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[[File:Pourbus Francis Bacon.jpg |right|230px|thumb|[[Francis Bacon]] by Frans Purbus]]

[[File:Somer Francis Bacon.jpg |right|230px|thumb|[[Francis Bacon]] by Frans Purbus]]

[[File:Henri Poincaré-2.jpg|right|230px|thumb|[[Henri Poincaré]]]]

[[File:Henri Poincaré-2.jpg|right|230px|thumb|[[Henri Poincaré]]]]

[[File:Karl Popper.jpg|right|200px|thumb|[[Karl Popper]]]]

[[File:Karl Popper.jpg|right|200px|thumb|[[Karl Popper]]]]

'''Philosophy of science''' is the part of [[philosophy]] that studies the [[sciences]].  

'''Philosophy of science''' is the part of [[philosophy]] that studies the [[sciences]].

[[Philosopher]]s who are interested in science study how knowledge is built up by scientists, and what makes science different from other activities. No doubt, modern science has advanced knowledge in a wide range of fields. How has it done this? To tackle this issue, a number of other issues have to be tackled also.  

[[Philosopher]]s who are interested in science study how knowledge is built up by scientists, and what makes science different from other activities. No doubt, modern science has advanced knowledge in a wide range of fields. How has it done this? To tackle this issue, a number of other issues have to be tackled also.

== What makes science distinct? ==

== What makes science distinct? ==

The demarcation problem refers to the distinction between science and non-science (including [[pseudoscience]]). [[Karl Popper]] called this the central question in the philosophy of science.<ref name="Thornton2006">{{cite web|url = http://plato.stanford.edu/entries/popper/|title = Karl Popper|accessdate = 2007-12-01|last = Thornton|first = Stephen|year = 006|work = Stanford Encyclopedia of Philosophy}}</ref> No account of the problem has got full agreement among philosophers; some regard the problem as insoluble or uninteresting.<ref name="Laudan1983">{{cite book | last = Laudan | first = Larry | editor = Adolf Grünbaum, Robert Sonné Cohen, Larry Laudan | title = Physics, philosophy, and psychoanalysis: essays in honor of Adolf Grünbaum | year = 1983 | publisher = Springer | isbn = 90-277-1533-5 | chapter = The demise of the demarcation problem}}</ref>

The demarcation problem refers to the distinction between science and non-science (including [[pseudoscience]]). [[Karl Popper]] called this the central question in the philosophy of science.<ref name="Thornton2006">{{cite web|url = http://plato.stanford.edu/entries/popper/|title = Karl Popper|accessdate = 2007-12-01|last = Thornton|first = Stephen|year = 006|work = Stanford Encyclopedia of Philosophy}}</ref> No account of the problem has got full agreement among philosophers; some regard the problem as insoluble or uninteresting.<ref name="Laudan1983">{{cite book | last = Laudan | first = Larry | editor = Adolf Grünbaum, Robert Sonné Cohen, Larry Laudan | title = Physics, philosophy, and psychoanalysis: essays in honor of Adolf Grünbaum | year = 1983 | publisher = Springer | isbn = 90-277-1533-5 | chapter = The demise of the demarcation problem}}</ref>

The [[logical positivists]] tried to base science on observation. In their view, truth was achieved by [[verification]]. Non-science was non-observational and meaningless.<ref name="Uebel2006">{{cite web|url = http://plato.stanford.edu/entries/vienna-circle/|title = Vienna Circle|accessdate = 2007-12-01|last = Uebel|first = Thomas|year = 2006|work = Stanford Encyclopedia of Philosophy}}</ref>  

The [[logical positivists]] tried to base science on observation. In their view, truth was achieved by [[verification]]. Non-science was non-observational and meaningless.<ref name="Uebel2006">{{cite web|url = http://plato.stanford.edu/entries/vienna-circle/|title = Vienna Circle|accessdate = 2007-12-01|last = Uebel|first = Thomas|year = 2006|work = Stanford Encyclopedia of Philosophy}}</ref>

Against that, Popper argued that the central property of science is [[falsifiability]]. All scientific claims can be proved false, at least in principle. If no such proof can be found despite sufficient effort, then the claim is likely true.<ref name="Popper1959">{{cite book | last = Popper | first = Karl | authorlink = Karl Popper | title = The logic of scientific discovery | year = 2004 reprint | publisher = Routledge Classics | location = London & New York | url=http://books.google.com/books?id=Yq6xeupNStMC&printsec=frontcover&dq=the+logic+of+scientific+discovery&hl=en&sa=X&ei=j_eYT4D6I8L1mAX05pGJBg&ved=0CC8Q6AEwAA | isbn=0-415-27844-9 | postscript=&nbsp;&nbsp;First published 1959 by Hutchinson & Co.}}</ref> Popper's ideas were applauded by many scientists (like [[Peter Medawar]]). However, sceptics noticed that theories were often not discarded when a prediction was refuted. The theory was simply adjusted to take into account the new findings. It was clear from this that, although falsifiability was important, it could not be a simple way to distinguish science from non-science.  

