If you're not doing that, you're not just not writing, there's a very real sense in which you're not thinking at all, at least in any sense in which I understand the term.

As a lapsed academic, I still feel like I haven’t read a book until I’ve written *something* about it. That’s why writing appealed to me so urgently: my brain’s a disorganized old barn. Hewing sentences and paragraphs allows me to think coherently.

Gah, could I say "in a very real sense" more in this thread? In a very real sense, I could not.