Class nouns are used with the definite article:
#1. When the noun denotes an object or objects which the speaker singles out from all the objects of a given class. An object is singled out in the following cases:
- when the speaker and the hearer know what particular object is No special indication is necessary.
How did you like the play?
I Have got the magazine.
N о t e — It should be borne in mind that there is a difference between knowing what object is spoken about and knowing the object itself.
A: I do not care to speak to the girl. 1 have never seen her. Won’t you speak to her?
B: But I do not know the girl either.
A: Who told you about it?
B: A girl.
B: What girl?
A: My sister.
In the first dialogue the speaker and the hearer do not know the person at all, but they know whom they mean, so the definite article is used. In the second the speaker knows the person, but he presents her to the hearer merely as one of a class, so the indefinite article is used.
- when the speaker uses an attribute pointing out a particular
This is the house that Jack built.
- when the situation itself makes the object
The wedding looked dismal. The bride was too old and the bridegroom was too young. (Dickens)
When an object is singled out from all the objects of a given class the definite article retains its demonstrative meaning, and the English use the definite article much oftener than the demonstrative pronouns this or that.
You told me before you wished to be a governess; but, my dear, if you remember, I did not encourage the idea. (Ch. Bronte)
#2. When the noun denotes a thing unique (the sun, the moon, the universe) or a class.
The sun was getting warmer. (Abrahams)
The bourgeoisie is cowardly. (London)
The indefinite article can be used when we mean a certain aspect in which the sun, moon and sky appear to us, a certain state of the sun, the moon, the sky. In this case an attribute is used.
A pearl-white moon smiles through the green trees. (Ch. Bronte)
#3. With nouns used in a generic sense.
A noun used in a generic sense denotes a genus taken as a whole, a thing taken as a type, a genre.
The tiger has always had the reputation of being a man-eater.
The telephone was invented in the 19th century.
The tragedy and the comedy first appeared in Greece.
When the noun man is used in a generic sense no article is used.
Silas felt that his trust in man had been cruelly destroyed. (Eliot)
When the noun woman is used in a generic sense it is used with the definite article or occasionally without an article.
He had always been interested, in that mysterious being — the woman. (Bennett)
Woman is man’s helpmate.
A noun used in a generic sense should not be confused with a noun used in a general sense.
A noun used in a general sense denotes an object regarded as an individual representative of a class.
A detective story helps to while away the time. (Every or any detective story is meant here.)
A noun in a generic sense denotes the whole class.
Conan Doyle is a master of the detective story. (The detective story is regarded here as a certain genre.)