Why 'an education'?

Education can be either countable or uncountable, like many other nouns.

Thanks.

Countable
A good education, a bad education, an education that was interrupted, my education, your education.

Non-countable
Education in Europe, education is a good thing, the study of education.

Thanks, again, contrex. BTW, is 'education' a variable noun, since it is both singular and plural.

is 'education' a variable noun, since it is both singular and plural. [/quote]
A variable noun is one that varies from the singular form to the plural form - e.g. cat/cats, house/houses, man/men etc. An invariable noun is one that does not e.g. sheep.

Education is an invariable noun when countable and uncountable.