema that would turn out to have considerable influence in the development of current scientific method generally. Peirce accelerated the progress on several fronts. Firstly, speaking in broader context in [http://www.cspeirce.com/menu/library/bycsp/ideas/id-frame.htm "How to Make Our Ideas Clear" (1878)], Peirce outlined an objectively verifiable method to test the truth of putative knowledge on a way that goes beyond mere foundational alternatives, focusing upon both ''deduction'' and ''induction''. He thus placed induction and deduction in a complementary rather than competitive context (the latter of which had been the primary trend at least since [[David Hume]], who wrote in the mid-to-late 18th century). Secondly, and of more direct importance to modern method, Peirce put forth the basic schema for hypothesis/testing that continues to prevail today. Extracting the theory of inquiry from its raw materials in classical logic, he refined it in parallel with the early development of symbolic logic to address the then-current problems in scientific reasoning. Peirce examined and articulated the three fundamental modes of reasoning that, as discussed above in this article, play a role in inquiry today, the processes that are currently known as [[abductive reasoning|abductive]], [[deductive reasoning|deductive]], and [[inductive reasoning|inductive]] inference. Thirdly, he played a major role in the progress of symbolic logic itself — indeed this was his primary specialty.
 
Beginning in the 1930s, [[Karl Popper]] argued that there is no such thing as inductive reasoning.<ref name=popper2>''Logik der Forschung'', new appendices ''*XVII''&ndash;''*XIX'' (not yet available in the English edition ''Logic of scientific discovery'')</ref> All inferences ever made, including in science, are purely<ref>''Logic of Scientific discovery'', p. 20</ref> deductive according to this view. Accordingly, he claimed that the empirical character of science has nothing to do with induction&mdash;but with the deductive property of [[falsifiability]] that scientific hypotheses have. Contrasting his views with inductivism and positivism, he even denied the existence of scientific method: "(1) There is no method of discovering a scientific theory (2) There is no method for ascertaining the truth of a scientific hypothesis, i.e., no method of verification; (3) There is no method for ascertaining whether a hypothesis is 'probable', or probably true".<ref name=popper>Karl Popper: On the non-existence of scientific method. ''Realism and the Aim of Science'' (1983)</ref> Instead, he held that there is only one universal method, a method not particular to science: The negative method of criticism, or colloquially termed [[trial and error]]. It covers not only all products of the human mind, including science, mathematics, philosophy, art and so on, but also the evolution of life. Following Peirce and others, Popper argued that science is fallible and has no authority.<ref name=popper/> In contrast to empiricist-inductivist views, he welcomed metaphysics and philosophical discussion and even gave qualified support to myths<ref>Karl Popper: Science: Conjectures and Refutations. ''Conjectures and Refuations'', section VII</ref> and pseudosciences.<ref>Karl Popper: On knowledge. ''In search of a better world'', section II</ref> Popper's view has become known as [[critical rationalism]].
 
==Relationship with mathematics==
Science is the process of gathering, comparing, and evaluating proposed models against [[observable]]s. A model can be a simulation, mathematical or chemical formula, or set of proposed steps. Science is like mathematics in that researchers in both disciplines can clearly distinguish what is ''known'' from what is ''unknown'' at each stage of discovery. Models, in both science and mathematics, need to be internally consistent and also ought to be ''[[falsifiable]]'' (capable of disproof). In mathematics, a statement need not yet be proven; at such a stage, that statement would be called a [[conjecture]]. But when a statement has attained mathematical proof, that statement gains a kind of immortality which is highly prized by mathematicians, and for which some mathematicians devote their lives.<ref>
"When we are working intensively, we feel keenly the progress of our work; we are elated when our progress is rapid, we are depressed when it is slow." — the mathematician {{harvnb|Pólya|1957|p=131}} in the section on 'Modern [[heuristic]]'.</ref>
 
Mathematical work and scientific work can inspire each other.<ref>
"Philosophy [i.e., physics] is written in this grand book--I mean the universe--which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering around in a dark labyrinth." —Galileo Galilei, ''Il Saggiatore'' (''[[The Assayer]]'', 1623), as translated by [[Stillman Drake]] (1957), ''Discoveries and Opinions of Galileo'' pp. 237-8,
as quoted by {{harvnb|di Francia|1981|p=10}}.
</ref> For example, the technical concept of [[time]] arose in [[science]], and timelessness was a hallmark of a mathematical topic. But today, the [[Poincaré conjecture]] has been proven using time as a mathematical concept in which objects can flow (see [[Ricci flow]]).
 
