I'm a great admirer of David Hockney, but his introduction to Jeffery Camp's Draw: How to Master the Art makes a mess of the difference between drawing and writing:
Everybody learns to write. We are taught to write by copying marks, and even when we copy marks we all make them individually, we all have different kinds of handwriting. Within a year or two of being taught to write, things happen to our handwriting and personal ways of making marks develop very quickly. That's the way, really, you learn to draw. And in learning to draw (unlike learning to write) you learn to look. It's not the beauty of the marks we like in writing, it's the beauty of the ideas. But in drawing it's a bit of both - it's beauty of ideas, of feelings and of marks.
Later on he makes the following outrageous assertion: "Drawing is a more interesting way than writing of passing on feelings about the world you see, the world you feel about." Anyone who writes often knows that the marks themselves (even when typed) have an aesthetic dimension. And while learning how to write letters may not teach you how to look (at anything but letters), learning how to write prose certainly does imply improving your ability to see things in the world.
I know a woman whose instinctive response to people who claim they don't know how to draw pictures is, "How do you see?" I sometimes feel the same way about people who claim they can't write. How can you think? How can you be sure you know anything at all? "The only time I know something is true," said Jean Malaquais to Norman Mailer, "is the moment I discover it in the act of writing." It strikes me as absolute rubbish to suggest that writing is a less interesting means of expression than drawing.
The analogy of drawing really does help us to think clearly about what it means to write.
And we can go further. If a picture tells you how something looks, a diagram tells you how something works. But there is an asymmetry in this elegant formula. A picture is, arguably, a “diagram of what you see”; a diagram, however, is already something to look at. Perfect symmetry would correlate the diagram’s “seeing in order to do” with a picture’s “doing in order to see”. When, then, is a picture not something we look at but something we do? When is it something we do (with our hands) in order to see better (with our eyes), just as a diagram is something we see (with our eyes) in order to do better (with our hands)? The answer is: when we are in the act of sketching or drawing something. A drawing (the act of drawing) is a doing-done-with-our-hands to improve our vision, our receptivity to light. A diagram, meanwhile, is a seeing-seen-with-our-eye to improve our manipulations, our capacity for motion.
Pictures and diagrams can, of course, be represented in prose.
Hockney thinks that "learning how to write" is a matter of learning how to form the letters. He reduces style to handwriting, and then claims that writing style has nothing interesting to do with seeing or feeling. But in order to write a good sentence you have to be able to see your world, feel it, think it. The beauty of the ideas does not, perhaps, depend on the beauty of the individual marks, but it does depend on how you mark up the page, on where you put the words, and what words you put there. It takes more than a working knowledge of the alphabet to write.
Hockney rightly emphasizes the importance of copying when learning how to draw. It "is a first-rate way to learn to look because it is looking through somebody else's eyes, a the way that person saw something and ordered it around on paper." The same goes for writing. Direct copying in writing (especially when typing) is of course not nearly as instructive as drawing (with your own hand) a hand that someone else has drawn first. (The idea is not completely ridiculous, however, as Hunter S. Thompson's approach shows.) Still, there is a lot to learn from describing something that someone else has already described and trying to do so in that author's style. "One shouldn't be afraid of being influenced," Hockney says. "If you are influenced by something because it has attracted your eye or your mind, and if you begin to deal with it, you quickly sort out what it was that attracted you to it and it can be made into something." What is it the author had to see in order to be able to do that? What did she sense before she could mean it?