Theoretical definition
Encyclopedia
A theoretical definition gives the meaning of a word in terms of the theories of a specific discipline. This type of definition
assumes both knowledge and acceptance of the theories that it depends on. To theoretically define is to create a hypothetical construct. This method of operationalization
is not to be confused with operationally defining
.
An example of a theoretical definition is that of "Heat
" in physics, which actually puts forth an entire theory of heat (involving accelerating molecules, etc.).
(e.g. how many metres exactly is a "tall" person?) and ambiguity
(e.g. "I purchased a bat" could have many meanings). Theoretical definitions specify exactly when the word should and should not be applied. In this regard they are unlike persuasive definitions, which can be both vague and ambiguous. Theoretical definitions do, however, have one thing in common with persuasive definitions: they are normative, and not merely descriptive. To create a theoretical definition is to propose a way of thinking about an issue. Indeed, theoretical definitions contain built-in theories; they cannot be simply reduced to describing a set of observations. The definition will contain implicit induction
s and deductive consequences that are part of the theory it pushes. The word "Heat" in physics is not simply describing molecules, it is proposing various laws of nature and predicting certain results.
Like Stipulative definitions, it is not a valid criticism to say that a theoretical definition is "wrong about how most people use the word" nor that "the definition itself is false". Instead one might say that a theoretical definition is unhelpful. This is unlike lexical definitions, which themselves claim to be common, popular uses of a word. In contrast, a theoretical definition is only a bad one if the theories that it supports are invalidated or falsified (which occurs through conflict with other theories that have been accepted). It is at that point - once they describe falsified theories - that these kinds of definitions become unhelpful or 'unpromising' (e.g. the theoretical definition of "demonic possession" is not itself false, the ideas are, and so the term is useless to modern medicine).
It is in this way that professional fields build frameworks of agreed-upon theoretical definitions. A case in point, consider "Heat". If a physicist's theories of molecules turn out to be wrong in some sense, this would make "Heat" an unhelpful theoretical definition, not a false one (i.e. this kind of definition only invites us to use certain theories, and the theories make the truth claims). Moreover, like the theories that build them, theoretical definitions change as scientific understanding grows.
Psychology
has many examples of ideas that required conceptual definitions, including intelligence
, knowledge, tolerance, and preference. Following the establishment of a theoretical definition, the researcher must use an operational definition
to indicate how the abstract concept will be measured.
Theoretical definitions are common in scientific contexts, where theories tend to be more precisely defined, and results are more widely accepted as correct. The definitions of substances as various configurations of atoms are theoretical definitions, as are definitions of color
s as specific wavelength
s of reflected light. In such cases one definition of a term is unlikely to contradict another definition based on a different theory. However, in areas such as philosophy
and the social sciences
, theoretical definitions of the same term often contradict each other depending on whose theory is being used as the basis.
Another example of a theoretical definition: the length of a metre
is "the distance traveled by light
in a vacuum
during a time interval of 1/299,792,458 of a second
". This is based on the first postulate of special relativity
theory that the speed of light
in vacuum is the same to all inertial observers (i.e. it is a constant, and therefore a good measure of length). Thus we have defined 'metre' according to other ideas contained in modern scientific theory. Rejection of the theory underlying a theoretical definition leaves the definition invalid for use in argument with those who reject it — neither side will advance its position by using terms the others do not accept.
For example, John Searle
's Chinese room
thought experiment
illustrates how differing theoretical definitions of "thinking" have caused conflict amongst artificial intelligence philosophers
. Some philosophers might call "thought" merely "having the ability to convince another person that you can think". An accompanying operational definition
for this theoretical definition could be a simple conversation test (e.g. Turing test
). In contrast, Searle believes that better theoretical and operational definitions are required.
A recent effect of differing theoretical definitions occurred when millions of Americans went from normal to overweight in a day's time. The change in the theoretical definition of "overweight
" was based on new theories put forth by the National Institutes of Health
suggesting greater risks than originally believed. The government then changed the operational definition of "overweight" to "having a BMI
over 25" (rather than 27 for women and 28 for men). Changing our understanding of when someone is "overweight" put several million more in that category, even though they had not actually gained or lost any weight.