Nevertheless, the connection between mathematics and reality (and so science to the extent it describes reality) remains obscure. [[Eugene Wigner]]'s paper, ''[[The Unreasonable Effectiveness of Mathematics in the Natural Sciences]]'', is a very well-known account of the issue from a Nobel Prize physicist. In fact, some observers (including some well known mathematicians such as [[Gregory Chaitin]], and others such as [[Where Mathematics Comes From|Lakoff and Núñez]]) have suggested that mathematics is the result of practitioner bias and human limitation (including cultural ones), somewhat like the post-modernist view of science.
 
[[George Pólya]]'s work on [[problem solving]],<ref>
{{harvnb|Pólya|1957}} 2nd ed.
</ref> the construction of mathematical [[Mathematical proof|proofs]], and [[heuristic]]<ref>
George Pólya (1954), ''Mathematics and Plausible Reasoning Volume I: Induction and Analogy in Mathematics'',
</ref><ref>
George Pólya (1954), ''Mathematics and Plausible Reasoning Volume II: Patterns of Plausible Reasoning''.
 
</ref> show that the mathematical method and the scientific method differ in detail, while nevertheless resembling each other in using iterative or recursive steps.
 
{| class="wikitable"
|-
 
!
!'''[[How to Solve It|Mathematical method]]'''
![[Scientific method#Elements of scientific method|Scientific method]]
|-
| '''1'''
| [[Understanding]]
| [[Scientific method#Characterizations|Characterization from experience and observation]]
|-
| '''2'''
| [[Analysis]]
| [[Scientific method#Hypothesis development|Hypothesis: a proposed explanation]]
|-
| '''3'''
| [[wikt:Synthesis|Synthesis]]
| [[Scientific method#Predictions from the hypothesis|Deduction: prediction from the hypothesis]]
|-
| '''4'''
| [[Review]]/[[Generalization|Extend]]
| [[Scientific method#Experiments|Test and experiment]]
|}
 
In Pólya's view, ''understanding'' involves restating unfamiliar definitions in your own words, resorting to geometrical figures, and questioning what we know and do not know already; ''analysis'', which Pólya takes from [[Pappus of Alexandria|Pappus]],<ref>
{{harvnb|Pólya|1957|p=142}}
</ref> involves free and heuristic construction of plausible arguments, [[working backward from the goal]], and devising a plan for constructing the proof; ''synthesis'' is the strict [[Euclid]]ean exposition of step-by-step details<ref>
{{harvnb|Pólya|1957|p=144}}
</ref> of the proof; ''review'' involves reconsidering and re-examining the result and the path taken to it.
 
[[Carl Friedrich Gauss|Gauss]], when asked how he came about his [[theorem]]s, once replied "durch planmässiges Tattonieren" (through [[Constructivism (mathematics)|systematic palpable experimentation]]).<ref>{{harvnb|Mackay|1991}} p.100</ref>
 
[[Imre Lakatos]] argued that mathematicians actually use contradiction, criticism and revision as principles for improving their work.<ref>See the development, by generations of mathematicians, of [[Euler's formula for polyhedra]] as documented by {{Citation|first=Imre| last=Lakatos|year=1976|title=[[Proofs and refutations]]|authorlink=Imre Lakatos |location=Cambridge |publisher=Cambridge University Press| isbn=0-521-29038-4}}</ref>
 
==See also==
{{col-begin}}
{{col-break}}
* [[Confirmability]]
* [[Contingency]]
* [[Falsifiability]]
* [[Hypothesis]]
* [[Statistical hypothesis testing|Hypothesis testing]]
* [[Inquiry]]
* [[Information theory]]
{{col-break}}
* [[Logic]]
** [[Abductive reasoning]]
** [[Deductive reasoning]]
** [[Inductive reasoning]]
** [[Inference]]
** [[Strong inference]]
** [[Tautology (logic)|Tautology]]
{{col-break}}
* [[Methodology]]
** [[Baconian method]]
** [[Empirical method]]
** [[Historical method]]
** [[Philosophical method]]
** [[Phronetic method]]
** [[Scholarly method]]
* [[Mathematics]]
* [[OGHET]]
{{col-break}}
* [[Operationalization]]
* [[Quantitative research]]
* [[Reproducibility]]
* [[Research]]
* [[Social research]]
* [[Statistics]]
* [[Testability]]
* [[Theory]]
* [[Verification and Validation]]
{{col-end}}
 
