With writing it is this way.

One says: ‘I feel good, too good. I don’t need to write. I want to live.’ One is inside, enjoying life, living without formulation. No echoes, no registering. Then one day, without reason, life is split into two channels: being, and formulating. An activity resembling a motion picture starts to run inside one’s head. (One can hear the purring of the machine.)

I am writing. It is not analyzing, or meditating, or a monologue, it is writing. It is living in terms of immediate phraseology, with great excitement as before, a discovery of appropriate words, an anxiety to capture, retain, to be precise, felicitous. It comes on unexpectedly, like a fever, and goes away, like a fever. It is distinct from all other activities.

The Diary of Anais Nin, Volume Two