In the philosophy of science, observations are said to be "theory‐laden" when they are affected by the theoretical presuppositions held by the investigator. The thesis of theory‐ladenness is most strongly associated with the late 1950s and early 1960s work of Norwood Russell Hanson, Thomas Kuhn, and Paul Feyerabend, and was probably first put forth (at least implicitly) by Pierre Duhem about 50 years earlier.[1]


Two forms of theory‐ladenness should be kept separate: (a) The semantic form: the meaning of observational terms is partially determined by theoretical presuppositions; (b) The perceptual form: the theories held by the investigator, at a very basic cognitive level, impinge on the perceptions of the investigator. The former may be referred to as semantic and the latter as perceptual theory‐ladenness.

In a book showing the theory-ladenness of psychiatric evidences, Massimiliano Aragona (Il mito dei fatti, 2009) distinguished three forms of theory-ladenness. The "weak form" was already affirmed by Popper (it is weak because he maintains the idea of a theoretical progress directed to the truth of scientific theories). The "strong" form was sustained by Kuhn and Feyerabend, with their notion of incommensurability.

However, Kuhn was a moderate relativist and maintained the Kantian view that although reality is not directly knowable, it manifests itself "resisting" to our interpretations. On the contrary, Feyerabend completely reversed the relationship between observations and theories, introducing an "extra-strong" form of theory-ladenness in which "anything goes".

See also


  1. ^ Bogen, Jim (2014): "Theory and Observation in Science", In: Edward N. Zalta (ed.), The Stanford Encyclopedia of Philosophy (Summer 2014 Edition).
Arturo Carsetti

Arturo Carsetti is an Italian Philosopher of sciences and former Professor of philosophy of science at the University of Bari and the University of Rome Tor Vergata. He is the editor of the Italian Journal for the philosophy of science La Nuova Critica founded in 1957 by Valerio Tonini. He is notable for his contributions, also as a member of the European Academy of Sciences and Arts, to philosophy of science, epistemology, cognitive science and philosophy of mind.

Cognitive bias

A cognitive bias is a systematic pattern of deviation from norm or rationality in judgment. Individuals create their own "subjective social reality" from their perception of the input. An individual's construction of social reality, not the objective input, may dictate their behaviour in the social world. Thus, cognitive biases may sometimes lead to perceptual distortion, inaccurate judgment, illogical interpretation, or what is broadly called irrationality.Some cognitive biases are presumably adaptive. Cognitive biases may lead to more effective actions in a given context. Furthermore, allowing cognitive biases enable faster decisions which can be desirable when timeliness is more valuable than accuracy, as illustrated in heuristics. Other cognitive biases are a "by-product" of human processing limitations, resulting from a lack of appropriate mental mechanisms (bounded rationality), or simply from a limited capacity for information processing.A continually evolving list of cognitive biases has been identified over the last six decades of research on human judgment and decision-making in cognitive science, social psychology, and behavioral economics. Kahneman and Tversky (1996) argue that cognitive biases have efficient practical implications for areas including clinical judgment, entrepreneurship, finance, and management.

Confirmation holism

In philosophy of science, confirmation holism, also called epistemological holism, is the view that no individual statement can be confirmed or disconfirmed by an empirical test, but only a set of statements (a whole theory).

It is attributed to Willard Van Orman Quine who motivated his holism through extending Pierre Duhem's problem of underdetermination in physical theory to all knowledge claims. Duhem's idea was, roughly, that no theory of any type can be tested in isolation but only when embedded in a background of other hypotheses, e.g. hypotheses about initial conditions. Quine thought that this background involved not only such hypotheses but also our whole web-of-belief, which, among other things, includes our mathematical and logical theories and our scientific theories. This last claim is sometimes known as the Duhem–Quine thesis. A related claim made by Quine, though contested by some (see Adolf Grünbaum 1962), is that one can always protect one's theory against refutation by attributing failure to some other part of our web-of-belief. In his own words, "Any statement can be held true come what may, if we make drastic enough adjustments elsewhere in the system.".

