Definite or indefinite article

Dear Mr. Alan. There is something that I don’t find very clear in your text on articles. I will copy two parts of it:
the first one

“Before a singular countable noun which is used as an example of a class of things.
«A book is something you read.»”

and the second one:
“Before singular nouns used to represent a class of objects.
«The donkey is a very obstinate animal.»”
ESL Lesson: Articles in English: The vs. A/an

I saw this kind of explanation in several textbooks but I’ve never understood it completely. Both examples seem to be the same, and still we use both definite and indefinite article.

Hi ljiljan,

Yes, it’s a difficult point to grasp and has a lot to do with how you are thinking of the object and how it seems to you.

As you say, both seem to point in the same direction. I could say: The horse is a noble animal. I could also say A horse is a noble animal.

I could say: A book is a treasure of knowledge. I could also say: The book is a treasure of knowledge.

In both examples using ‘the’ I am not thinking of the horse I know or have mentioned before or the book I have read and have mentioned before. What I am doing is putting the objects: horse book on a pedestal. I am in a way revering them both and showing great respect to both by using the definite article the and not the indefinite article a

I hope that throws some light on the problem.

If not, I’ll try again.


If I understood correctly, I can say it in both ways.

I appreciate your reply very much.

Hi ljiljan

Generally speaking, you should use “a” most of the time to talk about a general class of things.

Using the word “the” this way is a much more specialized usage.


Well, yes that’s the whole point. When you use ‘the’ in this classification way, you are specialising by the very fact that it is ‘the’ and not ‘a’.

Take this for example:

The car is regarded by some as a curse on humanity.

But to the rest of us mortals:

A car is considered to be an extremly useful device.