It's also sort of a misleading gloss of what is going on in that dialogue, which, it is important to note _is in a book_ -- one of many that Plato wrote. Plato has Socrates recount a story (supposedly) from ancient Egypt in which an Egyptian god claims that books will make people forgetful. He never makes that claim himself, as a character, and certainly Plato didn't believe it, because he wrote lots of books before and after that dialogue. The general thrust of that section of the dialogue is that writing can be a useful tool for remembering, but _not_ sufficient for learning, which requires person to person interaction and dialogue.