Cultural bias

Cultural bias is the phenomenon of interpreting and judging phenomena by standards inherent to one's own culture. The phenomenon is sometimes considered a problem central to social and human sciences, such as economics, psychology, anthropology, and sociology. Some practitioners of the aforementioned fields have attempted to develop methods and theories to compensate for or eliminate cultural bias.

Cultural bias occurs when people of a culture make assumptions about conventions, including conventions of language, notation, proof and evidence. They are then accused of mistaking these assumptions for laws of logic or nature. Numerous such biases exist, concerning cultural norms for color, mate selection, concepts of justice, linguistic and logical validity, the acceptability of evidence, and taboos.


A statement, hypothesis, or theory has falsifiability (or is falsifiable) if it is contradicted by a basic statement, which, in an eventual successful or failed falsification, must respectively correspond to a true or hypothetical observation. For example, the claim "all swans are white and have always been white" is falsifiable since it is contradicted by this basic statement: "In 1697, during the Dutch explorer Willem de Vlamingh expedition, there were black swans on the shore of the Swan River in Australia", which in this case is a true observation. The concept is also known by the terms refutable and refutability.

The concept was introduced by the philosopher of science Karl Popper. He saw falsifiability as the logical part and the cornerstone of his scientific epistemology, which sets the limits of scientific inquiry. He proposed that statements and theories that are not falsifiable are unscientific. Declaring an unfalsifiable theory to be scientific would then be pseudoscience.


Heterophenomenology ("phenomenology of another, not oneself") is a term coined by Daniel Dennett to describe an explicitly third-person, scientific approach to the study of consciousness and other mental phenomena. It consists of applying the scientific method with an anthropological bent, combining the subject's self-reports with all other available evidence to determine their mental state. The goal is to discover how the subject sees the world him- or herself, without taking the accuracy of the subject's view for granted.

John Weckert

John Weckert (BA – University of Adelaide, Graduate Diploma in Computer Science – La Trobe University, Master of Arts – La Trobe University, Doctor of Philosophy – University of Melbourne) is an Australian philosopher who has been an influential figure in, and substantial contributor to the field of information and computer ethics. He has published many books and journal articles outlining his research in this field.

He is the founder and Editor-in-Chief of the journal Nanoethics: Ethics for Technologies that Converge at the Nanoscale, as well as the Australian Computer Society (ACS) representative on the Technical Committee on Computers and Society. He works closely with the ACS on various projects, including developing case studies to accompany the ACS Code of Ethics, with the case studies linking to clauses outlined in the CoE. He is also the manager of the Centre for Applied Philosophy and Public Ethics (CAPPE) Program on Emerging Technologies: IT and Nanotechnology at Charles Sturt University. He is currently the Senior Professor of Information Technology in the School of Information Studies at Charles Sturt University.


Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the recording of data via the use of scientific instruments. The term may also refer to any data collected during the scientific activity. Observations can be qualitative, that is, only the absence or presence of a property is noted, or quantitative if a numerical value is attached to the observed phenomenon by counting or measuring.

Observational study

In fields such as epidemiology, social sciences, psychology and statistics, an observational study draws inferences from a sample to a population where the independent variable is not under the control of the researcher because of ethical concerns or logistical constraints. One common observational study is about the possible effect of a treatment on subjects, where the assignment of subjects into a treated group versus a control group is outside the control of the investigator. This is in contrast with experiments, such as randomized controlled trials, where each subject is randomly assigned to a treated group or a control group.

Personal equation

The term personal equation, in 19th- and early 20th-century science, referred to the idea that every individual observer had an inherent bias when it came to measurements and observations.

