A definition is a statement that gives the meaning of a term.
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Derived from the Latin word definire which means to
enclose within limits or to make boundaries or limits
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The boundary of a field is defined by indicating
the limits within which a field is confined and bounded which it is marked off
from other fields; similarly, a term is defined by indicating the limits within
which it is used and by which it is marked off from other terms.
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Definition is not a proposition or sentence but
a term, generally a complex term.
Parts of a Definition
1. Definiendum
– the word that is defined
2. Definiens
– the phrase that explains the definiendum
Kinds of
Definition
I.
Kinds
of Definition Based on Usage
A.
Lexical
Definition
A lexical definition (Latin, lexis
which means “word”) is the definition of a word according to the meaning
customarily assigned to it by the community of users. It simply reports the meaning which a word already
has among the users of the language in which the word occurs. A dictionary or
lexicon comprises this kind of definition.
E.g.: Lexicon - dictionary: a reference book that alphabetically lists words
and their meanings, e.g. of an ancient language
River
- large natural channel of water: a natural stream of water that flows
through land and empties into a body of water such as an ocean or lake
B.
Stipulative
Definition
A stipulative definition is a kind of definition in which a new word or
term is coined in order to signify a meaning or object for which no word in the
language has previously been given.
For example, the word selfie
has been invented in order to signify a person who loves to take picture of
himself or herself.
Suppose that another living creature was found in another planet. Surely,
there is no word in our language to signify such creature. We, then, have to stipulate that the creature shall be
known by this or that particular name. Doing this means making a stipulative
definition.
C.
Precising
Definition
The purpose of a precising definition is to reduce the vagueness of a
word. There are terms in our language which must have precise definitions
because some future actions are based on our knowledge of them.
For example, the arguments for or against contraception requires a clear,
precise, and unambiguous definition of life
of human organism because such definition implies the moral bearing of
contraception.
Other examples which need precising definitions are legal terms like
“theft”, “murder”, “private property”, “rights”, and “sovereignty” since the
definition sets the condition of understanding laws and legislative praxis.
D.
Theoretical
Definition
Theoretical definitions attempt to define an object according to its true
nature, and not necessarily according to the way the word is used by a community
of users.
Take, for instance, the definition of table salt as sodium chloride.
Unless the persons involved have some acquaintance with elementary chemistry,
this would be a bad definition, for it would define the familiar in terms of
the unfamiliar. For those acquainted with the principles of chemistry, however,
this definition is the best one, for it reveals the real nature of salt. Other
familiar theoretical definitions are “force equals mass times acceleration,” or
“light is electromagnetic energy (of a certain range of wavelengths).” For
scientific purposes, theoretical definitions are necessary and cannot be
replaced by other types of definitions. A theoretical definition answers the
question, “What really is x?” where “x” is the object whose name is to be
defined.
Philosophers, too, are interested in theoretical definitions. The desire
to know what is really the nature of “human person”, “knowledge”, “existence”,
“being”, “beauty” etc., tells us why philosophy today have so many branches
like Philosophy of the Human Person, Epistemology, Existentialism, Metaphysics,
and Aesthetics which endeavour to get correct theoretical definitions of the
objects just mentioned.
E.
Persuasive
Definition
Some definitions are intended either mainly or at least partly to
influence attitudes. Persuasive definition, under which these definitions are
categorized, incites either favourable or unfavourable responses to the object
so defined. Here are examples of persuasive definitions:
Democracy is a government of the weak, inferior race.
Democracy is a government of the people by the people for the people.
A dictator is one who achieves greatness by violence in the political
sphere.
Love is only an illusion on people who do
not know the difference between reality and fantasy.
Contraception is the deliberate prevention
of unwanted pregnancy so that families may be able to give the best care to
their children.
Contraception is the wilful interference
of God’s will so that children who would have seen the light of day are
deliberately prevented from doing so.
Persuasive is not really concerned
with revealing the true nature of the concept defined but of influencing
attitude by using phrases that appeal to one’s emotion.
II.
Kinds
of Definition Based on Extension and Intension
A. Extensional Definition
Also known as Denotative Definition, it is a way of defining a word based on
giving examples of the things or objects referred to by a term. For example,
defining a computer for someone who never saw a computer before would be
utterly lacking. It is important, therefore, to show him or her a computer.
Showing a computer to describe a term “computer” is an extensional definition.
2
Types:
1.
Definition
by Example – a definition in which we list or give examples of the objects
denoted by the term
2.
Ostensive
– an extensional definition which merely points out an object referred by a
term.
3.
Quasi-ostensive
– an extensional definition which does not only point the object referred to by
the term but also gives a description about the object being pointed out.
Extensional or denotative
definitions are important especially when a term requires a demonstration in
order to be understood. For example, one cannot define “color red” without
pointing to something that is of color red.
