THE ART OF LOGICAL THINKING/PART 7
CHAPTER VII.
THE MEANING OF TERMS
Every
term has its meaning, or content, as some authorities
prefer to call it. The word or words of which the term is composed are merely
vocal sounds, serving as a symbol for the real meaning of the
term, which meaning exists only in the mind of the person
understanding it. To one not understanding the meaning of the term, the latter
is but as a meaningless sound, but to one understanding it the sound awakens
mental associations and representation and thus serves its purpose as a symbol
of thought.
Each
concrete general term has two meanings, (1) the actual concrete
thing, person or object to which the term is applied; and (2) the qualities,
attributes or properties of those objects, persons or things in consequence of
which the term is applied. For instance, in the case of the concrete term book,
the first meaning consists of the general idea of the thing which we think of
as a book, and the second meaning consists of the various qualities
which go to make that thing a book, as the printed pages, the binding, the
form, the cover, etc. Not only is that particular thing a book, but
every other thing having the same or similar properties also must be a
book. And so, whenever I call a thing a book it must
possess the said qualities. And, whenever I combine the ideas of these
qualities in thought, I must think of a book. As Jevons says:
"In reality, every ordinary general term has a double meaning: it means
the things to which it is applied, ... it also means, in a totally different
way, the qualities and peculiarities implied as being in the
things. Logicians say that the number of things to which a term applies is
the extension of the term; while the number of qualities or
peculiarities implied is the intension."
The
extension and intension of terms has been referred to in the previous chapter.
The general classification of the degrees of extension of a
general term is expressed by the two terms, Genus and Species,
respectively. The classification of the character of the intension of
a term is expressed by the term, Difference, Property and Accident,
respectively.
Genus is
a term indicating: "a class of objects containing several species; a class
more extensive than a species; a universal which is predicable of several
things of different species."
Species is
a term denoting: "a smaller class of objects than a genus, and of two or
more of which a genus is composed; a predicable that expresses the whole
essence of its subject in so far as any common term can express it."
An
authority says: "The names species and genus are
merely relative and the same common term may, in one case, be the species which
is predicated of an individual, and in another case the individual of which a
species is predicated. Thus the individual, George, belongs to the logical
species Man, while Man is an individual of the logical species Animal."
Jevons says: "It is desirable to have names by which to show that one
class is contained in another, and accordingly we call the class which is
divided into two or more smaller ones, the genus, and the smaller
ones into which it is divided, the species." Animal is
a genus of which man is a species;
while man, in turn, is a genus of which Caucasian is
a species; and Caucasian, in turn, becomes a genus of
which Socrates becomes a species. The student must avoid
confusing the logical meaning of the terms genus and species with
the use of the same terms in Natural History. Each class is a
"genus" to the class below it in extension; and each class is a
"species" to the class above it in extension. At the lowest
extreme of the scale we reach what is called the infima species,
which cannot be further subdivided, as for instance "Socrates"—this
lowest species must always be an individual object, person or thing. At the
highest extreme of the scale we reach what is summum genus, or
highest genus, which is never a species of anything, for there is no class
higher than it, as for instance, "being, existence, reality, truth, the
absolute, the infinite, the ultimate," etc. Hyslop says: "In reality
there is but one summum genus, while there may be an indefinite
number of infimae species. All intermediate terms between these
extremes are sometimes called subalterns, as being either
genera or species, according to the relation in which they are viewed."
Passing
on to the classification of the character of the intension of
terms, we find:
Difference, a
term denoting: "The mark or marks by which the species is distinguished
from the rest of the genus; the specific characteristic." Thus the color
of the skin is a difference between the Negro and the
Caucasian; the number of feet the difference between the biped
and the quadruped; the form and shape of leaves the difference between
the oak and the elm trees, etc. Hyslop says: "Whatever distinguishes one
object from another can be called the differentia. It is some characteristic
in addition to the common qualities and determines the species or individual
under the genus."
Property, a
term denoting: "A peculiar quality of anything; that which is inherent in
or naturally essential to anything." Thus a property is a
distinguishing mark of a class. Thus black skin is a property of
the Negro race; four feet a property of quadrupeds; a certain
form of leaf a property of the oak tree. Thus a difference between
two species may be a property of one of the species.
Accident, a
term denoting: "Any quality or circumstance which may or may not belong to
a class, accidentally as it were; or, whatever does not really constitute an
essential part of an object, person or thing." As, for instance, the
redness of a rose, for a rose might part with its redness and still be a
rose—the color is the accident of the rose. Or, a brick may be
white and still be a brick, although the majority of bricks are red—the redness
or whiteness of the brick are its accidents and not its
essential properties. Whately says: "Accidents in
Logic are of two kinds—separable and inseparable. If walking be the accident of
a particular man, it is a separable one, for he would not cease to be that man
though he stood still; while, on the contrary, if Spaniard is the accident connected
with him, it is an inseparable one, since he never can cease to be,
ethnologically considered, what he was born."
Arising
from the classification of the meaning or content of terms, we find the process
termed "Definition."
Definition is a term denoting: "An
explanation of a word or term." In Logic the term is used to denote the
process of analysis in which the properties and differences of
a term are clearly stated. There are of course several kinds of definitions.
For instance, there is what is called a Real Definition, which
Whately defines as: "A definition which explains the nature of the thing
by a particular name." There is also what is called a Physical
Definition, which is: "A definition made by enumerating such parts as
are actually separable, such as the hull, masts, etc., of a ship." Also
a Logical Definition, which is: "A definition consisting of
the genus and the difference. Thus if a planet be defined as 'a wandering
star,' star is the genus, and wandering points
out the difference between a planet and an ordinary star." An Accidental
Definition is: "A definition of the accidental qualities
of a thing."An Essential Definition is: "a definition
of the essential properties and differences of
an object, person or thing."
Crabbe
discriminates between a Definition and an Explanation, as follows:
"A definition is correct or precise; an explanation is
general or ample. The definition of a word defines or limits
the extent of its signification; it is the rule for the scholar in the use of
any word; the explanation of a word may include both
definition and illustration; the former admits of no more words than will
include the leading features in the meaning of any term; the latter admits of
an unlimited scope for diffuseness on the part of the explainer."
Hyslop
gives the following excellent explanation of the Logical Definition,
which as he states is the proper meaning of the term in Logic. He states:
"The
rules which regulate Logical Definition are as follows:
1. A
definition should state the essential attributes of the species defined.
2. A
definition must not contain the name of word defined. Otherwise the definition
is called a circulus in definiendo.
3.
The definition must be exactly equivalent to the species defined.
4. A
definition should not be expressed in obscure, figurative, or ambiguous
language.
5. A
definition must not be negative when it can be affirmative."
A
correct definition necessarily requires the manifestation of the two
respective processes of Analysis and Synthesis.
Analysis is
a term denoting: "The separation of anything into its constituent
elements, qualities, properties and attributes." It is seen at once that
in order to correctly define an object, person or thing, it is first necessary
to analyze the latter in order to perceive its essential and accidental
properties or differences. Unless the qualities, properties and attributes are
clearly and fully perceived, we cannot properly define the object itself.
Synthesis is
a term denoting: "The act of joining or putting two or more things
together; in Logic: the method by composition, in opposition to the method of
resolution or analysis." In stating a definition we must necessarily join
together the various essential qualities, properties and attributes, which we
have discovered by the process of analysis; and the synthesized combination,
considered as a whole, is the definition of the object expressed by the term.
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