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Philosophy of science

(philosophyscience,philosophy science)

The philosophy of science is the branch of philosophy whichstudies the philosophical foundations, presumptions and implications of science bothof the natural sciences like physics and biology and the social sciences such as psychology and economics . In this respect, the philosophy of science is closely related to epistemology and ontology . Itseeks to explain such things as: the nature of scientific statements and concepts; the way in which they are produced; howscience explains, predicts and harnesses nature; the means for determining the validity of information; the formulation and useof the scientific method; the types of reasoning used to arrive at conclusions; and the implications of scientific methods andmodels for the larger society, and for the sciences themselves.

All sciences have an underlying philosophy regardless of claims to the contrary:

There is no such thing as philosophy-free science; there is only science whose philosophical baggage is taken on boardwithout examination.Daniel Dennett

This article is not exhaustive; it covers only those topics that are seen as central by all of the major philosophies ofscience.


Nature of scientific statements and concepts

Science makes assumptions about the way the world is, and the way in which theory relates to the world.


A central concept in the philosophy of science is empiricism , or dependenceon evidence. Empiricism is the view that knowledge derives from experience of the world. In this sense, scientific statements aresubject to and derived from our experiences or observations. Scientific theories are developed and tested through experiments and observations , via empirical methods . Once reproduced widely enough this informationcounts as evidence, upon which the scientific community bases its explanations of how things work.

Observations involve perception , and so arethemselves cognitive acts. That is, observations are themselves embedded in our understanding of the way in which the worldworks; as this understanding changes, the observations themselves may apparently change.

Scientists attempt to use induction , deduction and quasi-empiricalmethods , and invoke key conceptual metaphors to workobservations into a coherent, self-consistent structure.

Scientific realism and instrumentalism

Scientific realism , or naive empiricism , is the view that the universe really is as explained by scientific statements.Realists hold that things like electrons and magnetic fields actually exist. It is naïve in the sense of taking scientific modelsat face value, and is the view that most scientists adopt.

In contrast to realism, instrumentalism holds that ourperceptions, scientific ideas and theories do not necessarily reflect the real world accurately, but are useful instruments toexplain, predict and control our experiences. To an instrumentalist, electrons and magnetic fields are convenient ideas that mayor may not actually exist. For instrumentalists, empirical method is used to do no more than show that theories are consistentwith observations. Instrumentalism is derived in part from John Dewey 's pragmatism .

Social constructivism

Some historians, philosophers, and sociologists of science believe that scientific theories are shaped by their social andpolitical context. This approach is usually known as socialconstructivism . Social constructivism is in one sense an extension of instrumentalism that incorporates the social aspects ofscience. In its strongest form, it sees science as merely a discourse between scientists, with objective fact playing a smallrole if any. A weaker form of the constructivist position might hold that social factors play a large role in the acceptance ofnew scientific theories.

On the stronger account, the existence of Mars the planet is irrelevant, since all we really have are the observations,theories and myths, which are all themselves constructed by social interaction. On this account, scientific statements are abouteach other, and an empirical test is no more than checking the consistency between different sets of social constructed theories.This account rejects realism. It becomes difficult, then, to explain how science differs from any other discipline; equally,however, it becomes difficult to give an account of the extraordinary success of science in producing usable technology.

On the weaker account, Mars the planet might be said to have a real existence, separate and distinct from our observations,theories and myths about it. Although theories and observations are socially constructed, part of the construction processinvolves ensuring a correspondence of some sort with this reality. On this account, scientific statements 'are' about the realworld. The crucial issue for this account is explaining this correspondence. What justification is there for claiming that photosfrom the latest probe are in some sense more real than the Roman myths aboutMars? It is important, therefore, for Social Constructivists to consider how scientific statements are justified.

Analysis and reductionism

Analysis is the activity of breaking an observation or theory down into simplerconcepts in order to understand it. Analysis is as essential to science as it is to all rational enterprises. It would beimposible, for instance, to describe mathematicaly the motion of a projectile without separating out the force of gravity , angle of projection and initialvelocity. Only after this analysis is it possible to formulate a suitable theory of motion.