Against that, Popper argued that the central property of science is [[falsifiability]]. All scientific claims can be proved false, at least in principle. If no such proof can be found despite sufficient effort, then the claim is likely true.<ref name="Popper1959">{{cite book | last = Popper | first = Karl | authorlink = Karl Popper | title = The logic of scientific discovery | year = 2004 | publisher = Routledge Classics | location = London & New York | url=https://books.google.com/books?id=Yq6xeupNStMC&printsec=frontcover&dq=the+logic+of+scientific+discovery&hl=en&sa=X&ei=j_eYT4D6I8L1mAX05pGJBg&ved=0CC8Q6AEwAA | isbn=0-415-27844-9 | postscript=&nbsp;&nbsp;First published 1959 by Hutchinson & Co.}}</ref> Popper's ideas were applauded by many scientists (like [[Peter Medawar]]). However, sceptics noticed that theories were often not discarded when a prediction was refuted. The theory was simply adjusted to take into account the new findings. It was clear from this that, although falsifiability was important, it could not be a simple way to distinguish science from non-science.

Other approaches were tried. One idea that science was a problem-solving process aimed at finding answers to questions.<ref>Bunge, Mario 1967. ''Scientific research''. Volume 1: ''The search for system''; volume 2: ''The search for truth''. Springer-Verlag, Berlin & New York.  Reprinted as ''Philosophy of science'', Transaction, 1998.</ref> Of course, many other fields try to answer questions and solve problems. Another approach was to define science as the search for objective truth. But [[objectivity (science)|objectivity]] is very difficult to define, and whether science really is objective is open to question.

Other approaches were tried. One idea that science was a problem-solving process aimed at finding answers to questions.<ref>Bunge, Mario 1967. ''Scientific research''. Volume 1: ''The search for system''; volume 2: ''The search for truth''. Springer-Verlag, Berlin & New York.  Reprinted as ''Philosophy of science'', Transaction, 1998.</ref> Of course, many other fields try to answer questions and solve problems. Another approach was to define science as the search for objective truth. But [[objectivity (science)|objectivity]] is very difficult to define, and whether science really is objective is open to question.

== Theories and observations ==

== Theories and observations ==

Both theory and observations are part of science, and they are tied together in a kind of cycle. A very clear example was the prediction of [[Einstein]] that a source of [[gravity]] (such as a star) would bend light passing nearby. An expedition was organised in 1919 to record the positions of stars around the Sun during a solar [[eclipse]]. The observation of star positions showed that the apparent star positions close to the Sun were changed slightly from their normal expected positions. In effect, the light passing the Sun was pulled towards the sun by gravitation. This confirmed predictions of gravitational lensing made by Albert Einstein in the [[general theory of relativity]], published in 1915. This was the first solid evidence in favour of Einstein's theory.  

Both theory and observations are part of science, and they are tied together in a kind of cycle. A very clear example was the prediction of [[Einstein]] that a source of [[gravity]] (such as a star) would bend light passing nearby. An expedition was organised in 1919 to record the positions of stars around the Sun during a solar [[eclipse]]. The observation of star positions showed that the apparent star positions close to the Sun were changed slightly from their normal expected positions. In effect, the light passing the Sun was pulled towards the sun by gravitation. This confirmed predictions of gravitational lensing made by Albert Einstein in the [[general theory of relativity]], published in 1915. This was the first solid evidence in favour of Einstein's theory.

The point here is that the observation and the theory were connected. The observation would not have been made but for the theory, and then the observation was convincing evidence in favour of the theory. The theory had passed a [[critical test]]. Since then, many more tests have been made of Einstein's ideas, and all have been consistent with his theory.

The point here is that the observation and the theory were connected. The observation would not have been made but for the theory, and then the observation was convincing evidence in favour of the theory. The theory had passed a [[critical test]]. Since then, many more tests have been made of Einstein's ideas, and all have been consistent with his theory.

=== A “naive” conception of science ===

=== A “naive” conception of science ===

According to [[common sense]],<ref name=Alan>Chalmers, Alan F. 1976/99. ''What is this thing called science? An assessment of the nature and status of science and its methods''. Open University Press. ISBN 0-335-20109-1</ref> [[science]] begins with observations: all scientific [[knowledge]] come from the [[fact]]s of [[experience]]. [[Theory|Theories]] are produced by observation of these facts and are then tested by [[prediction]].

According to [[common sense]],<ref name=Alan>Chalmers, Alan F. 1976/99. ''What is this thing called science? An assessment of the nature and status of science and its methods''. Open University Press. {{ISBN|0-335-20109-1}}</ref> [[science]] begins with observations: all scientific [[knowledge]] come from the [[fact]]s of [[experience]]. [[Theory|Theories]] are produced by observation of these facts and are then tested by [[prediction]].

Here is a schema of this [[idea]] of science that some philosophers call a ''[[naive]]'' conception of science:<ref name=Alan/>

Here is a schema of this [[idea]] of science that some philosophers call a ''[[naive]]'' conception of science:<ref name=Alan/>

       |                                                            |

       |                                                            |

       |                                  PREDICTIONS AND EXPLANATIONS

       |                                  PREDICTIONS AND EXPLANATIONS

  FACTS OF EXPERIENCE                                        

  FACTS OF EXPERIENCE

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.

== Other ideas ==

== Other ideas ==

===Critiques of scientific method===

===Critiques of scientific method===

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.

== Other pages ==

==Related pages==

*[[Empiricism]]

*[[Empiricism]]

*[[Epistemology]]

*[[Epistemology]]

*[[Materialism]]

*[[Materialism]]

*[[Naturalism (philosophy)]]

*[[Naturalism (philosophy)]]

*[[Positivism]]

*[[Positivism]]

*[[Logical positivism]]

*[[Logical positivism]]

*[[Rationalism]]

*[[Rationalism]]

*[[Scepticism]]

*[[Scepticism]]

*[[Causality]]

*[[Causality]]