At first glance, this question seems too obvious to bother answering. We write to communicate, of course. But then the question arises, why do we communicate? And that question has as many answers as there are moments in a human life.
We communicate to express our needs, to share our experiences, to entertain, to persuade, and to inform. We communicate our love, our hatred, and everything in between. We ask for help. We point out danger. We insult or praise. We wish for something or someone. We communicate to humans, animals, and gods. We communicate when we want to alter the world, usually according to our wishes.
What you are reading now is one of the two oldest forms of communications technology: ideas encoded as abstract symbols and put in order according to a set of intelligible rules, otherwise known as writing. The other oldest form of communications technology is visual art, and it is impossible to say which of the two is older. Some writing systems use symbols that encode the sounds of human speech, and some writing systems use symbols that stand in for entire concepts. But the effect of all writing is the same. Whatever the human mind can contain or invent can be stored in a piece of writing and retrieved at another time and place by the mind that created it or by others.
Writing has some distinct functional advantages over speech and pictures. Like pictures, writing has a life beyond the moment of its making.
When we write, we send our influence outward in space and forward in time. Wherever and whenever there is a copy of our words, we are wielding power.
If it proves sufficiently useful to a succession of readers, writing can travel farther forward in time than the original intention or even the lifespan of the writer. This has had some wonderful and terrible consequences for humanity, but that is a subject for another essay.
Writing is more efficient than speech. We need only write once, and our writing will do our desired work as long as at least one copy of it exists and is paid attention to and understood. Writing has another great advantage over speech, perfectibility. When we write, we can meticulously prepare what we want to say and get it just right, giving our words the best chance of doing exactly what we want them to. We are always as brilliant as our rewriting makes us sound.
Writing is more precise than visual communication. It is true that pictures tend to arouse emotions in the viewer more easily than words can. It is also true that most people remember images more easily than words. But pictures cannot convey the same complex sequences of ideas that words can. When people repeat the phrase “A picture is worth a thousand words,” what they really mean is that pictures make us more emotional quicker and can be remembered more easily, not that pictures can do the same work of writing but do it better. And with enough practice, a writer can use words to paint pictures in the reader’s mind that are as emotionally powerful as pictures seen by the eyes.
Writing, then, can contain visual art, either by describing pieces of art or by using words that put original images in the reader’s mind without their realizing it. The ancient Greeks had a word for this, ekphrasis. When a piece of writing has a long, powerful description of a work of art, it is still said to be ekphrastic. Modern screenwriters in Hollywood understand the power of good writing to contain all the emotional power of moving images. You can tell a good screenplay, they say, because it makes you laugh and cry just as much as the movie or TV show made from it.
Once composed, the potential readership and thus influence of a piece of writing is infinite. Thinking clearly and laying words down is as hard as it has always been, but making those words available to vast numbers of people is easier than ever before. All you need is a device with an Internet connection.
But, while putting your writing online is easy, getting people to pay attention to it is not. The fame and status of the writer, the prominence of where it is posted, and of course how interesting and understandable the writing is all determine how many people pay attention to it. No matter how much technology changes, attention will remain a finite resource. Putting ideas into words that will be understood and remembered is still a rare and useful skill.
So: the question “why write?” is best answered by two other questions: “What do you want to say?” and “Who do you want to say it to?”