Scientific realism
Encyclopedia
Scientific realism is, at the most general level, the view that the world described by science (perhaps ideal science) is the real world, as it is, independent of what we might take it to be. Within philosophy of science
, it is often framed as an answer to the question "how is the success of science to be explained?" The debate over what the success of science involves centers primarily on the status of unobservable entities
apparently talked about by scientific theories
. Generally, those who are scientific realists assert that one can make reliable claims about unobservables (viz., that they have the same ontological
status) as observables, as opposed to instrumentalism
.
According to scientific realism, an ideal scientific theory has the following features:
Combining the first and the second claim entails that an ideal scientific theory says definite things about genuinely existing entities. The third claim says that we have reasons to believe that the things said about these entities are true.
Scientific realism usually holds that science makes progress, i.e. scientific theories usually get successively better, or, rather, answer more and more questions. For this reason, many people, scientific realist or otherwise, hold that realism should make sense of the progress of science in terms of theories being successively more like the ideal theory that scientific realists describe.
and realism
. However, it is a thesis about science developed in the twentieth century. Portraying scientific realism in terms of its ancient, medieval, and early modern cousins is at best misleading.
Scientific realism is developed largely as a reaction to logical positivism
. Logical positivism was the first philosophy of science in the twentieth century and the forerunner of scientific realism, holding that a sharp distinction can be drawn between observational terms and theoretical terms, the latter capable of semantic analysis in observational and logical terms.
Logical positivism encountered difficulties with:
These difficulties for logical positivism suggest, but do not entail, scientific realism, and lead to the development of realism as a philosophy of science.
Realism became the dominant philosophy of science after positivism. Bas van Fraassen developed constructive empiricism
as an alternative to realism. Responses to van Fraassen have sharpened realist positions and lead to some revisions of scientific realism.
Arguments for scientific realism often appeal to abductive reasoning
or "inference to the best explanation". Scientific realists point to the success of scientific theories in predicting and explaining a variety of phenomena, and argue that from this we can infer that our scientific theories (or at least the best ones) provide true descriptions of the world, or approximately so.
On the other hand, pessimistic induction
, one of the main arguments against realism, argues that the history of science contains many theories once regarded as empirically successful but which are now believed to be false. Additionally, the history of science contains many empirically successful theories whose unobservable terms are not believed to genuinely refer. For example, the effluvial theory of static electricity is an empirically successful theory whose central unobservable terms have been replaced by later theories. Realists reply that replacement of particular realist theories with better ones is to be expected due to the progressive nature of scientific knowledge, and when such replacements occur only superfluous unobservables are dropped. For example, Albert Einstein
's theory of special relativity
showed that the concept of the luminiferous ether could be dropped because it had contributed nothing to the success of the theories of mechanics
and electromagnetism
. On the other hand, when theory replacement occurs, a well-supported concept, such as the concept of atom
s, is not dropped but is incorporated into the new theory in some form.
Also against scientific realism social constructivists
might argue that scientific realism is unable to account for the rapid change that occurs in scientific knowledge during periods of revolution. Constructivists may also argue that the success of theories is only a part of the construction. However, these arguments ignore the fact that many scientists are not realists. In fact, during what is perhaps the most notable example of revolution in science—the development of quantum mechanics
in the 1920s—the dominant philosophy of science was logical positivism
. The alternative realist Bohm interpretation
and many-worlds interpretation
of quantum mechanics do not make such a revolutionary break with the concepts of classical physics
.
Another argument against scientific realism, deriving from the underdetermination problem
, is not so historically motivated as these others. It claims that observational data can in principle be explained by multiple theories that are mutually incompatible. Realists might counter by saying that there have been few actual cases of underdetermination in the history of science. Usually the requirement of explaining the data is so exacting that scientists are lucky to find even one theory that fulfills it. Furthermore, if we take the underdetermination argument seriously, it implies that we can know about only what we have directly observed
. For example, we could not theorize that dinosaur
s once lived based on the fossil
evidence because other theories (e.g., that the fossils are clever hoaxes) can account for the same data. Realists claim that, in addition to empirical adequacy, there are other criteria for theory choice, such as parsimony.
Philosophy of science
The philosophy of science is concerned with the assumptions, foundations, methods and implications of science. It is also concerned with the use and merit of science and sometimes overlaps metaphysics and epistemology by exploring whether scientific results are actually a study of truth...
, it is often framed as an answer to the question "how is the success of science to be explained?" The debate over what the success of science involves centers primarily on the status of unobservable entities
Unobservables
An unobservable is an entity whose existence, nature, properties, qualities or relations are not directly observable by man. In philosophy of science typical examples of "unobservables" are atomic particles, the force of gravity, causation and beliefs or desires . However, some philosophers An...
apparently talked about by scientific theories
Theory
The English word theory was derived from a technical term in Ancient Greek philosophy. The word theoria, , meant "a looking at, viewing, beholding", and referring to contemplation or speculation, as opposed to action...
