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This naive conception is not held by many philosophers today. For one thing, it sees science as a one-way engine from 'facts' (what are they?) to theories and predictions. As shown by the Einstein example, where a theory led the other way round, the model does not fit much of science. In fact the relationship between the parts of a scientific philosophy are extremely complex.

This naive conception is not held by many philosophers today. For one thing, it sees science as a one-way engine from 'facts' (what are they?) to theories and predictions. As shown by the Einstein example, where a theory led the other way round, the model does not fit much of science. In fact the relationship between the parts of a scientific philosophy are extremely complex.

== Testing a prediction ==

== Testing a prediction ==

According to [[Pierre Duhem]] and [[W.V. Quine]], it is impossible to test a theory in isolation. For example, to test [[Newton's law of universal gravitation|Newton's Law of Gravitation]] in our solar system, one needs information about the masses and positions of the Sun and all the planets. Famously, the failure to predict the orbit of [[Uranus]] in the 19th century did not lead to the rejection of Newton's Law. Instead, it lead to the rejection of the hypothesis that there are only seven planets in our solar system. The investigations that followed led to the discovery of an eighth planet, [[Neptune]]. If a test fails, something is wrong. But there is a problem in figuring out what that something is: a missing planet, badly calibrated test equipment, an unsuspected curvature of space, etc.

According to [[Pierre Duhem]] and [[W.V. Quine]], it is impossible to test a theory in isolation. For example, to test [[Newton's law of universal gravitation|Newton's Law of Gravitation]] in our [[Solar System|solar system]], one needs information about the masses and positions of the Sun and all the planets. Famously, the failure to predict the orbit of [[Uranus]] in the 19th century did not lead to the rejection of Newton's Law. Instead, it lead to the rejection of the [[hypothesis]] that there are only seven planets in our solar system. The investigations that followed led to the discovery of an eighth planet, [[Neptune]]. If a test fails, something is wrong. But there is a problem in figuring out what that something is: a missing planet, badly calibrated test equipment, an unsuspected curvature of space, etc.

One consequence of the Duhem-Quine thesis is that any theory can be made compatible with any empirical observation by the addition of extra ([[List of Latin phrases (A)|ad hoc]]) hypotheses. This is why science uses [[Occam's Razor]]; hypotheses without justification are eliminated.  This led [[Karl Popper]], to reject [[Falsifiability#Naïve falsification|naïve falsification]] in favor of 'survival of the fittest', or most falsifiable, of scientific theories. In Popper's view, any hypothesis that does not make testable predictions is simply not science. Such a hypothesis may be useful or valuable, but it cannot be said to be science. W.V. Quine thought that empirical data are not enough to make a judgment between theories. In this view, a theory can always be made to fit with the available empirical data. However, this does not necessarily imply that all theories are of equal value, because scientists often use guiding principles such as Occam's Razor.

One consequence of the Duhem-Quine thesis is that any theory can be made compatible with any empirical observation by the addition of extra ([[List of Latin phrases (A)|ad hoc]]) hypotheses. This is why science uses [[Occam's Razor]]; hypotheses without justification are eliminated.  This led [[Karl Popper]], to reject [[Falsifiability#Naïve falsification|naïve falsification]] in favor of 'survival of the fittest', or most falsifiable, of scientific theories. In Popper's view, any hypothesis that does not make testable predictions is simply not science. Such a hypothesis may be useful or valuable, but it cannot be said to be science. W.V. Quine thought that empirical data are not enough to make a judgment between theories. In this view, a theory can always be made to fit with the available empirical data. However, this does not necessarily imply that all theories are of equal value, because scientists often use guiding principles such as Occam's Razor.