Definition
A definition is a passage that explains the meaning of a term , or a type of thing. The term to be defined is the definiendum. A term may have many different senses or meanings...
assumes both knowledge and acceptance of the theories that it depends on. To theoretically define is to create a hypothetical construct. This method of operationalization
Operationalization
In humanities, operationalization is the process of defining a fuzzy concept so as to make the concept clearly distinguishable or measurable and to understand it in terms of empirical observations...
is not to be confused with operationally defining
Operational definition
An operational definition defines something in terms of the specific process or set of validation tests used to determine its presence and quantity. That is, one defines something in terms of the operations that count as measuring it. The term was coined by Percy Williams Bridgman and is a part of...
.
An example of a theoretical definition is that of "Heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
" in physics, which actually puts forth an entire theory of heat (involving accelerating molecules, etc.).
Overview
Theoretical definitions are common in both philosophy and science, and can be difficult to understand because of their strict, and often conceptual uses. The goal is to eliminate vaguenessVagueness
The term vagueness denotes a property of concepts . A concept is vague:* if the concept's extension is unclear;* if there are objects which one cannot say with certainty whether belong to a group of objects which are identified with this concept or which exhibit characteristics that have this...
(e.g. how many metres exactly is a "tall" person?) and ambiguity
Ambiguity
Ambiguity of words or phrases is the ability to express more than one interpretation. It is distinct from vagueness, which is a statement about the lack of precision contained or available in the information.Context may play a role in resolving ambiguity...
(e.g. "I purchased a bat" could have many meanings). Theoretical definitions specify exactly when the word should and should not be applied. In this regard they are unlike persuasive definitions, which can be both vague and ambiguous. Theoretical definitions do, however, have one thing in common with persuasive definitions: they are normative, and not merely descriptive. To create a theoretical definition is to propose a way of thinking about an issue. Indeed, theoretical definitions contain built-in theories; they cannot be simply reduced to describing a set of observations. The definition will contain implicit induction
Induction
-General use:* Induction , induction of childbirth* Rite of passage** Introduction of an individual into a body such as the armed forces** Formal introduction of a priest into possession of the position to which she or he has been presented and instituted...
s and deductive consequences that are part of the theory it pushes. The word "Heat" in physics is not simply describing molecules, it is proposing various laws of nature and predicting certain results.
Like Stipulative definitions, it is not a valid criticism to say that a theoretical definition is "wrong about how most people use the word" nor that "the definition itself is false". Instead one might say that a theoretical definition is unhelpful. This is unlike lexical definitions, which themselves claim to be common, popular uses of a word. In contrast, a theoretical definition is only a bad one if the theories that it supports are invalidated or falsified (which occurs through conflict with other theories that have been accepted). It is at that point - once they describe falsified theories - that these kinds of definitions become unhelpful or 'unpromising' (e.g. the theoretical definition of "demonic possession" is not itself false, the ideas are, and so the term is useless to modern medicine).
It is in this way that professional fields build frameworks of agreed-upon theoretical definitions. A case in point, consider "Heat". If a physicist's theories of molecules turn out to be wrong in some sense, this would make "Heat" an unhelpful theoretical definition, not a false one (i.e. this kind of definition only invites us to use certain theories, and the theories make the truth claims). Moreover, like the theories that build them, theoretical definitions change as scientific understanding grows.
Psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
has many examples of ideas that required conceptual definitions, including intelligence
Intelligence
Intelligence has been defined in different ways, including the abilities for abstract thought, understanding, communication, reasoning, learning, planning, emotional intelligence and problem solving....
, knowledge, tolerance, and preference. Following the establishment of a theoretical definition, the researcher must use an operational definition
Operational definition
An operational definition defines something in terms of the specific process or set of validation tests used to determine its presence and quantity. That is, one defines something in terms of the operations that count as measuring it. The term was coined by Percy Williams Bridgman and is a part of...
to indicate how the abstract concept will be measured.