There are, however,
serious limitations of extensional or denotative definitions. One limitation is
that a person who uses this kind of definition is that he may not be able to
articulate what the thing really is because he knows only what the thing is
like. Articulation of meaning is important because it clarifies ambiguity in
understanding, and more importantly, it indicates the depth of understanding a
person has of a particular term. Another reason is that extensional definitions
cannot define terms that have no extension. For instance, how can we
extensionally define terms like “length”, “infinite”, “nothingness”, “value”,
etc?
B. Intensional Definition
Also known as connotative definition or definition by comprehension, it is a way
of defining a word by giving its meaning. Giving the meaning of the term may be
done through giving its etymological origin or its synonym, or stating the
essential attributes of the concept signified by the term.
4 Types:
1.
Etymological
Definition - Defines a word by giving the meaning of the word or words from
which it is derived. E.g. Philosophy is
derived from philos, a Greek word which
means “loving,” and Sophia, which
means “wisdom”.
2.
Definition
by Synonym - Defines a word by giving a synonym (either of the same
language as the word to be defined or of a different language) that is better
known than the word to be defined. E.g. anthropos
means man, to confect means to put
together
3.
Operational
Definition – A type of intensional definition widely used in science. It
defines a word or an occurrence by stating the necessary conditions that are
required in order for something to be called such a term. It has a form
“Something is X, if and only if…”
For instance, X is magnetic, if and only if, whenever any
piece of iron, nickel or cobalt is placed closed to it, it attracts the latter
toward itself.
Another example: X is harder than Y, if and only if, when a
point of X is drawn on the surface of Y, X scratches Y.
4.
Definition
by Genus and Difference or Real Definition – is regarded as the best type
of definition because it tells us what a thing really is. It is defining a term
by giving a larger class to which the concept signified by the term belongs
(called as genus) and stating the
properties that a concept has that differentiates it from other concepts under
the same genus (called as difference).
For example:
Man is a rational animal. (“Animal” is the genus because it is the larger
class to which the concept “man” belongs. “Rational” is the difference because
it is what differs man from all other animals.)
Girl is a young woman. (Genus = woman; Difference = young)
Triangle is a plane figure bounded by three straight lines. (Genus = plane
figure; Difference = bounded by three straight lines)
Limits of Real Definition:
a.
Only
common terms can be defined by real definition. Proper names such as names of
places, things, or people are identified rather than defined.
b.
Transcendental concepts (“being”, “thing”,
“something”, and so on) cannot be defined by a strict definition but can only
be described.
c.
Supreme genera (“being”, “substance”) cannot be
defined by real definition because they do not have genus.
d.
Immediate data of experience like color, taste,
smell, etc. cannot be defined by real definition.
Rules of
Definition:
1.
A
definition should state the essential attributes of the object being defined.
Essential attributes are attributes which make the object what it is. So,
a good definition of “X” must be able to answer the question “What really is
X?”
The definition of man as a rational
animal satisfies this criterion, for it tells us what man really is.
However, defining man as an animal who is
capable of speech violates this rule because being able to speak is not
what makes man as “man”.
2.
A
definition should be neither too broad nor too narrow.
When a definition is too broad, it might include objects which are not
proper extensions of the term, and when it is too narrow, it might exclude
objects which are really extensions of the term.
For instance, if we define man as a bipedal
mammal then we have to include, based on that definition, other mammals which
are also bipedal like apes. Or, if we define man as a rational animal with two legs, two hands, and one head, then our
definition is too narrow since it would exclude people who do not have complete
legs or hands.
3.
A
definition must not be circular.
This means that the definiendum must not appear in the definiens. A
definition violates this rule when the term that is supposed to be defined is
used to define itself.
Examples of
definition that violates this rule:
“Sympathy” is the feeling of a
person who feels sympathetic.
“Fallacy” is an argument that is
fallacious.
A “circle” is a plane figure that has a circular
shape.
4.
A
definition should not be expressed in figurative, obscure and ambiguous
language.
Good definitions do not use metaphor or figurative languages. The purpose
of definition is to give us clear idea of what a thing is, and using figurative
language will not allow us to achieve that. No matter how appealing such a
definition, still it gives no clear idea of what it tries to define. It also
defeats the purpose of definition if we define words using other words that are
more unfamiliar and obscure.
Examples of
definition that violates this rule:
An elephant is an animal with a
long prosboscis.
A lover is someone who gives you
sunshine.
God is the alpha and the omega.
5.
A
definition should as much as possible be affirmative, rather than negative.
The purpose of
definition is primarily to tell us what a thing is, not what a thing is not.
Examples of
definition that violate this rule:
A plant is a living thing that
is not an animal.
A girl is a person who is not a
boy.
Life means the opposite of
death.
But there are
terms which are essentially negative, and a defining such terms requires
negative definition. Hence, such negative definitions do not violate this rule.
Here are the examples:
A bald person is someone who has
no hair in the head.
A mute person is someone who
cannot speak.
Nothingness is the absence of existence.
