If our thought is to be clear and we are to succeed in
communicating it to other people, wemust have some method of
fixing the meaning of the words we use. When we use a word
whosemeaning is not certain, we may well be asked to define it.
There is a useful traditional device for doing this by indicating
the class to which whatever is indicated by the term belongs,
and also the particular property which distinguishes it from all
other members of the same class. Thus we maydefine a whale as
a marine animal that spouts’. ‘Marine animal’ in this definition
indicates the general class to which the whale belongs, and
‘spouts’ indicates the particular property that distinguishes whales from other such marine animals as fishes, seals, jellyfish
and lobsters. In the same way, we can define an even number as
a finite integer divisible by two, or a democracy as a system of
government in which the people themselves rule.
There are other ways, of course, of indicating the
meanings ofwords.We may, for example, find it hard to make a
suitable definition of theword ‘animal’, sowe say that an animal
is such a thing as a rabbit, dog, fish or goat. Similarly, we may
say that religion is such a system as Christianity, Islam, Judaism
and Buddhism. This way of indicating themeaning of a term by
enumerating examples ofwhat it includes is obviously of limited
usefulness. If we indicated our use of the word ‘animal’ as above,
our hearers might, for example, be doubtful whether a seaanemone
or a slug was to be included in the class of animals. It
is, however, a useful way of supplementing a definition if the
definition itself is definite without being easily understandable.
Failure of an attempt at definition to serve its purpose may result
from giving as distinguishing mark one which either does not
belong to all the things the definition is intended to include, or
does belong to some members of the same general class which
the definition is intended to exclude.
The expression we may well be asked as used in the
From the passage, which of these is a disadvantage of
defining by enumeration.