Examples
| Conceptual definition | Operational definition Operational definition An operational definition defines something in terms of the specific process or set of validation tests used to determine its presence and quantity. That is, one defines something in terms of the operations that count as measuring it. The term was coined by Percy Williams Bridgman and is a part of... |
| Weight: a measurement of gravitational force acting on an object | a result of measurement of an object on a Newton spring scale Spring scale The spring scale apparatus is simply a spring fixed at one end with a hook to attach an object at the other. It works by Hooke's Law, which states that the force needed to extend a spring is proportional to the distance that spring is extended from its rest position... |
Theoretical definitions are common in scientific contexts, where theories tend to be more precisely defined, and results are more widely accepted as correct. The definitions of substances as various configurations of atoms are theoretical definitions, as are definitions of color
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
s as specific wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s of reflected light. In such cases one definition of a term is unlikely to contradict another definition based on a different theory. However, in areas such as philosophy
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...
and the social sciences
Social sciences
Social science is the field of study concerned with society. "Social science" is commonly used as an umbrella term to refer to a plurality of fields outside of the natural sciences usually exclusive of the administrative or managerial sciences...
, theoretical definitions of the same term often contradict each other depending on whose theory is being used as the basis.
Another example of a theoretical definition: the length of a metre
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
is "the distance traveled by light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
in a vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
during a time interval of 1/299,792,458 of a second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
". This is based on the first postulate 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...
theory that the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
in vacuum is the same to all inertial observers (i.e. it is a constant, and therefore a good measure of length). Thus we have defined 'metre' according to other ideas contained in modern scientific theory. Rejection of the theory underlying a theoretical definition leaves the definition invalid for use in argument with those who reject it — neither side will advance its position by using terms the others do not accept.
John Searle
John Rogers Searle is an American philosopher and currently the Slusser Professor of Philosophy at the University of California, Berkeley.-Biography:...
's Chinese room
Chinese room
The Chinese room is a thought experiment by John Searle, which first appeared in his paper "Minds, Brains, and Programs", published in Behavioral and Brain Sciences in 1980...
thought experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
illustrates how differing theoretical definitions of "thinking" have caused conflict amongst artificial intelligence philosophers
Philosophy of artificial intelligence
The philosophy of artificial intelligence attempts to answer such questions as:* Can a machine act intelligently? Can it solve any problem that a person would solve by thinking?...
. Some philosophers might call "thought" merely "having the ability to convince another person that you can think". An accompanying operational definition
Operational definition
An operational definition defines something in terms of the specific process or set of validation tests used to determine its presence and quantity. That is, one defines something in terms of the operations that count as measuring it. The term was coined by Percy Williams Bridgman and is a part of...
for this theoretical definition could be a simple conversation test (e.g. Turing test
Turing test
The Turing test is a test of a machine's ability to exhibit intelligent behaviour. In Turing's original illustrative example, a human judge engages in a natural language conversation with a human and a machine designed to generate performance indistinguishable from that of a human being. All...
). In contrast, Searle believes that better theoretical and operational definitions are required.
A recent effect of differing theoretical definitions occurred when millions of Americans went from normal to overweight in a day's time. The change in the theoretical definition of "overweight
Overweight
Overweight is generally defined as having more body fat than is optimally healthy. Being overweight is a common condition, especially where food supplies are plentiful and lifestyles are sedentary...
" was based on new theories put forth by the National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
suggesting greater risks than originally believed. The government then changed the operational definition of "overweight" to "having a BMI
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...
over 25" (rather than 27 for women and 28 for men). Changing our understanding of when someone is "overweight" put several million more in that category, even though they had not actually gained or lost any weight.
See also
- General Conference on Weights and MeasuresGeneral Conference on Weights and MeasuresThe General Conference on Weights and Measures is the English name of the Conférence générale des poids et mesures . It is one of the three organizations established to maintain the International System of Units under the terms of the Convention du Mètre of 1875...
- International Committee for Weights and MeasuresInternational Committee for Weights and MeasuresThe Interglobal Committee for Weights and Measures is the English name of the Comité international des poids et mesures . It consists of eighteen persons from Member States of the Metre Convention...