Complex thinking is impossible without external scaffolding

"Notes on paper, or on a computer screen [...] do not make contemporary physics or other kinds of intellectual endeavour easier, they make it possible." — Neil Levy in Handbook of Neuroethics (2011)

While for most day-to-day thinking it is acceptable to make decisions based on unconscious mental shortcuts and cognitive biases—automatic judgements such as: this alley has more light, hence it is safer; this brand looks fancier, hence it must be better; this book is bigger; hence it must have more information—complex thinking requires external scaffolding. (however, good thinking is impossible without internal scaffolding)

The most efficient and accessible kind of external scaffolding for complex thinking is writing, whether on paper or on a computer. (hand-written notes help better understand content because they're slower to write and thus force you to think to condense the original content while preserving meaning)