===Problems and issues===
{{col-begin}}
{{col-break}}
* [[Inductive reasoning|Induction]]
* [[Problem of induction]]
* [[Occam's razor]]
* [[Skeptical hypotheses]]
{{col-break}}
* [[Poverty of the stimulus]]
* [[Reference class problem]]
* [[Underdetermination]]
{{col-break}}
* [[Demarcation problem]]
* [[Holistic science]]
{{col-break}}
* [[Junk science]]
* [[Pseudoscience]]
* [[Scientific misconduct]]
{{col-end}}
 
===History, philosophy, sociology===
{{col-begin}}
{{col-break}}
* [[Epistemology]]
* [[Epistemic theories of truth|Epistemic truth]]
{{col-break}}
* [[History of science]]
* [[History of scientific method]]
{{col-break}}
* [[Instrumentalism]]
* [[Mertonian norms|Mertonian norms (Cudos)]]
* [[Philosophy of science]]
{{col-break}}
* [[Science studies]]
* [[Sociology of scientific knowledge]]
* [[Timeline of the history of scientific method|Timeline of scientific method]]
{{col-end}}
 
==Notes==
{{Reflist|2}}


==References==
==References==
* {{Citation|first=Max|last=Born|author-link=Max Born|year=1949|title=Natural Philosophy of Cause and Chance|publisher=Peter Smith}}, also published by Dover, 1964. From the Waynflete Lectures, 1948. [http://www.archive.org/stream/naturalphilosoph032159mbp/naturalphilosoph032159mbp_djvu.txt On the web. N.B.: the web version does not have the 3 addenda by Born, 1950, 1964, in which he notes that all knowledge is subjective. Born then proposes a solution in Appendix 3 (1964)]
<references />
* {{Citation|first=Thomas A.|last=Brody|year=1993|title=The Philosophy Behind Physics|publisher=Springer Verlag|isbn=0-387-55914-0}}. (Luis De La Peña and Peter E. Hodgson, eds.)
* {{Citation|first=Leonard C. |last=Bruno|authorlink=Leonard C. Bruno |year=1989| title=The Landmarks of Science| isbn=0-8160-2137-6}}
* {{Citation|last=Bynum|first=W.F.|last2=Porter|first2=Roy|year=2005|title=Oxford Dictionary of Scientific Quotations|publisher=Oxford|isbn=0-19-858409-1}}.
* {{Citation|last=di Francia|first=G. Toraldo|year=1981|title=The Investigation of the Physical World|publisher=Cambridge University Press|isbn=0-521-29925-X}}.
* {{Citation|author1-link=Albert Einstein|author2-link=Leopold Infeld|last1=Einstein|first1=Albert|last2=Infeld|first2=Leopold|year=1938|title=The Evolution of Physics: from early concepts to relativity and quanta|isbn= 0-671-20156-5|publisher=Simon and Schuster|location=New York}}
* {{Citation|last=Feynman |first=Richard |author-link=Richard Feynman |year=1965|title=[[The Character of Physical Law]]|location=Cambridge|publisher= M.I.T. Press| isbn=0-262-56003-8}}.
* {{Citation|first=Ludwik |last=Fleck|author-link=Ludwik Fleck|year=1979|title=Genesis and Development of a Scientific Fact|publisher=Univ. of Chicago|isbn=0-226-25325-2}}. (written in German, 1935, ''Entstehung und Entwickelung einer wissenschaftlichen Tatsache: Einführung in die Lehre vom Denkstil und Denkkollectiv'') [http://books.google.com/books?id=0KAGUpaUaGYC&printsec=frontcover&dq=Ludwik+Fleck&source=bl&ots=LcJSSRN_ym&sig=TKrx9GLwFYRGlgIprAcdPFnhJIE&hl=en&ei=rbCWTPGpD8Oblgfmw9iiCg&sa=X&oi=book_result&ct=result&resnum=3&ved=0CB8Q6AEwAg#v=onepage&q&f=false English translation, 1979]
* {{Citation|last=Galileo|authorlink=Galileo Galilei|title=[[Two New Sciences]]|year=1638|location=[[Leiden]]|publisher=[[Lodewijk Elzevir]]| isbn= 0-486-60099-8}} Translated by Henry Crew and Alfonso de Salvio. Introduction by Antonio Favaro. xxv+300 pages, index.
* {{Citation|last=Gauch|first=Hugh G., Jr.|title=Scientific Method in Practice|url=http://books.google.com/?id=iVkugqNG9dAC|year=2003|publisher=Cambridge University Press| isbn= 0-521-01708-4}} 435 pages
