Niklas Luhmann in a paper describing his note-taking method says that “It is impossible to think without writing; at least it is impossible in any sophisticated of networked fashion.”
“we must mark differences, and capture distinctions which are either implicitly or explicitly contained in concepts. Only if we have secured in this way the constancy of the schema that produces information, can the consistency of the subsequent processes of processing information be guaranteed.”
Breaking the above down:
“…we must mark …distinctions which are either implicitly or explicitly contained in concepts” – Concepts are built when we are able to identify how the concept we are talking about is different from similar-sounding concepts. We have to justify how a concept is different, but also how the concept is similar. It is rather impossible to do make distinction without writing things down and thinking deeply about such things.
“Only if we have secured … be guaranteed” – Concepts build on top of simpler concepts. Only when we have the simpler concepts figured out, with all their distinctive features and noted down how these simpler concepts are related to other simpler concepts, can we build complex concepts on top of them, and more on top of those.
And hence writing is an essential part of thinking deeply.
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