Editing Reproducibility (section)

==History==
[[File:Boyle air pump.jpg|thumb|right|Boyle's air pump was, in terms of the 17th century, a complicated and expensive scientific apparatus, making reproducibility of results difficult.]]
The first to stress the importance of reproducibility in science was the Anglo-Irish chemist [[Robert Boyle]], in [[England]] in the 17th century. Boyle's [[air pump]] was designed to generate and study [[vacuum]], which at the time was a very controversial concept. Indeed, distinguished philosophers such as [[René Descartes]] and [[Thomas Hobbes]] denied the very possibility of vacuum existence. [[History of science|Historians of science]] [[Steven Shapin]] and [[Simon Schaffer]], in their 1985 book ''[[Leviathan and the Air-Pump]]'', describe the debate between Boyle and Hobbes, ostensibly over the nature of vacuum, as fundamentally an argument about how useful knowledge should be gained. Boyle, a pioneer of the [[experimental method]], maintained that the foundations of knowledge should be constituted by experimentally produced facts, which can be made believable to a scientific community by their reproducibility. By repeating the same experiment over and over again, Boyle argued, the certainty of fact will emerge.

The air pump, which in the 17th century was a complicated and expensive apparatus to build, also led to one of the first documented disputes over the reproducibility of a particular [[scientific phenomenon]]. In the 1660s, the Dutch scientist [[Christiaan Huygens]] built his own air pump in [[Amsterdam]], the first one outside the direct management of Boyle and his assistant at the time [[Robert Hooke]]. Huygens reported an effect he termed "anomalous suspension", in which water appeared to levitate in a glass jar inside his air pump (in fact suspended over an air bubble), but Boyle and Hooke could not replicate this phenomenon in their own pumps. As Shapin and Schaffer describe, "it became clear that unless the phenomenon could be produced in England with one of the two pumps available, then no one in England would accept the claims Huygens had made, or his competence in working the pump". Huygens was finally invited to England in 1663, and under his personal guidance Hooke was able to replicate anomalous suspension of water. Following this Huygens was elected a Foreign Member of the [[Royal Society]]. However, Shapin and Schaffer also note that "the accomplishment of replication was dependent on contingent acts of judgment. One cannot write down a formula saying when replication was or was not achieved".<ref>[[Steven Shapin]] and [[Simon Schaffer]], ''[[Leviathan and the Air-Pump]]'', Princeton University Press, Princeton, New Jersey (1985).</ref>

The [[Philosophy of science|philosopher of science]] [[Karl Popper]] noted briefly in his famous 1934 book ''[[The Logic of Scientific Discovery]]'' that "non-reproducible single occurrences are of no significance to science".<ref>This citation is from the 1959 translation to English, [[Karl Popper]], ''[[The Logic of Scientific Discovery]]'', Routledge, London, 1992, p. 66.</ref> The [[Statistics|statistician]] [[Ronald Fisher]] wrote in his 1935 book ''[[The Design of Experiments]]'', which set the foundations for the modern scientific practice of [[hypothesis testing]] and [[statistical significance]], that "we may say that a phenomenon is experimentally demonstrable when we know how to conduct an experiment which will rarely fail to give us statistically significant results".<ref>[[Ronald Fisher]], ''[[The Design of Experiments]]'', (1971) [1935](9th ed.), Macmillan, p. 14.</ref> Such assertions express a common [[dogma]] in modern science that reproducibility is a necessary condition (although not necessarily [[Necessity and sufficiency|sufficient]]) for establishing a scientific fact, and in practice for establishing scientific authority in any field of knowledge. However, as noted above by Shapin and Schaffer, this dogma is not well-formulated quantitatively, such as statistical significance for instance, and therefore it is not explicitly established how many times must a fact be replicated to be considered reproducible.