* {{Citation|last=Glen|first=William (ed.)|author-link=William Glen (geologist and historian)|title=The Mass-Extinction Debates: How Science Works in a Crisis|publisher=Stanford University Press|year=1994|location=Stanford, CA|isbn=0-8047-2285-4}}.
* {{Citation|first=Peter|last=Godfrey-Smith|author-link=Peter Godfrey-Smith|year=2003|title=Theory and Reality: An introduction to the philosophy of science|publisher=University of Chicago Press|isbn=0-226-30063-3}}.
* {{Citation|first1=Alfred Scharff|last1=Goldhaber|first2=Michael Martin |last2=Nieto|year=2010|date=January–March 2010|title=Photon and graviton mass limits|journal=[[Rev. Mod. Phys.]]|volume=82|pages=939|publisher=American Physical Society|doi=10.1103/RevModPhys.82.939}}. pages 939-979.
* {{Citation|first=William Stanley|last=Jevons|author-link=William Stanley Jevons|year=1874|title=The Principles of Science: A Treatise on Logic and Scientific Method|publisher=Dover Publications|isbn=1430487755}}. 1877, 1879. Reprinted with a foreword by [[Ernst Nagel]], New York, NY, 1958.
* {{Citation| authorlink= Thomas Kuhn|last= Kuhn |first= Thomas S.| title= [[The Structure of Scientific Revolutions]]| publisher= University of Chicago Press |location= Chicago, IL| year= 1962}}. 2nd edition 1970. 3rd edition 1996.
* {{Citation|first=Alan L. (ed.)|last=Mackay| year=1991|title=Dictionary of Scientific Quotations|location=London|publisher=IOP Publishing Ltd| isbn=0-7503-0106-6}}
* {{Citation|first=Victor K.|last=McElheny|title=Watson & DNA: Making a scientific revolution|year=2004|publisher=Basic Books|isbn=0-7382-0866-3}}.
* {{Citation|first1=Forest Ray |last1=Moulton|first2=Justus J. (eds., Second Edition)|last2=Schifferes| year= 1960| title=The Autobiography of Science|publisher=Doubleday}}.
*{{Citation| year=1954 | last1=Needham |first1=Joseph| last2=Wang |first2=Ling (王玲)|author1-link=Joseph Needham|author2-link=Wang Ling (historian)|title=[[Science and Civilisation in China]]|publisher=Cambridge University Press|volume=1 ''Introductory Orientations''|ref=harv}}
* {{Citation|last=Newton|first=Isaac|year=1999|author-link=Isaac Newton|date=1687, 1713, 1726|title=[[Philosophiae Naturalis Principia Mathematica]]|publisher=University of California Press| isbn= 0-520-08817-4}}, Third edition. From [[I. Bernard Cohen]] and Anne Whitman's 1999 translation, 974 pages.
* {{Citation|last=Ørsted|first=Hans Christian | year=1997| author-link=Hans Christian Ørsted|title=Selected Scientific Works of Hans Christian Ørsted| publisher=Princeton |isbn=0-691-04334-5 }}. Translated to English by Karen Jelved, Andrew D. Jackson, and Ole Knudsen, (translators 1997).
* Peirce, C. S. — see [[Charles Sanders Peirce bibliography]].
* {{Citation|last=Poincaré|first=Henri|authorlink=Henri Poincaré|title=Science and Hypothesis|year=1905}} [http://www.brocku.ca/MeadProject/Poincare/Poincare_1905_toc.html Eprint]
* {{Citation|year=1957|last=Pólya|first=George|author-link=George Pólya|title=[[How to Solve It]]|publisher=Princeton University Press|isbn=-691-08097-6}}
* [[Karl Popper|Popper, Karl R.]], ''[[The Logic of Scientific Discovery]]'', 1934, 1959.
* {{Citation|first=Shmuel (ed.)|last=Sambursky |year=1974|title= Physical Thought from the Presocratics to the Quantum Physicists|publisher=Pica Press| isbn =0-87663-712-8}}.
* {{Citation
| first = Nassim Nicholas
| last = Taleb
| author-link = Nassim Nicholas Taleb
| title = [[The Black Swan (Taleb book)|The Black Swan]]
| year = 2007
| publisher = Random House
| isbn = 978-1-4000-6351-2
}}
* {{Citation|first=James D.|last=Watson|author-link=James D. Watson|year=1968|title=[[The Double Helix]]|location= New York| publisher=Atheneum|id= Library of Congress card number 68-16217}}.
 