Reductionism in science can have several differentsenses. One type of reductionism is the belief that all fields of study are ultimately amenable to scientific explanation.Perhaps an historical event might be explained in sociological and psychological terms, which in turn might be described in termsof human physiology, which in turn might be described in terms of chemistry and physics. The historical event will have beenreduced to a physical event. This might be seen as implying that the historical event was 'nothing but' the physical event,denying the existence of emergent phenomena.

Daniel Dennett invented the term greedy reductionism to describe the assumption that suchreductionism was possible. He claims that it is just ' bad science ', seekingto find explanations which are appealing or eloquent, rather than those that are of use in predicting natural phenomena.

Arguments made against greedy reductionism through reference to emergent phenomena rely upon the fact that self-referential systems can be said to contain more information than can be described through individual analysis of their component parts. Examples includesystems that contain strange loops , fractal organisation and strange attractors in phase space . Analysis of such systems is necessarily information-destructivebecause the observer must select a sample of the system that can be at best partially representative. Information theory can be used to calculate the magnitude ofinformation loss and is one of the techniques applied by Chaos theory .

The justification of scientific statements

The most powerful statements in science are those with the widest applicability. Newton’s Third Law - "for every actionthere is an opposite and equal reaction" - is a powerful statement because it applies to every action, anywhere, and at anytime.

But it is not possible for scientists to have tested every incidence of an action, and found a reaction. How is it, then, thatthey can assert that the Third Law is in some sense true? They have, of course, tested many, many actions, and in each one havebeen able to find the corresponding reaction. But can we be sure that the next time we test the Third Law, it will be found tohold true?


One solution to this problem is to rely on the notion of induction . Inductivereasoning maintains that if a situation holds in all observed cases, then the situation holds in all such cases. So, aftercompleting a series of experiments that support the Third Law, one is justified in maintaining that the Law holds in allcases.

Explaining why induction commonly works has been somewhat problematic. One cannot use deduction, the usual process of movinglogically from premise to conclusion, because there is simply no syllogism that will allow such a move. No matter how many times17th Century biologists observed white swans , and in how many different locations, there isno deductive path that can lead them to the conclusion that all swans are white. This is just as well, since, as it turned out,that conclusion would have been wrong. Similarly, it is at least possible that an observation will be done tomorrow that shows anoccasion in which an action is not accompanied by a reaction; the same is true of any scientific law.

One answer has been to conceive of a different form of rational argument, one that does not relying on deduction. Whereasdeduction allows one to formulate a specific truth from a general truth (all crows are black; this is a crow; therefore this isblack), induction somehow allows one to formulate a general truth from some series of specific observations (this is a crow andit is black; that is a crow and it is black; therefore all crows are black).

The problem of induction is one of considerable debateand moment in the philosophy of science: is induction indeed justified, and if so, how?


Another way to use logic to justify scientific statements, first formally discussed by Karl Popper , is falsifiability . This principle statesthat in order to be useful (or even scientific at all), a scientific statement ('fact', theory, 'law', principle, etc) must befalsifiable, i.e. able to be proven wrong. Without this property, it would be difficult (if not impossible) totest a scientific statement against the evidence. Falsification's aim is to re-introduce deductive reasoning into the debate. Itis not possible to deduce a general statement from a series of specific ones, but it is possible for one specific statement toprove that a general statement is false. Finding a black swan might besufficient to show that the general statement 'all swans are white' is false.

Falsifiability neatly avoids the problem of induction, because it does not make use of inductive reasoning. However, itintroduces its own difficulties. When an apparent falsification occurs, it is always possible to introduce an addition to atheory that will render it unfalsified. So, for instance, ornithologists might have simply argued that the large black bird foundin Australia was not a member of the genus Cygnus, but of some other, or perhaps some new, genus.