Scientific method

The scientific method is an empirical method of acquiring knowledge that has characterized the development of science since at least the 17th century. It involves careful observation, applying rigorous skepticism about what is observed, given that cognitive assumptions can distort how one interprets the observation. It involves formulating hypotheses, via induction, based on such observations; experimental and measurement-based testing of deductions drawn from the hypotheses; and refinement (or elimination) of the hypotheses based on the experimental findings. These are principles of the scientific method, as distinguished from a definitive series of steps applicable to all scientific enterprises.Though diverse models for the scientific method are available, there is in general a continuous process that includes observations about the natural world. People are naturally inquisitive, so they often come up with questions about things they see or hear, and they often develop ideas or hypotheses about why things are the way they are. The best hypotheses lead to predictions that can be tested in various ways. The most conclusive testing of hypotheses comes from reasoning based on carefully controlled experimental data. Depending on how well additional tests match the predictions, the original hypothesis may require refinement, alteration, expansion or even rejection. If a particular hypothesis becomes very well supported, a general theory may be developed.Although procedures vary from one field of inquiry to another, they are frequently the same from one to another. The process of the scientific method involves making conjectures (hypotheses), deriving predictions from them as logical consequences, and then carrying out experiments or empirical observations based on those predictions. A hypothesis is a conjecture, based on knowledge obtained while seeking answers to the question. The hypothesis might be very specific, or it might be broad. Scientists then test hypotheses by conducting experiments or studies. A scientific hypothesis must be falsifiable, implying that it is possible to identify a possible outcome of an experiment or observation that conflicts with predictions deduced from the hypothesis; otherwise, the hypothesis cannot be meaningfully tested.The purpose of an experiment is to determine whether observations agree with or conflict with the predictions derived from a hypothesis. Experiments can take place anywhere from a garage to CERN's Large Hadron Collider. There are difficulties in a formulaic statement of method, however. Though the scientific method is often presented as a fixed sequence of steps, it represents rather a set of general principles.

Not all steps take place in every scientific inquiry (nor to the same degree), and they are not always in the same order. Some philosophers and scientists have argued that there is no scientific method; they include physicist Lee Smolin and philosopher Paul Feyerabend (in his Against Method). Robert Nola and Howard Sankey remark that "For some, the whole idea of a theory of scientific method is yester-year's debate, the continuation of which can be summed up as yet more of the proverbial deceased equine castigation. We beg to differ."

Scientific realism

Scientific realism is the view that the universe described by science is real regardless of how it may be interpreted.

Within philosophy of science, this view is often an answer to the question "how is the success of science to be explained?" The discussion on the success of science in this context 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 valid claims about unobservables (viz., that they have the same ontological status) as observables, as opposed to instrumentalism.

Werner Leinfellner

Werner Leinfellner (January 27, 1921 – April 6, 2010) was professor of philosophy at the University of Nebraska–Lincoln and at the Vienna University of Technology. After recovering from life-threatening wounds during World War II, he studied chemistry and physics at the Universities of Vienna and Graz, eventually turning to the study of the philosophy of science, and receiving his Ph.D. in 1959. He moved to the United States in 1967, in part, because of problems faced by empirically oriented philosophers in obtaining academic positions in Austria and Germany. He is notable for his contributions to philosophy of science, as a member of European Academy of Sciences and Arts, for founding the journal Theory and Decision, for co-founding Theory and Decision Library, and for co-founding the Austrian Ludwig Wittgenstein Society and International Wittgenstein Symposium.

William C. Wimsatt

William C. Wimsatt (born May 27, 1941) is professor emeritus in the Department of Philosophy, the Committee on Conceptual and Historical Studies of Science (previously Conceptual Foundations of Science), and the Committee on Evolutionary Biology at the University of Chicago. He is currently a Winton Professor of the Liberal Arts at the University of Minnesota and Residential Fellow of the Minnesota Center for Philosophy of Science. He specializes in the philosophy of biology, where his areas of interest include reductionism, heuristics, emergence, scientific modeling, heredity, and cultural evolution.

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