There is a very close relationship between writing well and thinking well. You cannot write well until you think well.
The relationship with thinking is what excites me about writing.
When we write (and this could be a few words or even a diagram) we take the fuzzy, unformed ideas sitting in the back of our heads and make them explicit. We put them on a page or a screen. When we see our thoughts on paper, we are better able to interact with ideas, and thinking becomes richer and clearer.
The think-write-think process helps us figure out the best way of explaining ideas to others – we talk to ourselves and other people with greater clarity.
Poor writing is often the result of poor thinking. Ideas may be there, but if they haven’t been worked over and refined by writing and re-writing, they are unlikely to be understood by people other than the writer.
The down-side
The close relationship between writing and thinking means that every time you write something, you are exposing your thinking. That may be an uncomfortable thought. People may make judgements about your thinking capability based on the text you generate.
It’s all the more reason to strive to write plainly and clearly, so that readers can see through your words to interact with your ideas.