Is there any scientific method at all? [[Paul Feyerabend]] argued that no description of scientific method could possibly encompass all the approaches and methods used by scientists. Feyerabend objected to prescriptive scientific method on the grounds that any such method would stifle and cramp scientific progress. Feyerabend claimed, "the only principle that does not inhibit progress is: ''anything goes''".<ref>Feyerabend, Paul 1975. ''Against method: outline of an anarchistic theory of knowledge''. {{ISBN|0-391-00381-X}}, {{ISBN|0-86091-222-1}}, {{ISBN|0-86091-481-X}}, {{ISBN|0-86091-646-4}}, {{ISBN|0-86091-934-X}}, {{ISBN|0-902308-91-2}}</ref>

Is there any scientific method at all? [[Paul Feyerabend]] argued that no description of scientific method could possibly encompass all the approaches and methods used by scientists. Feyerabend objected to prescriptive scientific method on the grounds that any such method would stifle and cramp scientific progress. Feyerabend claimed, "the only principle that does not inhibit progress is: ''anything goes''".<ref>Feyerabend, Paul 1975. ''Against method: outline of an anarchistic theory of knowledge''. {{ISBN|0-391-00381-X}}, {{ISBN|0-86091-222-1}}, {{ISBN|0-86091-481-X}}, {{ISBN|0-86091-646-4}}, {{ISBN|0-86091-934-X}}, {{ISBN|0-902308-91-2}}</ref>

== Scientific revolutions ==

== Scientific revolutions ==

[[Thomas Kuhn]] denied that it is ever possible to isolate the hypothesis being tested from the influence of the theory in which the observations are grounded. He argued that observations always rely on a specific paradigm, and that it is not possible to evaluate competing paradigms independently. By "paradigm" he meant a  consistent "portrait" of the world, one that involves no logical contradictions and that is consistent with observations made from the point of view of the paradigm. More than one such logically consistent construct can paint a usable likeness of the world, but there is no common ground from which to pit two against each other, theory against theory. Neither is a standard by which the other can be judged. Instead, the question is which "portrait" is judged by some set of people to promise the most useful in terms of scientific "puzzle solving".

[[Thomas Kuhn]] denied that it is ever possible to isolate the hypothesis being tested from the influence of the theory in which the observations are grounded. He argued that observations always rely on a specific paradigm, and that it is not possible to evaluate competing paradigms independently. By "[[paradigm]]" he meant a  consistent "portrait" of the world, one that involves no logical contradictions and that is consistent with observations made from the point of view of the paradigm. More than one such logically consistent construct can paint a usable likeness of the world, but there is no common ground from which to pit two against each other, theory against theory. Neither is a standard by which the other can be judged. Instead, the question is which "portrait" is judged by some set of people to promise the most useful in terms of scientific "puzzle solving".

For Kuhn, the choice of paradigm was sustained by, but not ultimately determined by, logical processes. The individual's choice between paradigms involves setting two or more "portraits" against the world and deciding which likeness is most promising. In the case of a general acceptance of one paradigm or another, Kuhn believed that it represented the consensus of the community of scientists. Acceptance or rejection of some paradigm is, he argued, a [[social]] process as much as a [[logic]]al process. Kuhn's position, however, is not one of [[relativism]].<ref>Kuhn T.S. 1970. ''The structure of scientific revolutions''. 2nd ed, University of Chicago Press. p206 {{ISBN|0-226-45804-0}}</ref> According to Kuhn, a paradigm shift occurs when a number of observational anomalies (problems) in the old paradigm have made the new paradigm more useful. That is, the choice of a new paradigm is based on observations, even though those observations are made against the background of the old paradigm. A new paradigm is chosen because it does a better job of solving scientific problems than the old one.