==Further reading==
{{Refbegin}}
* [[Henry H. Bauer|Bauer, Henry H.]], ''Scientific Literacy and the Myth of the Scientific Method'', University of Illinois Press, Champaign, IL, 1992
* [[William Ian Beardmore Beveridge|Beveridge, William I. B.]], ''The Art of Scientific Investigation'', [[Heinemann (book publisher)|Heinemann]], Melbourne, Australia, 1950.
* [[Richard J. Bernstein|Bernstein, Richard J.]], ''Beyond Objectivism and Relativism: Science, Hermeneutics, and Praxis'', University of Pennsylvania Press, Philadelphia, PA, 1983.
* [[Stevo Bozinovski|Bozinovski, Stevo]], ''Consequence Driven Systems: Teaching, Learning, and Self-Learning Agents'', GOCMAR Publishers, Bitola, Macedonia, 1991.
* [[Baruch A. Brody|Brody, Baruch A.]] and [[Nicholas Capaldi|Capaldi, Nicholas]], [http://books.google.com/books?id=d1heAAAAIAAJ&pgis=1 ''Science: Men, Methods, Goals: A Reader: Methods of Physical Science''], [[W. A. Benjamin]], 1968
* [[Baruch A. Brody|Brody, Baruch A.]], and [[Richard E. Grandy|Grandy, Richard E.]], ''Readings in the Philosophy of Science'', 2nd edition, Prentice Hall, Englewood Cliffs, NJ, 1989.
* [[Arthur W. Burks|Burks, Arthur W.]], ''Chance, Cause, Reason — An Inquiry into the Nature of Scientific Evidence'', University of Chicago Press, Chicago, IL, 1977.
* [[Alan Chalmers]]. ''[[What is this thing called science?]]''. Queensland University Press and Open University Press, 1976.
* [[Noam Chomsky|Chomsky, Noam]], ''Reflections on Language'', Pantheon Books, New York, NY, 1975.
* {{cite |last=Crick|first=Francis|authorlink=Francis Crick|title=[[What Mad Pursuit: A Personal View of Scientific Discovery]]|year=1988|location=New York|publisher=Basic Books|isbn=0-465-09137-7}}.
* [[John Dewey|Dewey, John]], ''How We Think'', D.C. Heath, Lexington, MA, 1910. Reprinted, [[Prometheus Books]], Buffalo, NY, 1991.
* [[John Earman|Earman, John]] (ed.), ''Inference, Explanation, and Other Frustrations: Essays in the Philosophy of Science'', University of California Press, Berkeley & Los Angeles, CA, 1992.
* [[Bas C. van Fraassen|Fraassen, Bas C. van]], ''The Scientific Image'', Oxford University Press, Oxford, UK, 1980.
* {{Citation|last=Franklin |first=James |author-link=James Franklin (philosopher) |year=2009|title=What Science Knows: And How It Knows It|location=New York|publisher=Encounter Books| isbn=1594032076}}.
* [[Hans-Georg Gadamer|Gadamer, Hans-Georg]], ''Reason in the Age of Science'', Frederick G. Lawrence (trans.), MIT Press, Cambridge, MA, 1981.
* [[Ronald N. Giere|Giere, Ronald N.]] (ed.), ''Cognitive Models of Science'', vol. 15 in 'Minnesota Studies in the Philosophy of Science', University of Minnesota Press, Minneapolis, MN, 1992.
* [[Ian Hacking|Hacking, Ian]], ''Representing and Intervening, Introductory Topics in the Philosophy of Natural Science'', Cambridge University Press, Cambridge, UK, 1983.