. Generally, those who are scientific realists assert that one can make reliable claims about unobservables (viz., that they have the same ontological
Ontology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
status) as observables, as opposed to instrumentalism
Instrumentalism
In the philosophy of science, instrumentalism is the view that a scientific theory is a useful instrument in understanding the world. A concept or theory should be evaluated by how effectively it explains and predicts phenomena, as opposed to how accurately it describes objective...
.
Main features of scientific realism
Scientific realism involves two basic positions. First, it is a set of claims about the features of an ideal scientific theory; an ideal theory is the sort of theory science aims to produce. Second, it is the commitment that science will eventually produce theories very much like an ideal theory and that science has done pretty well thus far in some domains. It is important to note that one might be a scientific realist regarding some sciences while not being a realist regarding others. For example, one might hold realist attitudes toward physics, chemistry and biology, and not toward economics, psychology and sociology.According to scientific realism, an ideal scientific theory has the following features:
- The claims the theory makes are either true or false, depending on whether the entities talked about by the theory exist and are correctly described by the theory. This is the semantic commitment of scientific realism.
- The entities described by the scientific theory exist objectively and mind-independently. This is the metaphysicalMetaphysicsMetaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
commitment of scientific realism. - There are reasons to believe some significant portion of what the theory says. This is the epistemological commitment.
Combining the first and the second claim entails that an ideal scientific theory says definite things about genuinely existing entities. The third claim says that we have reasons to believe that the things said about these entities are true.
Scientific realism usually holds that science makes progress, i.e. scientific theories usually get successively better, or, rather, answer more and more questions. For this reason, many people, scientific realist or otherwise, hold that realism should make sense of the progress of science in terms of theories being successively more like the ideal theory that scientific realists describe.
Characteristic claims
The following claims are typical of those held by scientific realists. Due to the wide disagreements over the nature of science's success and the role of realism in its success, a scientific realist would agree with some but not all of the following positions.- The best scientific theories are at least partially true.
- The best theories do not employ central terms that are non referring expressions.
- To say that a theory is approximately true is sufficient explanation of the degree of its predictive success.
- The approximate truth of a theory is the only explanation of its predictive success.
- Even if a theory employs expressions that do not have a reference, a scientific theory may be approximately true.
- Scientific theories are in a historical process of progress towards a true account of the physical world.
- Scientific theories make genuine, existential claims
- Theoretical claims of scientific theories should be read literally and are definitively either true or false.
- The degree of the predictive success of a theory is evidence of the referential success of its central terms.
- The goal of science is an account of the physical world that is literally true. Science has been successful because this is the goal that it has been making progress towards.
History of scientific realism
Scientific realism is related to much older philosophical positions including rationalismRationalism
In epistemology and in its modern sense, rationalism is "any view appealing to reason as a source of knowledge or justification" . In more technical terms, it is a method or a theory "in which the criterion of the truth is not sensory but intellectual and deductive"...
and realism
Philosophical realism
Contemporary philosophical realism is the belief that our reality, or some aspect of it, is ontologically independent of our conceptual schemes, linguistic practices, beliefs, etc....
. However, it is a thesis about science developed in the twentieth century. Portraying scientific realism in terms of its ancient, medieval, and early modern cousins is at best misleading.
Scientific realism is developed largely as a reaction to logical positivism
Logical positivism
Logical positivism is a philosophy that combines empiricism—the idea that observational evidence is indispensable for knowledge—with a version of rationalism incorporating mathematical and logico-linguistic constructs and deductions of epistemology.It may be considered as a type of analytic...
. Logical positivism was the first philosophy of science in the twentieth century and the forerunner of scientific realism, holding that a sharp distinction can be drawn between observational terms and theoretical terms, the latter capable of semantic analysis in observational and logical terms.
Logical positivism encountered difficulties with:
- The verification theory of meaning (for which see HempelCarl Gustav HempelCarl Gustav "Peter" Hempel was a philosopher of science and a major figure in 20th-century logical empiricism...
(1950)). - Troubles with the analytic-synthetic distinction (for which see Quine (1950)).
- The theory ladenness of observation (for which see Kuhn (1970) and Quine (1960)).
- Difficulties moving from the observationality of terms to observationality of sentences (for which see PutnamHilary PutnamHilary Whitehall Putnam is an American philosopher, mathematician and computer scientist, who has been a central figure in analytic philosophy since the 1960s, especially in philosophy of mind, philosophy of language, philosophy of mathematics, and philosophy of science...
(1962)). - The vagueness of the observational-theoretical distinction (for which see Maxwell (1962)).