For Kuhn, the choice of paradigm was sustained by, but not ultimately determined by, logical processes. The individual's choice between paradigms involves setting two or more "portraits" against the world and deciding which likeness is most promising. In the case of a general [[acceptance]] of one paradigm or another, Kuhn believed that it represented the consensus of the community of scientists. Acceptance or rejection of some paradigm is, he argued, a [[social]] process as much as a [[logic]]al process. Kuhn's position, however, is not one of [[relativism]].<ref>Kuhn T.S. 1970. ''The structure of scientific revolutions''. 2nd ed, University of Chicago Press. p206 {{ISBN|0-226-45804-0}}</ref> According to Kuhn, a [[paradigm shift]] occurs when a number of observational anomalies (problems) in the old paradigm have made the new paradigm more useful. That is, the choice of a new paradigm is based on observations, even though those observations are made against the background of the old paradigm. A new paradigm is chosen because it does a better job of solving scientific problems than the old one.

The fact that observation is embedded in theory does not mean observations are irrelevant to science. Scientific understanding derives from observation, but the acceptance of scientific statements is dependent on the related theoretical paradigm as well as on observation. Of course, further testing may resolve differences of opinion.

The fact that observation is embedded in theory does not mean observations are irrelevant to science. Scientific understanding derives from observation, but the acceptance of scientific statements is dependent on the related theoretical paradigm as well as on observation. Of course, further testing may resolve differences of opinion.

== Philosophy Of Science Media ==

== Philosophy Of Science Media ==

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File:Chicken farmer in Ghana (5926941911).jpg|The expectations chickens might form about farmer behavior illustrate the "problem of induction".

File:Allan Ramsay - David Hume, 1711 - 1776. Historian and philosopher - PG 3521 - National Galleries of Scotland.jpg|In formulating 'the problem of induction', David Hume devised one of the most pervasive puzzles in the philosophy of science.

File:Einstein cross.jpg|Seen through a telescope, the [[Einstein cross]] seems to provide evidence for five different objects, but this observation is theory-laden. If we assume the theory of [[general relativity]], the image only provides evidence for two objects.

File:Einstein cross.jpg|تقاطع أينشتاين: أربع صور لنفس النجم الزائف البعيد (وذلك بفعل عدسة الجاذبية الناتجة عن المجرة الأقرب لنا، والظاهرة في المقدمة، وهي مجرة عدسة هاكرا).

File:Francis Bacon statue, Gray's Inn.jpg|Francis Bacon's statue at [[Gray's Inn]], South Square, London

File:Thomas-kuhn-portrait.png|Thomas Kuhn is credited with coining the term "[[paradigm shift]]" to describe the creation and evolution of scientific theories.

File:Epicycle and deferent.svg|For [[Thomas Kuhn|Kuhn]], the addition of [[Deferent and epicycle|epicycles]] in Ptolemaic astronomy was "normal science" within a paradigm, whereas the [[The Structure of Scientific Revolutions#Copernican Revolution|Copernican revolution]] was a paradigm shift.

File:Francis Bacon statue, Gray's Inn.jpg|Statue of Francis Bacon, South Square, Gray's Inn, London WC1

 

File:Hierarchy of the Sciences - diagram.svg|Theory of Science by Auguste Comte

File:JeremiahHorrocks.jpg|[[Jeremiah Horrocks]] makes the first observation of the transit of Venus in 1639, as imagined by the artist [[William Richard Lavender|W.&nbsp;R.&nbsp;Lavender]] in 1903.

File:JeremiahHorrocks.jpg|[[Jeremiah Horrocks]] makes the first observation of the transit of Venus in 1639, as imagined by the artist [[William Richard Lavender|W.&nbsp;R.&nbsp;Lavender]] in 1903.

File:P1160335 peter godfrey-smith reading.jpg|Peter Godfrey-Smith was awarded the [[Lakatos Award]] for his 2009 book ''Darwinian Populations and Natural Selection'', which discusses the philosophical foundations of the theory of [[evolution]].

File:P1160335 peter godfrey-smith reading.jpg|Peter Godfrey-Smith was awarded the [[Lakatos Award]] for his 2009 book ''Darwinian Populations and Natural Selection'', which discusses the philosophical foundations of the theory of [[evolution]].

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== Related pages ==

== Related pages ==