The problem with falsificationism is that scientific theories are simply never falsifiable. That is, it is always possible toadd ad hoc hypotheses to a theory to save it from falsification. A value judgment is therefore involved in the rejectionof any theory.


Induction and Falsification both attempt to justify scientific statements by reference to other specific scientificstatements. Both must avoid the problem of thecriterion , in which any justification must in turn be justified, resulting in an infinite regress. The regress argument has been used to justify one way out of the infiniteregress, foundationalism . Foundationalism claims that there are somebasic statements that do not require justification. Both induction and falsification are forms of foundationalism in that theyrely on basic statements that derive directly from observations.

The way in which basic statements are derived from observation complicates the problem. Observation is a cognitive act; thatis, it relies on our existing understanding - our set of beliefs. An observation of a transit of Venus requires a huge range of auxiliary beliefs, such as those that describe the opticsof telescopes, the mechanics of the telescope mount, and an understanding of celestial mechanics. At first sight, the observationdoes not appear to be 'basic'.

Coherentism offers an alternative by claiming that statements can bejustified by their being a part of a coherent system. In the case of science, the system is usually taken to be the complete setof beliefs of an individual or of the community of scientists. W. V. Quine argued for a Coherentist approach to science. An observation of a transit of Venus is justified by its being coherent with ourbeliefs about optics, telescope mounts and celestial mechanics. Where this observation is at odds with one of these auxiliarybeliefs, an adjustment in the system will be required to remove the contradiction.

Occam's Razor

Occam's Razor is another notable touchstone in the philosophy ofscience. William of Occam (or Ockhegm or several other spellings)suggested that the simplest account which ' explains ' the phenomenon is to bepreferred. He did not suggest that it would be true, or even more likely to be true, though 'simpler' has very often turned outto be more likely to be right (in hindsight) than 'more complex'.

Occam's Razor has usually been used just as a rule of thumb forchoosing between equally ' explanatory ' hypotheses (ie, theories) about one ormore observed phenomena. However, it is rare that two theories explain equally, so its use has been limited. There arenow mathematical approaches based on information theory thatbalance explanatory power with simplicity. One such is minimum message length inference.

Occam's Razor is often abused and cited where it is inapplicable. It does not say that the simplest account is to be preferredregardless of its capacity to explain outliers, exceptions, or other phenomena in question. The principle of falsifiabilityrequires that any exception that can be reliably reproduced should invalidate the simplest theory, and that the next-simplestaccount which can actually incorporate the exception as part of the theory should then be preferred to the first.

Social accountability

Scientific infallibility

A critical question in science is, to what degree the current body of scientific knowledge can be taken as an indicator ofwhat is actually 'true' about the physical world in which we live. The acceptance of knowledge as if it were absolutely 'true'and unquestionable (in the sense of theology or ideology ) is called scientism .

However, it is common for members of the public to have the opposite view of science — many lay people believe thatscientists are making claims of infallibility. Science serves in the process of consensus decision making by which people of varyingmoral and ethical views come to agree on 'what is real'. In secular and technological societies, without any stronger conceptionof reality based on other shared ethical or moral or religious grounds, science has come to serve as the primary arbiter indisputes. This leads to the abuse of scientific dialogue for political or commercial ends.

Concerned about the wide disparity between how scientists work, and how their work is perceived has lead to public campaignsto educate lay people about scientific skepticism and the scientific method .

Critiques of science

Paul Feyerabend argued that no description of scientific methodcould possibly be broad enough to encompass all the approaches and methods used by scientists. Feyerabend objected toprescriptive scientific method on the grounds that any such method would stifle and cramp scientific progress. Feyerabendclaimed, "the only principle that does not inhibit progress is: anything goes."

See also


Philosophy of science topics


  • Snyder, Paul, Toward One Science: The Convergence of Traditions, St Martin's Press, 1977, cloth ISBN 0-312-81011-3 , paper ISBN 0-312-81012-1 .
  • Van Fraassen, Bas C., The Scientific Image, Oxford: Clarendon Press, 1980, ISBN 0-198-24427-4 .

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