Writing is thinking
There is a text renaissance. Organic thinking tools include chatting with someone, doodling, mathematics, and writing. To me, writing is the most flexible and richest one of these thinking tools. Writing your thoughts (not taking raw notes) forces you to face them in a way I haven't found just talking does. It's a forcing vector to articulate ideas in a more definitive way—definitive not meaning the idea is set in stone, but rather than it is captured at a t time and goes from fleeting to really coming into existence. A thought that's not written ceases to exist as soon as it's forgotten. A written thought starts to live a life of its own.
If the thought is written in a note that's then itself abandoned and forgotten about, it's a short, sad life, but a life nonetheless. However, if the thought is revisited, shared, edited, branched into more thoughts—thought babies! Idea sex!—then it can live a long, happy live, way beyond its expiration date.
In my case, the thought often starts with the title I give to a new note. I see these as a prompt. I often only have a vague notion of what exactly this idea encapsulates. The act of writing is what allows me to unravel the thread of sub-ideas under the generic note title. Most of my insights and ideas happen during the process of writing, not before. Plus, complex thinking is impossible without external scaffolding such as writing.
I find that writing as if I had an audience is the most effective way to induce clear thinking. More often than note, the audience is my future self, with her new experiences and imperfect memory. Writing clearly today ensures I can understand myself tomorrow.