These difficulties for logical positivism suggest, but do not entail, scientific realism, and lead to the development of realism as a philosophy of science.
Realism became the dominant philosophy of science after positivism. Bas van Fraassen developed constructive empiricism
Constructive empiricism
In philosophy, constructive empiricism is a form of empiricism. Bas van Fraassen is nearly solely responsible for the initial development of constructive empiricism; its historically most important presentation appears in his The Scientific Image...
as an alternative to realism. Responses to van Fraassen have sharpened realist positions and lead to some revisions of scientific realism.
Arguments for and against scientific realism
One of the main arguments for scientific realism centers on the notion that scientific knowledge is progressive in nature, and that it is able to predict phenomena successfully. Many realists (e.g., Ernan McMullin, Richard Boyd) think the operational success of a theory lends credence to the idea that its more unobservable aspects exist, because they were how the theory reasoned its predictions. For example, a scientific realist would argue that science must derive some ontological support for atoms from the outstanding phenomenological success of all the theories using them.Arguments for scientific realism often appeal to abductive reasoning
Abductive reasoning
Abduction is a kind of logical inference described by Charles Sanders Peirce as "guessing". The term refers to the process of arriving at an explanatory hypothesis. Peirce said that to abduce a hypothetical explanation a from an observed surprising circumstance b is to surmise that a may be true...
or "inference to the best explanation". Scientific realists point to the success of scientific theories in predicting and explaining a variety of phenomena, and argue that from this we can infer that our scientific theories (or at least the best ones) provide true descriptions of the world, or approximately so.
On the other hand, pessimistic induction
Pessimistic induction
In the philosophy of science, the pessimistic induction, also known as the pessimistic meta-induction, is an argument which seeks to rebut scientific realism, particularly the scientific realist's notion of epistemic optimism....
, one of the main arguments against realism, argues that the history of science contains many theories once regarded as empirically successful but which are now believed to be false. Additionally, the history of science contains many empirically successful theories whose unobservable terms are not believed to genuinely refer. For example, the effluvial theory of static electricity is an empirically successful theory whose central unobservable terms have been replaced by later theories. Realists reply that replacement of particular realist theories with better ones is to be expected due to the progressive nature of scientific knowledge, and when such replacements occur only superfluous unobservables are dropped. For example, Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
's theory of special relativity
Special relativity
Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...
showed that the concept of the luminiferous ether could be dropped because it had contributed nothing to the success of the theories of mechanics
Mechanics
Mechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....
and electromagnetism
Electromagnetism
Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
. On the other hand, when theory replacement occurs, a well-supported concept, such as the concept of atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s, is not dropped but is incorporated into the new theory in some form.
Also against scientific realism social constructivists
Constructivist epistemology
Constructivist epistemology is an epistemological perspective in philosophy about the nature of scientific knowledge. Constructivists maintain that scientific knowledge is constructed by scientists and not discovered from the world. Constructivists claim that the concepts of science are mental...
might argue that scientific realism is unable to account for the rapid change that occurs in scientific knowledge during periods of revolution. Constructivists may also argue that the success of theories is only a part of the construction. However, these arguments ignore the fact that many scientists are not realists. In fact, during what is perhaps the most notable example of revolution in science—the development of quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
in the 1920s—the dominant philosophy of science was logical positivism
Logical positivism
Logical positivism is a philosophy that combines empiricism—the idea that observational evidence is indispensable for knowledge—with a version of rationalism incorporating mathematical and logico-linguistic constructs and deductions of epistemology.It may be considered as a type of analytic...
. The alternative realist Bohm interpretation
Bohm interpretation
The de Broglie–Bohm theory, also called the pilot-wave theory, Bohmian mechanics, and the causal interpretation, is an interpretation of quantum theory. In addition to a wavefunction on the space of all possible configurations, it also includes an actual configuration, even in situations where...
and many-worlds interpretation
Many-worlds interpretation
The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction, but denies the actuality of wavefunction collapse. Many-worlds implies that all possible alternative histories and futures are real, each representing an...
of quantum mechanics do not make such a revolutionary break with the concepts of classical physics
Classical physics
What "classical physics" refers to depends on the context. When discussing special relativity, it refers to the Newtonian physics which preceded relativity, i.e. the branches of physics based on principles developed before the rise of relativity and quantum mechanics...
.
Another argument against scientific realism, deriving from the underdetermination problem
Underdetermination
In scientific theory, underdetermination refers to situations where the evidence available is insufficient to identify which belief we should hold about that evidence...
