Some nouns are used countably to emphasise that they represent something subdivisible, and uncountably otherwise
DIFFICULTY OF DEFINING COUNTABILITY BY ITS MEANING
Countable nouns are nouns that can be plural and, when singular, must follow an article (a or the) or equivalent. Examples are houses/a house, ideas/an idea and days/a day. If a noun cannot usually be plural, and can stand alone in the singular, it is either uncountable (e.g. flour) or a proper noun with a capital letter, such as London: we cannot usually say flours/a flour or Londons/a London (see 110. Nouns without “the” or “a” and 47. Article Errors with Proper Nouns). Knowing whether or not a noun is countable is important for getting certain grammar choices right, for example whether or not to add an article, and whether to make the noun singular or plural (see 12. Singular and Plural Verb Choices).
Some grammar books say that the countability of nouns can be discovered from their meaning. They suggest, for example, that uncountable nouns stand for things that cannot be counted, or things that do not have a fixed shape, like flour and water. This use of meaning does sometimes help us to recognise whether a noun is countable or uncountable, but it has the well-known problem of subjectivity: one person’s idea of what can and cannot be counted is different from another’s. This becomes clear when we compare English with other European languages. Although most English uncountable nouns are also uncountable in other languages, some are not. The uncountable nouns information, access, advice and research are all countable in French, for example. Another well-known problem is the fact that the uncountable noun money for many people stands for one of the most obviously countable things in the world!
SUBTYPES: A USEFUL MEANING FOR DEFINING SOME COUNTABLE NOUNS
Yet meaning can be used in another way to help us identify countability. Rather than looking for very wide meanings of all countable or uncountable nouns,we can seek smaller general meanings belonging to subgroups of countable and uncountable nouns. There are some particularly interesting subgroups associated with nouns that have two meanings, one countable and one uncountable. These nouns are of at least four different kinds.
Three other posts across this blog identify the countable noun meanings of “action outcomes”, “activity locations” and “substance locations” (see 14. Countable Noun Meanings 1, 19. Countable Noun Meanings 2 and 43. Countable Noun Meanings 4). This post is about the way countable nouns show existence of subtypes. An example of a countable noun showing existence of subtypes is fuels (or a fuel). If we read it in a text, we would understand that there are different fuel types, even if we did not know what they were (coal, oil, uranium, etc.). Here is an example of its use:
(a) The price of fuels varies.
This sentence suggests that prices differ according to the type of fuel on sale. If we replaced fuels with the uncountable fuel (singular without a or the), the reader would be more likely to consider other causes of varying prices, such as where the goods were sold. This is because the existence of fuel subtypes would not be highlighted.
In general, the uncountable use is preferred when the existence of different subtypes is not important to what we are saying, for example when we mention something that is true for all subtypes, like this:
(b) Fuel is necessary for machines to function.
We could again say fuels are instead of fuel is here, but it would be unusual because the existence of types of fuels is not obviously relevant to the point being made.
Now consider this further example of the countable use:
(c) Nuclear energy is a fuel obtained by splitting uranium atoms.
This definition suggests that nuclear energy is only one of many fuel types (and perhaps that other fuel types are obtained in different ways). Again, we could replace the countable a fuel with the uncountable fuel, thus giving less attention to the existence of other fuel types. However, the existence of other types is very relevant when we are defining.
COUNTABLE NOUNS EXPRESSING SUBTYPES
Here are some more examples of nouns whose uncountable form means a general substance or abstract concept and countable one suggests the existence of subtypes. Try naming some of the subtypes in each case:
(a) colour, (a) difficulty, (a) food, (a) fruit, (an) industry, (a) language, (a) metal, (a) philosophy, (a) power, (a) science, (a) sky, (a) society, (a) stone, (an) understanding, (a) virtue, (a) wood.
A problem with some of these is that they have more than one meaning. Stones are not always types of stone (exemplified by marble), but also small, roundish objects made out of (uncountable) stone, whose type does not matter. In this sense, they are “substance locations” (see 43. Countable Noun Meanings 4). In the same way, powers are not only types of power (e.g. the power to authorise a payment) but also powerful countries, places where power is located; and woods are either types of wood (e.g. mahogany) or places where it is located in the form of trees. Slightly different is the uncountable industry, which can express not only the general meaning of “industrial companies” (as in Industry is unhappy), but also the activity meaning of “hard work” (as in Industry will be rewarded). This means that the countable form an industry is both a subtype and an activity location (see 19. Activity Locations).
Finally, it is worth noting the exceptional contrast between salt and a salt. We would expect salt to mean any substance with the properties of a salt – the same meaning as salts but not highlighting the existence of subtypes. Thus, sodium chloride and potassium chloride should both be describable as either “salt” or “salts” just as coal and oil can both be called either “fuel” or “fuels”. In fact, however, salt means only sodium chloride (the type you put on your food with pepper). If we want to generalise about all substances similar to it, we can only say salts.
Now here is an exercise offering further practice with countable subtype-highlighting nouns. Answers are given after it.
EXERCISE: In the following sentences, which show countable and uncountable meanings of the same word, one space is best with a(n) and one is not. Decide where a(n) should go each time (answers below).
1. Cars need ………. fuel, but petrol is ………. expensive fuel.
2. ………. metal that does not behave like ………. metal is mercury.
3. Most people have ………. personal philosophy not based on ………. philosophy.
4. ………. society can change if ………. society within it changes.
5. Care is needed when choosing ………. colour for internal decoration, in order to avoid a clash of ………. colour overall.
6. ………. wood is suitable for furniture-making, and oak is ………. particularly beautiful and durable wood.
ANSWERS: The article a(n) goes best in the first space in Nos 2,3 and 5.