Most people assume writing is the transcription of thoughts already formed—you think, then you write. Didion reverses this: the act of writing *creates* the thinking, not the other way around. She's describing something closer to discovery than expression, the way a painter might find the color she needs only by applying it to canvas. A student wrestling with an essay on a subject she half-understands knows this feeling—somewhere between the third paragraph and the fifth, an argument suddenly clarifies that she couldn't have articulated before putting words down. Writing, in this view, isn't a mirror held up to thought; it's the thought itself becoming visible.