To put "the" or not to put "the"

Question

I am sometimes confused about whether to put the in front of a noun or not, so to solve such dilemmas, I have come up with the following strategy.

When in doubt, whether to put the in front of a noun, try to think of cases where you would put a/an in front of that noun. If you can't find it, there is no way you would need to put the, but if you can find it, then consider whether you are talking about a specific case of that noun (for example, a specific apple in a group of apples).

For example, just 5min ago, I have thinking whether to put the or leave it blank to the place of X in the following sentence.

[...] along X y-direction.

Eventually, I leave it blank beucase I thought I would never say something like along a y-direction (I am not sure whether it was correct to that), but my question is

Question: Is this strategy correct? Is there any example of whether that would fail? and if so, do you have any other strategy that one can use in such situations?

Answer 1

Even though many widely accepted "rules" of grammar have exceptions, your strategy has far too many flaws for me to say it is even a good rule of thumb.

Your strategy suggests that if there is no reason to put the indefinite article before a noun then you should not use the definite article either.

The first problem is that any specific noun may require an article or not depending on the context. For example, you don't often use articles with proper nouns such as the names of people you know, but there are exceptions:

-I had dinner with Donald Trump last night.
-Do you mean the Donald Trump?

-Do you know anyone named David?
-Yes, I know a David.

Common nouns are more likely to require articles, but there are contexts where they do not:

• I bought a pineapple.
• Did you eat the pineapple I bought?
• I can't eat pineapple.
• This cake has pineapple in it.

The specific context of your example "in a northerly direction" requires an article. You would use the definite article for a specific direction, for example, "follow the direction I gave you". However, I can think of several contexts where you don't need an article for the noun "direction":

• She keeps looking in my direction.
• I have a good sense of direction.
• Please can you give me directions to the bank?