Words have a definite meaning. That is the first point every writer must address (though of course not every writer answers that question as I just have).
In fact, it’s become fashionable to say that language is arbitrary and definitions are, at best, approximations. Indeed, many writers accept these tenets without even realizing that they’ve accepted them and without any regard whatsoever for the fact that it’s not actually possible to write clearly unless you know the meaning of the words you’re using.
If you don’t know the meaning of the words you’re using, your writing will be unclear, and readers will not grasp your intent.
Clarity is the number one priority in all issues of writing style.
It is certainly true that language evolves, and that words develop nuances and new meanings. This is natural and it is good.
This natural process does not, however, negate objectivity, but just the opposite: the evolutionary process of language is gradual, so that at any given period, the words you’re using do possess a definite meaning.
If a word does not possess a definite meaning, it’s a non-word (and there are examples of these: “postmodernism” being one of them).
What I’ve just described is the place from which every writer must proceed: Words possess a definite meaning. That is the beginning. This point is critical to note, because it’s the foundation upon which the rest of all literary knowledge is built.
But to fully understand the nature of words, we must ask ourselves next: what are words, exactly?
Words are what philosophers call abstractions. Abstractions are the human method of grasping things in nature. Our brains work by means of abstractions — i.e. concepts — which are, in essence, words.
For instance, when as a child you first discovered the meaning of the word “pencil,” you had to at some point be shown what in actuality a pencil is — i.e. this object. Once you learned that that’s what the word “pencil” referred to, the word was absorbed and retained by your brain, so that thereafter when you heard or saw the word “pencil,” you knew automatically what a pencil was. You grasped the actual thing in reality — this is a pencil — and that knowledge paved the way for you to differentiate it from, for example, a pen, or a crayon.
That, in a nutshell, is the uniquely human method of learning, which language empowers us with.
Thus you yourself learned to use the word pencil in a meaningful way: The sentence “I write with a pencil” became for your mind not an unintelligible string of words, but denoted an act that you understood.
That very process which I’ve just outlined is, in abbreviated form, the process we all must go through in learning every single word we know.
The art of writing is this same process in more intensive form.
Why is this important?
Art by definition is communication — communication between the artist and the audience. If it’s not communicable, it’s not art.
If in your literature you reject the notion that language is definite, you will not only confuse and frustrate your readers, but worse: you will confuse and frustrate yourself, because you won’t know the meaning of the things you’re trying to communicate.
And that is why intelligibility is the hallmark of good art.