* [[Werner Heisenberg|Heisenberg, Werner]], ''Physics and Beyond, Encounters and Conversations'', A.J. Pomerans (trans.), Harper and Row, New York, NY 1971, pp.&nbsp;63–64.
* [[Gerald Holton|Holton, Gerald]], ''Thematic Origins of Scientific Thought, Kepler to Einstein'', 1st edition 1973, revised edition, Harvard University Press, Cambridge, MA, 1988.
* Kuhn, Thomas S., ''The Essential Tension, Selected Studies in Scientific Tradition and Change'', University of Chicago Press, Chicago, IL, 1977.
* [[Bruno Latour|Latour, Bruno]], ''Science in Action, How to Follow Scientists and Engineers through Society'', Harvard University Press, Cambridge, MA, 1987.
* [[John Losee|Losee, John]], ''A Historical Introduction to the Philosophy of Science'', Oxford University Press, Oxford, UK, 1972. 2nd edition, 1980.
* [[Nicholas Maxwell|Maxwell, Nicholas]], ''The Comprehensibility of the Universe: A New Conception of Science'', Oxford University Press, Oxford, 1998. Paperback 2003.
* [[Maclyn McCarty]] (1985) The Transforming Principle: Discovering that genes are made of DNA. New York: W. W. Norton. 252 p.&nbsp;ISBN 0-393-30450-7. Memoir of a researcher in the [[Avery–MacLeod–McCarty experiment]].
* [[William McComas|McComas, William F.]], ed. {{PDFlink|[http://coehp.uark.edu/pase/TheMythsOfScience.pdf The Principal Elements of the Nature of Science: Dispelling the Myths]|189&nbsp;KB}}, from ''The Nature of Science in Science Education'', pp53–70, Kluwer Academic Publishers, Netherlands 1998.
* [[Cheryl J. Misak|Misak, Cheryl J.]], ''Truth and the End of Inquiry, A Peircean Account of Truth'', Oxford University Press, Oxford, UK, 1991.
* [[Allen Newell|Newell, Allen]], ''Unified Theories of Cognition'', Harvard University Press, Cambridge, MA, 1990.
* [[Massimo Piattelli-Palmarini|Piattelli-Palmarini, Massimo]] (ed.), ''Language and Learning, The Debate between Jean Piaget and Noam Chomsky'', Harvard University Press, Cambridge, MA, 1980.
* Popper, Karl R., ''Unended Quest, An Intellectual Autobiography'', Open Court, La Salle, IL, 1982.
* [[Hilary Putnam|Putnam, Hilary]], ''Renewing Philosophy'', Harvard University Press, Cambridge, MA, 1992.
* [[Richard Rorty|Rorty, Richard]], ''Philosophy and the Mirror of Nature'', Princeton University Press, Princeton, NJ, 1979.
* [[Wesley C. Salmon|Salmon, Wesley C.]], ''Four Decades of Scientific Explanation'', University of Minnesota Press, Minneapolis, MN, 1990.
* [[Abner Shimony|Shimony, Abner]], ''Search for a Naturalistic World View: Vol. 1, Scientific Method and Epistemology, Vol. 2, Natural Science and Metaphysics'', Cambridge University Press, Cambridge, UK, 1993.
* [[Paul Thagard|Thagard, Paul]], ''Conceptual Revolutions'', Princeton University Press, Princeton, NJ, 1992.
* [[John Ziman|Ziman, John]] (2000). ''Real Science: what it is, and what it means''. Cambridge, UK: Cambridge University Press.
 
