In "Conversations with Wittgenstein" (in Recollections of Wittgenstein), M. O’C. Drury writes:
I told Wittgenstein that my friend James, who had been working on his Ph.D. thesis for a year, had decided in the end that he had nothing original to say and would therefore not submit his thesis or obtain his degree.
Wittgenstein: For that action alone they should give him his Ph.D. degree.
Drury: Dawes Hicks was very displeased with James about this decision. He told James that when he started to write his book on Kant he had no idea what he was going to say. This seems to me an extraordinary, queer attitude.
Wittgenstein: No, Dawes Hicks was quite right in one way. It is only the attempt to write down your ideas that enables them to develop.
Notice that Wittgenstein did not say "Dawes Hicks was quite right” but said "Dawes Hicks was quite right in one way". If Hicks really had no idea at all what he was going to say in his book, then there were probably no ideas that he could attempt to write down. However, if he had some ideas but did not know how they would develop, then attempting to write down his ideas might be the best way to enable them to develop. Actually I have this kind of experience quite often. It is as if my mind is too small for the ideas and they need the space between written sentences to become active, to get connected with one another, and to generate new ideas.