Which is correct - than I or than me?

Than I or than me? So far, this has been the most interesting yet mind boggling topic I have ever encountered in my experience as an English tutor.

I found out that it's not  just the pronoun following than that makes this topic debatable, but also than itself!

Well, than can be a conjunction or a preposition. The problem is to what part of speech does than which is being used with comparative degrees of adjectives belong?

She is taller than I.

She is taller than me.

If we classify than here as a conjunction, then sentence number one is correct. We have learned that conjunctions connect parallel terms. Since she is a subject pronoun, I, instead of me, should be used.

But, if than here is considered a preposition, then me is correct. Prepositions are followed by object pronouns, not subject.

I read an article before (I just could not remember the title and the author) that says than in this case is considered by most grammarians as a conjunction, therefore, than I is said to be correct.

Now, how are we going to really determine which of the two terms is correct.

She is taller than I (am).

She is taller than me.

Let's try to twist the sentence. Perhaps this will help.

I am shorter than she (is).

Me is shorter than she (is).

Upon reading the reversed sentences, it comes out that only the first one is correct.

Now, there are also other authors that say both than I and than me are correct. They are interchangeable. 

Well, let's see if they really are. Try to study the following examples.

He loves the dog more than I.

He loves the dog more than me.

Are the two sentences the same? Let us try to dig what does each sentence mean.

Sentence #1: He and I both love the dog, but his love is bigger than my love. He loves the dog more than I do. (do here can be omitted)

Sentence #2: He loves the dog and me, but his love for the dog is bigger than his love for me.

There you go! Than I and than me are not the same. They are not interchangeable, either. 

I do hope this article helps you. If you have suggestions, corrections, additions or comments, please feel free to let me know. There's a space below provided just for you.