I learned in class that:
a. A tiger is a dangerous animal.
b. Tigers are dangerous animals.
c. The tiger is a dangerous animal.
These three sentences are used generically.
But I just saw:
- The tiger is in danger of becoming extinct.
- Tigers are in danger of becoming extinct.
- A tiger is in danger of becoming extinct.
the previous sentences and number '1' and '2' are used generically but example 3. is not.
Is there anyone who can tell me why the latter examples are different from the former ones? Also, is there any difference in meaning depending on the article?
Best Answer
I will address your two questions in turn.
1. When can one use the indefinite article + singular count noun to make a generic reference?
As others have already said, one way to run into trouble is if, for the purpose of generic reference, you try to use a singular noun with the indefinite article in cases where you are trying to assign a property that can only be applied to a set. A typical example of such a property is going extinct: only a set of individuals can go extinct, not any one individual.
A different sort of trouble with indefinite articles is in expressions that, in principle, could have generic meaning, but which seem more likely to have a specific meaning. When you say a ring-tailed lemur lives in Madagascar, it seems more likely that you are talking about a specific (but so far indefinite) lemur. The question becomes how to judge which properties are such that the specific interpretation is more likely than a generic one. And I don't know if anyone can do better than simply give a list of such properties. Here are the well-known elements of that list: the location or existence of a type of animal, thing, or person. Other kinds of properties will be ambiguous and the context will be crucial in deciding whether the reference is specific or generic. For example, if you say a dinosaur roared very loudly, we would need more context to decide whether a dinosaur should here be interpreted generically ('any dinosaur') or specifically ('some particular, but so far indefinite, dinosaur').
It's not really about there being any subtle difference in meaning; rather, there are some classes of things and some contexts where one way of making generic reference is much more standard than the others.
For example, it is customary in the medical profession to refer generically to parts of the body by using the definite article. So one says, This chapter deals with the lower part of the leg. It wouldn't be wrong, exactly, to write instead This chapter deals with lower parts of legs, but the fact is that no one would do that.
True, in the former case, the leg is to be understood as denoting the class of legs, while in the latter case, legs is to be understood to denote 'all the legs'. But these differences do not result in any perceptible change in the content of the final sentence. You end up saying the same thing two different ways. Nevertheless, in the context of medicine and body parts, it is so much more customary to use the definite article that using the plural sounds weird—even though it's not really wrong.
Similarly with inventions: it's the invention of the telephone; it is not wrong to say the invention of telephones, but no one would actually say that. Again, it's not that there is some subtle difference in meaning; it's just that it is customary to use the definite article when making generic reference to inventions.
These things I just said about body parts in medicine and inventions we might call 'special guidelines' for generic reference. Let's not call them 'rules', because you can disobey them and still end up with acceptable expressions, but definitely guidelines. Some other guidelines like that can be found in the excerpts I'm reproducing below.
Relevant discussions from some reputable sources
Here are the relevant sections from Collins COBUILD English Guides: Articles (pp. 36–37):
And here are the relevant sections from CGEL (pp. 406–407):