{{Refend}}
<div class="references-small" style="-moz-column-count:2; column-count:2;">
</div>
 
==External links==
{{Wikibooks|The Scientific Method}}
* [http://www.geo.sunysb.edu/esp/files/scientific-method.html An Introduction to Science: Scientific Thinking and a scientific method] by Steven D. Schafersman.
* [http://teacher.nsrl.rochester.edu/phy_labs/AppendixE/AppendixE.html Introduction to a scientific method]
* [http://www.galilean-library.org/theory.html Theory-ladenness] by Paul Newall at The Galilean Library
* [http://web.archive.org/web/20060428080832/http://pasadena.wr.usgs.gov/office/ganderson/es10/lectures/lecture01/lecture01.html Lecture on Scientific Method by Greg Anderson]
* [http://www.sciencemadesimple.com/scientific_method.html Using the scientific method for designing science fair projects]
* [http://emotionalcompetency.com/sci/booktoc.html SCIENTIFIC METHODS an online book by Richard D. Jarrard]
* [http://helios.hampshire.edu/%7EapmNS/design/RESOURCES/HOW_READ.html How to Read a Scientific Research Paper]
* [http://www.youtube.com/watch?v=b240PGCMwV0 Richard Feynman on the Key to Science] (one minute, three seconds), from the Cornell Lectures.
{{philosophy of science}}
 
{{DEFAULTSORT:Scientific Method}}
[[Category:Scientific method| ]]
[[Category:Science studies]]
[[Category:Scientific revolution]]
[[Category:Charles Sanders Peirce]]
 
{{Link GA|eo}}
 
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Revision as of 18:15, 1 June 2013

Aristotle, 384 BC–322 BC. "As regards his method, Aristotle is recognized as the inventor of scientific method because of his refined analysis of logical implications contained in demonstrative discourse, which goes well beyond natural logic and does not owe anything to the ones who philosophized before him."—Riccardo Pozzo[1]

The scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.[2] To be termed scientific, a method of inquiry must be based on empirical and measurable evidence subject to specific principles of reasoning.[3] The Oxford English Dictionary defines the scientific method as "a method or procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses."[4]

The chief characteristic which arguably distinguishes the scientific method from other methods of acquiring knowledge is that scientists attempt to let the scientific method deliver truths about reality, supporting a theory when a theory's predictions are confirmed and challenging a theory when its predictions prove false.[5] Although procedures vary from one field of inquiry to another, identifiable features distinguish scientific inquiry from other methods of obtaining knowledge. Scientific researchers propose hypotheses as explanations of phenomena, and design experimental studies to test these hypotheses via predictions which can be derived from them. These steps must be repeatable, to guard against mistake or confusion in any particular experimenter. Theories that encompass wider domains of inquiry may bind many independently derived hypotheses together in a coherent, supportive structure. Theories, in turn, may help form new hypotheses or place groups of hypotheses into context.

Scientific inquiry is generally intended to be as objective as possible in order to reduce biased interpretations of results. Another basic expectation is to document, archive, and share all data and methodology so they are available for careful scrutiny by other scientists, giving them the opportunity to verify results by attempting to reproduce them. This practice is sometimes referred to as replicability or full disclosure, and it allows statistical measures of the reliability of these data to be established, especially when data is sampled or compared to chance.[6]

References

  1. Pozzo, Riccardo (2004). The Impact of Aristotelianism on Modern Philosophy. CUA Press. p. 41. ISBN 0813213479. http://books.google.com/books?id=vayp8jxcPr0C&lpg=PP1&pg=PA41. 
  2. Goldhaber, Alfred Scharff; Nieto, Michael Martin (January–March 2010). "Photon and graviton mass limits". Reviews of Modern Physics (American Physical Society) 82: 939–979. doi:10.1103/RevModPhys.82.939. http://rmp.aps.org/abstract/RMP/v82/i1/p939_1. 
  3. Newton, Isaac (6 May 1726). Philosophiae Naturalis Principia Mathematica (Third ed.). University of California Press. pp. 794–6. ISBN 0-520-08817-4. 
  4. "scientific method". Oxford Dictionaries (US English). Oxford University Press. http://oxforddictionaries.com/us/definition/american_english/scientific-method?q=scientific+method. Retrieved 01 June 2013. 
  5. Gower, Barry (1997). Scientific Method: An Historical and Philosophical Introduction. Psychology Press. p. 126. ISBN 0415122821. http://books.google.com/books?id=D3rV2t2XkWYC&pg=PA126. 
  6. McEnery, Tony; Hardie, Andrew (2011). Corpus Linguistics: Method, Theory and Practice. Cambridge University Press. p. 14–16. ISBN 1139502441. http://books.google.com/books?id=3j3Wn_ZT1qwC&pg=PA16.