Like the definite article, recently I started to see what are traditionally known as demonstatives not as a group of words but rather as a single word.
If you analyze it as an inflected word with a variable function, it simplifies a lot of logic.
In other words, the demostrative inflects for number, singular and plural, and distance, near or far, producing the following four forms:
this, that, these, those
In addition, the demostrative, can have one of two grammatical functions. It can function as a determiner:
Or it can funtion as a pronoun:
This is better.
If inflected verbs can be thought of as one word, why not other words with a common stem and meaning?