To write is to choose not to be oral. In seeking to read or write, we are, in some sense, seeking to escape orality. The oral paradigm is distinguished by various characteristics. We write to enjoy alternatives to all of these characteristics. To write is to spacialize language.
Words are otherwise only ephemeral sound.
With writing, we can structure language and thought, we can enjoy the illusion of moving forward, or setting something out, of building toward something. We write because there is no other technology to render this illusion of movement possible. No other technology that enables us to create architectural structures with language. To enjoy the illusion of an advance in one's thinking. To travel, to go distances, to be exposed to the unknown, by virtue of words alone.