, is not so historically motivated as these others. It claims that observational data can in principle be explained by multiple theories that are mutually incompatible. Realists might counter by saying that there have been few actual cases of underdetermination in the history of science. Usually the requirement of explaining the data is so exacting that scientists are lucky to find even one theory that fulfills it. Furthermore, if we take the underdetermination argument seriously, it implies that we can know about only what we have directly observed
Observation
Observation is either an activity of a living being, such as a human, consisting of receiving knowledge of the outside world through the senses, or the recording of data using scientific instruments. The term may also refer to any data collected during this activity...
. For example, we could not theorize that dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s once lived based on the fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
evidence because other theories (e.g., that the fossils are clever hoaxes) can account for the same data. Realists claim that, in addition to empirical adequacy, there are other criteria for theory choice, such as parsimony.
See also
- Anti-realismAnti-realismIn analytic philosophy, the term anti-realism is used to describe any position involving either the denial of an objective reality of entities of a certain type or the denial that verification-transcendent statements about a type of entity are either true or false...
- Constructivist epistemologyConstructivist epistemologyConstructivist epistemology is an epistemological perspective in philosophy about the nature of scientific knowledge. Constructivists maintain that scientific knowledge is constructed by scientists and not discovered from the world. Constructivists claim that the concepts of science are mental...
- Constructive empiricismConstructive empiricismIn philosophy, constructive empiricism is a form of empiricism. Bas van Fraassen is nearly solely responsible for the initial development of constructive empiricism; its historically most important presentation appears in his The Scientific Image...
- Confirmation holismConfirmation holismConfirmation holism, also called epistemological holism is the claim that a single scientific theory cannot be tested in isolation; a test of one theory always depends on other theories and hypotheses....
- Critical realismCritical realismIn the philosophy of perception, critical realism is the theory that some of our sense-data can and do accurately represent external objects, properties, and events, while other of our sense-data do not accurately represent any external objects, properties, and events...
- Entity realismEntity realismEntity realism is a philosophical position within the debate about scientific realism. Whereas traditional scientific realism argues that our best scientific theories are true, or approximately true, or closer to the truth than their predecessors, entity realism does not commit itself to judgments...
- InstrumentalismInstrumentalismIn the philosophy of science, instrumentalism is the view that a scientific theory is a useful instrument in understanding the world. A concept or theory should be evaluated by how effectively it explains and predicts phenomena, as opposed to how accurately it describes objective...
- Naïve realismNaïve realismNaïve realism, also known as direct realism or common sense realism, is a philosophy of mind rooted in a common sense theory of perception that claims that the senses provide us with direct awareness of the external world...
- Pessimistic inductionPessimistic inductionIn the philosophy of science, the pessimistic induction, also known as the pessimistic meta-induction, is an argument which seeks to rebut scientific realism, particularly the scientific realist's notion of epistemic optimism....
- Scientific materialism
- Structural realism
Further reading
- Bunge, Mario. (2006). Chasing Reality: Strife over Realism. Toronto Studies in Philosophy: University of Toronto Press
- Hempel, Carl. (1950). "Empiricist Criteria of Cognitive Significance" in Boyd, Richard et al. eds. (1990). The Philosophy of Science Cambridge: MIT Press..
- Kukla, A. (2000). Social constructivism and the philosophy of science. London: Routledge.
- Kuhn, Thomas. (1970). The Structure of Scientific Revolutions, 2nd Edition Chicago: University of Chicago Press.
- Laudan, Larry. (1981). "A Confutation of Convergent Realism" Philosophy of Science
- Leplin, Jarrett. (1984). Scientific Realism. California: University of California Press.
- Leplin, Jarrett. (1997). A Novel Defense of Scientific Realism. Oxford: Oxford University Press.
- Maxwell, Grover (1962). "The Ontological Status of Theoretical Entities" in Feigl and Maxwell Scientific Explanation, Space, and Time vol. 3, Minnesota Studies in the Philosophy of Science, 3-15.
- Okasha, Samir. (2002). Philosophy of science: A very short introduction. Oxford: Oxford University Press. See especially chapter 4, "Realism and Anti-Realism."
- Putnam, Hilary. (1962). "What Theories are Not" in Ernst Nagel et al. (1962). Logic, Methodology, and Philosophy of Science Stanford University Press.
- Psillos, Stathis. (1999). Scientific realism: How science tracks truth. London: Routledge.
- Quine, W.V.O. (1951). "Two Dogmas of Empiricism" in his (1953)http://www.ditext.com/quine/quine.html. From a Logical Point of View Cambridge: Harvard University Press.
- Quine, W.V.O. (1960). Word and ObjectWord and ObjectWord and Object is a 1960 book of epistemology by Willard Van Orman Quine. In it, Quine develops his thesis of the Indeterminacy of translation....
Cambridge: MIT Press. - Sankey, H. (2001). "Scientific Realism: An Elaboration and a Defense" retrieved from http://philsci-archive.pitt.edu