Singular Vs plural while making a general statement

Question

I'm having a hard time understanding whether to use plural or singular while making general sentences.

Doing a bit of research I found both can be used. For example:

1. Dogs are loyal animals.

2. A dog is a loyal animal.

(Both these sentences are talking about all/any dogs in general)

3. A child needs care.

4. Children need care.

(Both these sentences talk about all/ any children in general).

Now, as for the question:
Recently, I looked up in the internet as to when is a definite article used. It says "We use the definite article in front of a noun when we believe 'the reader' knows exactly what we are referring to."

I think this statement is a general statement about the use of definite article. My first question, am I right in thinking that this is a general statement?

Second question is, what if we use 'readers' in place of 'the reader'? Will there be a change in meaning then? I'm asking this question because if this is a general statement then if I use 'a reader' or 'readers' in place of 'the reader' then it should all mean the same, i.e., all of them should be expressing 'any reader' just like the examples above (1 to 4). Right?

Another example:

(1) Banks are financial institutions where 'a lender' meets 'a borrower'.

I guess this is also a general statement about banks. So can I phrase this sentence like this without any change in meaning?

(2) Banks are financial institutions where 'lenders' meet 'borrowers'.

In sentence (1), 'a lender' expresses just one lender or any lender? In sentence (2), 'lenders' expresses more than one lender or any lender in general?

Answer 1

Now coming to the question - Recently i looked up in the internet as to: when is a definite article used ? It says - "We use the definite article in front of a noun when we believe 'the reader' knows exactly what we are referring to."

I think this statement is a general statement about the use of definite article. My first question, Am i right to say that this is a general statement ?

Yes, you are right. "The" can serve a number of specific grammatical functions that are not covered by this general statement. For instance, in the phrase "the more, the merrier", the matching instances of "the" have nothing to do with the reader's knowledge about what is being discussed. They're simply part of a fixed structure.

Second question is, What if we use 'readers' in place of 'the reader', will there be a change in meaning then ?

There will be little or no change in meaning, but there will be a slight change in style. Using the plural is the unmarked way to make general statements. Using the singular can be more vivid, and also more literary, which may or may not be what you want. It also has an air of instruction to it, indicating that the speaker/writer is about to embark on a discussion that singles out a specific representative of each class being discussed. In cases like yours, it can, but need not, indicate a one-to-one relationship. Sometimes the plural is used to avoid the necessity of a singular third-person pronoun, which would have to be gender-marked ("he" or "she", "his" or "her", etc.) or inanimate ("it", "its", etc.) or enumerate all genders ("he or she", "his or her", etc.). For example, compare:

"Banks are financial institutions where a lender meets a borrower. The lender gives {his, his or her} money to the borrower..."

with this:

"Banks are financial institutions where lenders meet borrowers. Lenders give their money to the borrowers..."

Both have weaknesses and both strengths. The former is more specific: one lender gives money to one borrower. (This may or may not match reality, but if it is what you wanted to convey, it would be more accurate.) However, the latter is concise and avoids the games writers need to play in order to avoid excluding members of a gender.

In sentence (1), 'a lender' expresses just one lender or any lender ? In sentence (2), 'lenders' expresses more than one lender or any lender in general ?

In sentence (1), the context and the reader's prior knowledge make it clear that you are talking about any lender. In sentence (2), the context and the reader's prior knowledge make it clear that you are talking about any lender in general. If the writer suspects that context and the reader's prior knowledge are insufficient to make things clear, and clarity on this point is important, he or she should choose another means to clarify things. For instance, if you wanted to clarify that the relationship between a lender and a borrower is one-to-many (a lender may lend to multiple borrowers, but a borrower only borrows from one lender), you might say:

"Banks are financial institutions where a lender finds one or more borrowers..."

Answer 2

I'll address all questions individually, but I'll make no attempt to infer a general question.

We use the definite article in front of a noun when we believe 'the reader' knows exactly what we are referring to

• My first question, am I right in thinking that this is a general statement?

That describes the definite article, definitely. Generality is not the correct aspect, because as you noted, there are different ways to express it. Ironically in that sentence, the reader does not exactly know that which is referred to, otherwise the explanation would not have had been necessary.

• what if we use 'readers' in place of 'the reader'?

That would be correct in some sense, but the noun would not be definite. The difference is the same as between the or a reader. In "a reader", the singular is determined, but the referent is explicitly not defined. One could ask for which reader was meant. Likewise, in "readers" the plural is determined, but in "the readers" the referent group is definite. Talking about all the readers assumes that the distinction is definite. The indefinite reference is less specific, it implies a specific distinction within the group of the readers. It's rather philosophical, if not mathematical.

Both versions are used. "the" seems formal, to me.

• I'm asking this question because if this is a general statement then if I use 'a reader' or 'readers' in place of 'the reader' then it should all mean the same, i.e., all of them should be expressing 'any reader' just like the examples above (1 to 4). Right?

No, that is not entirely correct. 2 and 3 talk about one out of many, as if the sentence wasn't true for all the other members of the group. Concerning plural vs singular, notice e.g. how I tried to use singular in the previous sentence, "the sentence/group", to achieve a general statement, because your sentence 2 is obviously not true for the groups of the other sentences. This seems to be the only viable alternative of those four (sentences, a sentence, the sentence and the sentences).

(1) Banks are financial institutions where 'a lender' meets 'a borrower'.

(2) Banks are financial institutions where 'lenders' meet 'borrowers'.

• I guess this (1) is also a general statement about banks. So can I phrase this sentence like this (2) without any change in meaning?

Yes, you can. Actually you improved it, because a bank with a single lender and borrower would be exceptional. Although, in the example (1), the indefinite singular obviously implies a plurality, simply from context. Whereas, the other way around, a plural form meaning at least one is not wrong either, to my mind, but this understanding might lead to confusion because not everyone agrees with this interpretation.

• In sentence (1), 'a lender' expresses just one lender or any lender? In sentence (2), 'lenders' expresses more than one lender or any lender in general?

(1) expresses a one-to-one relationship, which can be extended to mean any of one-to-many relationships ...

Edit: The article "a" can mean e.g. "one" or "any", "anyone" and much more, depending on context. It is unspecific by design, hence indefinite.

Edit 2: Context matters, ie. the expectation of the writers and the readers. It is unspecific on purpose and could mean anything. With laws, e.g. the expectation is that they are general. With specific questions, the expectation is that the answer would be as precise as possible.

"The dog is an animal" is the correct way to frame a definition (hence definite article), but the indefinite article is commonly accepted, too. With loyal dogs the picture is different, because the saying all dogs were loyal would be a gross over-generalization. The commonly accepted answer says "a ... is ..." is a generalization.

See also here and here and here and here and here and here.