In
philosophy of science
Philosophy of science is the branch of philosophy concerned with the foundations, methods, and implications of science. Amongst its central questions are the difference between science and non-science, the reliability of scientific theories, ...
, an
observation
Observation in the natural sciences is an act or instance of noticing or perceiving and the acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the percep ...
is said to be "theory-laden" when shaped by the investigator's theoretical
presupposition
In linguistics and philosophy, a presupposition is an implicit assumption about the world or background belief relating to an utterance whose truth is taken for granted in discourse. Examples of presuppositions include:
* ''Jane no longer writes ...
s. The thesis is chiefly associated with the late 1950s–early 1960s work of
Norwood Russell Hanson
Norwood Russell Hanson (August 17, 1924 – April 18, 1967) was an American philosopher of science. Hanson was a pioneer in advancing the argument that observation is theory-laden — that observation language and theory language are deeply in ...
,
Thomas Kuhn
Thomas Samuel Kuhn (; July 18, 1922 – June 17, 1996) was an American History and philosophy of science, historian and philosopher of science whose 1962 book ''The Structure of Scientific Revolutions'' was influential in both academic and ...
, and
Paul Feyerabend
Paul Karl Feyerabend (; ; January 13, 1924 – February 11, 1994) was an Austrian philosopher best known for his work in the philosophy of science. He started his academic career as lecturer in the philosophy of science at the University of Bri ...
, though it was likely first put forth some 50 years earlier, at least implicitly, by
Pierre Duhem
Pierre Maurice Marie Duhem (; 9 June 1861 – 14 September 1916) was a French theoretical physicist who made significant contributions to thermodynamics, hydrodynamics, and the theory of Elasticity (physics), elasticity. Duhem was also a prolif ...
.
[Bogen, Jim (2014)]
"Theory and Observation in Science"
In: Edward N. Zalta (ed.), ''The Stanford Encyclopedia of Philosophy'' (Summer 2014 Edition).
Semantic theory-ladenness refers to the impact of theoretical assumptions on the meaning of observational terms, while perceptual theory-ladenness refers to their impact on the
perceptual experience itself. Theory-ladenness is also relevant for
measurement
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events.
In other words, measurement is a process of determining how large or small a physical quantity is as compared to ...
outcomes: the data thus acquired may be said to be theory-laden since it is meaningless by itself unless interpreted as the outcome of the measurement processes involved.
Theory-ladenness poses a problem for the confirmation of
scientific theories
A scientific theory is an explanation of an aspect of the natural world that can be or that has been repeatedly tested and has corroborating evidence in accordance with the scientific method, using accepted protocols of observation, measureme ...
since the
observational evidence may already ''implicitly presuppose'' the thesis it is supposed to justify. This effect can present a challenge for reaching
scientific consensus
Scientific consensus is the generally held judgment, position, and opinion of the majority or the supermajority of scientists in a particular field of study at any particular time.
Consensus is achieved through scholarly communication at confer ...
if the disagreeing parties make different observations due to their different theoretical backgrounds.
Forms
Two forms of theory-ladenness should be kept separate: (a) ''The semantic form'': the meaning of
observational term
Ramsey sentences are formal logical reconstructions of theoretical propositions attempting to draw a line between science and metaphysics. A Ramsey sentence aims at rendering propositions containing non-observable theoretical terms (terms employed ...
s 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
Karl Popper
Sir Karl Raimund Popper (28 July 1902 – 17 September 1994) was an Austrian–British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the ...
(it is weak because he maintains the idea of 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
Kantianism () is the philosophy of Immanuel Kant, a German philosopher born in Königsberg, Prussia (now Kaliningrad, Russia). The term ''Kantianism'' or ''Kantian'' is sometimes also used to describe contemporary positions in philosophy of mi ...
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".
Measurement outcomes
Van Fraassen distinguishes between observations, phenomena (observed entities) and appearances (the contents of measurement outcomes). An example of an appearance is the temperature of 38°C of a patient as measured using a thermometer. The number "38" is meaningless by itself unless we interpret it as the outcome of a measurement process. Such an interpretation implicitly assumes various other theses about how the thermometer was used, how thermometers work etc.
All appearances are theory-laden in this sense. But in many cases this does not pose serious practical problems as long as the presumed theses are either correct or only contain mistakes irrelevant to the intended application.
Problem of confirmation
Theory-ladenness is particularly relevant for the problem of
confirmation of scientific theories. According to the
scientific method
The scientific method is an Empirical evidence, empirical method for acquiring knowledge that has been referred to while doing science since at least the 17th century. Historically, it was developed through the centuries from the ancient and ...
, observational evidence is needed to develop scientific theories and to test their predictions. But if an observation is theory-laden then it ''already implicitly presumes'' various theses and therefore cannot act as neutral arbitrator between theories which affirm (or deny) the ''presumed theses''.
This is akin to the
informal fallacy
Informal fallacies are a type of incorrect argument in natural language. The source of the error is not just due to the ''form'' of the argument, as is the case for formal fallacies, but can also be due to their ''content'' and ''context''. Fallac ...
of
begging the question
In classical rhetoric and logic, begging the question or assuming the conclusion (Latin: ) is an informal fallacy that occurs when an argument's premises assume the truth of the conclusion. Historically, begging the question refers to a fault i ...
.
Problem of scientific consensus
Theory-ladenness also poses problems for
scientific consensus
Scientific consensus is the generally held judgment, position, and opinion of the majority or the supermajority of scientists in a particular field of study at any particular time.
Consensus is achieved through scholarly communication at confer ...
. Different researchers may initially hold different background beliefs. ''Ideally'', the observations they make in the course of their research would enable each of them to discern which of these beliefs are false. So they would eventually reach an agreement on the central issues. But their different background beliefs may cause them to make different observations despite the fact that both observe the ''same phenomena''.
In such a case the disagreement happens not just on the level of the ''supported theories'' but also on the level of the ''supporting observational evidence'' that is supposed to arbitrate between the theories. Under those circumstances, gathering more theory-laden evidence would only deepen the problem instead of solving it.
The problem of unresolved disagreements is more severe in the social sciences and philosophy than in the natural sciences. For example, disagreements in ethics or in metaphysics often end in a clash of the brute intuitions which act as evidence for or against the competing theories.
But it is an open question to which extent these disagreements are due to theory-ladenness or other factors.
See also
*
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 rather that only a set of statements (a whole theory) can be so. ...
*
Duhem–Quine thesis
In philosophy of science, the Duhem–Quine thesis, also called the Duhem–Quine problem, says that unambiguous falsifications of a scientific hypothesis are impossible, because an empirical test of the hypothesis requires one or more back ...
*
Observation
Observation in the natural sciences is an act or instance of noticing or perceiving and the acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the percep ...
*
Metaphysics of presence
Metaphysics of presence () is a view held by Martin Heidegger in ''Being and Time'' that holds the entire history of Western philosophy
Western philosophy refers to the Philosophy, philosophical thought, traditions and works of the Western wor ...
References
{{philosophy of science
Metatheory of science
Observation